[PATCH v6] atmel_flexcom: Support resuming after a chip reset

[PATCH v6] atmel_flexcom: Support resuming after a chip reset

[Romain Izard]

The controller used by a flexcom module is configured at boot, and left
alone after this. In the suspend mode called "backup with self-refresh"
available on SAMA5D2, the chip will resume with most of its registers
reset. In this case, we need to restore the state of the flexcom driver
on resume.

Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
---
Changes in v5:
* extract from the patch series, and send as a standalone patch

Changes in v6:
* Reword the patch title and description
* Rename the internal structure to ddata

 drivers/mfd/atmel-flexcom.c | 63 ++++++++++++++++++++++++++++++++++-----------
 1 file changed, 48 insertions(+), 15 deletions(-)

diff --git a/drivers/mfd/atmel-flexcom.c b/drivers/mfd/atmel-flexcom.c
index 064bde9cff5a..f684a93a3340 100644
--- a/drivers/mfd/atmel-flexcom.c
+++ b/drivers/mfd/atmel-flexcom.c
@@ -39,34 +39,43 @@
 #define FLEX_MR_OPMODE(opmode)	(((opmode) << FLEX_MR_OPMODE_OFFSET) &	\
 				 FLEX_MR_OPMODE_MASK)
 
+struct atmel_flexcom {
+	void __iomem *base;
+	u32 opmode;
+	struct clk *clk;
+};
 
 static int atmel_flexcom_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
-	struct clk *clk;
 	struct resource *res;
-	void __iomem *base;
-	u32 opmode;
+	struct atmel_flexcom *ddata;
 	int err;
 
-	err = of_property_read_u32(np, "atmel,flexcom-mode", &opmode);
+	ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
+	if (!ddata)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, ddata);
+
+	err = of_property_read_u32(np, "atmel,flexcom-mode", &ddata->opmode);
 	if (err)
 		return err;
 
-	if (opmode < ATMEL_FLEXCOM_MODE_USART ||
-	    opmode > ATMEL_FLEXCOM_MODE_TWI)
+	if (ddata->opmode < ATMEL_FLEXCOM_MODE_USART ||
+	    ddata->opmode > ATMEL_FLEXCOM_MODE_TWI)
 		return -EINVAL;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	base = devm_ioremap_resource(&pdev->dev, res);
-	if (IS_ERR(base))
-		return PTR_ERR(base);
+	ddata->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(ddata->base))
+		return PTR_ERR(ddata->base);
 
-	clk = devm_clk_get(&pdev->dev, NULL);
-	if (IS_ERR(clk))
-		return PTR_ERR(clk);
+	ddata->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(ddata->clk))
+		return PTR_ERR(ddata->clk);
 
-	err = clk_prepare_enable(clk);
+	err = clk_prepare_enable(ddata->clk);
 	if (err)
 		return err;
 
@@ -76,9 +85,9 @@ static int atmel_flexcom_probe(struct platform_device *pdev)
 	 * inaccessible and are read as zero. Also the external I/O lines of the
 	 * Flexcom are muxed to reach the selected device.
 	 */
-	writel(FLEX_MR_OPMODE(opmode), base + FLEX_MR);
+	writel(FLEX_MR_OPMODE(ddata->opmode), ddata->base + FLEX_MR);
 
-	clk_disable_unprepare(clk);
+	clk_disable_unprepare(ddata->clk);
 
 	return devm_of_platform_populate(&pdev->dev);
 }
@@ -89,10 +98,34 @@ static const struct of_device_id atmel_flexcom_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match);
 
+#ifdef CONFIG_PM_SLEEP
+static int atmel_flexcom_resume(struct device *dev)
+{
+	struct atmel_flexcom *ddata = dev_get_drvdata(dev);
+	int err;
+	u32 val;
+
+	err = clk_prepare_enable(ddata->clk);
+	if (err)
+		return err;
+
+	val = FLEX_MR_OPMODE(ddata->opmode),
+	writel(val, ddata->base + FLEX_MR);
+
+	clk_disable_unprepare(ddata->clk);
+
+	return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(atmel_flexcom_pm_ops, NULL,
+			 atmel_flexcom_resume);
+
 static struct platform_driver atmel_flexcom_driver = {
 	.probe	= atmel_flexcom_probe,
 	.driver	= {
 		.name		= "atmel_flexcom",
+		.pm		= &atmel_flexcom_pm_ops,
 		.of_match_table	= atmel_flexcom_of_match,
 	},
 };
-- 
2.14.1

Re: [PATCH v6] atmel_flexcom: Support resuming after a chip reset

[Alexandre Belloni]

On 12/12/2017 at 17:21:19 +0100, Romain Izard wrote:
> The controller used by a flexcom module is configured at boot, and left
> alone after this. In the suspend mode called "backup with self-refresh"
> available on SAMA5D2, the chip will resume with most of its registers
> reset. In this case, we need to restore the state of the flexcom driver
> on resume.
> 
> Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>

Seems good to me

Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

> ---
> Changes in v5:
> * extract from the patch series, and send as a standalone patch
> 
> Changes in v6:
> * Reword the patch title and description
> * Rename the internal structure to ddata
> 
>  drivers/mfd/atmel-flexcom.c | 63 ++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 48 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/mfd/atmel-flexcom.c b/drivers/mfd/atmel-flexcom.c
> index 064bde9cff5a..f684a93a3340 100644
> --- a/drivers/mfd/atmel-flexcom.c
> +++ b/drivers/mfd/atmel-flexcom.c
> @@ -39,34 +39,43 @@
>  #define FLEX_MR_OPMODE(opmode)	(((opmode) << FLEX_MR_OPMODE_OFFSET) &	\
>  				 FLEX_MR_OPMODE_MASK)
>  
> +struct atmel_flexcom {
> +	void __iomem *base;
> +	u32 opmode;
> +	struct clk *clk;
> +};
>  
>  static int atmel_flexcom_probe(struct platform_device *pdev)
>  {
>  	struct device_node *np = pdev->dev.of_node;
> -	struct clk *clk;
>  	struct resource *res;
> -	void __iomem *base;
> -	u32 opmode;
> +	struct atmel_flexcom *ddata;
>  	int err;
>  
> -	err = of_property_read_u32(np, "atmel,flexcom-mode", &opmode);
> +	ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
> +	if (!ddata)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, ddata);
> +
> +	err = of_property_read_u32(np, "atmel,flexcom-mode", &ddata->opmode);
>  	if (err)
>  		return err;
>  
> -	if (opmode < ATMEL_FLEXCOM_MODE_USART ||
> -	    opmode > ATMEL_FLEXCOM_MODE_TWI)
> +	if (ddata->opmode < ATMEL_FLEXCOM_MODE_USART ||
> +	    ddata->opmode > ATMEL_FLEXCOM_MODE_TWI)
>  		return -EINVAL;
>  
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> -	base = devm_ioremap_resource(&pdev->dev, res);
> -	if (IS_ERR(base))
> -		return PTR_ERR(base);
> +	ddata->base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(ddata->base))
> +		return PTR_ERR(ddata->base);
>  
> -	clk = devm_clk_get(&pdev->dev, NULL);
> -	if (IS_ERR(clk))
> -		return PTR_ERR(clk);
> +	ddata->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(ddata->clk))
> +		return PTR_ERR(ddata->clk);
>  
> -	err = clk_prepare_enable(clk);
> +	err = clk_prepare_enable(ddata->clk);
>  	if (err)
>  		return err;
>  
> @@ -76,9 +85,9 @@ static int atmel_flexcom_probe(struct platform_device *pdev)
>  	 * inaccessible and are read as zero. Also the external I/O lines of the
>  	 * Flexcom are muxed to reach the selected device.
>  	 */
> -	writel(FLEX_MR_OPMODE(opmode), base + FLEX_MR);
> +	writel(FLEX_MR_OPMODE(ddata->opmode), ddata->base + FLEX_MR);
>  
> -	clk_disable_unprepare(clk);
> +	clk_disable_unprepare(ddata->clk);
>  
>  	return devm_of_platform_populate(&pdev->dev);
>  }
> @@ -89,10 +98,34 @@ static const struct of_device_id atmel_flexcom_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match);
>  
> +#ifdef CONFIG_PM_SLEEP
> +static int atmel_flexcom_resume(struct device *dev)
> +{
> +	struct atmel_flexcom *ddata = dev_get_drvdata(dev);
> +	int err;
> +	u32 val;
> +
> +	err = clk_prepare_enable(ddata->clk);
> +	if (err)
> +		return err;
> +
> +	val = FLEX_MR_OPMODE(ddata->opmode),
> +	writel(val, ddata->base + FLEX_MR);
> +
> +	clk_disable_unprepare(ddata->clk);
> +
> +	return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(atmel_flexcom_pm_ops, NULL,
> +			 atmel_flexcom_resume);
> +
>  static struct platform_driver atmel_flexcom_driver = {
>  	.probe	= atmel_flexcom_probe,
>  	.driver	= {
>  		.name		= "atmel_flexcom",
> +		.pm		= &atmel_flexcom_pm_ops,
>  		.of_match_table	= atmel_flexcom_of_match,
>  	},
>  };
> -- 
> 2.14.1
> 

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

Re: [PATCH v6] atmel_flexcom: Support resuming after a chip reset

[Lee Jones]

On Tue, 12 Dec 2017, Romain Izard wrote:

> The controller used by a flexcom module is configured at boot, and left
> alone after this. In the suspend mode called "backup with self-refresh"
> available on SAMA5D2, the chip will resume with most of its registers
> reset. In this case, we need to restore the state of the flexcom driver
> on resume.
> 
> Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
> ---
> Changes in v5:
> * extract from the patch series, and send as a standalone patch
> 
> Changes in v6:
> * Reword the patch title and description
> * Rename the internal structure to ddata
> 
>  drivers/mfd/atmel-flexcom.c | 63 ++++++++++++++++++++++++++++++++++-----------
>  1 file changed, 48 insertions(+), 15 deletions(-)

Applied, thanks.

-- 
Lee Jones
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH v6] atmel_flexcom: Support resuming after a chip reset

[Nicolas Ferre]

On 18/12/2017 at 21:19, Alexandre Belloni wrote:
> On 12/12/2017 at 17:21:19 +0100, Romain Izard wrote:
>> The controller used by a flexcom module is configured at boot, and left
>> alone after this. In the suspend mode called "backup with self-refresh"
>> available on SAMA5D2, the chip will resume with most of its registers
>> reset. In this case, we need to restore the state of the flexcom driver
>> on resume.
>>
>> Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
> 
> Seems good to me
> 
> Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

Thanks Romain, of course I can add the tags that I gave you already:

Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Tested-by: Nicolas Ferre <nicolas.ferre@microchip.com>

Lee,
It seems that you already gave your tag for the v5 of this patch. The
wording is even better with this patch. So, can you take this patch in
your tree?

Best regards,
  Nicolas


>> ---
>> Changes in v5:
>> * extract from the patch series, and send as a standalone patch
>>
>> Changes in v6:
>> * Reword the patch title and description
>> * Rename the internal structure to ddata
>>
>>  drivers/mfd/atmel-flexcom.c | 63 ++++++++++++++++++++++++++++++++++-----------
>>  1 file changed, 48 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/mfd/atmel-flexcom.c b/drivers/mfd/atmel-flexcom.c
>> index 064bde9cff5a..f684a93a3340 100644
>> --- a/drivers/mfd/atmel-flexcom.c
>> +++ b/drivers/mfd/atmel-flexcom.c
>> @@ -39,34 +39,43 @@
>>  #define FLEX_MR_OPMODE(opmode)	(((opmode) << FLEX_MR_OPMODE_OFFSET) &	\
>>  				 FLEX_MR_OPMODE_MASK)
>>  
>> +struct atmel_flexcom {
>> +	void __iomem *base;
>> +	u32 opmode;
>> +	struct clk *clk;
>> +};
>>  
>>  static int atmel_flexcom_probe(struct platform_device *pdev)
>>  {
>>  	struct device_node *np = pdev->dev.of_node;
>> -	struct clk *clk;
>>  	struct resource *res;
>> -	void __iomem *base;
>> -	u32 opmode;
>> +	struct atmel_flexcom *ddata;
>>  	int err;
>>  
>> -	err = of_property_read_u32(np, "atmel,flexcom-mode", &opmode);
>> +	ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
>> +	if (!ddata)
>> +		return -ENOMEM;
>> +
>> +	platform_set_drvdata(pdev, ddata);
>> +
>> +	err = of_property_read_u32(np, "atmel,flexcom-mode", &ddata->opmode);
>>  	if (err)
>>  		return err;
>>  
>> -	if (opmode < ATMEL_FLEXCOM_MODE_USART ||
>> -	    opmode > ATMEL_FLEXCOM_MODE_TWI)
>> +	if (ddata->opmode < ATMEL_FLEXCOM_MODE_USART ||
>> +	    ddata->opmode > ATMEL_FLEXCOM_MODE_TWI)
>>  		return -EINVAL;
>>  
>>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> -	base = devm_ioremap_resource(&pdev->dev, res);
>> -	if (IS_ERR(base))
>> -		return PTR_ERR(base);
>> +	ddata->base = devm_ioremap_resource(&pdev->dev, res);
>> +	if (IS_ERR(ddata->base))
>> +		return PTR_ERR(ddata->base);
>>  
>> -	clk = devm_clk_get(&pdev->dev, NULL);
>> -	if (IS_ERR(clk))
>> -		return PTR_ERR(clk);
>> +	ddata->clk = devm_clk_get(&pdev->dev, NULL);
>> +	if (IS_ERR(ddata->clk))
>> +		return PTR_ERR(ddata->clk);
>>  
>> -	err = clk_prepare_enable(clk);
>> +	err = clk_prepare_enable(ddata->clk);
>>  	if (err)
>>  		return err;
>>  
>> @@ -76,9 +85,9 @@ static int atmel_flexcom_probe(struct platform_device *pdev)
>>  	 * inaccessible and are read as zero. Also the external I/O lines of the
>>  	 * Flexcom are muxed to reach the selected device.
>>  	 */
>> -	writel(FLEX_MR_OPMODE(opmode), base + FLEX_MR);
>> +	writel(FLEX_MR_OPMODE(ddata->opmode), ddata->base + FLEX_MR);
>>  
>> -	clk_disable_unprepare(clk);
>> +	clk_disable_unprepare(ddata->clk);
>>  
>>  	return devm_of_platform_populate(&pdev->dev);
>>  }
>> @@ -89,10 +98,34 @@ static const struct of_device_id atmel_flexcom_of_match[] = {
>>  };
>>  MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match);
>>  
>> +#ifdef CONFIG_PM_SLEEP
>> +static int atmel_flexcom_resume(struct device *dev)
>> +{
>> +	struct atmel_flexcom *ddata = dev_get_drvdata(dev);
>> +	int err;
>> +	u32 val;
>> +
>> +	err = clk_prepare_enable(ddata->clk);
>> +	if (err)
>> +		return err;
>> +
>> +	val = FLEX_MR_OPMODE(ddata->opmode),
>> +	writel(val, ddata->base + FLEX_MR);
>> +
>> +	clk_disable_unprepare(ddata->clk);
>> +
>> +	return 0;
>> +}
>> +#endif
>> +
>> +static SIMPLE_DEV_PM_OPS(atmel_flexcom_pm_ops, NULL,
>> +			 atmel_flexcom_resume);
>> +
>>  static struct platform_driver atmel_flexcom_driver = {
>>  	.probe	= atmel_flexcom_probe,
>>  	.driver	= {
>>  		.name		= "atmel_flexcom",
>> +		.pm		= &atmel_flexcom_pm_ops,
>>  		.of_match_table	= atmel_flexcom_of_match,
>>  	},
>>  };
>> -- 
>> 2.14.1
>>
> 


-- 
Nicolas Ferre

Re: [PATCH v6] atmel_flexcom: Support resuming after a chip reset

[Lee Jones]

On Tue, 19 Dec 2017, Nicolas Ferre wrote:

> On 18/12/2017 at 21:19, Alexandre Belloni wrote:
> > On 12/12/2017 at 17:21:19 +0100, Romain Izard wrote:
> >> The controller used by a flexcom module is configured at boot, and left
> >> alone after this. In the suspend mode called "backup with self-refresh"
> >> available on SAMA5D2, the chip will resume with most of its registers
> >> reset. In this case, we need to restore the state of the flexcom driver
> >> on resume.
> >>
> >> Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
> > 
> > Seems good to me
> > 
> > Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
> 
> Thanks Romain, of course I can add the tags that I gave you already:
> 
> Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
> Tested-by: Nicolas Ferre <nicolas.ferre@microchip.com>
> 
> Lee,
> It seems that you already gave your tag for the v5 of this patch. The
> wording is even better with this patch. So, can you take this patch in
> your tree?

Done. :)

-- 
Lee Jones
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog