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Groups > linux.kernel > #1378878 > unrolled thread

[PATCH] i2c: designware-platdrv: implement bus recovery

Started byJisheng Zhang <jszhang@marvell.com>
First post2016-04-14 16:10 +0200
Last post2016-04-14 19:40 +0200
Articles 7 — 4 participants

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Contents

  [PATCH] i2c: designware-platdrv: implement bus recovery Jisheng Zhang <jszhang@marvell.com> - 2016-04-14 16:10 +0200
    Re: [PATCH] i2c: designware-platdrv: implement bus recovery Mika Westerberg <mika.westerberg@linux.intel.com> - 2016-04-14 16:40 +0200
      Re: [PATCH] i2c: designware-platdrv: implement bus recovery Martinez Kristofer <kristofer.s.martinez@gmail.com> - 2016-04-14 17:00 +0200
      Re: [PATCH] i2c: designware-platdrv: implement bus recovery Jisheng Zhang <jszhang@marvell.com> - 2016-04-15 08:20 +0200
        Re: [PATCH] i2c: designware-platdrv: implement bus recovery Mika Westerberg <mika.westerberg@linux.intel.com> - 2016-04-15 09:10 +0200
          Re: [PATCH] i2c: designware-platdrv: implement bus recovery Jisheng Zhang <jszhang@marvell.com> - 2016-04-15 09:40 +0200
    Re: [PATCH] i2c: designware-platdrv: implement bus recovery Rob Herring <robh@kernel.org> - 2016-04-14 19:40 +0200

#1378878 — [PATCH] i2c: designware-platdrv: implement bus recovery

FromJisheng Zhang <jszhang@marvell.com>
Date2016-04-14 16:10 +0200
Subject[PATCH] i2c: designware-platdrv: implement bus recovery
Message-ID<rnQ82-2QW-9@gated-at.bofh.it>
Implement bus recovery methods for i2c designware so we can recover
from situations where SCL/SDA are stuck low.

The recovery method is similar as i2c-imx: "config the i2c pinctrl to
gpio mode by calling pinctrl sleep set function, and then use GPIO to
emulate the i2c protocol to send nine dummy clock to recover i2c
device. After recovery, set i2c pinctrl to default group setting.

Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
---
depends on runtime pm patches
http://lists.infradead.org/pipermail/linux-arm-kernel/2016-April/422202.html
 .../devicetree/bindings/i2c/i2c-designware.txt     | 12 ++++++
 drivers/i2c/busses/i2c-designware-core.c           |  6 ++-
 drivers/i2c/busses/i2c-designware-core.h           |  4 ++
 drivers/i2c/busses/i2c-designware-platdrv.c        | 50 ++++++++++++++++++++++
 4 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
index fee26dc..51a55c6 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
@@ -20,6 +20,13 @@ Optional properties :
  - i2c-sda-falling-time-ns : should contain the SDA falling time in nanoseconds.
    This value which is by default 300ns is used to compute the tHIGH period.
 
+ - scl-gpios: specify the gpio related to SCL pin
+
+ - sda-gpios: specify the gpio related to SDA pin
+
+ - pinctrl: add extra pinctrl to configure i2c pins to gpio function for i2c
+   bus recovery, call it "gpio" state
+
 Example :
 
 	i2c@f0000 {
@@ -42,4 +49,9 @@ Example :
 		i2c-sda-hold-time-ns = <300>;
 		i2c-sda-falling-time-ns = <300>;
 		i2c-scl-falling-time-ns = <300>;
+		pinctrl-names = "default", "gpio";
+		pinctrl-0 = <&pinctrl_i2c1_default>;
+		pinctrl-1 = <&pinctrl_i2c1_gpio>;
+		scl-gpios = <&porta 26 GPIO_ACTIVE_HIGH>;
+		sda-gpios = <&porta 27 GPIO_ACTIVE_HIGH>;
 	};
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index 4255eaa..be40de1 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -399,7 +399,10 @@ static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
 	while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
 		if (timeout <= 0) {
 			dev_warn(dev->dev, "timeout waiting for bus ready\n");
-			return -ETIMEDOUT;
+			i2c_recover_bus(&dev->adapter);
+			if (dw_readl(dev, DW_IC_STATUS)
+					& DW_IC_STATUS_ACTIVITY)
+				return -ETIMEDOUT;
 		}
 		timeout--;
 		usleep_range(1000, 1100);
@@ -665,6 +668,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 	/* wait for tx to complete */
 	if (!wait_for_completion_timeout(&dev->cmd_complete, HZ)) {
 		dev_err(dev->dev, "controller timed out\n");
+		i2c_recover_bus(&dev->adapter);
 		/* i2c_dw_init implicitly disables the adapter */
 		i2c_dw_init(dev);
 		ret = -ETIMEDOUT;
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index cd409e7..26c84ee 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -104,6 +104,10 @@ struct dw_i2c_dev {
 	u16			fs_lcnt;
 	int			(*acquire_lock)(struct dw_i2c_dev *dev);
 	void			(*release_lock)(struct dw_i2c_dev *dev);
+	struct i2c_bus_recovery_info rinfo;
+	struct pinctrl		*pinctrl;
+	struct pinctrl_state	*pinctrl_pins_default;
+	struct pinctrl_state	*pinctrl_pins_gpio;
 	bool			pm_runtime_disabled;
 };
 
diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 1488cea..62bded9 100644
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -33,6 +33,7 @@
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/of.h>
+#include <linux/of_gpio.h>
 #include <linux/platform_device.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
@@ -148,6 +149,49 @@ static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare)
 	return 0;
 }
 
+static void i2c_dw_plat_prepare_recovery(struct i2c_adapter *adap)
+{
+	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
+
+	pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_gpio);
+}
+
+static void i2c_dw_plat_unprepare_recovery(struct i2c_adapter *adap)
+{
+	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
+
+	pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_default);
+}
+
+static void i2c_dw_plat_init_recovery_info(struct dw_i2c_dev *dev,
+					   struct platform_device *pdev)
+{
+	struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
+
+	dev->pinctrl_pins_default = pinctrl_lookup_state(dev->pinctrl,
+			PINCTRL_STATE_DEFAULT);
+	dev->pinctrl_pins_gpio = pinctrl_lookup_state(dev->pinctrl,
+			"gpio");
+	rinfo->sda_gpio = of_get_named_gpio(pdev->dev.of_node, "sda-gpios", 0);
+	rinfo->scl_gpio = of_get_named_gpio(pdev->dev.of_node, "scl-gpios", 0);
+
+	if (!gpio_is_valid(rinfo->sda_gpio) ||
+	    !gpio_is_valid(rinfo->scl_gpio) ||
+	    IS_ERR(dev->pinctrl_pins_default) ||
+	    IS_ERR(dev->pinctrl_pins_gpio)) {
+		dev_dbg(&pdev->dev, "recovery information incomplete\n");
+		return;
+	}
+
+	dev_dbg(&pdev->dev, "using scl-gpio %d and sda-gpio %d for recovery\n",
+		rinfo->sda_gpio, rinfo->scl_gpio);
+
+	rinfo->prepare_recovery = i2c_dw_plat_prepare_recovery;
+	rinfo->unprepare_recovery = i2c_dw_plat_unprepare_recovery;
+	rinfo->recover_bus = i2c_generic_gpio_recovery;
+	dev->adapter.bus_recovery_info = rinfo;
+}
+
 static int dw_i2c_plat_probe(struct platform_device *pdev)
 {
 	struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
@@ -165,6 +209,12 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
 	if (!dev)
 		return -ENOMEM;
 
+	dev->pinctrl = devm_pinctrl_get(&pdev->dev);
+	if (IS_ERR(dev->pinctrl))
+		return PTR_ERR(dev->pinctrl);
+
+	i2c_dw_plat_init_recovery_info(dev, pdev);
+
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	dev->base = devm_ioremap_resource(&pdev->dev, mem);
 	if (IS_ERR(dev->base))
-- 
2.8.0.rc3

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#1378952

FromMika Westerberg <mika.westerberg@linux.intel.com>
Date2016-04-14 16:40 +0200
Message-ID<rnQB5-33W-51@gated-at.bofh.it>
In reply to#1378878
On Thu, Apr 14, 2016 at 10:04:56PM +0800, Jisheng Zhang wrote:
> Implement bus recovery methods for i2c designware so we can recover
> from situations where SCL/SDA are stuck low.
> 
> The recovery method is similar as i2c-imx: "config the i2c pinctrl to
> gpio mode by calling pinctrl sleep set function, and then use GPIO to
> emulate the i2c protocol to send nine dummy clock to recover i2c
> device. After recovery, set i2c pinctrl to default group setting.
> 
> Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
> ---
> depends on runtime pm patches
> http://lists.infradead.org/pipermail/linux-arm-kernel/2016-April/422202.html
>  .../devicetree/bindings/i2c/i2c-designware.txt     | 12 ++++++
>  drivers/i2c/busses/i2c-designware-core.c           |  6 ++-
>  drivers/i2c/busses/i2c-designware-core.h           |  4 ++
>  drivers/i2c/busses/i2c-designware-platdrv.c        | 50 ++++++++++++++++++++++
>  4 files changed, 71 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> index fee26dc..51a55c6 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> @@ -20,6 +20,13 @@ Optional properties :
>   - i2c-sda-falling-time-ns : should contain the SDA falling time in nanoseconds.
>     This value which is by default 300ns is used to compute the tHIGH period.
>  
> + - scl-gpios: specify the gpio related to SCL pin
> +
> + - sda-gpios: specify the gpio related to SDA pin
> +
> + - pinctrl: add extra pinctrl to configure i2c pins to gpio function for i2c
> +   bus recovery, call it "gpio" state
> +
>  Example :
>  
>  	i2c@f0000 {
> @@ -42,4 +49,9 @@ Example :
>  		i2c-sda-hold-time-ns = <300>;
>  		i2c-sda-falling-time-ns = <300>;
>  		i2c-scl-falling-time-ns = <300>;
> +		pinctrl-names = "default", "gpio";
> +		pinctrl-0 = <&pinctrl_i2c1_default>;
> +		pinctrl-1 = <&pinctrl_i2c1_gpio>;
> +		scl-gpios = <&porta 26 GPIO_ACTIVE_HIGH>;
> +		sda-gpios = <&porta 27 GPIO_ACTIVE_HIGH>;
>  	};
> diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
> index 4255eaa..be40de1 100644
> --- a/drivers/i2c/busses/i2c-designware-core.c
> +++ b/drivers/i2c/busses/i2c-designware-core.c
> @@ -399,7 +399,10 @@ static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
>  	while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
>  		if (timeout <= 0) {
>  			dev_warn(dev->dev, "timeout waiting for bus ready\n");
> -			return -ETIMEDOUT;
> +			i2c_recover_bus(&dev->adapter);
> +			if (dw_readl(dev, DW_IC_STATUS)
> +					& DW_IC_STATUS_ACTIVITY)
> +				return -ETIMEDOUT;
>  		}
>  		timeout--;
>  		usleep_range(1000, 1100);
> @@ -665,6 +668,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
>  	/* wait for tx to complete */
>  	if (!wait_for_completion_timeout(&dev->cmd_complete, HZ)) {
>  		dev_err(dev->dev, "controller timed out\n");
> +		i2c_recover_bus(&dev->adapter);
>  		/* i2c_dw_init implicitly disables the adapter */
>  		i2c_dw_init(dev);
>  		ret = -ETIMEDOUT;
> diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
> index cd409e7..26c84ee 100644
> --- a/drivers/i2c/busses/i2c-designware-core.h
> +++ b/drivers/i2c/busses/i2c-designware-core.h
> @@ -104,6 +104,10 @@ struct dw_i2c_dev {
>  	u16			fs_lcnt;
>  	int			(*acquire_lock)(struct dw_i2c_dev *dev);
>  	void			(*release_lock)(struct dw_i2c_dev *dev);
> +	struct i2c_bus_recovery_info rinfo;
> +	struct pinctrl		*pinctrl;
> +	struct pinctrl_state	*pinctrl_pins_default;
> +	struct pinctrl_state	*pinctrl_pins_gpio;
>  	bool			pm_runtime_disabled;
>  };
>  
> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
> index 1488cea..62bded9 100644
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -33,6 +33,7 @@
>  #include <linux/err.h>
>  #include <linux/interrupt.h>
>  #include <linux/of.h>
> +#include <linux/of_gpio.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm.h>
>  #include <linux/pm_runtime.h>
> @@ -148,6 +149,49 @@ static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare)
>  	return 0;
>  }
>  
> +static void i2c_dw_plat_prepare_recovery(struct i2c_adapter *adap)
> +{
> +	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
> +
> +	pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_gpio);
> +}
> +
> +static void i2c_dw_plat_unprepare_recovery(struct i2c_adapter *adap)
> +{
> +	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
> +
> +	pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_default);
> +}
> +
> +static void i2c_dw_plat_init_recovery_info(struct dw_i2c_dev *dev,
> +					   struct platform_device *pdev)
> +{
> +	struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
> +
> +	dev->pinctrl_pins_default = pinctrl_lookup_state(dev->pinctrl,
> +			PINCTRL_STATE_DEFAULT);
> +	dev->pinctrl_pins_gpio = pinctrl_lookup_state(dev->pinctrl,
> +			"gpio");
> +	rinfo->sda_gpio = of_get_named_gpio(pdev->dev.of_node, "sda-gpios", 0);
> +	rinfo->scl_gpio = of_get_named_gpio(pdev->dev.of_node, "scl-gpios", 0);
> +
> +	if (!gpio_is_valid(rinfo->sda_gpio) ||
> +	    !gpio_is_valid(rinfo->scl_gpio) ||
> +	    IS_ERR(dev->pinctrl_pins_default) ||
> +	    IS_ERR(dev->pinctrl_pins_gpio)) {
> +		dev_dbg(&pdev->dev, "recovery information incomplete\n");
> +		return;
> +	}
> +
> +	dev_dbg(&pdev->dev, "using scl-gpio %d and sda-gpio %d for recovery\n",
> +		rinfo->sda_gpio, rinfo->scl_gpio);
> +
> +	rinfo->prepare_recovery = i2c_dw_plat_prepare_recovery;
> +	rinfo->unprepare_recovery = i2c_dw_plat_unprepare_recovery;
> +	rinfo->recover_bus = i2c_generic_gpio_recovery;

This whole thing is DT specific and I don't see how we can do the same
for ACPI. Should it be enabled only when the controller was enumerated
from DT?

> +	dev->adapter.bus_recovery_info = rinfo;
> +}
> +
>  static int dw_i2c_plat_probe(struct platform_device *pdev)
>  {
>  	struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
> @@ -165,6 +209,12 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
>  	if (!dev)
>  		return -ENOMEM;
>  
> +	dev->pinctrl = devm_pinctrl_get(&pdev->dev);
> +	if (IS_ERR(dev->pinctrl))
> +		return PTR_ERR(dev->pinctrl);
> +
> +	i2c_dw_plat_init_recovery_info(dev, pdev);
> +
>  	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	dev->base = devm_ioremap_resource(&pdev->dev, mem);
>  	if (IS_ERR(dev->base))
> -- 
> 2.8.0.rc3

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#1378981

FromMartinez Kristofer <kristofer.s.martinez@gmail.com>
Date2016-04-14 17:00 +0200
Message-ID<rnQUq-3jQ-27@gated-at.bofh.it>
In reply to#1378952
On Thu, Apr 14, 2016 at 10:39 PM, Mika Westerberg
<mika.westerberg@linux.intel.com> wrote:
> On Thu, Apr 14, 2016 at 10:04:56PM +0800, Jisheng Zhang wrote:
>> Implement bus recovery methods for i2c designware so we can recover
>> from situations where SCL/SDA are stuck low.
>>
>> The recovery method is similar as i2c-imx: "config the i2c pinctrl to
>> gpio mode by calling pinctrl sleep set function, and then use GPIO to
>> emulate the i2c protocol to send nine dummy clock to recover i2c
>> device. After recovery, set i2c pinctrl to default group setting.
>>
>> Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
>> ---
>> depends on runtime pm patches
>> http://lists.infradead.org/pipermail/linux-arm-kernel/2016-April/422202.html
>>  .../devicetree/bindings/i2c/i2c-designware.txt     | 12 ++++++
>>  drivers/i2c/busses/i2c-designware-core.c           |  6 ++-
>>  drivers/i2c/busses/i2c-designware-core.h           |  4 ++
>>  drivers/i2c/busses/i2c-designware-platdrv.c        | 50 ++++++++++++++++++++++
>>  4 files changed, 71 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
>> index fee26dc..51a55c6 100644
>> --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
>> +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
>> @@ -20,6 +20,13 @@ Optional properties :
>>   - i2c-sda-falling-time-ns : should contain the SDA falling time in nanoseconds.
>>     This value which is by default 300ns is used to compute the tHIGH period.
>>
>> + - scl-gpios: specify the gpio related to SCL pin
>> +
>> + - sda-gpios: specify the gpio related to SDA pin
>> +
>> + - pinctrl: add extra pinctrl to configure i2c pins to gpio function for i2c
>> +   bus recovery, call it "gpio" state
>> +
>>  Example :
>>
>>       i2c@f0000 {
>> @@ -42,4 +49,9 @@ Example :
>>               i2c-sda-hold-time-ns = <300>;
>>               i2c-sda-falling-time-ns = <300>;
>>               i2c-scl-falling-time-ns = <300>;
>> +             pinctrl-names = "default", "gpio";
>> +             pinctrl-0 = <&pinctrl_i2c1_default>;
>> +             pinctrl-1 = <&pinctrl_i2c1_gpio>;
>> +             scl-gpios = <&porta 26 GPIO_ACTIVE_HIGH>;
>> +             sda-gpios = <&porta 27 GPIO_ACTIVE_HIGH>;
>>       };
>> diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
>> index 4255eaa..be40de1 100644
>> --- a/drivers/i2c/busses/i2c-designware-core.c
>> +++ b/drivers/i2c/busses/i2c-designware-core.c
>> @@ -399,7 +399,10 @@ static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
>>       while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
>>               if (timeout <= 0) {
>>                       dev_warn(dev->dev, "timeout waiting for bus ready\n");
>> -                     return -ETIMEDOUT;
>> +                     i2c_recover_bus(&dev->adapter);
>> +                     if (dw_readl(dev, DW_IC_STATUS)
>> +                                     & DW_IC_STATUS_ACTIVITY)
>> +                             return -ETIMEDOUT;
>>               }
>>               timeout--;
>>               usleep_range(1000, 1100);
>> @@ -665,6 +668,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
>>       /* wait for tx to complete */
>>       if (!wait_for_completion_timeout(&dev->cmd_complete, HZ)) {
>>               dev_err(dev->dev, "controller timed out\n");
>> +             i2c_recover_bus(&dev->adapter);
>>               /* i2c_dw_init implicitly disables the adapter */
>>               i2c_dw_init(dev);
>>               ret = -ETIMEDOUT;
>> diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
>> index cd409e7..26c84ee 100644
>> --- a/drivers/i2c/busses/i2c-designware-core.h
>> +++ b/drivers/i2c/busses/i2c-designware-core.h
>> @@ -104,6 +104,10 @@ struct dw_i2c_dev {
>>       u16                     fs_lcnt;
>>       int                     (*acquire_lock)(struct dw_i2c_dev *dev);
>>       void                    (*release_lock)(struct dw_i2c_dev *dev);
>> +     struct i2c_bus_recovery_info rinfo;
>> +     struct pinctrl          *pinctrl;
>> +     struct pinctrl_state    *pinctrl_pins_default;
>> +     struct pinctrl_state    *pinctrl_pins_gpio;
>>       bool                    pm_runtime_disabled;
>>  };
>>
>> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
>> index 1488cea..62bded9 100644
>> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
>> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
>> @@ -33,6 +33,7 @@
>>  #include <linux/err.h>
>>  #include <linux/interrupt.h>
>>  #include <linux/of.h>
>> +#include <linux/of_gpio.h>
>>  #include <linux/platform_device.h>
>>  #include <linux/pm.h>
>>  #include <linux/pm_runtime.h>
>> @@ -148,6 +149,49 @@ static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare)
>>       return 0;
>>  }
>>
>> +static void i2c_dw_plat_prepare_recovery(struct i2c_adapter *adap)
>> +{
>> +     struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
>> +
>> +     pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_gpio);
>> +}
>> +
>> +static void i2c_dw_plat_unprepare_recovery(struct i2c_adapter *adap)
>> +{
>> +     struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
>> +
>> +     pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_default);
>> +}
>> +
>> +static void i2c_dw_plat_init_recovery_info(struct dw_i2c_dev *dev,
>> +                                        struct platform_device *pdev)
>> +{
>> +     struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
>> +
>> +     dev->pinctrl_pins_default = pinctrl_lookup_state(dev->pinctrl,
>> +                     PINCTRL_STATE_DEFAULT);
>> +     dev->pinctrl_pins_gpio = pinctrl_lookup_state(dev->pinctrl,
>> +                     "gpio");
>> +     rinfo->sda_gpio = of_get_named_gpio(pdev->dev.of_node, "sda-gpios", 0);
>> +     rinfo->scl_gpio = of_get_named_gpio(pdev->dev.of_node, "scl-gpios", 0);
>> +
>> +     if (!gpio_is_valid(rinfo->sda_gpio) ||
>> +         !gpio_is_valid(rinfo->scl_gpio) ||
>> +         IS_ERR(dev->pinctrl_pins_default) ||
>> +         IS_ERR(dev->pinctrl_pins_gpio)) {
>> +             dev_dbg(&pdev->dev, "recovery information incomplete\n");
>> +             return;
>> +     }
>> +
>> +     dev_dbg(&pdev->dev, "using scl-gpio %d and sda-gpio %d for recovery\n",
>> +             rinfo->sda_gpio, rinfo->scl_gpio);
>> +
>> +     rinfo->prepare_recovery = i2c_dw_plat_prepare_recovery;
>> +     rinfo->unprepare_recovery = i2c_dw_plat_unprepare_recovery;
>> +     rinfo->recover_bus = i2c_generic_gpio_recovery;
>
> This whole thing is DT specific and I don't see how we can do the same
> for ACPI. Should it be enabled only when the controller was enumerated
> from DT?
>
For ACPI, probably result in the panic-alike function calling chain at
i2c_dw_init --> dev->get_clk_rate_khz(dev).
Mika, I think you need to take ACPI into account while not focus on DT only

KM

>> +     dev->adapter.bus_recovery_info = rinfo;
>> +}
>> +
>>  static int dw_i2c_plat_probe(struct platform_device *pdev)
>>  {
>>       struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
>> @@ -165,6 +209,12 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
>>       if (!dev)
>>               return -ENOMEM;
>>
>> +     dev->pinctrl = devm_pinctrl_get(&pdev->dev);
>> +     if (IS_ERR(dev->pinctrl))
>> +             return PTR_ERR(dev->pinctrl);
>> +
>> +     i2c_dw_plat_init_recovery_info(dev, pdev);
>> +
>>       mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>>       dev->base = devm_ioremap_resource(&pdev->dev, mem);
>>       if (IS_ERR(dev->base))
>> --
>> 2.8.0.rc3
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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#1379470

FromJisheng Zhang <jszhang@marvell.com>
Date2016-04-15 08:20 +0200
Message-ID<ro5gJ-6Sg-1@gated-at.bofh.it>
In reply to#1378952
Dear Mika,

On Thu, 14 Apr 2016 17:39:16 +0300 Mika Westerberg wrote:

> On Thu, Apr 14, 2016 at 10:04:56PM +0800, Jisheng Zhang wrote:
> > Implement bus recovery methods for i2c designware so we can recover
> > from situations where SCL/SDA are stuck low.
> > 
> > The recovery method is similar as i2c-imx: "config the i2c pinctrl to
> > gpio mode by calling pinctrl sleep set function, and then use GPIO to
> > emulate the i2c protocol to send nine dummy clock to recover i2c
> > device. After recovery, set i2c pinctrl to default group setting.
> > 
> > Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
> > ---
> > depends on runtime pm patches
> > http://lists.infradead.org/pipermail/linux-arm-kernel/2016-April/422202.html
> >  .../devicetree/bindings/i2c/i2c-designware.txt     | 12 ++++++
> >  drivers/i2c/busses/i2c-designware-core.c           |  6 ++-
> >  drivers/i2c/busses/i2c-designware-core.h           |  4 ++
> >  drivers/i2c/busses/i2c-designware-platdrv.c        | 50 ++++++++++++++++++++++
> >  4 files changed, 71 insertions(+), 1 deletion(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> > index fee26dc..51a55c6 100644
> > --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> > +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> > @@ -20,6 +20,13 @@ Optional properties :
> >   - i2c-sda-falling-time-ns : should contain the SDA falling time in nanoseconds.
> >     This value which is by default 300ns is used to compute the tHIGH period.
> >  
> > + - scl-gpios: specify the gpio related to SCL pin
> > +
> > + - sda-gpios: specify the gpio related to SDA pin
> > +
> > + - pinctrl: add extra pinctrl to configure i2c pins to gpio function for i2c
> > +   bus recovery, call it "gpio" state
> > +
> >  Example :
> >  
> >  	i2c@f0000 {
> > @@ -42,4 +49,9 @@ Example :
> >  		i2c-sda-hold-time-ns = <300>;
> >  		i2c-sda-falling-time-ns = <300>;
> >  		i2c-scl-falling-time-ns = <300>;
> > +		pinctrl-names = "default", "gpio";
> > +		pinctrl-0 = <&pinctrl_i2c1_default>;
> > +		pinctrl-1 = <&pinctrl_i2c1_gpio>;
> > +		scl-gpios = <&porta 26 GPIO_ACTIVE_HIGH>;
> > +		sda-gpios = <&porta 27 GPIO_ACTIVE_HIGH>;
> >  	};
> > diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
> > index 4255eaa..be40de1 100644
> > --- a/drivers/i2c/busses/i2c-designware-core.c
> > +++ b/drivers/i2c/busses/i2c-designware-core.c
> > @@ -399,7 +399,10 @@ static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
> >  	while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
> >  		if (timeout <= 0) {
> >  			dev_warn(dev->dev, "timeout waiting for bus ready\n");
> > -			return -ETIMEDOUT;
> > +			i2c_recover_bus(&dev->adapter);
> > +			if (dw_readl(dev, DW_IC_STATUS)
> > +					& DW_IC_STATUS_ACTIVITY)
> > +				return -ETIMEDOUT;
> >  		}
> >  		timeout--;
> >  		usleep_range(1000, 1100);
> > @@ -665,6 +668,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
> >  	/* wait for tx to complete */
> >  	if (!wait_for_completion_timeout(&dev->cmd_complete, HZ)) {
> >  		dev_err(dev->dev, "controller timed out\n");
> > +		i2c_recover_bus(&dev->adapter);
> >  		/* i2c_dw_init implicitly disables the adapter */
> >  		i2c_dw_init(dev);
> >  		ret = -ETIMEDOUT;
> > diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
> > index cd409e7..26c84ee 100644
> > --- a/drivers/i2c/busses/i2c-designware-core.h
> > +++ b/drivers/i2c/busses/i2c-designware-core.h
> > @@ -104,6 +104,10 @@ struct dw_i2c_dev {
> >  	u16			fs_lcnt;
> >  	int			(*acquire_lock)(struct dw_i2c_dev *dev);
> >  	void			(*release_lock)(struct dw_i2c_dev *dev);
> > +	struct i2c_bus_recovery_info rinfo;
> > +	struct pinctrl		*pinctrl;
> > +	struct pinctrl_state	*pinctrl_pins_default;
> > +	struct pinctrl_state	*pinctrl_pins_gpio;
> >  	bool			pm_runtime_disabled;
> >  };
> >  
> > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
> > index 1488cea..62bded9 100644
> > --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> > @@ -33,6 +33,7 @@
> >  #include <linux/err.h>
> >  #include <linux/interrupt.h>
> >  #include <linux/of.h>
> > +#include <linux/of_gpio.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/pm.h>
> >  #include <linux/pm_runtime.h>
> > @@ -148,6 +149,49 @@ static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare)
> >  	return 0;
> >  }
> >  
> > +static void i2c_dw_plat_prepare_recovery(struct i2c_adapter *adap)
> > +{
> > +	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
> > +
> > +	pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_gpio);
> > +}
> > +
> > +static void i2c_dw_plat_unprepare_recovery(struct i2c_adapter *adap)
> > +{
> > +	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
> > +
> > +	pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_default);
> > +}
> > +
> > +static void i2c_dw_plat_init_recovery_info(struct dw_i2c_dev *dev,
> > +					   struct platform_device *pdev)
> > +{
> > +	struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
> > +
> > +	dev->pinctrl_pins_default = pinctrl_lookup_state(dev->pinctrl,
> > +			PINCTRL_STATE_DEFAULT);
> > +	dev->pinctrl_pins_gpio = pinctrl_lookup_state(dev->pinctrl,
> > +			"gpio");
> > +	rinfo->sda_gpio = of_get_named_gpio(pdev->dev.of_node, "sda-gpios", 0);
> > +	rinfo->scl_gpio = of_get_named_gpio(pdev->dev.of_node, "scl-gpios", 0);
> > +
> > +	if (!gpio_is_valid(rinfo->sda_gpio) ||
> > +	    !gpio_is_valid(rinfo->scl_gpio) ||
> > +	    IS_ERR(dev->pinctrl_pins_default) ||
> > +	    IS_ERR(dev->pinctrl_pins_gpio)) {
> > +		dev_dbg(&pdev->dev, "recovery information incomplete\n");
> > +		return;

For ACPI, we should return here, right?

> > +	}
> > +
> > +	dev_dbg(&pdev->dev, "using scl-gpio %d and sda-gpio %d for recovery\n",
> > +		rinfo->sda_gpio, rinfo->scl_gpio);
> > +
> > +	rinfo->prepare_recovery = i2c_dw_plat_prepare_recovery;
> > +	rinfo->unprepare_recovery = i2c_dw_plat_unprepare_recovery;
> > +	rinfo->recover_bus = i2c_generic_gpio_recovery;  
> 
> This whole thing is DT specific and I don't see how we can do the same
> for ACPI. Should it be enabled only when the controller was enumerated
> from DT?

Per my understanding, for ACPI, the pinctrl_pins_default, pinctrl_pins_gpio,
sda_gpio and scl_gpio will be invalid or err, so we won't setup rinfo
at all. However, I have no acpi platform which have i2c designware to double
confirm.

> 
> > +	dev->adapter.bus_recovery_info = rinfo;
> > +}
> > +
> >  static int dw_i2c_plat_probe(struct platform_device *pdev)
> >  {
> >  	struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
> > @@ -165,6 +209,12 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
> >  	if (!dev)
> >  		return -ENOMEM;
> >  
> > +	dev->pinctrl = devm_pinctrl_get(&pdev->dev);
> > +	if (IS_ERR(dev->pinctrl))
> > +		return PTR_ERR(dev->pinctrl);
> > +
> > +	i2c_dw_plat_init_recovery_info(dev, pdev);
> > +
> >  	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >  	dev->base = devm_ioremap_resource(&pdev->dev, mem);
> >  	if (IS_ERR(dev->base))
> > -- 
> > 2.8.0.rc3

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#1379501

FromMika Westerberg <mika.westerberg@linux.intel.com>
Date2016-04-15 09:10 +0200
Message-ID<ro638-7wR-27@gated-at.bofh.it>
In reply to#1379470
On Fri, Apr 15, 2016 at 02:08:43PM +0800, Jisheng Zhang wrote:
> Dear Mika,
> 
> On Thu, 14 Apr 2016 17:39:16 +0300 Mika Westerberg wrote:
> 
> > On Thu, Apr 14, 2016 at 10:04:56PM +0800, Jisheng Zhang wrote:
> > > Implement bus recovery methods for i2c designware so we can recover
> > > from situations where SCL/SDA are stuck low.
> > > 
> > > The recovery method is similar as i2c-imx: "config the i2c pinctrl to
> > > gpio mode by calling pinctrl sleep set function, and then use GPIO to
> > > emulate the i2c protocol to send nine dummy clock to recover i2c
> > > device. After recovery, set i2c pinctrl to default group setting.
> > > 
> > > Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
> > > ---
> > > depends on runtime pm patches
> > > http://lists.infradead.org/pipermail/linux-arm-kernel/2016-April/422202.html
> > >  .../devicetree/bindings/i2c/i2c-designware.txt     | 12 ++++++
> > >  drivers/i2c/busses/i2c-designware-core.c           |  6 ++-
> > >  drivers/i2c/busses/i2c-designware-core.h           |  4 ++
> > >  drivers/i2c/busses/i2c-designware-platdrv.c        | 50 ++++++++++++++++++++++
> > >  4 files changed, 71 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> > > index fee26dc..51a55c6 100644
> > > --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> > > +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> > > @@ -20,6 +20,13 @@ Optional properties :
> > >   - i2c-sda-falling-time-ns : should contain the SDA falling time in nanoseconds.
> > >     This value which is by default 300ns is used to compute the tHIGH period.
> > >  
> > > + - scl-gpios: specify the gpio related to SCL pin
> > > +
> > > + - sda-gpios: specify the gpio related to SDA pin
> > > +
> > > + - pinctrl: add extra pinctrl to configure i2c pins to gpio function for i2c
> > > +   bus recovery, call it "gpio" state
> > > +
> > >  Example :
> > >  
> > >  	i2c@f0000 {
> > > @@ -42,4 +49,9 @@ Example :
> > >  		i2c-sda-hold-time-ns = <300>;
> > >  		i2c-sda-falling-time-ns = <300>;
> > >  		i2c-scl-falling-time-ns = <300>;
> > > +		pinctrl-names = "default", "gpio";
> > > +		pinctrl-0 = <&pinctrl_i2c1_default>;
> > > +		pinctrl-1 = <&pinctrl_i2c1_gpio>;
> > > +		scl-gpios = <&porta 26 GPIO_ACTIVE_HIGH>;
> > > +		sda-gpios = <&porta 27 GPIO_ACTIVE_HIGH>;
> > >  	};
> > > diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
> > > index 4255eaa..be40de1 100644
> > > --- a/drivers/i2c/busses/i2c-designware-core.c
> > > +++ b/drivers/i2c/busses/i2c-designware-core.c
> > > @@ -399,7 +399,10 @@ static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
> > >  	while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
> > >  		if (timeout <= 0) {
> > >  			dev_warn(dev->dev, "timeout waiting for bus ready\n");
> > > -			return -ETIMEDOUT;
> > > +			i2c_recover_bus(&dev->adapter);
> > > +			if (dw_readl(dev, DW_IC_STATUS)
> > > +					& DW_IC_STATUS_ACTIVITY)
> > > +				return -ETIMEDOUT;
> > >  		}
> > >  		timeout--;
> > >  		usleep_range(1000, 1100);
> > > @@ -665,6 +668,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
> > >  	/* wait for tx to complete */
> > >  	if (!wait_for_completion_timeout(&dev->cmd_complete, HZ)) {
> > >  		dev_err(dev->dev, "controller timed out\n");
> > > +		i2c_recover_bus(&dev->adapter);
> > >  		/* i2c_dw_init implicitly disables the adapter */
> > >  		i2c_dw_init(dev);
> > >  		ret = -ETIMEDOUT;
> > > diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
> > > index cd409e7..26c84ee 100644
> > > --- a/drivers/i2c/busses/i2c-designware-core.h
> > > +++ b/drivers/i2c/busses/i2c-designware-core.h
> > > @@ -104,6 +104,10 @@ struct dw_i2c_dev {
> > >  	u16			fs_lcnt;
> > >  	int			(*acquire_lock)(struct dw_i2c_dev *dev);
> > >  	void			(*release_lock)(struct dw_i2c_dev *dev);
> > > +	struct i2c_bus_recovery_info rinfo;
> > > +	struct pinctrl		*pinctrl;
> > > +	struct pinctrl_state	*pinctrl_pins_default;
> > > +	struct pinctrl_state	*pinctrl_pins_gpio;
> > >  	bool			pm_runtime_disabled;
> > >  };
> > >  
> > > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
> > > index 1488cea..62bded9 100644
> > > --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> > > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> > > @@ -33,6 +33,7 @@
> > >  #include <linux/err.h>
> > >  #include <linux/interrupt.h>
> > >  #include <linux/of.h>
> > > +#include <linux/of_gpio.h>
> > >  #include <linux/platform_device.h>
> > >  #include <linux/pm.h>
> > >  #include <linux/pm_runtime.h>
> > > @@ -148,6 +149,49 @@ static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare)
> > >  	return 0;
> > >  }
> > >  
> > > +static void i2c_dw_plat_prepare_recovery(struct i2c_adapter *adap)
> > > +{
> > > +	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
> > > +
> > > +	pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_gpio);
> > > +}
> > > +
> > > +static void i2c_dw_plat_unprepare_recovery(struct i2c_adapter *adap)
> > > +{
> > > +	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
> > > +
> > > +	pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_default);
> > > +}
> > > +
> > > +static void i2c_dw_plat_init_recovery_info(struct dw_i2c_dev *dev,
> > > +					   struct platform_device *pdev)
> > > +{
> > > +	struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
> > > +
> > > +	dev->pinctrl_pins_default = pinctrl_lookup_state(dev->pinctrl,
> > > +			PINCTRL_STATE_DEFAULT);
> > > +	dev->pinctrl_pins_gpio = pinctrl_lookup_state(dev->pinctrl,
> > > +			"gpio");
> > > +	rinfo->sda_gpio = of_get_named_gpio(pdev->dev.of_node, "sda-gpios", 0);
> > > +	rinfo->scl_gpio = of_get_named_gpio(pdev->dev.of_node, "scl-gpios", 0);
> > > +
> > > +	if (!gpio_is_valid(rinfo->sda_gpio) ||
> > > +	    !gpio_is_valid(rinfo->scl_gpio) ||
> > > +	    IS_ERR(dev->pinctrl_pins_default) ||
> > > +	    IS_ERR(dev->pinctrl_pins_gpio)) {
> > > +		dev_dbg(&pdev->dev, "recovery information incomplete\n");
> > > +		return;
> 
> For ACPI, we should return here, right?

I hope so. And I do not want to see any useless messages about
incomplete recovery information on my PC.

> > > +	}
> > > +
> > > +	dev_dbg(&pdev->dev, "using scl-gpio %d and sda-gpio %d for recovery\n",
> > > +		rinfo->sda_gpio, rinfo->scl_gpio);
> > > +
> > > +	rinfo->prepare_recovery = i2c_dw_plat_prepare_recovery;
> > > +	rinfo->unprepare_recovery = i2c_dw_plat_unprepare_recovery;
> > > +	rinfo->recover_bus = i2c_generic_gpio_recovery;  
> > 
> > This whole thing is DT specific and I don't see how we can do the same
> > for ACPI. Should it be enabled only when the controller was enumerated
> > from DT?
> 
> Per my understanding, for ACPI, the pinctrl_pins_default, pinctrl_pins_gpio,
> sda_gpio and scl_gpio will be invalid or err, so we won't setup rinfo
> at all. However, I have no acpi platform which have i2c designware to double
> confirm.

What happens to those of_get_ functions when you pass NULL of_node? If
they do not crash then I suppose it is fine.

Anyhow it might be good idea to do something like

	if (!pdev->dev.of_node)
		return;

in the beginning of that function.

> > 
> > > +	dev->adapter.bus_recovery_info = rinfo;
> > > +}
> > > +
> > >  static int dw_i2c_plat_probe(struct platform_device *pdev)
> > >  {
> > >  	struct dw_i2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
> > > @@ -165,6 +209,12 @@ static int dw_i2c_plat_probe(struct platform_device *pdev)
> > >  	if (!dev)
> > >  		return -ENOMEM;
> > >  
> > > +	dev->pinctrl = devm_pinctrl_get(&pdev->dev);
> > > +	if (IS_ERR(dev->pinctrl))
> > > +		return PTR_ERR(dev->pinctrl);
> > > +
> > > +	i2c_dw_plat_init_recovery_info(dev, pdev);
> > > +
> > >  	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > >  	dev->base = devm_ioremap_resource(&pdev->dev, mem);
> > >  	if (IS_ERR(dev->base))
> > > -- 
> > > 2.8.0.rc3

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#1379514

FromJisheng Zhang <jszhang@marvell.com>
Date2016-04-15 09:40 +0200
Message-ID<ro6wa-7KF-21@gated-at.bofh.it>
In reply to#1379501
On Fri, 15 Apr 2016 10:07:46 +0300
Mika Westerberg <mika.westerberg@linux.intel.com> wrote:

> On Fri, Apr 15, 2016 at 02:08:43PM +0800, Jisheng Zhang wrote:
> > Dear Mika,
> > 
> > On Thu, 14 Apr 2016 17:39:16 +0300 Mika Westerberg wrote:
> >   
> > > On Thu, Apr 14, 2016 at 10:04:56PM +0800, Jisheng Zhang wrote:  
> > > > Implement bus recovery methods for i2c designware so we can recover
> > > > from situations where SCL/SDA are stuck low.
> > > > 
> > > > The recovery method is similar as i2c-imx: "config the i2c pinctrl to
> > > > gpio mode by calling pinctrl sleep set function, and then use GPIO to
> > > > emulate the i2c protocol to send nine dummy clock to recover i2c
> > > > device. After recovery, set i2c pinctrl to default group setting.
> > > > 
> > > > Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
> > > > ---
> > > > depends on runtime pm patches
> > > > http://lists.infradead.org/pipermail/linux-arm-kernel/2016-April/422202.html
> > > >  .../devicetree/bindings/i2c/i2c-designware.txt     | 12 ++++++
> > > >  drivers/i2c/busses/i2c-designware-core.c           |  6 ++-
> > > >  drivers/i2c/busses/i2c-designware-core.h           |  4 ++
> > > >  drivers/i2c/busses/i2c-designware-platdrv.c        | 50 ++++++++++++++++++++++
> > > >  4 files changed, 71 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> > > > index fee26dc..51a55c6 100644
> > > > --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> > > > +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> > > > @@ -20,6 +20,13 @@ Optional properties :
> > > >   - i2c-sda-falling-time-ns : should contain the SDA falling time in nanoseconds.
> > > >     This value which is by default 300ns is used to compute the tHIGH period.
> > > >  
> > > > + - scl-gpios: specify the gpio related to SCL pin
> > > > +
> > > > + - sda-gpios: specify the gpio related to SDA pin
> > > > +
> > > > + - pinctrl: add extra pinctrl to configure i2c pins to gpio function for i2c
> > > > +   bus recovery, call it "gpio" state
> > > > +
> > > >  Example :
> > > >  
> > > >  	i2c@f0000 {
> > > > @@ -42,4 +49,9 @@ Example :
> > > >  		i2c-sda-hold-time-ns = <300>;
> > > >  		i2c-sda-falling-time-ns = <300>;
> > > >  		i2c-scl-falling-time-ns = <300>;
> > > > +		pinctrl-names = "default", "gpio";
> > > > +		pinctrl-0 = <&pinctrl_i2c1_default>;
> > > > +		pinctrl-1 = <&pinctrl_i2c1_gpio>;
> > > > +		scl-gpios = <&porta 26 GPIO_ACTIVE_HIGH>;
> > > > +		sda-gpios = <&porta 27 GPIO_ACTIVE_HIGH>;
> > > >  	};
> > > > diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
> > > > index 4255eaa..be40de1 100644
> > > > --- a/drivers/i2c/busses/i2c-designware-core.c
> > > > +++ b/drivers/i2c/busses/i2c-designware-core.c
> > > > @@ -399,7 +399,10 @@ static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
> > > >  	while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
> > > >  		if (timeout <= 0) {
> > > >  			dev_warn(dev->dev, "timeout waiting for bus ready\n");
> > > > -			return -ETIMEDOUT;
> > > > +			i2c_recover_bus(&dev->adapter);
> > > > +			if (dw_readl(dev, DW_IC_STATUS)
> > > > +					& DW_IC_STATUS_ACTIVITY)
> > > > +				return -ETIMEDOUT;
> > > >  		}
> > > >  		timeout--;
> > > >  		usleep_range(1000, 1100);
> > > > @@ -665,6 +668,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
> > > >  	/* wait for tx to complete */
> > > >  	if (!wait_for_completion_timeout(&dev->cmd_complete, HZ)) {
> > > >  		dev_err(dev->dev, "controller timed out\n");
> > > > +		i2c_recover_bus(&dev->adapter);
> > > >  		/* i2c_dw_init implicitly disables the adapter */
> > > >  		i2c_dw_init(dev);
> > > >  		ret = -ETIMEDOUT;
> > > > diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
> > > > index cd409e7..26c84ee 100644
> > > > --- a/drivers/i2c/busses/i2c-designware-core.h
> > > > +++ b/drivers/i2c/busses/i2c-designware-core.h
> > > > @@ -104,6 +104,10 @@ struct dw_i2c_dev {
> > > >  	u16			fs_lcnt;
> > > >  	int			(*acquire_lock)(struct dw_i2c_dev *dev);
> > > >  	void			(*release_lock)(struct dw_i2c_dev *dev);
> > > > +	struct i2c_bus_recovery_info rinfo;
> > > > +	struct pinctrl		*pinctrl;
> > > > +	struct pinctrl_state	*pinctrl_pins_default;
> > > > +	struct pinctrl_state	*pinctrl_pins_gpio;
> > > >  	bool			pm_runtime_disabled;
> > > >  };
> > > >  
> > > > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
> > > > index 1488cea..62bded9 100644
> > > > --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> > > > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> > > > @@ -33,6 +33,7 @@
> > > >  #include <linux/err.h>
> > > >  #include <linux/interrupt.h>
> > > >  #include <linux/of.h>
> > > > +#include <linux/of_gpio.h>
> > > >  #include <linux/platform_device.h>
> > > >  #include <linux/pm.h>
> > > >  #include <linux/pm_runtime.h>
> > > > @@ -148,6 +149,49 @@ static int i2c_dw_plat_prepare_clk(struct dw_i2c_dev *i_dev, bool prepare)
> > > >  	return 0;
> > > >  }
> > > >  
> > > > +static void i2c_dw_plat_prepare_recovery(struct i2c_adapter *adap)
> > > > +{
> > > > +	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
> > > > +
> > > > +	pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_gpio);
> > > > +}
> > > > +
> > > > +static void i2c_dw_plat_unprepare_recovery(struct i2c_adapter *adap)
> > > > +{
> > > > +	struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
> > > > +
> > > > +	pinctrl_select_state(dev->pinctrl, dev->pinctrl_pins_default);
> > > > +}
> > > > +
> > > > +static void i2c_dw_plat_init_recovery_info(struct dw_i2c_dev *dev,
> > > > +					   struct platform_device *pdev)
> > > > +{
> > > > +	struct i2c_bus_recovery_info *rinfo = &dev->rinfo;
> > > > +
> > > > +	dev->pinctrl_pins_default = pinctrl_lookup_state(dev->pinctrl,
> > > > +			PINCTRL_STATE_DEFAULT);
> > > > +	dev->pinctrl_pins_gpio = pinctrl_lookup_state(dev->pinctrl,
> > > > +			"gpio");
> > > > +	rinfo->sda_gpio = of_get_named_gpio(pdev->dev.of_node, "sda-gpios", 0);
> > > > +	rinfo->scl_gpio = of_get_named_gpio(pdev->dev.of_node, "scl-gpios", 0);
> > > > +
> > > > +	if (!gpio_is_valid(rinfo->sda_gpio) ||
> > > > +	    !gpio_is_valid(rinfo->scl_gpio) ||
> > > > +	    IS_ERR(dev->pinctrl_pins_default) ||
> > > > +	    IS_ERR(dev->pinctrl_pins_gpio)) {
> > > > +		dev_dbg(&pdev->dev, "recovery information incomplete\n");
> > > > +		return;  
> > 
> > For ACPI, we should return here, right?  
> 
> I hope so. And I do not want to see any useless messages about
> incomplete recovery information on my PC.

Got your points.

> 
> > > > +	}
> > > > +
> > > > +	dev_dbg(&pdev->dev, "using scl-gpio %d and sda-gpio %d for recovery\n",
> > > > +		rinfo->sda_gpio, rinfo->scl_gpio);
> > > > +
> > > > +	rinfo->prepare_recovery = i2c_dw_plat_prepare_recovery;
> > > > +	rinfo->unprepare_recovery = i2c_dw_plat_unprepare_recovery;
> > > > +	rinfo->recover_bus = i2c_generic_gpio_recovery;    
> > > 
> > > This whole thing is DT specific and I don't see how we can do the same
> > > for ACPI. Should it be enabled only when the controller was enumerated
> > > from DT?  
> > 
> > Per my understanding, for ACPI, the pinctrl_pins_default, pinctrl_pins_gpio,
> > sda_gpio and scl_gpio will be invalid or err, so we won't setup rinfo
> > at all. However, I have no acpi platform which have i2c designware to double
> > confirm.  
> 
> What happens to those of_get_ functions when you pass NULL of_node? If
> they do not crash then I suppose it is fine.

I just checked the code,
If CONFIG_OF isn't enabled, of_get_* will return error.
If CONFIG_OF is enabled, but NULL of_node is passed, of_get_* will also return
error, so it's fine ;)

> 
> Anyhow it might be good idea to do something like
> 
> 	if (!pdev->dev.of_node)
> 		return;
> 
> in the beginning of that function.

Sounds a good idea, will do in next version.

Thanks for your review,
Jisheng

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#1379144

FromRob Herring <robh@kernel.org>
Date2016-04-14 19:40 +0200
Message-ID<rnTpg-5FL-9@gated-at.bofh.it>
In reply to#1378878
On Thu, Apr 14, 2016 at 10:04:56PM +0800, Jisheng Zhang wrote:
> Implement bus recovery methods for i2c designware so we can recover
> from situations where SCL/SDA are stuck low.
> 
> The recovery method is similar as i2c-imx: "config the i2c pinctrl to
> gpio mode by calling pinctrl sleep set function, and then use GPIO to
> emulate the i2c protocol to send nine dummy clock to recover i2c
> device. After recovery, set i2c pinctrl to default group setting.
> 
> Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
> ---
> depends on runtime pm patches
> http://lists.infradead.org/pipermail/linux-arm-kernel/2016-April/422202.html
>  .../devicetree/bindings/i2c/i2c-designware.txt     | 12 ++++++
>  drivers/i2c/busses/i2c-designware-core.c           |  6 ++-
>  drivers/i2c/busses/i2c-designware-core.h           |  4 ++
>  drivers/i2c/busses/i2c-designware-platdrv.c        | 50 ++++++++++++++++++++++
>  4 files changed, 71 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> index fee26dc..51a55c6 100644
> --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt
> @@ -20,6 +20,13 @@ Optional properties :
>   - i2c-sda-falling-time-ns : should contain the SDA falling time in nanoseconds.
>     This value which is by default 300ns is used to compute the tHIGH period.
>  
> + - scl-gpios: specify the gpio related to SCL pin
> +
> + - sda-gpios: specify the gpio related to SDA pin
> +
> + - pinctrl: add extra pinctrl to configure i2c pins to gpio function for i2c
> +   bus recovery, call it "gpio" state
> +

Make these common properties in i2c.txt (and a separate patch).

>  Example :
>  
>  	i2c@f0000 {
> @@ -42,4 +49,9 @@ Example :
>  		i2c-sda-hold-time-ns = <300>;
>  		i2c-sda-falling-time-ns = <300>;
>  		i2c-scl-falling-time-ns = <300>;
> +		pinctrl-names = "default", "gpio";
> +		pinctrl-0 = <&pinctrl_i2c1_default>;
> +		pinctrl-1 = <&pinctrl_i2c1_gpio>;
> +		scl-gpios = <&porta 26 GPIO_ACTIVE_HIGH>;
> +		sda-gpios = <&porta 27 GPIO_ACTIVE_HIGH>;
>  	};

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