[PATCH] serial: of-serial: add PM suspend/resume support

[PATCH] serial: of-serial: add PM suspend/resume support

[Jingchang Lu]

This adds PM suspend/resume support for the of-serial driver
to provide power management support on devices attatched to it.

Signed-off-by: Jingchang Lu <jingchang.lu-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
---
 drivers/tty/serial/of_serial.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c
index 27981e2..8bc2563 100644
--- a/drivers/tty/serial/of_serial.c
+++ b/drivers/tty/serial/of_serial.c
@@ -240,6 +240,32 @@ static int of_platform_serial_remove(struct platform_device *ofdev)
 	return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int of_serial_suspend(struct device *dev)
+{
+	struct of_serial_info *info = dev_get_drvdata(dev);
+
+	serial8250_suspend_port(info->line);
+	if (info->clk)
+		clk_disable_unprepare(info->clk);
+
+	return 0;
+}
+
+static int of_serial_resume(struct device *dev)
+{
+	struct of_serial_info *info = dev_get_drvdata(dev);
+
+	if (info->clk)
+		clk_prepare_enable(info->clk);
+
+	serial8250_resume_port(info->line);
+
+	return 0;
+}
+#endif
+static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
+
 /*
  * A few common types, add more as needed.
  */
@@ -271,6 +297,7 @@ static struct platform_driver of_platform_serial_driver = {
 		.name = "of_serial",
 		.owner = THIS_MODULE,
 		.of_match_table = of_platform_serial_table,
+		.pm = &of_serial_pm_ops,
 	},
 	.probe = of_platform_serial_probe,
 	.remove = of_platform_serial_remove,
-- 
1.8.0

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Re: [PATCH] serial: of-serial: add PM suspend/resume support

[Arnd Bergmann]

On Tuesday 23 September 2014 16:34:12 Jingchang Lu wrote:
> This adds PM suspend/resume support for the of-serial driver
> to provide power management support on devices attatched to it.
> 
> Signed-off-by: Jingchang Lu <jingchang.lu@freescale.com>
> 

Looks good to me,

Acked-by: Arnd Bergmann <arnd@arndb.de>

Re: [PATCH] serial: of-serial: add PM suspend/resume support

[Joseph Lo]

Hi,

This patch might have a potential issue that cause system hard hung 
immediately when it accesses to registers with no clock. This could 
happen on many chips that mainline kernel supporting with the setting 
"no_console_suspend=1" during suspend time.

On 09/23/2014 04:34 PM, Jingchang Lu wrote:
> This adds PM suspend/resume support for the of-serial driver
> to provide power management support on devices attatched to it.
>
> Signed-off-by: Jingchang Lu <jingchang.lu-KZfg59tc24xl57MIdRCFDg@public.gmane.org>
> ---
>   drivers/tty/serial/of_serial.c | 27 +++++++++++++++++++++++++++
>   1 file changed, 27 insertions(+)
>
> diff --git a/drivers/tty/serial/of_serial.c b/drivers/tty/serial/of_serial.c
> index 27981e2..8bc2563 100644
> --- a/drivers/tty/serial/of_serial.c
> +++ b/drivers/tty/serial/of_serial.c
> @@ -240,6 +240,32 @@ static int of_platform_serial_remove(struct platform_device *ofdev)
>   	return 0;
>   }
>
> +#ifdef CONFIG_PM_SLEEP
> +static int of_serial_suspend(struct device *dev)
> +{
> +	struct of_serial_info *info = dev_get_drvdata(dev);
> +
> +	serial8250_suspend_port(info->line);
> +	if (info->clk)
The fix would be something like this.
	if (info->clk && console_suspend_enabled)

> +		clk_disable_unprepare(info->clk);
> +
> +	return 0;
> +}
> +
> +static int of_serial_resume(struct device *dev)
> +{
> +	struct of_serial_info *info = dev_get_drvdata(dev);
> +
> +	if (info->clk)
Ditto.

Thanks,
-Joseph
> +		clk_prepare_enable(info->clk);
> +
> +	serial8250_resume_port(info->line);
> +
> +	return 0;
> +}
> +#endif
> +static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
> +
>   /*
>    * A few common types, add more as needed.
>    */
> @@ -271,6 +297,7 @@ static struct platform_driver of_platform_serial_driver = {
>   		.name = "of_serial",
>   		.owner = THIS_MODULE,
>   		.of_match_table = of_platform_serial_table,
> +		.pm = &of_serial_pm_ops,
>   	},
>   	.probe = of_platform_serial_probe,
>   	.remove = of_platform_serial_remove,
>
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RE: [PATCH] serial: of-serial: add PM suspend/resume support

[Jingchang Lu]

>-----Original Message-----
>From: Joseph Lo [mailto:josephl@nvidia.com]
>Sent: Friday, October 03, 2014 3:46 PM
>To: Lu Jingchang-B35083; gregkh@linuxfoundation.org
>Cc: devicetree@vger.kernel.org; arnd@arndb.de; linux-
>kernel@vger.kernel.org; linux-serial@vger.kernel.org; linux-arm-
>kernel@lists.infradead.org
>Subject: Re: [PATCH] serial: of-serial: add PM suspend/resume support
>
>Hi,
>
>This patch might have a potential issue that cause system hard hung
>immediately when it accesses to registers with no clock. This could happen
>on many chips that mainline kernel supporting with the setting
>"no_console_suspend=1" during suspend time.
>
>On 09/23/2014 04:34 PM, Jingchang Lu wrote:
>> This adds PM suspend/resume support for the of-serial driver to
>> provide power management support on devices attatched to it.
>>
>> Signed-off-by: Jingchang Lu <jingchang.lu@freescale.com>
>> ---
>>   drivers/tty/serial/of_serial.c | 27 +++++++++++++++++++++++++++
>>   1 file changed, 27 insertions(+)
>>
>> diff --git a/drivers/tty/serial/of_serial.c
>> b/drivers/tty/serial/of_serial.c index 27981e2..8bc2563 100644
>> --- a/drivers/tty/serial/of_serial.c
>> +++ b/drivers/tty/serial/of_serial.c
>> @@ -240,6 +240,32 @@ static int of_platform_serial_remove(struct
>platform_device *ofdev)
>>   	return 0;
>>   }
>>
>> +#ifdef CONFIG_PM_SLEEP
>> +static int of_serial_suspend(struct device *dev) {
>> +	struct of_serial_info *info = dev_get_drvdata(dev);
>> +
>> +	serial8250_suspend_port(info->line);
>> +	if (info->clk)
>The fix would be something like this.
>	if (info->clk && console_suspend_enabled)
>
Yes, there will be, I will send a fix on this, thanks!

Best Regards,
Jingchang