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Groups > linux.kernel > #1244825 > unrolled thread

[PATCH v9 2/9] Input: goodix - reset device at init

Started byIrina Tirdea <irina.tirdea@intel.com>
First post2015-10-12 17:30 +0200
Last post2015-10-14 15:50 +0200
Articles 9 — 4 participants

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  [PATCH v9 2/9] Input: goodix - reset device at init Irina Tirdea <irina.tirdea@intel.com> - 2015-10-12 17:30 +0200
    Re: [PATCH v9 2/9] Input: goodix - reset device at init Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-10-12 18:50 +0200
      RE: [PATCH v9 2/9] Input: goodix - reset device at init "Tirdea, Irina" <irina.tirdea@intel.com> - 2015-10-13 08:40 +0200
        Re: [PATCH v9 2/9] Input: goodix - reset device at init Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-10-13 09:10 +0200
          RE: [PATCH v9 2/9] Input: goodix - reset device at init "Tirdea, Irina" <irina.tirdea@intel.com> - 2015-10-13 11:00 +0200
            Re: [PATCH v9 2/9] Input: goodix - reset device at init "mika.westerberg@linux.intel.com" <mika.westerberg@linux.intel.com> - 2015-10-13 12:10 +0200
              Re: [PATCH v9 2/9] Input: goodix - reset device at init Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-10-14 08:30 +0200
                Re: [PATCH v9 2/9] Input: goodix - reset device at init "mika.westerberg@linux.intel.com" <mika.westerberg@linux.intel.com> - 2015-10-14 13:30 +0200
                  Re: [PATCH v9 2/9] Input: goodix - reset device at init "mika.westerberg@linux.intel.com" <mika.westerberg@linux.intel.com> - 2015-10-14 15:50 +0200

#1244825 — [PATCH v9 2/9] Input: goodix - reset device at init

FromIrina Tirdea <irina.tirdea@intel.com>
Date2015-10-12 17:30 +0200
Subject[PATCH v9 2/9] Input: goodix - reset device at init
Message-ID<qiNd1-2Xu-53@gated-at.bofh.it>
After power on, it is recommended that the driver resets the device.
The reset procedure timing is described in the datasheet and is used
at device init (before writing device configuration) and
for power management. It is a sequence of setting the interrupt
and reset pins high/low at specific timing intervals. This procedure
also includes setting the slave address to the one specified in the
ACPI/device tree.

This is based on Goodix datasheets for GT911 and GT9271 and on Goodix
driver gt9xx.c for Android (publicly available in Android kernel
trees for various devices).

For reset the driver needs to control the interrupt and
reset gpio pins (configured through ACPI/device tree). For devices
that do not have the gpio pins properly declared, the functionality
depending on these pins will not be available, but the device can still
be used with basic functionality.

For both device tree and ACPI, the interrupt gpio pin configuration is
read from the "irq-gpio" property and the reset pin configuration is
read from the "reset-gpio" property. For ACPI 5.1, named properties
can be specified using the _DSD section. This functionality will not be
available for devices that use indexed gpio pins declared in the _CRS
section (we need to provide backward compatibility with devices
that do not support using the interrupt gpio pin as output).

For ACPI, the pins can be specified using ACPI 5.1:
Device (STAC)
{
    Name (_HID, "GDIX1001")
    ...

    Method (_CRS, 0, Serialized)
    {
        Name (RBUF, ResourceTemplate ()
        {
            I2cSerialBus (0x0014, ControllerInitiated, 0x00061A80,
                AddressingMode7Bit, "\\I2C0",
                0x00, ResourceConsumer, ,
                )

            GpioInt (Edge, ActiveHigh, Exclusive, PullNone, 0x0000,
                "\\I2C0", 0x00, ResourceConsumer, ,
                 )
                 {   // Pin list
                     0
                 }

            GpioIo (Exclusive, PullDown, 0x0000, 0x0000,
                IoRestrictionOutputOnly, "\\I2C0", 0x00,
                ResourceConsumer, ,
                )
                {
                     1
                }
        })
        Return (RBUF)
    }

    Name (_DSD,  Package ()
    {
        ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
        Package ()
        {
            Package (2) {"irq-gpio", Package() {^STAC, 0, 0, 0 }},
            Package (2) {"reset-gpio", Package() {^STAC, 1, 0, 0 }},
            ...
        }
    }

Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Acked-by: Bastien Nocera <hadess@hadess.net>
Tested-by: Bastien Nocera <hadess@hadess.net>
Tested-by: Aleksei Mamlin <mamlinav@gmail.com>
---
 .../bindings/input/touchscreen/goodix.txt          |   5 +
 drivers/input/touchscreen/Kconfig                  |   1 +
 drivers/input/touchscreen/goodix.c                 | 101 +++++++++++++++++++++
 3 files changed, 107 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
index 8ba98ee..7137881 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
+++ b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
@@ -12,6 +12,8 @@ Required properties:
  - reg			: I2C address of the chip. Should be 0x5d or 0x14
  - interrupt-parent	: Interrupt controller to which the chip is connected
  - interrupts		: Interrupt to which the chip is connected
+ - irq-gpio		: GPIO pin used for IRQ
+ - reset-gpio		: GPIO pin used for reset
 
 Example:
 
@@ -23,6 +25,9 @@ Example:
 			reg = <0x5d>;
 			interrupt-parent = <&gpio>;
 			interrupts = <0 0>;
+
+			irq-gpio = <&gpio1 0 0>;
+			reset-gpio = <&gpio1 1 0>;
 		};
 
 		/* ... */
diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 771d95c..76f5a9d 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -324,6 +324,7 @@ config TOUCHSCREEN_FUJITSU
 config TOUCHSCREEN_GOODIX
 	tristate "Goodix I2C touchscreen"
 	depends on I2C
+	depends on GPIOLIB
 	help
 	  Say Y here if you have the Goodix touchscreen (such as one
 	  installed in Onda v975w tablets) connected to your
diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
index 56d0330..87304ac 100644
--- a/drivers/input/touchscreen/goodix.c
+++ b/drivers/input/touchscreen/goodix.c
@@ -16,6 +16,7 @@
 
 #include <linux/kernel.h>
 #include <linux/dmi.h>
+#include <linux/gpio.h>
 #include <linux/i2c.h>
 #include <linux/input.h>
 #include <linux/input/mt.h>
@@ -37,8 +38,13 @@ struct goodix_ts_data {
 	unsigned int int_trigger_type;
 	bool rotated_screen;
 	int cfg_len;
+	struct gpio_desc *gpiod_int;
+	struct gpio_desc *gpiod_rst;
 };
 
+#define GOODIX_GPIO_INT_NAME		"irq"
+#define GOODIX_GPIO_RST_NAME		"reset"
+
 #define GOODIX_MAX_HEIGHT		4096
 #define GOODIX_MAX_WIDTH		4096
 #define GOODIX_INT_TRIGGER		1
@@ -237,6 +243,88 @@ static irqreturn_t goodix_ts_irq_handler(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static int goodix_int_sync(struct goodix_ts_data *ts)
+{
+	int error;
+
+	error = gpiod_direction_output(ts->gpiod_int, 0);
+	if (error)
+		return error;
+	msleep(50);				/* T5: 50ms */
+
+	return gpiod_direction_input(ts->gpiod_int);
+}
+
+/**
+ * goodix_reset - Reset device during power on
+ *
+ * @ts: goodix_ts_data pointer
+ */
+static int goodix_reset(struct goodix_ts_data *ts)
+{
+	int error;
+
+	/* begin select I2C slave addr */
+	error = gpiod_direction_output(ts->gpiod_rst, 0);
+	if (error)
+		return error;
+	msleep(20);				/* T2: > 10ms */
+	/* HIGH: 0x28/0x29, LOW: 0xBA/0xBB */
+	error = gpiod_direction_output(ts->gpiod_int, ts->client->addr == 0x14);
+	if (error)
+		return error;
+	usleep_range(100, 2000);		/* T3: > 100us */
+	error = gpiod_direction_output(ts->gpiod_rst, 1);
+	if (error)
+		return error;
+	usleep_range(6000, 10000);		/* T4: > 5ms */
+	/* end select I2C slave addr */
+	error = gpiod_direction_input(ts->gpiod_rst);
+	if (error)
+		return error;
+	return goodix_int_sync(ts);
+}
+
+/**
+ * goodix_get_gpio_config - Get GPIO config from ACPI/DT
+ *
+ * @ts: goodix_ts_data pointer
+ */
+static int goodix_get_gpio_config(struct goodix_ts_data *ts)
+{
+	int error;
+	struct device *dev;
+	struct gpio_desc *gpiod;
+
+	if (!ts->client)
+		return -EINVAL;
+	dev = &ts->client->dev;
+
+	/* Get the interrupt GPIO pin number */
+	gpiod = devm_gpiod_get(dev, GOODIX_GPIO_INT_NAME, GPIOD_IN);
+	if (IS_ERR(gpiod)) {
+		error = PTR_ERR(gpiod);
+		if (error != -EPROBE_DEFER)
+			dev_dbg(dev, "Failed to get %s GPIO: %d\n",
+				GOODIX_GPIO_INT_NAME, error);
+		return error;
+	}
+	ts->gpiod_int = gpiod;
+
+	/* Get the reset line GPIO pin number */
+	gpiod = devm_gpiod_get(dev, GOODIX_GPIO_RST_NAME, GPIOD_IN);
+	if (IS_ERR(gpiod)) {
+		error = PTR_ERR(gpiod);
+		if (error != -EPROBE_DEFER)
+			dev_dbg(dev, "Failed to get %s GPIO: %d\n",
+				GOODIX_GPIO_RST_NAME, error);
+		return error;
+	}
+	ts->gpiod_rst = gpiod;
+
+	return 0;
+}
+
 /**
  * goodix_read_config - Read the embedded configuration of the panel
  *
@@ -405,6 +493,19 @@ static int goodix_ts_probe(struct i2c_client *client,
 	ts->client = client;
 	i2c_set_clientdata(client, ts);
 
+	error = goodix_get_gpio_config(ts);
+	if (error == -EPROBE_DEFER)
+		return error;
+
+	if (ts->gpiod_int && ts->gpiod_rst) {
+		/* reset the controller */
+		error = goodix_reset(ts);
+		if (error) {
+			dev_err(&client->dev, "Controller reset failed.\n");
+			return error;
+		}
+	}
+
 	error = goodix_i2c_test(client);
 	if (error) {
 		dev_err(&client->dev, "I2C communication failure: %d\n", error);
-- 
1.9.1

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#1244908

FromDmitry Torokhov <dmitry.torokhov@gmail.com>
Date2015-10-12 18:50 +0200
Message-ID<qiOsp-4II-3@gated-at.bofh.it>
In reply to#1244825
On Mon, Oct 12, 2015 at 06:24:30PM +0300, Irina Tirdea wrote:
> After power on, it is recommended that the driver resets the device.
> The reset procedure timing is described in the datasheet and is used
> at device init (before writing device configuration) and
> for power management. It is a sequence of setting the interrupt
> and reset pins high/low at specific timing intervals. This procedure
> also includes setting the slave address to the one specified in the
> ACPI/device tree.
> 
> This is based on Goodix datasheets for GT911 and GT9271 and on Goodix
> driver gt9xx.c for Android (publicly available in Android kernel
> trees for various devices).
> 
> For reset the driver needs to control the interrupt and
> reset gpio pins (configured through ACPI/device tree). For devices
> that do not have the gpio pins properly declared, the functionality
> depending on these pins will not be available, but the device can still
> be used with basic functionality.
> 
> For both device tree and ACPI, the interrupt gpio pin configuration is
> read from the "irq-gpio" property and the reset pin configuration is
> read from the "reset-gpio" property. For ACPI 5.1, named properties
> can be specified using the _DSD section. This functionality will not be
> available for devices that use indexed gpio pins declared in the _CRS
> section (we need to provide backward compatibility with devices
> that do not support using the interrupt gpio pin as output).
> 
> For ACPI, the pins can be specified using ACPI 5.1:
> Device (STAC)
> {
>     Name (_HID, "GDIX1001")
>     ...
> 
>     Method (_CRS, 0, Serialized)
>     {
>         Name (RBUF, ResourceTemplate ()
>         {
>             I2cSerialBus (0x0014, ControllerInitiated, 0x00061A80,
>                 AddressingMode7Bit, "\\I2C0",
>                 0x00, ResourceConsumer, ,
>                 )
> 
>             GpioInt (Edge, ActiveHigh, Exclusive, PullNone, 0x0000,
>                 "\\I2C0", 0x00, ResourceConsumer, ,
>                  )
>                  {   // Pin list
>                      0
>                  }
> 
>             GpioIo (Exclusive, PullDown, 0x0000, 0x0000,
>                 IoRestrictionOutputOnly, "\\I2C0", 0x00,
>                 ResourceConsumer, ,
>                 )
>                 {
>                      1
>                 }
>         })
>         Return (RBUF)
>     }
> 
>     Name (_DSD,  Package ()
>     {
>         ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
>         Package ()
>         {
>             Package (2) {"irq-gpio", Package() {^STAC, 0, 0, 0 }},
>             Package (2) {"reset-gpio", Package() {^STAC, 1, 0, 0 }},
>             ...
>         }
>     }
> 
> Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
> Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
> Acked-by: Bastien Nocera <hadess@hadess.net>
> Tested-by: Bastien Nocera <hadess@hadess.net>
> Tested-by: Aleksei Mamlin <mamlinav@gmail.com>
> ---
>  .../bindings/input/touchscreen/goodix.txt          |   5 +
>  drivers/input/touchscreen/Kconfig                  |   1 +
>  drivers/input/touchscreen/goodix.c                 | 101 +++++++++++++++++++++
>  3 files changed, 107 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> index 8ba98ee..7137881 100644
> --- a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> +++ b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> @@ -12,6 +12,8 @@ Required properties:
>   - reg			: I2C address of the chip. Should be 0x5d or 0x14
>   - interrupt-parent	: Interrupt controller to which the chip is connected
>   - interrupts		: Interrupt to which the chip is connected
> + - irq-gpio		: GPIO pin used for IRQ
> + - reset-gpio		: GPIO pin used for reset
>  
>  Example:
>  
> @@ -23,6 +25,9 @@ Example:
>  			reg = <0x5d>;
>  			interrupt-parent = <&gpio>;
>  			interrupts = <0 0>;
> +
> +			irq-gpio = <&gpio1 0 0>;
> +			reset-gpio = <&gpio1 1 0>;
>  		};
>  
>  		/* ... */
> diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> index 771d95c..76f5a9d 100644
> --- a/drivers/input/touchscreen/Kconfig
> +++ b/drivers/input/touchscreen/Kconfig
> @@ -324,6 +324,7 @@ config TOUCHSCREEN_FUJITSU
>  config TOUCHSCREEN_GOODIX
>  	tristate "Goodix I2C touchscreen"
>  	depends on I2C
> +	depends on GPIOLIB
>  	help
>  	  Say Y here if you have the Goodix touchscreen (such as one
>  	  installed in Onda v975w tablets) connected to your
> diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
> index 56d0330..87304ac 100644
> --- a/drivers/input/touchscreen/goodix.c
> +++ b/drivers/input/touchscreen/goodix.c
> @@ -16,6 +16,7 @@
>  
>  #include <linux/kernel.h>
>  #include <linux/dmi.h>
> +#include <linux/gpio.h>
>  #include <linux/i2c.h>
>  #include <linux/input.h>
>  #include <linux/input/mt.h>
> @@ -37,8 +38,13 @@ struct goodix_ts_data {
>  	unsigned int int_trigger_type;
>  	bool rotated_screen;
>  	int cfg_len;
> +	struct gpio_desc *gpiod_int;
> +	struct gpio_desc *gpiod_rst;
>  };
>  
> +#define GOODIX_GPIO_INT_NAME		"irq"
> +#define GOODIX_GPIO_RST_NAME		"reset"
> +
>  #define GOODIX_MAX_HEIGHT		4096
>  #define GOODIX_MAX_WIDTH		4096
>  #define GOODIX_INT_TRIGGER		1
> @@ -237,6 +243,88 @@ static irqreturn_t goodix_ts_irq_handler(int irq, void *dev_id)
>  	return IRQ_HANDLED;
>  }
>  
> +static int goodix_int_sync(struct goodix_ts_data *ts)
> +{
> +	int error;
> +
> +	error = gpiod_direction_output(ts->gpiod_int, 0);
> +	if (error)
> +		return error;
> +	msleep(50);				/* T5: 50ms */
> +
> +	return gpiod_direction_input(ts->gpiod_int);
> +}
> +
> +/**
> + * goodix_reset - Reset device during power on
> + *
> + * @ts: goodix_ts_data pointer
> + */
> +static int goodix_reset(struct goodix_ts_data *ts)
> +{
> +	int error;
> +
> +	/* begin select I2C slave addr */
> +	error = gpiod_direction_output(ts->gpiod_rst, 0);
> +	if (error)
> +		return error;
> +	msleep(20);				/* T2: > 10ms */
> +	/* HIGH: 0x28/0x29, LOW: 0xBA/0xBB */
> +	error = gpiod_direction_output(ts->gpiod_int, ts->client->addr == 0x14);
> +	if (error)
> +		return error;
> +	usleep_range(100, 2000);		/* T3: > 100us */
> +	error = gpiod_direction_output(ts->gpiod_rst, 1);
> +	if (error)
> +		return error;
> +	usleep_range(6000, 10000);		/* T4: > 5ms */
> +	/* end select I2C slave addr */
> +	error = gpiod_direction_input(ts->gpiod_rst);
> +	if (error)
> +		return error;
> +	return goodix_int_sync(ts);
> +}
> +
> +/**
> + * goodix_get_gpio_config - Get GPIO config from ACPI/DT
> + *
> + * @ts: goodix_ts_data pointer
> + */
> +static int goodix_get_gpio_config(struct goodix_ts_data *ts)
> +{
> +	int error;
> +	struct device *dev;
> +	struct gpio_desc *gpiod;
> +
> +	if (!ts->client)
> +		return -EINVAL;
> +	dev = &ts->client->dev;
> +
> +	/* Get the interrupt GPIO pin number */
> +	gpiod = devm_gpiod_get(dev, GOODIX_GPIO_INT_NAME, GPIOD_IN);

Why isn't this devm_gpiod_get_optional()? Then you would not need to
clobber the return value down in goodix_ts_probe().

I can fix it up locally.

Thanks.

-- 
Dmitry
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#1245376

From"Tirdea, Irina" <irina.tirdea@intel.com>
Date2015-10-13 08:40 +0200
Message-ID<qj1pE-6O2-13@gated-at.bofh.it>
In reply to#1244908

> -----Original Message-----
> From: Dmitry Torokhov [mailto:dmitry.torokhov@gmail.com]
> Sent: 12 October, 2015 19:48
> To: Tirdea, Irina
> Cc: Bastien Nocera; Aleksei Mamlin; Karsten Merker; linux-input@vger.kernel.org; Mark Rutland; Purdila, Octavian; linux-
> kernel@vger.kernel.org; devicetree@vger.kernel.org
> Subject: Re: [PATCH v9 2/9] Input: goodix - reset device at init
> 
> On Mon, Oct 12, 2015 at 06:24:30PM +0300, Irina Tirdea wrote:
> > After power on, it is recommended that the driver resets the device.
> > The reset procedure timing is described in the datasheet and is used
> > at device init (before writing device configuration) and
> > for power management. It is a sequence of setting the interrupt
> > and reset pins high/low at specific timing intervals. This procedure
> > also includes setting the slave address to the one specified in the
> > ACPI/device tree.
> >
> > This is based on Goodix datasheets for GT911 and GT9271 and on Goodix
> > driver gt9xx.c for Android (publicly available in Android kernel
> > trees for various devices).
> >
> > For reset the driver needs to control the interrupt and
> > reset gpio pins (configured through ACPI/device tree). For devices
> > that do not have the gpio pins properly declared, the functionality
> > depending on these pins will not be available, but the device can still
> > be used with basic functionality.
> >
> > For both device tree and ACPI, the interrupt gpio pin configuration is
> > read from the "irq-gpio" property and the reset pin configuration is
> > read from the "reset-gpio" property. For ACPI 5.1, named properties
> > can be specified using the _DSD section. This functionality will not be
> > available for devices that use indexed gpio pins declared in the _CRS
> > section (we need to provide backward compatibility with devices
> > that do not support using the interrupt gpio pin as output).
> >
> > For ACPI, the pins can be specified using ACPI 5.1:
> > Device (STAC)
> > {
> >     Name (_HID, "GDIX1001")
> >     ...
> >
> >     Method (_CRS, 0, Serialized)
> >     {
> >         Name (RBUF, ResourceTemplate ()
> >         {
> >             I2cSerialBus (0x0014, ControllerInitiated, 0x00061A80,
> >                 AddressingMode7Bit, "\\I2C0",
> >                 0x00, ResourceConsumer, ,
> >                 )
> >
> >             GpioInt (Edge, ActiveHigh, Exclusive, PullNone, 0x0000,
> >                 "\\I2C0", 0x00, ResourceConsumer, ,
> >                  )
> >                  {   // Pin list
> >                      0
> >                  }
> >
> >             GpioIo (Exclusive, PullDown, 0x0000, 0x0000,
> >                 IoRestrictionOutputOnly, "\\I2C0", 0x00,
> >                 ResourceConsumer, ,
> >                 )
> >                 {
> >                      1
> >                 }
> >         })
> >         Return (RBUF)
> >     }
> >
> >     Name (_DSD,  Package ()
> >     {
> >         ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
> >         Package ()
> >         {
> >             Package (2) {"irq-gpio", Package() {^STAC, 0, 0, 0 }},
> >             Package (2) {"reset-gpio", Package() {^STAC, 1, 0, 0 }},
> >             ...
> >         }
> >     }
> >
> > Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
> > Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
> > Acked-by: Bastien Nocera <hadess@hadess.net>
> > Tested-by: Bastien Nocera <hadess@hadess.net>
> > Tested-by: Aleksei Mamlin <mamlinav@gmail.com>
> > ---
> >  .../bindings/input/touchscreen/goodix.txt          |   5 +
> >  drivers/input/touchscreen/Kconfig                  |   1 +
> >  drivers/input/touchscreen/goodix.c                 | 101 +++++++++++++++++++++
> >  3 files changed, 107 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > index 8ba98ee..7137881 100644
> > --- a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > +++ b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > @@ -12,6 +12,8 @@ Required properties:
> >   - reg			: I2C address of the chip. Should be 0x5d or 0x14
> >   - interrupt-parent	: Interrupt controller to which the chip is connected
> >   - interrupts		: Interrupt to which the chip is connected
> > + - irq-gpio		: GPIO pin used for IRQ
> > + - reset-gpio		: GPIO pin used for reset
> >
> >  Example:
> >
> > @@ -23,6 +25,9 @@ Example:
> >  			reg = <0x5d>;
> >  			interrupt-parent = <&gpio>;
> >  			interrupts = <0 0>;
> > +
> > +			irq-gpio = <&gpio1 0 0>;
> > +			reset-gpio = <&gpio1 1 0>;
> >  		};
> >
> >  		/* ... */
> > diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> > index 771d95c..76f5a9d 100644
> > --- a/drivers/input/touchscreen/Kconfig
> > +++ b/drivers/input/touchscreen/Kconfig
> > @@ -324,6 +324,7 @@ config TOUCHSCREEN_FUJITSU
> >  config TOUCHSCREEN_GOODIX
> >  	tristate "Goodix I2C touchscreen"
> >  	depends on I2C
> > +	depends on GPIOLIB
> >  	help
> >  	  Say Y here if you have the Goodix touchscreen (such as one
> >  	  installed in Onda v975w tablets) connected to your
> > diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
> > index 56d0330..87304ac 100644
> > --- a/drivers/input/touchscreen/goodix.c
> > +++ b/drivers/input/touchscreen/goodix.c
> > @@ -16,6 +16,7 @@
> >
> >  #include <linux/kernel.h>
> >  #include <linux/dmi.h>
> > +#include <linux/gpio.h>
> >  #include <linux/i2c.h>
> >  #include <linux/input.h>
> >  #include <linux/input/mt.h>
> > @@ -37,8 +38,13 @@ struct goodix_ts_data {
> >  	unsigned int int_trigger_type;
> >  	bool rotated_screen;
> >  	int cfg_len;
> > +	struct gpio_desc *gpiod_int;
> > +	struct gpio_desc *gpiod_rst;
> >  };
> >
> > +#define GOODIX_GPIO_INT_NAME		"irq"
> > +#define GOODIX_GPIO_RST_NAME		"reset"
> > +
> >  #define GOODIX_MAX_HEIGHT		4096
> >  #define GOODIX_MAX_WIDTH		4096
> >  #define GOODIX_INT_TRIGGER		1
> > @@ -237,6 +243,88 @@ static irqreturn_t goodix_ts_irq_handler(int irq, void *dev_id)
> >  	return IRQ_HANDLED;
> >  }
> >
> > +static int goodix_int_sync(struct goodix_ts_data *ts)
> > +{
> > +	int error;
> > +
> > +	error = gpiod_direction_output(ts->gpiod_int, 0);
> > +	if (error)
> > +		return error;
> > +	msleep(50);				/* T5: 50ms */
> > +
> > +	return gpiod_direction_input(ts->gpiod_int);
> > +}
> > +
> > +/**
> > + * goodix_reset - Reset device during power on
> > + *
> > + * @ts: goodix_ts_data pointer
> > + */
> > +static int goodix_reset(struct goodix_ts_data *ts)
> > +{
> > +	int error;
> > +
> > +	/* begin select I2C slave addr */
> > +	error = gpiod_direction_output(ts->gpiod_rst, 0);
> > +	if (error)
> > +		return error;
> > +	msleep(20);				/* T2: > 10ms */
> > +	/* HIGH: 0x28/0x29, LOW: 0xBA/0xBB */
> > +	error = gpiod_direction_output(ts->gpiod_int, ts->client->addr == 0x14);
> > +	if (error)
> > +		return error;
> > +	usleep_range(100, 2000);		/* T3: > 100us */
> > +	error = gpiod_direction_output(ts->gpiod_rst, 1);
> > +	if (error)
> > +		return error;
> > +	usleep_range(6000, 10000);		/* T4: > 5ms */
> > +	/* end select I2C slave addr */
> > +	error = gpiod_direction_input(ts->gpiod_rst);
> > +	if (error)
> > +		return error;
> > +	return goodix_int_sync(ts);
> > +}
> > +
> > +/**
> > + * goodix_get_gpio_config - Get GPIO config from ACPI/DT
> > + *
> > + * @ts: goodix_ts_data pointer
> > + */
> > +static int goodix_get_gpio_config(struct goodix_ts_data *ts)
> > +{
> > +	int error;
> > +	struct device *dev;
> > +	struct gpio_desc *gpiod;
> > +
> > +	if (!ts->client)
> > +		return -EINVAL;
> > +	dev = &ts->client->dev;
> > +
> > +	/* Get the interrupt GPIO pin number */
> > +	gpiod = devm_gpiod_get(dev, GOODIX_GPIO_INT_NAME, GPIOD_IN);
> 
> Why isn't this devm_gpiod_get_optional()? Then you would not need to
> clobber the return value down in goodix_ts_probe().
> 

I did not use devm_gpiod_get_optional() in order to ignore more errors
than -ENOENT. This is needed because the ACPI gpio core will fall back
to indexed gpios if named gpios are not found. In the common case of
having 2 indexed gpio pins declared in the ACPI table, the first
devm_gpiod_get() will successfully get indexed gpio pin 0 and the
second devm_gpiod_get() will try to get the same gpio pin 0 and return
-EBUSY. Considering this, I thought it is better to just ignore all errors in
order not to break any platforms currently using this driver.

> I can fix it up locally.
> 

Sure, you can replace devm_gpiod_get with devm_gpiod_get_optional,
but the error handling code should remain the same.

Thanks,
Irina

> Thanks.
> 
> --
> Dmitry
--
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#1245394

FromDmitry Torokhov <dmitry.torokhov@gmail.com>
Date2015-10-13 09:10 +0200
Message-ID<qj1SH-7Dx-23@gated-at.bofh.it>
In reply to#1245376
On Tue, Oct 13, 2015 at 06:38:23AM +0000, Tirdea, Irina wrote:
> 
> 
> > -----Original Message-----
> > From: Dmitry Torokhov [mailto:dmitry.torokhov@gmail.com]
> > Sent: 12 October, 2015 19:48
> > To: Tirdea, Irina
> > Cc: Bastien Nocera; Aleksei Mamlin; Karsten Merker; linux-input@vger.kernel.org; Mark Rutland; Purdila, Octavian; linux-
> > kernel@vger.kernel.org; devicetree@vger.kernel.org
> > Subject: Re: [PATCH v9 2/9] Input: goodix - reset device at init
> > 
> > On Mon, Oct 12, 2015 at 06:24:30PM +0300, Irina Tirdea wrote:
> > > After power on, it is recommended that the driver resets the device.
> > > The reset procedure timing is described in the datasheet and is used
> > > at device init (before writing device configuration) and
> > > for power management. It is a sequence of setting the interrupt
> > > and reset pins high/low at specific timing intervals. This procedure
> > > also includes setting the slave address to the one specified in the
> > > ACPI/device tree.
> > >
> > > This is based on Goodix datasheets for GT911 and GT9271 and on Goodix
> > > driver gt9xx.c for Android (publicly available in Android kernel
> > > trees for various devices).
> > >
> > > For reset the driver needs to control the interrupt and
> > > reset gpio pins (configured through ACPI/device tree). For devices
> > > that do not have the gpio pins properly declared, the functionality
> > > depending on these pins will not be available, but the device can still
> > > be used with basic functionality.
> > >
> > > For both device tree and ACPI, the interrupt gpio pin configuration is
> > > read from the "irq-gpio" property and the reset pin configuration is
> > > read from the "reset-gpio" property. For ACPI 5.1, named properties
> > > can be specified using the _DSD section. This functionality will not be
> > > available for devices that use indexed gpio pins declared in the _CRS
> > > section (we need to provide backward compatibility with devices
> > > that do not support using the interrupt gpio pin as output).
> > >
> > > For ACPI, the pins can be specified using ACPI 5.1:
> > > Device (STAC)
> > > {
> > >     Name (_HID, "GDIX1001")
> > >     ...
> > >
> > >     Method (_CRS, 0, Serialized)
> > >     {
> > >         Name (RBUF, ResourceTemplate ()
> > >         {
> > >             I2cSerialBus (0x0014, ControllerInitiated, 0x00061A80,
> > >                 AddressingMode7Bit, "\\I2C0",
> > >                 0x00, ResourceConsumer, ,
> > >                 )
> > >
> > >             GpioInt (Edge, ActiveHigh, Exclusive, PullNone, 0x0000,
> > >                 "\\I2C0", 0x00, ResourceConsumer, ,
> > >                  )
> > >                  {   // Pin list
> > >                      0
> > >                  }
> > >
> > >             GpioIo (Exclusive, PullDown, 0x0000, 0x0000,
> > >                 IoRestrictionOutputOnly, "\\I2C0", 0x00,
> > >                 ResourceConsumer, ,
> > >                 )
> > >                 {
> > >                      1
> > >                 }
> > >         })
> > >         Return (RBUF)
> > >     }
> > >
> > >     Name (_DSD,  Package ()
> > >     {
> > >         ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
> > >         Package ()
> > >         {
> > >             Package (2) {"irq-gpio", Package() {^STAC, 0, 0, 0 }},
> > >             Package (2) {"reset-gpio", Package() {^STAC, 1, 0, 0 }},
> > >             ...
> > >         }
> > >     }
> > >
> > > Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
> > > Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
> > > Acked-by: Bastien Nocera <hadess@hadess.net>
> > > Tested-by: Bastien Nocera <hadess@hadess.net>
> > > Tested-by: Aleksei Mamlin <mamlinav@gmail.com>
> > > ---
> > >  .../bindings/input/touchscreen/goodix.txt          |   5 +
> > >  drivers/input/touchscreen/Kconfig                  |   1 +
> > >  drivers/input/touchscreen/goodix.c                 | 101 +++++++++++++++++++++
> > >  3 files changed, 107 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > > index 8ba98ee..7137881 100644
> > > --- a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > > +++ b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > > @@ -12,6 +12,8 @@ Required properties:
> > >   - reg			: I2C address of the chip. Should be 0x5d or 0x14
> > >   - interrupt-parent	: Interrupt controller to which the chip is connected
> > >   - interrupts		: Interrupt to which the chip is connected
> > > + - irq-gpio		: GPIO pin used for IRQ
> > > + - reset-gpio		: GPIO pin used for reset
> > >
> > >  Example:
> > >
> > > @@ -23,6 +25,9 @@ Example:
> > >  			reg = <0x5d>;
> > >  			interrupt-parent = <&gpio>;
> > >  			interrupts = <0 0>;
> > > +
> > > +			irq-gpio = <&gpio1 0 0>;
> > > +			reset-gpio = <&gpio1 1 0>;
> > >  		};
> > >
> > >  		/* ... */
> > > diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> > > index 771d95c..76f5a9d 100644
> > > --- a/drivers/input/touchscreen/Kconfig
> > > +++ b/drivers/input/touchscreen/Kconfig
> > > @@ -324,6 +324,7 @@ config TOUCHSCREEN_FUJITSU
> > >  config TOUCHSCREEN_GOODIX
> > >  	tristate "Goodix I2C touchscreen"
> > >  	depends on I2C
> > > +	depends on GPIOLIB
> > >  	help
> > >  	  Say Y here if you have the Goodix touchscreen (such as one
> > >  	  installed in Onda v975w tablets) connected to your
> > > diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
> > > index 56d0330..87304ac 100644
> > > --- a/drivers/input/touchscreen/goodix.c
> > > +++ b/drivers/input/touchscreen/goodix.c
> > > @@ -16,6 +16,7 @@
> > >
> > >  #include <linux/kernel.h>
> > >  #include <linux/dmi.h>
> > > +#include <linux/gpio.h>
> > >  #include <linux/i2c.h>
> > >  #include <linux/input.h>
> > >  #include <linux/input/mt.h>
> > > @@ -37,8 +38,13 @@ struct goodix_ts_data {
> > >  	unsigned int int_trigger_type;
> > >  	bool rotated_screen;
> > >  	int cfg_len;
> > > +	struct gpio_desc *gpiod_int;
> > > +	struct gpio_desc *gpiod_rst;
> > >  };
> > >
> > > +#define GOODIX_GPIO_INT_NAME		"irq"
> > > +#define GOODIX_GPIO_RST_NAME		"reset"
> > > +
> > >  #define GOODIX_MAX_HEIGHT		4096
> > >  #define GOODIX_MAX_WIDTH		4096
> > >  #define GOODIX_INT_TRIGGER		1
> > > @@ -237,6 +243,88 @@ static irqreturn_t goodix_ts_irq_handler(int irq, void *dev_id)
> > >  	return IRQ_HANDLED;
> > >  }
> > >
> > > +static int goodix_int_sync(struct goodix_ts_data *ts)
> > > +{
> > > +	int error;
> > > +
> > > +	error = gpiod_direction_output(ts->gpiod_int, 0);
> > > +	if (error)
> > > +		return error;
> > > +	msleep(50);				/* T5: 50ms */
> > > +
> > > +	return gpiod_direction_input(ts->gpiod_int);
> > > +}
> > > +
> > > +/**
> > > + * goodix_reset - Reset device during power on
> > > + *
> > > + * @ts: goodix_ts_data pointer
> > > + */
> > > +static int goodix_reset(struct goodix_ts_data *ts)
> > > +{
> > > +	int error;
> > > +
> > > +	/* begin select I2C slave addr */
> > > +	error = gpiod_direction_output(ts->gpiod_rst, 0);
> > > +	if (error)
> > > +		return error;
> > > +	msleep(20);				/* T2: > 10ms */
> > > +	/* HIGH: 0x28/0x29, LOW: 0xBA/0xBB */
> > > +	error = gpiod_direction_output(ts->gpiod_int, ts->client->addr == 0x14);
> > > +	if (error)
> > > +		return error;
> > > +	usleep_range(100, 2000);		/* T3: > 100us */
> > > +	error = gpiod_direction_output(ts->gpiod_rst, 1);
> > > +	if (error)
> > > +		return error;
> > > +	usleep_range(6000, 10000);		/* T4: > 5ms */
> > > +	/* end select I2C slave addr */
> > > +	error = gpiod_direction_input(ts->gpiod_rst);
> > > +	if (error)
> > > +		return error;
> > > +	return goodix_int_sync(ts);
> > > +}
> > > +
> > > +/**
> > > + * goodix_get_gpio_config - Get GPIO config from ACPI/DT
> > > + *
> > > + * @ts: goodix_ts_data pointer
> > > + */
> > > +static int goodix_get_gpio_config(struct goodix_ts_data *ts)
> > > +{
> > > +	int error;
> > > +	struct device *dev;
> > > +	struct gpio_desc *gpiod;
> > > +
> > > +	if (!ts->client)
> > > +		return -EINVAL;
> > > +	dev = &ts->client->dev;
> > > +
> > > +	/* Get the interrupt GPIO pin number */
> > > +	gpiod = devm_gpiod_get(dev, GOODIX_GPIO_INT_NAME, GPIOD_IN);
> > 
> > Why isn't this devm_gpiod_get_optional()? Then you would not need to
> > clobber the return value down in goodix_ts_probe().
> > 
> 
> I did not use devm_gpiod_get_optional() in order to ignore more errors
> than -ENOENT. This is needed because the ACPI gpio core will fall back
> to indexed gpios if named gpios are not found. In the common case of
> having 2 indexed gpio pins declared in the ACPI table, the first
> devm_gpiod_get() will successfully get indexed gpio pin 0 and the
> second devm_gpiod_get() will try to get the same gpio pin 0 and return
> -EBUSY. Considering this, I thought it is better to just ignore all errors in
> order not to break any platforms currently using this driver.

This seems like issue with ACPI gpio lookup implementation. If I am
requesting named gpio and it is not present then I definitely do not
need to be returned some random gpio. Doing so breaks all other drivers
that use several names to retrieve GPIOs. We basically can't trust GPIO
API on ACPI systems.

I can see why we wanted to provide unnamed gpios even in presence of
con_id, but it does not work when using several names. I wonder if
acpi_find_gpio will have to keep track of state (requested names) and
stop falling back to unnamed gpios if more than one con_id was suppolied
for the same object.

Thanks.

-- 
Dmitry
--
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#1245476

From"Tirdea, Irina" <irina.tirdea@intel.com>
Date2015-10-13 11:00 +0200
Message-ID<qj3B8-1vR-13@gated-at.bofh.it>
In reply to#1245394

> -----Original Message-----
> From: Dmitry Torokhov [mailto:dmitry.torokhov@gmail.com]
> Sent: 13 October, 2015 10:08
> To: Tirdea, Irina
> Cc: Bastien Nocera; Aleksei Mamlin; Karsten Merker; linux-input@vger.kernel.org; Mark Rutland; Purdila, Octavian; linux-
> kernel@vger.kernel.org; devicetree@vger.kernel.org
> Subject: Re: [PATCH v9 2/9] Input: goodix - reset device at init
> 
> On Tue, Oct 13, 2015 at 06:38:23AM +0000, Tirdea, Irina wrote:
> >
> >
> > > -----Original Message-----
> > > From: Dmitry Torokhov [mailto:dmitry.torokhov@gmail.com]
> > > Sent: 12 October, 2015 19:48
> > > To: Tirdea, Irina
> > > Cc: Bastien Nocera; Aleksei Mamlin; Karsten Merker; linux-input@vger.kernel.org; Mark Rutland; Purdila, Octavian; linux-
> > > kernel@vger.kernel.org; devicetree@vger.kernel.org
> > > Subject: Re: [PATCH v9 2/9] Input: goodix - reset device at init
> > >
> > > On Mon, Oct 12, 2015 at 06:24:30PM +0300, Irina Tirdea wrote:
> > > > After power on, it is recommended that the driver resets the device.
> > > > The reset procedure timing is described in the datasheet and is used
> > > > at device init (before writing device configuration) and
> > > > for power management. It is a sequence of setting the interrupt
> > > > and reset pins high/low at specific timing intervals. This procedure
> > > > also includes setting the slave address to the one specified in the
> > > > ACPI/device tree.
> > > >
> > > > This is based on Goodix datasheets for GT911 and GT9271 and on Goodix
> > > > driver gt9xx.c for Android (publicly available in Android kernel
> > > > trees for various devices).
> > > >
> > > > For reset the driver needs to control the interrupt and
> > > > reset gpio pins (configured through ACPI/device tree). For devices
> > > > that do not have the gpio pins properly declared, the functionality
> > > > depending on these pins will not be available, but the device can still
> > > > be used with basic functionality.
> > > >
> > > > For both device tree and ACPI, the interrupt gpio pin configuration is
> > > > read from the "irq-gpio" property and the reset pin configuration is
> > > > read from the "reset-gpio" property. For ACPI 5.1, named properties
> > > > can be specified using the _DSD section. This functionality will not be
> > > > available for devices that use indexed gpio pins declared in the _CRS
> > > > section (we need to provide backward compatibility with devices
> > > > that do not support using the interrupt gpio pin as output).
> > > >
> > > > For ACPI, the pins can be specified using ACPI 5.1:
> > > > Device (STAC)
> > > > {
> > > >     Name (_HID, "GDIX1001")
> > > >     ...
> > > >
> > > >     Method (_CRS, 0, Serialized)
> > > >     {
> > > >         Name (RBUF, ResourceTemplate ()
> > > >         {
> > > >             I2cSerialBus (0x0014, ControllerInitiated, 0x00061A80,
> > > >                 AddressingMode7Bit, "\\I2C0",
> > > >                 0x00, ResourceConsumer, ,
> > > >                 )
> > > >
> > > >             GpioInt (Edge, ActiveHigh, Exclusive, PullNone, 0x0000,
> > > >                 "\\I2C0", 0x00, ResourceConsumer, ,
> > > >                  )
> > > >                  {   // Pin list
> > > >                      0
> > > >                  }
> > > >
> > > >             GpioIo (Exclusive, PullDown, 0x0000, 0x0000,
> > > >                 IoRestrictionOutputOnly, "\\I2C0", 0x00,
> > > >                 ResourceConsumer, ,
> > > >                 )
> > > >                 {
> > > >                      1
> > > >                 }
> > > >         })
> > > >         Return (RBUF)
> > > >     }
> > > >
> > > >     Name (_DSD,  Package ()
> > > >     {
> > > >         ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
> > > >         Package ()
> > > >         {
> > > >             Package (2) {"irq-gpio", Package() {^STAC, 0, 0, 0 }},
> > > >             Package (2) {"reset-gpio", Package() {^STAC, 1, 0, 0 }},
> > > >             ...
> > > >         }
> > > >     }
> > > >
> > > > Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
> > > > Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
> > > > Acked-by: Bastien Nocera <hadess@hadess.net>
> > > > Tested-by: Bastien Nocera <hadess@hadess.net>
> > > > Tested-by: Aleksei Mamlin <mamlinav@gmail.com>
> > > > ---
> > > >  .../bindings/input/touchscreen/goodix.txt          |   5 +
> > > >  drivers/input/touchscreen/Kconfig                  |   1 +
> > > >  drivers/input/touchscreen/goodix.c                 | 101 +++++++++++++++++++++
> > > >  3 files changed, 107 insertions(+)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > > b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > > > index 8ba98ee..7137881 100644
> > > > --- a/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > > > +++ b/Documentation/devicetree/bindings/input/touchscreen/goodix.txt
> > > > @@ -12,6 +12,8 @@ Required properties:
> > > >   - reg			: I2C address of the chip. Should be 0x5d or 0x14
> > > >   - interrupt-parent	: Interrupt controller to which the chip is connected
> > > >   - interrupts		: Interrupt to which the chip is connected
> > > > + - irq-gpio		: GPIO pin used for IRQ
> > > > + - reset-gpio		: GPIO pin used for reset
> > > >
> > > >  Example:
> > > >
> > > > @@ -23,6 +25,9 @@ Example:
> > > >  			reg = <0x5d>;
> > > >  			interrupt-parent = <&gpio>;
> > > >  			interrupts = <0 0>;
> > > > +
> > > > +			irq-gpio = <&gpio1 0 0>;
> > > > +			reset-gpio = <&gpio1 1 0>;
> > > >  		};
> > > >
> > > >  		/* ... */
> > > > diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
> > > > index 771d95c..76f5a9d 100644
> > > > --- a/drivers/input/touchscreen/Kconfig
> > > > +++ b/drivers/input/touchscreen/Kconfig
> > > > @@ -324,6 +324,7 @@ config TOUCHSCREEN_FUJITSU
> > > >  config TOUCHSCREEN_GOODIX
> > > >  	tristate "Goodix I2C touchscreen"
> > > >  	depends on I2C
> > > > +	depends on GPIOLIB
> > > >  	help
> > > >  	  Say Y here if you have the Goodix touchscreen (such as one
> > > >  	  installed in Onda v975w tablets) connected to your
> > > > diff --git a/drivers/input/touchscreen/goodix.c b/drivers/input/touchscreen/goodix.c
> > > > index 56d0330..87304ac 100644
> > > > --- a/drivers/input/touchscreen/goodix.c
> > > > +++ b/drivers/input/touchscreen/goodix.c
> > > > @@ -16,6 +16,7 @@
> > > >
> > > >  #include <linux/kernel.h>
> > > >  #include <linux/dmi.h>
> > > > +#include <linux/gpio.h>
> > > >  #include <linux/i2c.h>
> > > >  #include <linux/input.h>
> > > >  #include <linux/input/mt.h>
> > > > @@ -37,8 +38,13 @@ struct goodix_ts_data {
> > > >  	unsigned int int_trigger_type;
> > > >  	bool rotated_screen;
> > > >  	int cfg_len;
> > > > +	struct gpio_desc *gpiod_int;
> > > > +	struct gpio_desc *gpiod_rst;
> > > >  };
> > > >
> > > > +#define GOODIX_GPIO_INT_NAME		"irq"
> > > > +#define GOODIX_GPIO_RST_NAME		"reset"
> > > > +
> > > >  #define GOODIX_MAX_HEIGHT		4096
> > > >  #define GOODIX_MAX_WIDTH		4096
> > > >  #define GOODIX_INT_TRIGGER		1
> > > > @@ -237,6 +243,88 @@ static irqreturn_t goodix_ts_irq_handler(int irq, void *dev_id)
> > > >  	return IRQ_HANDLED;
> > > >  }
> > > >
> > > > +static int goodix_int_sync(struct goodix_ts_data *ts)
> > > > +{
> > > > +	int error;
> > > > +
> > > > +	error = gpiod_direction_output(ts->gpiod_int, 0);
> > > > +	if (error)
> > > > +		return error;
> > > > +	msleep(50);				/* T5: 50ms */
> > > > +
> > > > +	return gpiod_direction_input(ts->gpiod_int);
> > > > +}
> > > > +
> > > > +/**
> > > > + * goodix_reset - Reset device during power on
> > > > + *
> > > > + * @ts: goodix_ts_data pointer
> > > > + */
> > > > +static int goodix_reset(struct goodix_ts_data *ts)
> > > > +{
> > > > +	int error;
> > > > +
> > > > +	/* begin select I2C slave addr */
> > > > +	error = gpiod_direction_output(ts->gpiod_rst, 0);
> > > > +	if (error)
> > > > +		return error;
> > > > +	msleep(20);				/* T2: > 10ms */
> > > > +	/* HIGH: 0x28/0x29, LOW: 0xBA/0xBB */
> > > > +	error = gpiod_direction_output(ts->gpiod_int, ts->client->addr == 0x14);
> > > > +	if (error)
> > > > +		return error;
> > > > +	usleep_range(100, 2000);		/* T3: > 100us */
> > > > +	error = gpiod_direction_output(ts->gpiod_rst, 1);
> > > > +	if (error)
> > > > +		return error;
> > > > +	usleep_range(6000, 10000);		/* T4: > 5ms */
> > > > +	/* end select I2C slave addr */
> > > > +	error = gpiod_direction_input(ts->gpiod_rst);
> > > > +	if (error)
> > > > +		return error;
> > > > +	return goodix_int_sync(ts);
> > > > +}
> > > > +
> > > > +/**
> > > > + * goodix_get_gpio_config - Get GPIO config from ACPI/DT
> > > > + *
> > > > + * @ts: goodix_ts_data pointer
> > > > + */
> > > > +static int goodix_get_gpio_config(struct goodix_ts_data *ts)
> > > > +{
> > > > +	int error;
> > > > +	struct device *dev;
> > > > +	struct gpio_desc *gpiod;
> > > > +
> > > > +	if (!ts->client)
> > > > +		return -EINVAL;
> > > > +	dev = &ts->client->dev;
> > > > +
> > > > +	/* Get the interrupt GPIO pin number */
> > > > +	gpiod = devm_gpiod_get(dev, GOODIX_GPIO_INT_NAME, GPIOD_IN);
> > >
> > > Why isn't this devm_gpiod_get_optional()? Then you would not need to
> > > clobber the return value down in goodix_ts_probe().
> > >
> >
> > I did not use devm_gpiod_get_optional() in order to ignore more errors
> > than -ENOENT. This is needed because the ACPI gpio core will fall back
> > to indexed gpios if named gpios are not found. In the common case of
> > having 2 indexed gpio pins declared in the ACPI table, the first
> > devm_gpiod_get() will successfully get indexed gpio pin 0 and the
> > second devm_gpiod_get() will try to get the same gpio pin 0 and return
> > -EBUSY. Considering this, I thought it is better to just ignore all errors in
> > order not to break any platforms currently using this driver.
> 
> This seems like issue with ACPI gpio lookup implementation. If I am
> requesting named gpio and it is not present then I definitely do not
> need to be returned some random gpio. Doing so breaks all other drivers
> that use several names to retrieve GPIOs. We basically can't trust GPIO
> API on ACPI systems.
> 

I'm not sure there is a way to avoid fall back to indexed gpios when requesting
named gpios.
Adding Mika to this thread as he might help answer this.

> I can see why we wanted to provide unnamed gpios even in presence of
> con_id, but it does not work when using several names. I wonder if
> acpi_find_gpio will have to keep track of state (requested names) and
> stop falling back to unnamed gpios if more than one con_id was suppolied
> for the same object.
> 

For devices that need to support more than one named gpio, the driver has
to declare an acpi_gpio_mapping structure (that maps names to indexed gpios)
and register it with acpi_dev_add_driver_gpios [1].

I have actually implemented this in v7 of this patchset [2], before finding
out that the platforms Bastien was testing with do not support writing to the
interrupt pin. In order to avoid adding exceptions to the driver through dmi
quirks, the gpio dependent functionality is available only to devices that
declare named gpios.

Thanks,
Irina

[1] http://lxr.free-electrons.com/source/Documentation/acpi/gpio-properties.txt
[2] https://lkml.org/lkml/2015/10/8/222

> Thanks.
> 
> --
> Dmitry
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#1245529

From"mika.westerberg@linux.intel.com" <mika.westerberg@linux.intel.com>
Date2015-10-13 12:10 +0200
Message-ID<qj4GS-3km-17@gated-at.bofh.it>
In reply to#1245476
On Tue, Oct 13, 2015 at 08:54:12AM +0000, Tirdea, Irina wrote:
> > > I did not use devm_gpiod_get_optional() in order to ignore more errors
> > > than -ENOENT. This is needed because the ACPI gpio core will fall back
> > > to indexed gpios if named gpios are not found. In the common case of
> > > having 2 indexed gpio pins declared in the ACPI table, the first
> > > devm_gpiod_get() will successfully get indexed gpio pin 0 and the
> > > second devm_gpiod_get() will try to get the same gpio pin 0 and return
> > > -EBUSY. Considering this, I thought it is better to just ignore all errors in
> > > order not to break any platforms currently using this driver.
> > 
> > This seems like issue with ACPI gpio lookup implementation. If I am
> > requesting named gpio and it is not present then I definitely do not
> > need to be returned some random gpio. Doing so breaks all other drivers
> > that use several names to retrieve GPIOs. We basically can't trust GPIO
> > API on ACPI systems.
> > 
> 
> I'm not sure there is a way to avoid fall back to indexed gpios when requesting
> named gpios.
> Adding Mika to this thread as he might help answer this.

Before ACPI 5.1 _DSD device properties were introduced all we had was an
array of GPIOs returned by _CRS ACPI method. Ordering of those GPIOs
could change from one vendor to another :-(

We can (and do) use acpi_dev_add_driver_gpios() to pass correct mappings
where _DSD is not present based on the device ACPI ID for instance. Not
all drivers do that, though.

I would like to get rid of the fallback completely at some point. We
have had already problems with the API because then some ACPI only
drivers did this:

	reset_gpio = gpiod_get_index(dev, NULL, 0);
	power_gpio = gpiod_get_index(dev, NULL, 1);

which might not do what is expected on DT systems. That's why
acpi_dev_add_driver_gpios() was added in the first place IIRC.
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#1246323

FromDmitry Torokhov <dmitry.torokhov@gmail.com>
Date2015-10-14 08:30 +0200
Message-ID<qjnJw-6X9-17@gated-at.bofh.it>
In reply to#1245529
On Tue, Oct 13, 2015 at 01:07:24PM +0300, mika.westerberg@linux.intel.com wrote:
> On Tue, Oct 13, 2015 at 08:54:12AM +0000, Tirdea, Irina wrote:
> > > > I did not use devm_gpiod_get_optional() in order to ignore more errors
> > > > than -ENOENT. This is needed because the ACPI gpio core will fall back
> > > > to indexed gpios if named gpios are not found. In the common case of
> > > > having 2 indexed gpio pins declared in the ACPI table, the first
> > > > devm_gpiod_get() will successfully get indexed gpio pin 0 and the
> > > > second devm_gpiod_get() will try to get the same gpio pin 0 and return
> > > > -EBUSY. Considering this, I thought it is better to just ignore all errors in
> > > > order not to break any platforms currently using this driver.
> > > 
> > > This seems like issue with ACPI gpio lookup implementation. If I am
> > > requesting named gpio and it is not present then I definitely do not
> > > need to be returned some random gpio. Doing so breaks all other drivers
> > > that use several names to retrieve GPIOs. We basically can't trust GPIO
> > > API on ACPI systems.
> > > 
> > 
> > I'm not sure there is a way to avoid fall back to indexed gpios when requesting
> > named gpios.
> > Adding Mika to this thread as he might help answer this.
> 
> Before ACPI 5.1 _DSD device properties were introduced all we had was an
> array of GPIOs returned by _CRS ACPI method. Ordering of those GPIOs
> could change from one vendor to another :-(
> 
> We can (and do) use acpi_dev_add_driver_gpios() to pass correct mappings
> where _DSD is not present based on the device ACPI ID for instance. Not
> all drivers do that, though.
> 
> I would like to get rid of the fallback completely at some point. We
> have had already problems with the API because then some ACPI only
> drivers did this:
> 
> 	reset_gpio = gpiod_get_index(dev, NULL, 0);
> 	power_gpio = gpiod_get_index(dev, NULL, 1);
> 
> which might not do what is expected on DT systems. That's why
> acpi_dev_add_driver_gpios() was added in the first place IIRC.

I understand why one might use acpi_dev_add_driver_gpios() to augment
data in ACPI, however here we have completely different issue: driver
that expects named gpios gets returned gpio that has nothing to do with
what it requested, because gpiolib acpi code always falls back to
unnamed gpio if it does not find named gpio. That can be acceptable if
driver uses the same con_id for all requests to gpiolib, but is not
working when driver supplies different con_ids.

Thanks.

-- 
Dmitry
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#1246540

From"mika.westerberg@linux.intel.com" <mika.westerberg@linux.intel.com>
Date2015-10-14 13:30 +0200
Message-ID<qjspQ-5qz-11@gated-at.bofh.it>
In reply to#1246323
On Tue, Oct 13, 2015 at 11:23:03PM -0700, Dmitry Torokhov wrote:
> I understand why one might use acpi_dev_add_driver_gpios() to augment
> data in ACPI, however here we have completely different issue: driver
> that expects named gpios gets returned gpio that has nothing to do with
> what it requested, because gpiolib acpi code always falls back to
> unnamed gpio if it does not find named gpio. That can be acceptable if
> driver uses the same con_id for all requests to gpiolib, but is not
> working when driver supplies different con_ids.

Right, the ACPI fallback ignores con_id completely and uses only the
index.

AFAIK there is only one driver using ACPI _CRS index method:
sdhci-[acpi|pci].c. If we can convert that to use acpi_dev_add_driver_gpios()
to feed names for card detection GPIOs, I think we can remove the
fallback alltogether in favor of named GPIOs for ACPI.
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#1246761

From"mika.westerberg@linux.intel.com" <mika.westerberg@linux.intel.com>
Date2015-10-14 15:50 +0200
Message-ID<qjuBk-8B-17@gated-at.bofh.it>
In reply to#1246540
On Wed, Oct 14, 2015 at 02:18:20PM +0300, mika.westerberg@linux.intel.com wrote:
> On Tue, Oct 13, 2015 at 11:23:03PM -0700, Dmitry Torokhov wrote:
> > I understand why one might use acpi_dev_add_driver_gpios() to augment
> > data in ACPI, however here we have completely different issue: driver
> > that expects named gpios gets returned gpio that has nothing to do with
> > what it requested, because gpiolib acpi code always falls back to
> > unnamed gpio if it does not find named gpio. That can be acceptable if
> > driver uses the same con_id for all requests to gpiolib, but is not
> > working when driver supplies different con_ids.
> 
> Right, the ACPI fallback ignores con_id completely and uses only the
> index.
> 
> AFAIK there is only one driver using ACPI _CRS index method:
> sdhci-[acpi|pci].c. If we can convert that to use acpi_dev_add_driver_gpios()
> to feed names for card detection GPIOs, I think we can remove the
> fallback alltogether in favor of named GPIOs for ACPI.

Nah, there seems to be several drivers relying on this already :-/
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