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[PATCH 0/5] ACPI / gpio: Updates to properties

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  [PATCH 0/5] ACPI / gpio: Updates to properties Mika Westerberg <mika.westerberg@linux.intel.com> - 2016-09-23 17:00 +0200
    [PATCH 2/5] ACPI / gpio: Add support for naming GPIOs Mika Westerberg <mika.westerberg@linux.intel.com> - 2016-09-23 17:00 +0200
    [PATCH 4/5] ACPI / property: Allow holes in reference properties Mika Westerberg <mika.westerberg@linux.intel.com> - 2016-09-23 17:00 +0200
      Re: [PATCH 4/5] ACPI / property: Allow holes in reference properties "Rafael J. Wysocki" <rafael@kernel.org> - 2016-09-28 23:40 +0200
        Re: [PATCH 4/5] ACPI / property: Allow holes in reference properties Mika Westerberg <mika.westerberg@linux.intel.com> - 2016-09-29 09:00 +0200
          Re: [PATCH 4/5] ACPI / property: Allow holes in reference properties "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-09-29 13:50 +0200
            Re: [PATCH 4/5] ACPI / property: Allow holes in reference properties Mika Westerberg <mika.westerberg@linux.intel.com> - 2016-09-29 14:00 +0200
              Re: [PATCH 4/5] ACPI / property: Allow holes in reference properties "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-09-29 14:30 +0200
    [PATCH 3/5] ACPI / gpio: Add hogging support Mika Westerberg <mika.westerberg@linux.intel.com> - 2016-09-23 17:00 +0200
    [PATCH 5/5] ACPI / gpio: Allow holes in list of GPIOs for a device Mika Westerberg <mika.westerberg@linux.intel.com> - 2016-09-23 17:00 +0200
    Re: [PATCH 0/5] ACPI / gpio: Updates to properties "Rafael J. Wysocki" <rafael@kernel.org> - 2016-09-28 23:40 +0200
      Re: [PATCH 0/5] ACPI / gpio: Updates to properties Mika Westerberg <mika.westerberg@linux.intel.com> - 2016-09-29 09:10 +0200
        Re: [PATCH 0/5] ACPI / gpio: Updates to properties "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-09-29 14:30 +0200

#1490204 — [PATCH 0/5] ACPI / gpio: Updates to properties

Hi,

This series brings couple of useful GPIO related properties from Device
Tree to ACPI _DSD device properties:

  - Names for GPIO lines
  - GPIO hogging
  - Holes in GPIO property lists

We are using these to get Intel Galileo better supported in the mainline
kernel (but these may be useful for other boards as well). For example SPI
chip select on Galileo is connected to a GPIO line so we need to be able to
describe it in ACPI, and at the same time allow native chip selects.

GPIO hogging can be used to set initial state of certain GPIOs available on
the headers regardless of the BIOS settings (which may be wrong as it knows
nothing about which devices have been connected).

Mika Westerberg (5):
  ACPI / documentation: Use recommended name in GPIO property names
  ACPI / gpio: Add support for naming GPIOs
  ACPI / gpio: Add hogging support
  ACPI / property: Allow holes in reference properties
  ACPI / gpio: Allow holes in list of GPIOs for a device

 Documentation/acpi/gpio-properties.txt |  72 ++++++++++++++--
 drivers/acpi/property.c                | 116 +++++++++++++++++++-------
 drivers/gpio/gpiolib-acpi.c            | 147 ++++++++++++++++++++++++++++++---
 include/linux/acpi.h                   |   3 +
 4 files changed, 292 insertions(+), 46 deletions(-)

-- 
2.9.3

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#1490207 — [PATCH 2/5] ACPI / gpio: Add support for naming GPIOs

DT has property 'gpio-line-names' to name GPIO lines the controller has if
present. Use this very same property in ACPI as well to provide nice names
for the GPIOS.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 Documentation/acpi/gpio-properties.txt | 21 +++++++++++++++++
 drivers/gpio/gpiolib-acpi.c            | 43 ++++++++++++++++++++++++++++++++++
 2 files changed, 64 insertions(+)

diff --git a/Documentation/acpi/gpio-properties.txt b/Documentation/acpi/gpio-properties.txt
index 5aafe0b351a1..7875974823ae 100644
--- a/Documentation/acpi/gpio-properties.txt
+++ b/Documentation/acpi/gpio-properties.txt
@@ -51,6 +51,27 @@ it to 1 marks the GPIO as active low.
 In our Bluetooth example the "reset-gpios" refers to the second GpioIo()
 resource, second pin in that resource with the GPIO number of 31.
 
+Other supported properties
+--------------------------
+
+Following Device Tree compatible device properties are also supported by
+_DSD device properties for GPIO controllers:
+
+- gpio-line-names
+
+Example:
+
+  Package () {
+      "gpio-line-names",
+      Package () {
+          "SPI0_CS_N", "EXP2_INT", "MUX6_IO", "UART0_RXD", "MUX7_IO",
+          "LVL_C_A1", "MUX0_IO", "SPI1_MISO"
+      }
+  }
+
+See Documentation/devicetree/bindings/gpio/gpio.tx for more information
+about these properties.
+
 ACPI GPIO Mappings Provided by Drivers
 --------------------------------------
 
diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index af514618d7fb..202cf1b842de 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -805,6 +805,46 @@ static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip)
 	}
 }
 
+static void acpi_gpiochip_set_names(struct acpi_gpio_chip *achip)
+{
+	struct gpio_chip *chip = achip->chip;
+	struct gpio_device *gdev = chip->gpiodev;
+	const char **names;
+	int ret, i;
+
+	ret = device_property_read_string_array(chip->parent, "gpio-line-names",
+						NULL, 0);
+	if (ret < 0)
+		return;
+
+	if (ret != gdev->ngpio) {
+		dev_warn(chip->parent,
+			 "names %d do not match number of GPIOs %d\n", ret,
+			 gdev->ngpio);
+		return;
+	}
+
+	names = kcalloc(gdev->ngpio, sizeof(*names), GFP_KERNEL);
+	if (!names)
+		return;
+
+	ret = device_property_read_string_array(chip->parent, "gpio-line-names",
+						names, gdev->ngpio);
+	if (ret < 0) {
+		dev_warn(chip->parent, "Failed to read GPIO line names\n");
+		return;
+	}
+
+	/*
+	 * It is fine to assign the name, it will be allocated as long as
+	 * the ACPI device exists.
+	 */
+	for (i = 0; i < gdev->ngpio; i++)
+		gdev->descs[i].name = names[i];
+
+	kfree(names);
+}
+
 void acpi_gpiochip_add(struct gpio_chip *chip)
 {
 	struct acpi_gpio_chip *acpi_gpio;
@@ -835,6 +875,9 @@ void acpi_gpiochip_add(struct gpio_chip *chip)
 		return;
 	}
 
+	if (!chip->names)
+		acpi_gpiochip_set_names(acpi_gpio);
+
 	acpi_gpiochip_request_regions(acpi_gpio);
 	acpi_walk_dep_device_list(handle);
 }
-- 
2.9.3

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#1490208 — [PATCH 4/5] ACPI / property: Allow holes in reference properties

DT allows holes or empty phandles for references. This is used for example
in SPI subsystem where some chip selects are native and others are regular
GPIOs. In ACPI _DSD we currently do not support this but instead the
preceding reference "consumes" all following integer arguments.

For example we would like to support something like the below ASL fragment
for SPI:

  Package () {
      "cs-gpios",
      Package () {
          ^GPIO, 19, 0, 0, // GPIO CS0
          0,               // Native CS
          ^GPIO, 20, 0, 0, // GPIO CS1
      }
  }

The zero in the middle means "no entry" or NULL reference. To support this
we add a new function acpi_node_get_property_reference_fixed_args() that
takes number of expected arguments as parameter. Function returns -ENOENT
if the corresponding index resolves to the "no entry" reference.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/acpi/property.c | 116 +++++++++++++++++++++++++++++++++++-------------
 include/linux/acpi.h    |   3 ++
 2 files changed, 89 insertions(+), 30 deletions(-)

diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
index f2fd3fee588a..b255c4442a05 100644
--- a/drivers/acpi/property.c
+++ b/drivers/acpi/property.c
@@ -472,6 +472,7 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
  * @data: ACPI device data object containing the property
  * @propname: Name of the property
  * @index: Index of the reference to return
+ * @num_args: Maximum number of arguments after each reference
  * @args: Location to store the returned reference with optional arguments
  *
  * Find property with @name, verifify that it is a package containing at least
@@ -485,8 +486,8 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
  * Return: %0 on success, negative error code on failure.
  */
 static int acpi_data_get_property_reference(struct acpi_device_data *data,
-					    const char *propname, size_t index,
-					    struct acpi_reference_args *args)
+	const char *propname, size_t index, size_t num_args,
+	struct acpi_reference_args *args)
 {
 	const union acpi_object *element, *end;
 	const union acpi_object *obj;
@@ -532,41 +533,52 @@ static int acpi_data_get_property_reference(struct acpi_device_data *data,
 	while (element < end) {
 		u32 nargs, i;
 
-		if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
-			return -EPROTO;
-
-		ret = acpi_bus_get_device(element->reference.handle, &device);
-		if (ret)
-			return -ENODEV;
-
-		element++;
-		nargs = 0;
-
-		/* assume following integer elements are all args */
-		for (i = 0; element + i < end; i++) {
-			int type = element[i].type;
+		if (element->type == ACPI_TYPE_LOCAL_REFERENCE) {
+			ret = acpi_bus_get_device(element->reference.handle,
+						  &device);
+			if (ret)
+				return -ENODEV;
+
+			nargs = 0;
+			element++;
+
+			/* assume following integer elements are all args */
+			for (i = 0; element + i < end && i < num_args; i++) {
+				int type = element[i].type;
+
+				if (type == ACPI_TYPE_INTEGER)
+					nargs++;
+				else if (type == ACPI_TYPE_LOCAL_REFERENCE)
+					break;
+				else
+					return -EPROTO;
+			}
 
-			if (type == ACPI_TYPE_INTEGER)
-				nargs++;
-			else if (type == ACPI_TYPE_LOCAL_REFERENCE)
-				break;
-			else
+			if (nargs > MAX_ACPI_REFERENCE_ARGS)
 				return -EPROTO;
-		}
 
-		if (idx++ == index) {
-			args->adev = device;
-			args->nargs = nargs;
-			for (i = 0; i < nargs; i++)
-				args->args[i] = element[i].integer.value;
+			if (idx == index) {
+				args->adev = device;
+				args->nargs = nargs;
+				for (i = 0; i < nargs; i++)
+					args->args[i] = element[i].integer.value;
 
-			return 0;
+				return 0;
+			}
+
+			element += nargs;
+		} else if (element->type == ACPI_TYPE_INTEGER) {
+			if (idx == index)
+				return -ENOENT;
+			element++;
+		} else {
+			return -EPROTO;
 		}
 
-		element += nargs;
+		idx++;
 	}
 
-	return -EPROTO;
+	return -ENODATA;
 }
 
 /**
@@ -582,10 +594,54 @@ int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
 {
 	struct acpi_device_data *data = acpi_device_data_of_node(fwnode);
 
-	return data ? acpi_data_get_property_reference(data, name, index, args) : -EINVAL;
+	if (!data)
+		return -EINVAL;
+
+	return acpi_data_get_property_reference(data, name, index,
+		MAX_ACPI_REFERENCE_ARGS, args);
 }
 EXPORT_SYMBOL_GPL(acpi_node_get_property_reference);
 
+/**
+ * acpi_node_get_property_reference_fixed_args - get a reference from property
+ * @fwnode: Firmware node to get the property from.
+ * @propname: Name of the property.
+ * @index: Index of the reference to return.
+ * @num_args: Expected number of arguments following each reference.
+ * @args: Location to store the returned reference with optional arguments.
+ *
+ * Using this function it is possible to leave "holes" in the property
+ * value set like in an example below:
+ *
+ * Package () {
+ *     "cs-gpios",
+ *     Package () {
+ *        ^GPIO, 19, 0, 0,
+ *        ^GPIO, 20, 0, 0,
+ *        0,
+ *        ^GPIO, 21, 0, 0,
+ *     }
+ * }
+ *
+ * Calling this function with index %2 return %-ENOENT and with index %3
+ * returns the last entry. If the property does not contain any more values
+ * %-ENODATA is returned. The NULL entry must be single integer and
+ * preferably contain value %0.
+ */
+int acpi_node_get_property_reference_fixed_args(struct fwnode_handle *fwnode,
+	const char *name, size_t index, size_t num_args,
+	struct acpi_reference_args *args)
+{
+	struct acpi_device_data *data = acpi_device_data_of_node(fwnode);
+
+	if (!data)
+		return -EINVAL;
+
+	return acpi_data_get_property_reference(data, name, index, num_args,
+						args);
+}
+EXPORT_SYMBOL_GPL(acpi_node_get_property_reference_fixed_args);
+
 static int acpi_data_prop_read_single(struct acpi_device_data *data,
 				      const char *propname,
 				      enum dev_prop_type proptype, void *val)
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index c5eaf2f80a4c..c5d7c503843f 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -930,6 +930,9 @@ int acpi_dev_get_property(struct acpi_device *adev, const char *name,
 int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
 				     const char *name, size_t index,
 				     struct acpi_reference_args *args);
+int acpi_node_get_property_reference_fixed_args(struct fwnode_handle *fwnode,
+				const char *name, size_t index, size_t num_args,
+				struct acpi_reference_args *args);
 
 int acpi_node_prop_get(struct fwnode_handle *fwnode, const char *propname,
 		       void **valptr);
-- 
2.9.3

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#1493001 — Re: [PATCH 4/5] ACPI / property: Allow holes in reference properties

On Fri, Sep 23, 2016 at 4:57 PM, Mika Westerberg
<mika.westerberg@linux.intel.com> wrote:
> DT allows holes or empty phandles for references. This is used for example
> in SPI subsystem where some chip selects are native and others are regular
> GPIOs. In ACPI _DSD we currently do not support this but instead the
> preceding reference "consumes" all following integer arguments.
>
> For example we would like to support something like the below ASL fragment
> for SPI:
>
>   Package () {
>       "cs-gpios",
>       Package () {
>           ^GPIO, 19, 0, 0, // GPIO CS0
>           0,               // Native CS
>           ^GPIO, 20, 0, 0, // GPIO CS1
>       }
>   }
>
> The zero in the middle means "no entry" or NULL reference. To support this
> we add a new function acpi_node_get_property_reference_fixed_args() that
> takes number of expected arguments as parameter. Function returns -ENOENT
> if the corresponding index resolves to the "no entry" reference.
>
> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> ---
>  drivers/acpi/property.c | 116 +++++++++++++++++++++++++++++++++++-------------
>  include/linux/acpi.h    |   3 ++
>  2 files changed, 89 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
> index f2fd3fee588a..b255c4442a05 100644
> --- a/drivers/acpi/property.c
> +++ b/drivers/acpi/property.c
> @@ -472,6 +472,7 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
>   * @data: ACPI device data object containing the property
>   * @propname: Name of the property
>   * @index: Index of the reference to return
> + * @num_args: Maximum number of arguments after each reference
>   * @args: Location to store the returned reference with optional arguments
>   *
>   * Find property with @name, verifify that it is a package containing at least
> @@ -485,8 +486,8 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
>   * Return: %0 on success, negative error code on failure.
>   */
>  static int acpi_data_get_property_reference(struct acpi_device_data *data,
> -                                           const char *propname, size_t index,
> -                                           struct acpi_reference_args *args)
> +       const char *propname, size_t index, size_t num_args,
> +       struct acpi_reference_args *args)
>  {
>         const union acpi_object *element, *end;
>         const union acpi_object *obj;
> @@ -532,41 +533,52 @@ static int acpi_data_get_property_reference(struct acpi_device_data *data,
>         while (element < end) {
>                 u32 nargs, i;
>
> -               if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
> -                       return -EPROTO;
> -
> -               ret = acpi_bus_get_device(element->reference.handle, &device);
> -               if (ret)
> -                       return -ENODEV;
> -
> -               element++;
> -               nargs = 0;
> -
> -               /* assume following integer elements are all args */
> -               for (i = 0; element + i < end; i++) {
> -                       int type = element[i].type;
> +               if (element->type == ACPI_TYPE_LOCAL_REFERENCE) {
> +                       ret = acpi_bus_get_device(element->reference.handle,
> +                                                 &device);
> +                       if (ret)
> +                               return -ENODEV;
> +
> +                       nargs = 0;
> +                       element++;
> +
> +                       /* assume following integer elements are all args */
> +                       for (i = 0; element + i < end && i < num_args; i++) {
> +                               int type = element[i].type;
> +
> +                               if (type == ACPI_TYPE_INTEGER)
> +                                       nargs++;
> +                               else if (type == ACPI_TYPE_LOCAL_REFERENCE)
> +                                       break;
> +                               else
> +                                       return -EPROTO;
> +                       }
>
> -                       if (type == ACPI_TYPE_INTEGER)
> -                               nargs++;
> -                       else if (type == ACPI_TYPE_LOCAL_REFERENCE)
> -                               break;
> -                       else
> +                       if (nargs > MAX_ACPI_REFERENCE_ARGS)
>                                 return -EPROTO;
> -               }
>
> -               if (idx++ == index) {
> -                       args->adev = device;
> -                       args->nargs = nargs;
> -                       for (i = 0; i < nargs; i++)
> -                               args->args[i] = element[i].integer.value;
> +                       if (idx == index) {
> +                               args->adev = device;
> +                               args->nargs = nargs;
> +                               for (i = 0; i < nargs; i++)
> +                                       args->args[i] = element[i].integer.value;
>
> -                       return 0;
> +                               return 0;
> +                       }
> +
> +                       element += nargs;
> +               } else if (element->type == ACPI_TYPE_INTEGER) {
> +                       if (idx == index)
> +                               return -ENOENT;
> +                       element++;
> +               } else {
> +                       return -EPROTO;
>                 }
>
> -               element += nargs;
> +               idx++;
>         }
>
> -       return -EPROTO;
> +       return -ENODATA;
>  }
>
>  /**
> @@ -582,10 +594,54 @@ int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
>  {
>         struct acpi_device_data *data = acpi_device_data_of_node(fwnode);
>
> -       return data ? acpi_data_get_property_reference(data, name, index, args) : -EINVAL;
> +       if (!data)
> +               return -EINVAL;
> +
> +       return acpi_data_get_property_reference(data, name, index,
> +               MAX_ACPI_REFERENCE_ARGS, args);
>  }
>  EXPORT_SYMBOL_GPL(acpi_node_get_property_reference);

gpiolib-acpi is the only user of this AFAICS, so why don't we change
the definition of acpi_node_get_property_reference() to take one extra
argument and update the caller to pass MAX_ACPI_REFERENCE_ARGS?

We'd avoid having to define the thing below then.

>
> +/**
> + * acpi_node_get_property_reference_fixed_args - get a reference from property
> + * @fwnode: Firmware node to get the property from.
> + * @propname: Name of the property.
> + * @index: Index of the reference to return.
> + * @num_args: Expected number of arguments following each reference.
> + * @args: Location to store the returned reference with optional arguments.
> + *
> + * Using this function it is possible to leave "holes" in the property
> + * value set like in an example below:
> + *
> + * Package () {
> + *     "cs-gpios",
> + *     Package () {
> + *        ^GPIO, 19, 0, 0,
> + *        ^GPIO, 20, 0, 0,
> + *        0,
> + *        ^GPIO, 21, 0, 0,
> + *     }
> + * }
> + *
> + * Calling this function with index %2 return %-ENOENT and with index %3
> + * returns the last entry. If the property does not contain any more values
> + * %-ENODATA is returned. The NULL entry must be single integer and
> + * preferably contain value %0.
> + */
> +int acpi_node_get_property_reference_fixed_args(struct fwnode_handle *fwnode,
> +       const char *name, size_t index, size_t num_args,
> +       struct acpi_reference_args *args)
> +{
> +       struct acpi_device_data *data = acpi_device_data_of_node(fwnode);
> +
> +       if (!data)
> +               return -EINVAL;
> +
> +       return acpi_data_get_property_reference(data, name, index, num_args,
> +                                               args);
> +}
> +EXPORT_SYMBOL_GPL(acpi_node_get_property_reference_fixed_args);
> +
>  static int acpi_data_prop_read_single(struct acpi_device_data *data,
>                                       const char *propname,
>                                       enum dev_prop_type proptype, void *val)
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index c5eaf2f80a4c..c5d7c503843f 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -930,6 +930,9 @@ int acpi_dev_get_property(struct acpi_device *adev, const char *name,
>  int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
>                                      const char *name, size_t index,
>                                      struct acpi_reference_args *args);
> +int acpi_node_get_property_reference_fixed_args(struct fwnode_handle *fwnode,
> +                               const char *name, size_t index, size_t num_args,
> +                               struct acpi_reference_args *args);
>
>  int acpi_node_prop_get(struct fwnode_handle *fwnode, const char *propname,
>                        void **valptr);
> --

Thanks,
Rafael

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#1493168 — Re: [PATCH 4/5] ACPI / property: Allow holes in reference properties

On Wed, Sep 28, 2016 at 11:36:10PM +0200, Rafael J. Wysocki wrote:
> On Fri, Sep 23, 2016 at 4:57 PM, Mika Westerberg
> <mika.westerberg@linux.intel.com> wrote:
> > DT allows holes or empty phandles for references. This is used for example
> > in SPI subsystem where some chip selects are native and others are regular
> > GPIOs. In ACPI _DSD we currently do not support this but instead the
> > preceding reference "consumes" all following integer arguments.
> >
> > For example we would like to support something like the below ASL fragment
> > for SPI:
> >
> >   Package () {
> >       "cs-gpios",
> >       Package () {
> >           ^GPIO, 19, 0, 0, // GPIO CS0
> >           0,               // Native CS
> >           ^GPIO, 20, 0, 0, // GPIO CS1
> >       }
> >   }
> >
> > The zero in the middle means "no entry" or NULL reference. To support this
> > we add a new function acpi_node_get_property_reference_fixed_args() that
> > takes number of expected arguments as parameter. Function returns -ENOENT
> > if the corresponding index resolves to the "no entry" reference.
> >
> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > ---
> >  drivers/acpi/property.c | 116 +++++++++++++++++++++++++++++++++++-------------
> >  include/linux/acpi.h    |   3 ++
> >  2 files changed, 89 insertions(+), 30 deletions(-)
> >
> > diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
> > index f2fd3fee588a..b255c4442a05 100644
> > --- a/drivers/acpi/property.c
> > +++ b/drivers/acpi/property.c
> > @@ -472,6 +472,7 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
> >   * @data: ACPI device data object containing the property
> >   * @propname: Name of the property
> >   * @index: Index of the reference to return
> > + * @num_args: Maximum number of arguments after each reference
> >   * @args: Location to store the returned reference with optional arguments
> >   *
> >   * Find property with @name, verifify that it is a package containing at least
> > @@ -485,8 +486,8 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
> >   * Return: %0 on success, negative error code on failure.
> >   */
> >  static int acpi_data_get_property_reference(struct acpi_device_data *data,
> > -                                           const char *propname, size_t index,
> > -                                           struct acpi_reference_args *args)
> > +       const char *propname, size_t index, size_t num_args,
> > +       struct acpi_reference_args *args)
> >  {
> >         const union acpi_object *element, *end;
> >         const union acpi_object *obj;
> > @@ -532,41 +533,52 @@ static int acpi_data_get_property_reference(struct acpi_device_data *data,
> >         while (element < end) {
> >                 u32 nargs, i;
> >
> > -               if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
> > -                       return -EPROTO;
> > -
> > -               ret = acpi_bus_get_device(element->reference.handle, &device);
> > -               if (ret)
> > -                       return -ENODEV;
> > -
> > -               element++;
> > -               nargs = 0;
> > -
> > -               /* assume following integer elements are all args */
> > -               for (i = 0; element + i < end; i++) {
> > -                       int type = element[i].type;
> > +               if (element->type == ACPI_TYPE_LOCAL_REFERENCE) {
> > +                       ret = acpi_bus_get_device(element->reference.handle,
> > +                                                 &device);
> > +                       if (ret)
> > +                               return -ENODEV;
> > +
> > +                       nargs = 0;
> > +                       element++;
> > +
> > +                       /* assume following integer elements are all args */
> > +                       for (i = 0; element + i < end && i < num_args; i++) {
> > +                               int type = element[i].type;
> > +
> > +                               if (type == ACPI_TYPE_INTEGER)
> > +                                       nargs++;
> > +                               else if (type == ACPI_TYPE_LOCAL_REFERENCE)
> > +                                       break;
> > +                               else
> > +                                       return -EPROTO;
> > +                       }
> >
> > -                       if (type == ACPI_TYPE_INTEGER)
> > -                               nargs++;
> > -                       else if (type == ACPI_TYPE_LOCAL_REFERENCE)
> > -                               break;
> > -                       else
> > +                       if (nargs > MAX_ACPI_REFERENCE_ARGS)
> >                                 return -EPROTO;
> > -               }
> >
> > -               if (idx++ == index) {
> > -                       args->adev = device;
> > -                       args->nargs = nargs;
> > -                       for (i = 0; i < nargs; i++)
> > -                               args->args[i] = element[i].integer.value;
> > +                       if (idx == index) {
> > +                               args->adev = device;
> > +                               args->nargs = nargs;
> > +                               for (i = 0; i < nargs; i++)
> > +                                       args->args[i] = element[i].integer.value;
> >
> > -                       return 0;
> > +                               return 0;
> > +                       }
> > +
> > +                       element += nargs;
> > +               } else if (element->type == ACPI_TYPE_INTEGER) {
> > +                       if (idx == index)
> > +                               return -ENOENT;
> > +                       element++;
> > +               } else {
> > +                       return -EPROTO;
> >                 }
> >
> > -               element += nargs;
> > +               idx++;
> >         }
> >
> > -       return -EPROTO;
> > +       return -ENODATA;
> >  }
> >
> >  /**
> > @@ -582,10 +594,54 @@ int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
> >  {
> >         struct acpi_device_data *data = acpi_device_data_of_node(fwnode);
> >
> > -       return data ? acpi_data_get_property_reference(data, name, index, args) : -EINVAL;
> > +       if (!data)
> > +               return -EINVAL;
> > +
> > +       return acpi_data_get_property_reference(data, name, index,
> > +               MAX_ACPI_REFERENCE_ARGS, args);
> >  }
> >  EXPORT_SYMBOL_GPL(acpi_node_get_property_reference);
> 
> gpiolib-acpi is the only user of this AFAICS, so why don't we change
> the definition of acpi_node_get_property_reference() to take one extra
> argument and update the caller to pass MAX_ACPI_REFERENCE_ARGS?

Unfortunately there are these (which I think should not call that
function directly anyway):

drivers/net/ethernet/apm/xgene/xgene_enet_hw.c: status = acpi_node_get_property_reference(fw_node, "phy-handle", 0,
drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c:      rc = acpi_node_get_property_reference(
drivers/net/ethernet/hisilicon/hns/hns_enet.c:          ret = acpi_node_get_property_reference(dev->fwnode,

So we would need to update those as well. Not a big deal, though.

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#1493421 — Re: [PATCH 4/5] ACPI / property: Allow holes in reference properties

On Thursday, September 29, 2016 09:48:29 AM Mika Westerberg wrote:
> On Wed, Sep 28, 2016 at 11:36:10PM +0200, Rafael J. Wysocki wrote:
> > On Fri, Sep 23, 2016 at 4:57 PM, Mika Westerberg
> > <mika.westerberg@linux.intel.com> wrote:
> > > DT allows holes or empty phandles for references. This is used for example
> > > in SPI subsystem where some chip selects are native and others are regular
> > > GPIOs. In ACPI _DSD we currently do not support this but instead the
> > > preceding reference "consumes" all following integer arguments.
> > >
> > > For example we would like to support something like the below ASL fragment
> > > for SPI:
> > >
> > >   Package () {
> > >       "cs-gpios",
> > >       Package () {
> > >           ^GPIO, 19, 0, 0, // GPIO CS0
> > >           0,               // Native CS

One thing just occurred to me: what if this value is not 0?

> > >           ^GPIO, 20, 0, 0, // GPIO CS1
> > >       }
> > >   }
> > >
> > > The zero in the middle means "no entry" or NULL reference. To support this
> > > we add a new function acpi_node_get_property_reference_fixed_args() that
> > > takes number of expected arguments as parameter. Function returns -ENOENT
> > > if the corresponding index resolves to the "no entry" reference.
> > >
> > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > ---
> > >  drivers/acpi/property.c | 116 +++++++++++++++++++++++++++++++++++-------------
> > >  include/linux/acpi.h    |   3 ++
> > >  2 files changed, 89 insertions(+), 30 deletions(-)
> > >
> > > diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
> > > index f2fd3fee588a..b255c4442a05 100644
> > > --- a/drivers/acpi/property.c
> > > +++ b/drivers/acpi/property.c
> > > @@ -472,6 +472,7 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
> > >   * @data: ACPI device data object containing the property
> > >   * @propname: Name of the property
> > >   * @index: Index of the reference to return
> > > + * @num_args: Maximum number of arguments after each reference
> > >   * @args: Location to store the returned reference with optional arguments
> > >   *
> > >   * Find property with @name, verifify that it is a package containing at least
> > > @@ -485,8 +486,8 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
> > >   * Return: %0 on success, negative error code on failure.
> > >   */
> > >  static int acpi_data_get_property_reference(struct acpi_device_data *data,
> > > -                                           const char *propname, size_t index,
> > > -                                           struct acpi_reference_args *args)
> > > +       const char *propname, size_t index, size_t num_args,
> > > +       struct acpi_reference_args *args)
> > >  {
> > >         const union acpi_object *element, *end;
> > >         const union acpi_object *obj;
> > > @@ -532,41 +533,52 @@ static int acpi_data_get_property_reference(struct acpi_device_data *data,
> > >         while (element < end) {
> > >                 u32 nargs, i;
> > >
> > > -               if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
> > > -                       return -EPROTO;
> > > -
> > > -               ret = acpi_bus_get_device(element->reference.handle, &device);
> > > -               if (ret)
> > > -                       return -ENODEV;
> > > -
> > > -               element++;
> > > -               nargs = 0;
> > > -
> > > -               /* assume following integer elements are all args */
> > > -               for (i = 0; element + i < end; i++) {
> > > -                       int type = element[i].type;
> > > +               if (element->type == ACPI_TYPE_LOCAL_REFERENCE) {
> > > +                       ret = acpi_bus_get_device(element->reference.handle,
> > > +                                                 &device);
> > > +                       if (ret)
> > > +                               return -ENODEV;
> > > +
> > > +                       nargs = 0;
> > > +                       element++;
> > > +
> > > +                       /* assume following integer elements are all args */
> > > +                       for (i = 0; element + i < end && i < num_args; i++) {
> > > +                               int type = element[i].type;
> > > +
> > > +                               if (type == ACPI_TYPE_INTEGER)
> > > +                                       nargs++;
> > > +                               else if (type == ACPI_TYPE_LOCAL_REFERENCE)
> > > +                                       break;
> > > +                               else
> > > +                                       return -EPROTO;
> > > +                       }
> > >
> > > -                       if (type == ACPI_TYPE_INTEGER)
> > > -                               nargs++;
> > > -                       else if (type == ACPI_TYPE_LOCAL_REFERENCE)
> > > -                               break;
> > > -                       else
> > > +                       if (nargs > MAX_ACPI_REFERENCE_ARGS)
> > >                                 return -EPROTO;
> > > -               }
> > >
> > > -               if (idx++ == index) {
> > > -                       args->adev = device;
> > > -                       args->nargs = nargs;
> > > -                       for (i = 0; i < nargs; i++)
> > > -                               args->args[i] = element[i].integer.value;
> > > +                       if (idx == index) {
> > > +                               args->adev = device;
> > > +                               args->nargs = nargs;
> > > +                               for (i = 0; i < nargs; i++)
> > > +                                       args->args[i] = element[i].integer.value;
> > >
> > > -                       return 0;
> > > +                               return 0;
> > > +                       }
> > > +
> > > +                       element += nargs;
> > > +               } else if (element->type == ACPI_TYPE_INTEGER) {
> > > +                       if (idx == index)
> > > +                               return -ENOENT;
> > > +                       element++;
> > > +               } else {
> > > +                       return -EPROTO;
> > >                 }
> > >
> > > -               element += nargs;
> > > +               idx++;
> > >         }
> > >
> > > -       return -EPROTO;
> > > +       return -ENODATA;
> > >  }
> > >
> > >  /**
> > > @@ -582,10 +594,54 @@ int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
> > >  {
> > >         struct acpi_device_data *data = acpi_device_data_of_node(fwnode);
> > >
> > > -       return data ? acpi_data_get_property_reference(data, name, index, args) : -EINVAL;
> > > +       if (!data)
> > > +               return -EINVAL;
> > > +
> > > +       return acpi_data_get_property_reference(data, name, index,
> > > +               MAX_ACPI_REFERENCE_ARGS, args);
> > >  }
> > >  EXPORT_SYMBOL_GPL(acpi_node_get_property_reference);
> > 
> > gpiolib-acpi is the only user of this AFAICS, so why don't we change
> > the definition of acpi_node_get_property_reference() to take one extra
> > argument and update the caller to pass MAX_ACPI_REFERENCE_ARGS?
> 
> Unfortunately there are these (which I think should not call that
> function directly anyway):

Right.

It looks like exactly the same usage pattern that should better be
implemented as a library function, ie. workarounds for something missing.

> drivers/net/ethernet/apm/xgene/xgene_enet_hw.c: status = acpi_node_get_property_reference(fw_node, "phy-handle", 0,
> drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c:      rc = acpi_node_get_property_reference(
> drivers/net/ethernet/hisilicon/hns/hns_enet.c:          ret = acpi_node_get_property_reference(dev->fwnode,
> 
> So we would need to update those as well. Not a big deal, though.

Or rename it to __acpi_node_get_property_reference() and define
acpi_node_get_property_reference() as a static inline wrapper passing
MAX_ACPI_REFERENCE_ARGS to it.

Thanks,
Rafael

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#1493424 — Re: [PATCH 4/5] ACPI / property: Allow holes in reference properties

On Thu, Sep 29, 2016 at 01:53:50PM +0200, Rafael J. Wysocki wrote:
> On Thursday, September 29, 2016 09:48:29 AM Mika Westerberg wrote:
> > On Wed, Sep 28, 2016 at 11:36:10PM +0200, Rafael J. Wysocki wrote:
> > > On Fri, Sep 23, 2016 at 4:57 PM, Mika Westerberg
> > > <mika.westerberg@linux.intel.com> wrote:
> > > > DT allows holes or empty phandles for references. This is used for example
> > > > in SPI subsystem where some chip selects are native and others are regular
> > > > GPIOs. In ACPI _DSD we currently do not support this but instead the
> > > > preceding reference "consumes" all following integer arguments.
> > > >
> > > > For example we would like to support something like the below ASL fragment
> > > > for SPI:
> > > >
> > > >   Package () {
> > > >       "cs-gpios",
> > > >       Package () {
> > > >           ^GPIO, 19, 0, 0, // GPIO CS0
> > > >           0,               // Native CS
> 
> One thing just occurred to me: what if this value is not 0?

It can be any integer value actually. We allow it but 0 is the preferred
value. I did not find anything in DT saying what it should be either.

Alternatively I can add a check that it must be 0.

> > > >           ^GPIO, 20, 0, 0, // GPIO CS1
> > > >       }
> > > >   }
> > > >
> > > > The zero in the middle means "no entry" or NULL reference. To support this
> > > > we add a new function acpi_node_get_property_reference_fixed_args() that
> > > > takes number of expected arguments as parameter. Function returns -ENOENT
> > > > if the corresponding index resolves to the "no entry" reference.
> > > >
> > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > ---
> > > >  drivers/acpi/property.c | 116 +++++++++++++++++++++++++++++++++++-------------
> > > >  include/linux/acpi.h    |   3 ++
> > > >  2 files changed, 89 insertions(+), 30 deletions(-)
> > > >
> > > > diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
> > > > index f2fd3fee588a..b255c4442a05 100644
> > > > --- a/drivers/acpi/property.c
> > > > +++ b/drivers/acpi/property.c
> > > > @@ -472,6 +472,7 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
> > > >   * @data: ACPI device data object containing the property
> > > >   * @propname: Name of the property
> > > >   * @index: Index of the reference to return
> > > > + * @num_args: Maximum number of arguments after each reference
> > > >   * @args: Location to store the returned reference with optional arguments
> > > >   *
> > > >   * Find property with @name, verifify that it is a package containing at least
> > > > @@ -485,8 +486,8 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
> > > >   * Return: %0 on success, negative error code on failure.
> > > >   */
> > > >  static int acpi_data_get_property_reference(struct acpi_device_data *data,
> > > > -                                           const char *propname, size_t index,
> > > > -                                           struct acpi_reference_args *args)
> > > > +       const char *propname, size_t index, size_t num_args,
> > > > +       struct acpi_reference_args *args)
> > > >  {
> > > >         const union acpi_object *element, *end;
> > > >         const union acpi_object *obj;
> > > > @@ -532,41 +533,52 @@ static int acpi_data_get_property_reference(struct acpi_device_data *data,
> > > >         while (element < end) {
> > > >                 u32 nargs, i;
> > > >
> > > > -               if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
> > > > -                       return -EPROTO;
> > > > -
> > > > -               ret = acpi_bus_get_device(element->reference.handle, &device);
> > > > -               if (ret)
> > > > -                       return -ENODEV;
> > > > -
> > > > -               element++;
> > > > -               nargs = 0;
> > > > -
> > > > -               /* assume following integer elements are all args */
> > > > -               for (i = 0; element + i < end; i++) {
> > > > -                       int type = element[i].type;
> > > > +               if (element->type == ACPI_TYPE_LOCAL_REFERENCE) {
> > > > +                       ret = acpi_bus_get_device(element->reference.handle,
> > > > +                                                 &device);
> > > > +                       if (ret)
> > > > +                               return -ENODEV;
> > > > +
> > > > +                       nargs = 0;
> > > > +                       element++;
> > > > +
> > > > +                       /* assume following integer elements are all args */
> > > > +                       for (i = 0; element + i < end && i < num_args; i++) {
> > > > +                               int type = element[i].type;
> > > > +
> > > > +                               if (type == ACPI_TYPE_INTEGER)
> > > > +                                       nargs++;
> > > > +                               else if (type == ACPI_TYPE_LOCAL_REFERENCE)
> > > > +                                       break;
> > > > +                               else
> > > > +                                       return -EPROTO;
> > > > +                       }
> > > >
> > > > -                       if (type == ACPI_TYPE_INTEGER)
> > > > -                               nargs++;
> > > > -                       else if (type == ACPI_TYPE_LOCAL_REFERENCE)
> > > > -                               break;
> > > > -                       else
> > > > +                       if (nargs > MAX_ACPI_REFERENCE_ARGS)
> > > >                                 return -EPROTO;
> > > > -               }
> > > >
> > > > -               if (idx++ == index) {
> > > > -                       args->adev = device;
> > > > -                       args->nargs = nargs;
> > > > -                       for (i = 0; i < nargs; i++)
> > > > -                               args->args[i] = element[i].integer.value;
> > > > +                       if (idx == index) {
> > > > +                               args->adev = device;
> > > > +                               args->nargs = nargs;
> > > > +                               for (i = 0; i < nargs; i++)
> > > > +                                       args->args[i] = element[i].integer.value;
> > > >
> > > > -                       return 0;
> > > > +                               return 0;
> > > > +                       }
> > > > +
> > > > +                       element += nargs;
> > > > +               } else if (element->type == ACPI_TYPE_INTEGER) {
> > > > +                       if (idx == index)
> > > > +                               return -ENOENT;
> > > > +                       element++;
> > > > +               } else {
> > > > +                       return -EPROTO;
> > > >                 }
> > > >
> > > > -               element += nargs;
> > > > +               idx++;
> > > >         }
> > > >
> > > > -       return -EPROTO;
> > > > +       return -ENODATA;
> > > >  }
> > > >
> > > >  /**
> > > > @@ -582,10 +594,54 @@ int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
> > > >  {
> > > >         struct acpi_device_data *data = acpi_device_data_of_node(fwnode);
> > > >
> > > > -       return data ? acpi_data_get_property_reference(data, name, index, args) : -EINVAL;
> > > > +       if (!data)
> > > > +               return -EINVAL;
> > > > +
> > > > +       return acpi_data_get_property_reference(data, name, index,
> > > > +               MAX_ACPI_REFERENCE_ARGS, args);
> > > >  }
> > > >  EXPORT_SYMBOL_GPL(acpi_node_get_property_reference);
> > > 
> > > gpiolib-acpi is the only user of this AFAICS, so why don't we change
> > > the definition of acpi_node_get_property_reference() to take one extra
> > > argument and update the caller to pass MAX_ACPI_REFERENCE_ARGS?
> > 
> > Unfortunately there are these (which I think should not call that
> > function directly anyway):
> 
> Right.
> 
> It looks like exactly the same usage pattern that should better be
> implemented as a library function, ie. workarounds for something missing.
> 
> > drivers/net/ethernet/apm/xgene/xgene_enet_hw.c: status = acpi_node_get_property_reference(fw_node, "phy-handle", 0,
> > drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c:      rc = acpi_node_get_property_reference(
> > drivers/net/ethernet/hisilicon/hns/hns_enet.c:          ret = acpi_node_get_property_reference(dev->fwnode,
> > 
> > So we would need to update those as well. Not a big deal, though.
> 
> Or rename it to __acpi_node_get_property_reference() and define
> acpi_node_get_property_reference() as a static inline wrapper passing
> MAX_ACPI_REFERENCE_ARGS to it.

OK, I'll do this.

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#1493436 — Re: [PATCH 4/5] ACPI / property: Allow holes in reference properties

On Thursday, September 29, 2016 02:56:57 PM Mika Westerberg wrote:
> On Thu, Sep 29, 2016 at 01:53:50PM +0200, Rafael J. Wysocki wrote:
> > On Thursday, September 29, 2016 09:48:29 AM Mika Westerberg wrote:
> > > On Wed, Sep 28, 2016 at 11:36:10PM +0200, Rafael J. Wysocki wrote:
> > > > On Fri, Sep 23, 2016 at 4:57 PM, Mika Westerberg
> > > > <mika.westerberg@linux.intel.com> wrote:
> > > > > DT allows holes or empty phandles for references. This is used for example
> > > > > in SPI subsystem where some chip selects are native and others are regular
> > > > > GPIOs. In ACPI _DSD we currently do not support this but instead the
> > > > > preceding reference "consumes" all following integer arguments.
> > > > >
> > > > > For example we would like to support something like the below ASL fragment
> > > > > for SPI:
> > > > >
> > > > >   Package () {
> > > > >       "cs-gpios",
> > > > >       Package () {
> > > > >           ^GPIO, 19, 0, 0, // GPIO CS0
> > > > >           0,               // Native CS
> > 
> > One thing just occurred to me: what if this value is not 0?
> 
> It can be any integer value actually. We allow it but 0 is the preferred
> value. I did not find anything in DT saying what it should be either.
> 
> Alternatively I can add a check that it must be 0.

No need, I just was wondering. :-)

I think it's best to follow DT exactly here.

> > > > >           ^GPIO, 20, 0, 0, // GPIO CS1
> > > > >       }
> > > > >   }
> > > > >
> > > > > The zero in the middle means "no entry" or NULL reference. To support this
> > > > > we add a new function acpi_node_get_property_reference_fixed_args() that
> > > > > takes number of expected arguments as parameter. Function returns -ENOENT
> > > > > if the corresponding index resolves to the "no entry" reference.
> > > > >
> > > > > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > > > > ---
> > > > >  drivers/acpi/property.c | 116 +++++++++++++++++++++++++++++++++++-------------
> > > > >  include/linux/acpi.h    |   3 ++
> > > > >  2 files changed, 89 insertions(+), 30 deletions(-)
> > > > >
> > > > > diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c
> > > > > index f2fd3fee588a..b255c4442a05 100644
> > > > > --- a/drivers/acpi/property.c
> > > > > +++ b/drivers/acpi/property.c
> > > > > @@ -472,6 +472,7 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
> > > > >   * @data: ACPI device data object containing the property
> > > > >   * @propname: Name of the property
> > > > >   * @index: Index of the reference to return
> > > > > + * @num_args: Maximum number of arguments after each reference
> > > > >   * @args: Location to store the returned reference with optional arguments
> > > > >   *
> > > > >   * Find property with @name, verifify that it is a package containing at least
> > > > > @@ -485,8 +486,8 @@ static int acpi_data_get_property_array(struct acpi_device_data *data,
> > > > >   * Return: %0 on success, negative error code on failure.
> > > > >   */
> > > > >  static int acpi_data_get_property_reference(struct acpi_device_data *data,
> > > > > -                                           const char *propname, size_t index,
> > > > > -                                           struct acpi_reference_args *args)
> > > > > +       const char *propname, size_t index, size_t num_args,
> > > > > +       struct acpi_reference_args *args)
> > > > >  {
> > > > >         const union acpi_object *element, *end;
> > > > >         const union acpi_object *obj;
> > > > > @@ -532,41 +533,52 @@ static int acpi_data_get_property_reference(struct acpi_device_data *data,
> > > > >         while (element < end) {
> > > > >                 u32 nargs, i;
> > > > >
> > > > > -               if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
> > > > > -                       return -EPROTO;
> > > > > -
> > > > > -               ret = acpi_bus_get_device(element->reference.handle, &device);
> > > > > -               if (ret)
> > > > > -                       return -ENODEV;
> > > > > -
> > > > > -               element++;
> > > > > -               nargs = 0;
> > > > > -
> > > > > -               /* assume following integer elements are all args */
> > > > > -               for (i = 0; element + i < end; i++) {
> > > > > -                       int type = element[i].type;
> > > > > +               if (element->type == ACPI_TYPE_LOCAL_REFERENCE) {
> > > > > +                       ret = acpi_bus_get_device(element->reference.handle,
> > > > > +                                                 &device);
> > > > > +                       if (ret)
> > > > > +                               return -ENODEV;
> > > > > +
> > > > > +                       nargs = 0;
> > > > > +                       element++;
> > > > > +
> > > > > +                       /* assume following integer elements are all args */
> > > > > +                       for (i = 0; element + i < end && i < num_args; i++) {
> > > > > +                               int type = element[i].type;
> > > > > +
> > > > > +                               if (type == ACPI_TYPE_INTEGER)
> > > > > +                                       nargs++;
> > > > > +                               else if (type == ACPI_TYPE_LOCAL_REFERENCE)
> > > > > +                                       break;
> > > > > +                               else
> > > > > +                                       return -EPROTO;
> > > > > +                       }
> > > > >
> > > > > -                       if (type == ACPI_TYPE_INTEGER)
> > > > > -                               nargs++;
> > > > > -                       else if (type == ACPI_TYPE_LOCAL_REFERENCE)
> > > > > -                               break;
> > > > > -                       else
> > > > > +                       if (nargs > MAX_ACPI_REFERENCE_ARGS)
> > > > >                                 return -EPROTO;
> > > > > -               }
> > > > >
> > > > > -               if (idx++ == index) {
> > > > > -                       args->adev = device;
> > > > > -                       args->nargs = nargs;
> > > > > -                       for (i = 0; i < nargs; i++)
> > > > > -                               args->args[i] = element[i].integer.value;
> > > > > +                       if (idx == index) {
> > > > > +                               args->adev = device;
> > > > > +                               args->nargs = nargs;
> > > > > +                               for (i = 0; i < nargs; i++)
> > > > > +                                       args->args[i] = element[i].integer.value;
> > > > >
> > > > > -                       return 0;
> > > > > +                               return 0;
> > > > > +                       }
> > > > > +
> > > > > +                       element += nargs;
> > > > > +               } else if (element->type == ACPI_TYPE_INTEGER) {
> > > > > +                       if (idx == index)
> > > > > +                               return -ENOENT;
> > > > > +                       element++;
> > > > > +               } else {
> > > > > +                       return -EPROTO;
> > > > >                 }
> > > > >
> > > > > -               element += nargs;
> > > > > +               idx++;
> > > > >         }
> > > > >
> > > > > -       return -EPROTO;
> > > > > +       return -ENODATA;
> > > > >  }
> > > > >
> > > > >  /**
> > > > > @@ -582,10 +594,54 @@ int acpi_node_get_property_reference(struct fwnode_handle *fwnode,
> > > > >  {
> > > > >         struct acpi_device_data *data = acpi_device_data_of_node(fwnode);
> > > > >
> > > > > -       return data ? acpi_data_get_property_reference(data, name, index, args) : -EINVAL;
> > > > > +       if (!data)
> > > > > +               return -EINVAL;
> > > > > +
> > > > > +       return acpi_data_get_property_reference(data, name, index,
> > > > > +               MAX_ACPI_REFERENCE_ARGS, args);
> > > > >  }
> > > > >  EXPORT_SYMBOL_GPL(acpi_node_get_property_reference);
> > > > 
> > > > gpiolib-acpi is the only user of this AFAICS, so why don't we change
> > > > the definition of acpi_node_get_property_reference() to take one extra
> > > > argument and update the caller to pass MAX_ACPI_REFERENCE_ARGS?
> > > 
> > > Unfortunately there are these (which I think should not call that
> > > function directly anyway):
> > 
> > Right.
> > 
> > It looks like exactly the same usage pattern that should better be
> > implemented as a library function, ie. workarounds for something missing.
> > 
> > > drivers/net/ethernet/apm/xgene/xgene_enet_hw.c: status = acpi_node_get_property_reference(fw_node, "phy-handle", 0,
> > > drivers/net/ethernet/hisilicon/hns/hns_dsaf_mac.c:      rc = acpi_node_get_property_reference(
> > > drivers/net/ethernet/hisilicon/hns/hns_enet.c:          ret = acpi_node_get_property_reference(dev->fwnode,
> > > 
> > > So we would need to update those as well. Not a big deal, though.
> > 
> > Or rename it to __acpi_node_get_property_reference() and define
> > acpi_node_get_property_reference() as a static inline wrapper passing
> > MAX_ACPI_REFERENCE_ARGS to it.
> 
> OK, I'll do this.

Thanks!

Rafael

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#1490210 — [PATCH 3/5] ACPI / gpio: Add hogging support

GPIO hogging means that the GPIO controller can "hog" and configure certain
GPIOs without need for a driver or userspace to do that. This is useful in
open-connected boards where BIOS cannot possibly know beforehand which
devices will be connected to the board.

This adds GPIO hogging mechanism to ACPI analogous to Device Tree.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 Documentation/acpi/gpio-properties.txt | 26 ++++++++++++
 drivers/gpio/gpiolib-acpi.c            | 72 ++++++++++++++++++++++++++++++++++
 2 files changed, 98 insertions(+)

diff --git a/Documentation/acpi/gpio-properties.txt b/Documentation/acpi/gpio-properties.txt
index 7875974823ae..46df91c3512b 100644
--- a/Documentation/acpi/gpio-properties.txt
+++ b/Documentation/acpi/gpio-properties.txt
@@ -69,6 +69,32 @@ Example:
       }
   }
 
+- gpio-hog
+- output-high
+- output-low
+- input
+- line-name
+
+Example:
+
+  Name (_DSD, Package () {
+      // _DSD Hierarchical Properties Extension UUID
+      ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"),
+      Package () {
+          Package () {"hog-gpio8", "G8PU"}
+      }
+  })
+
+  Name (G8PU, Package () {
+      ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+      Package () {
+          Package () {"gpio-hog", 1},
+          Package () {"gpios", Package () {8, 0}},
+          Package () {"output-high", 1},
+          Package () {"line-name", "gpio8-pullup"},
+      }
+  })
+
 See Documentation/devicetree/bindings/gpio/gpio.tx for more information
 about these properties.
 
diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 202cf1b842de..4e50f8f5d597 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -14,6 +14,7 @@
 #include <linux/gpio.h>
 #include <linux/gpio/consumer.h>
 #include <linux/gpio/driver.h>
+#include <linux/gpio/machine.h>
 #include <linux/export.h>
 #include <linux/acpi.h>
 #include <linux/interrupt.h>
@@ -845,6 +846,76 @@ static void acpi_gpiochip_set_names(struct acpi_gpio_chip *achip)
 	kfree(names);
 }
 
+struct gpio_desc *acpi_gpiochip_parse_own_gpio(struct acpi_gpio_chip *achip,
+	struct fwnode_handle *fwnode, const char **name, unsigned int *lflags,
+	unsigned int *dflags)
+{
+	struct gpio_chip *chip = achip->chip;
+	struct gpio_desc *desc;
+	u32 gpios[2];
+	int ret;
+
+	ret = fwnode_property_read_u32_array(fwnode, "gpios", gpios,
+					     ARRAY_SIZE(gpios));
+	if (ret < 0)
+		return ERR_PTR(ret);
+
+	ret = acpi_gpiochip_pin_to_gpio_offset(chip->gpiodev, gpios[0]);
+	if (ret < 0)
+		return ERR_PTR(ret);
+
+	desc = gpiochip_get_desc(chip, ret);
+	if (IS_ERR(desc))
+		return desc;
+
+	*lflags = 0;
+	*dflags = 0;
+	*name = NULL;
+
+	if (gpios[1])
+		*lflags |= GPIO_ACTIVE_LOW;
+
+	if (fwnode_property_present(fwnode, "input"))
+		*dflags |= GPIOD_IN;
+	else if (fwnode_property_present(fwnode, "output-low"))
+		*dflags |= GPIOD_OUT_LOW;
+	else if (fwnode_property_present(fwnode, "output-high"))
+		*dflags |= GPIOD_OUT_HIGH;
+	else
+		return ERR_PTR(-EINVAL);
+
+	fwnode_property_read_string(fwnode, "line-name", name);
+
+	return desc;
+}
+
+static void acpi_gpiochip_scan_gpios(struct acpi_gpio_chip *achip)
+{
+	struct gpio_chip *chip = achip->chip;
+	struct fwnode_handle *fwnode;
+
+	device_for_each_child_node(chip->parent, fwnode) {
+		unsigned int lflags, dflags;
+		struct gpio_desc *desc;
+		const char *name;
+		int ret;
+
+		if (!fwnode_property_present(fwnode, "gpio-hog"))
+			continue;
+
+		desc = acpi_gpiochip_parse_own_gpio(achip, fwnode, &name,
+						    &lflags, &dflags);
+		if (IS_ERR(desc))
+			continue;
+
+		ret = gpiod_hog(desc, name, lflags, dflags);
+		if (ret) {
+			dev_err(chip->parent, "Failed to hog GPIO\n");
+			return;
+		}
+	}
+}
+
 void acpi_gpiochip_add(struct gpio_chip *chip)
 {
 	struct acpi_gpio_chip *acpi_gpio;
@@ -879,6 +950,7 @@ void acpi_gpiochip_add(struct gpio_chip *chip)
 		acpi_gpiochip_set_names(acpi_gpio);
 
 	acpi_gpiochip_request_regions(acpi_gpio);
+	acpi_gpiochip_scan_gpios(acpi_gpio);
 	acpi_walk_dep_device_list(handle);
 }
 
-- 
2.9.3

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#1490212 — [PATCH 5/5] ACPI / gpio: Allow holes in list of GPIOs for a device

Make it possible to have an empty GPIOs in a GPIO list for device. For
example a SPI master may use both GPIOs and native pins as chip selects and
we need to be able to distinguish between the two.

This makes it mandatory to have exactly 3 arguments for GPIOs and then
converts gpiolib to use of acpi_node_get_property_reference_fixed_args()
instead. In addition we make acpi_gpio_package_count() to handle holes as
well (this matches the DT version).

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 Documentation/acpi/gpio-properties.txt | 15 +++++++++++++++
 drivers/gpio/gpiolib-acpi.c            | 32 +++++++++++++++++++++-----------
 2 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/Documentation/acpi/gpio-properties.txt b/Documentation/acpi/gpio-properties.txt
index 46df91c3512b..2ccb70893122 100644
--- a/Documentation/acpi/gpio-properties.txt
+++ b/Documentation/acpi/gpio-properties.txt
@@ -51,6 +51,21 @@ it to 1 marks the GPIO as active low.
 In our Bluetooth example the "reset-gpios" refers to the second GpioIo()
 resource, second pin in that resource with the GPIO number of 31.
 
+It is possible to leave holes in the array of GPIOs. This is useful in
+cases like with SPI host controllers where some chip selects may be
+implemented as GPIOs and some as native signals. For example a SPI host
+controller can have chip selects 0 and 2 implemented as GPIOs and 1 as
+native:
+
+  Package () {
+      "cs-gpios",
+      Package () {
+          ^GPIO, 19, 0, 0, // chip select 0: GPIO
+          0,               // chip select 1: native signal
+          ^GPIO, 20, 0, 0, // chip select 2: GPIO
+      }
+  }
+
 Other supported properties
 --------------------------
 
diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 4e50f8f5d597..65c457b9541c 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -467,7 +467,8 @@ static int acpi_gpio_property_lookup(struct fwnode_handle *fwnode,
 	int ret;
 
 	memset(&args, 0, sizeof(args));
-	ret = acpi_node_get_property_reference(fwnode, propname, index, &args);
+	ret = acpi_node_get_property_reference_fixed_args(fwnode, propname,
+							  index, 3, &args);
 	if (ret) {
 		struct acpi_device *adev = to_acpi_device_node(fwnode);
 
@@ -482,13 +483,13 @@ static int acpi_gpio_property_lookup(struct fwnode_handle *fwnode,
 	 * on returned args.
 	 */
 	lookup->adev = args.adev;
-	if (args.nargs >= 2) {
-		lookup->index = args.args[0];
-		lookup->pin_index = args.args[1];
-		/* 3rd argument, if present is used to specify active_low. */
-		if (args.nargs >= 3)
-			lookup->active_low = !!args.args[2];
-	}
+	if (args.nargs != 3)
+		return -EPROTO;
+
+	lookup->index = args.args[0];
+	lookup->pin_index = args.args[1];
+	lookup->active_low = !!args.args[2];
+
 	return 0;
 }
 
@@ -979,18 +980,27 @@ void acpi_gpiochip_remove(struct gpio_chip *chip)
 	kfree(acpi_gpio);
 }
 
-static unsigned int acpi_gpio_package_count(const union acpi_object *obj)
+static int acpi_gpio_package_count(const union acpi_object *obj)
 {
 	const union acpi_object *element = obj->package.elements;
 	const union acpi_object *end = element + obj->package.count;
 	unsigned int count = 0;
 
 	while (element < end) {
-		if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
+		switch (element->type) {
+		case ACPI_TYPE_LOCAL_REFERENCE:
+			element += 3;
+			/* Fallthrough */
+		case ACPI_TYPE_INTEGER:
+			element++;
 			count++;
+			break;
 
-		element++;
+		default:
+			return -EPROTO;
+		}
 	}
+
 	return count;
 }
 
-- 
2.9.3

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#1492999

Hi,

On Fri, Sep 23, 2016 at 4:57 PM, Mika Westerberg
<mika.westerberg@linux.intel.com> wrote:
> Hi,
>
> This series brings couple of useful GPIO related properties from Device
> Tree to ACPI _DSD device properties:
>
>   - Names for GPIO lines
>   - GPIO hogging
>   - Holes in GPIO property lists
>
> We are using these to get Intel Galileo better supported in the mainline
> kernel (but these may be useful for other boards as well). For example SPI
> chip select on Galileo is connected to a GPIO line so we need to be able to
> describe it in ACPI, and at the same time allow native chip selects.
>
> GPIO hogging can be used to set initial state of certain GPIOs available on
> the headers regardless of the BIOS settings (which may be wrong as it knows
> nothing about which devices have been connected).
>
> Mika Westerberg (5):
>   ACPI / documentation: Use recommended name in GPIO property names
>   ACPI / gpio: Add support for naming GPIOs
>   ACPI / gpio: Add hogging support
>   ACPI / property: Allow holes in reference properties
>   ACPI / gpio: Allow holes in list of GPIOs for a device
>
>  Documentation/acpi/gpio-properties.txt |  72 ++++++++++++++--
>  drivers/acpi/property.c                | 116 +++++++++++++++++++-------
>  drivers/gpio/gpiolib-acpi.c            | 147 ++++++++++++++++++++++++++++++---
>  include/linux/acpi.h                   |   3 +
>  4 files changed, 292 insertions(+), 46 deletions(-)

I would like to tackle patches [1/5] and [4/5] first, as they are core
patches and the rest is against gpiolib-acpi.

Moreover, the documentation patch [1/5] looks like immediately applicable to me.

Thanks,
Rafael

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#1493173

On Wed, Sep 28, 2016 at 11:32:46PM +0200, Rafael J. Wysocki wrote:
> Hi,
> 
> On Fri, Sep 23, 2016 at 4:57 PM, Mika Westerberg
> <mika.westerberg@linux.intel.com> wrote:
> > Hi,
> >
> > This series brings couple of useful GPIO related properties from Device
> > Tree to ACPI _DSD device properties:
> >
> >   - Names for GPIO lines
> >   - GPIO hogging
> >   - Holes in GPIO property lists
> >
> > We are using these to get Intel Galileo better supported in the mainline
> > kernel (but these may be useful for other boards as well). For example SPI
> > chip select on Galileo is connected to a GPIO line so we need to be able to
> > describe it in ACPI, and at the same time allow native chip selects.
> >
> > GPIO hogging can be used to set initial state of certain GPIOs available on
> > the headers regardless of the BIOS settings (which may be wrong as it knows
> > nothing about which devices have been connected).
> >
> > Mika Westerberg (5):
> >   ACPI / documentation: Use recommended name in GPIO property names
> >   ACPI / gpio: Add support for naming GPIOs
> >   ACPI / gpio: Add hogging support
> >   ACPI / property: Allow holes in reference properties
> >   ACPI / gpio: Allow holes in list of GPIOs for a device
> >
> >  Documentation/acpi/gpio-properties.txt |  72 ++++++++++++++--
> >  drivers/acpi/property.c                | 116 +++++++++++++++++++-------
> >  drivers/gpio/gpiolib-acpi.c            | 147 ++++++++++++++++++++++++++++++---
> >  include/linux/acpi.h                   |   3 +
> >  4 files changed, 292 insertions(+), 46 deletions(-)
> 
> I would like to tackle patches [1/5] and [4/5] first, as they are core
> patches and the rest is against gpiolib-acpi.

Works for me.

I can re-arrange the series so that the two core patches (1,4/5) are
first and then the GPIO parts.

> Moreover, the documentation patch [1/5] looks like immediately applicable to me.

Yes, it just fixes the names to match what is preferred.

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#1493435

On Thursday, September 29, 2016 10:00:15 AM Mika Westerberg wrote:
> On Wed, Sep 28, 2016 at 11:32:46PM +0200, Rafael J. Wysocki wrote:
> > Hi,
> > 
> > On Fri, Sep 23, 2016 at 4:57 PM, Mika Westerberg
> > <mika.westerberg@linux.intel.com> wrote:
> > > Hi,
> > >
> > > This series brings couple of useful GPIO related properties from Device
> > > Tree to ACPI _DSD device properties:
> > >
> > >   - Names for GPIO lines
> > >   - GPIO hogging
> > >   - Holes in GPIO property lists
> > >
> > > We are using these to get Intel Galileo better supported in the mainline
> > > kernel (but these may be useful for other boards as well). For example SPI
> > > chip select on Galileo is connected to a GPIO line so we need to be able to
> > > describe it in ACPI, and at the same time allow native chip selects.
> > >
> > > GPIO hogging can be used to set initial state of certain GPIOs available on
> > > the headers regardless of the BIOS settings (which may be wrong as it knows
> > > nothing about which devices have been connected).
> > >
> > > Mika Westerberg (5):
> > >   ACPI / documentation: Use recommended name in GPIO property names
> > >   ACPI / gpio: Add support for naming GPIOs
> > >   ACPI / gpio: Add hogging support
> > >   ACPI / property: Allow holes in reference properties
> > >   ACPI / gpio: Allow holes in list of GPIOs for a device
> > >
> > >  Documentation/acpi/gpio-properties.txt |  72 ++++++++++++++--
> > >  drivers/acpi/property.c                | 116 +++++++++++++++++++-------
> > >  drivers/gpio/gpiolib-acpi.c            | 147 ++++++++++++++++++++++++++++++---
> > >  include/linux/acpi.h                   |   3 +
> > >  4 files changed, 292 insertions(+), 46 deletions(-)
> > 
> > I would like to tackle patches [1/5] and [4/5] first, as they are core
> > patches and the rest is against gpiolib-acpi.
> 
> Works for me.
> 
> I can re-arrange the series so that the two core patches (1,4/5) are
> first and then the GPIO parts.
> 
> > Moreover, the documentation patch [1/5] looks like immediately applicable to me.
> 
> Yes, it just fixes the names to match what is preferred.

OK, I'll apply it then, no need to resend.

Thanks,
Rafael

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