[PATCH v4] pwm: renesas-tpu: Add suspend/resume function

[PATCH v4] pwm: renesas-tpu: Add suspend/resume function

[Cao Van Dong]

This patch adds suspend/resume function support for Renesas the 16-Bit Timer
Pulse Unit (TPU) driver. This has been tested on the Salvator-XS board 
with R-Car M3-N and H3 at renesas-drivers-2019-05-21-v5.2-rc1 tag.
I expect this to work on other SoCs.

Test procedure:
  - Enable TPU and pin control in DTS.
  - Make sure switches { SW29-[1-2] are switched off or 
    SW31-[1-4] are switched off(only for Salvator-xs) }.
  - Exercise userspace PWM control for pwm[2,3] 
    of /sys/class/pwm/pwmchip1/ .
  - Inspect PWM signals on the input side of { CN29-[58,60] 
    or SW31-[1,2] (only for Salvator-xs) }
    before and after suspend/resume using an oscilloscope. 

Signed-off-by: Cao Van Dong <cv-dong@jinso.co.jp>
Tested-by: Cao Van Dong <cv-dong@jinso.co.jp>
---
Changes v3 -> v4:
  - Use pwm_is_enabled(pwm) to check channel instead of pwm_get_chip_data(&chip->pwms[i]).
  - Move tpu_pwm_disable() to tpu_pwm_suspend(), tpu_pwm_enable() to tpu_pwm_resume().
  - Remove tpu_pwm_restart_timer() function and remove pm_runtime_get_sync() in tpu_pwm_resume().
---
Changes v2 -> v3:
  - Changes '3' -> TPU_CHANNEL_MAX in loop.
  - Remove pm_runtime_put() function in tpu_pwm_suspend() function.
---
Changes v1 -> v2:
  - Repair the handling code to cover case of using multiple timers.
---
 drivers/pwm/pwm-renesas-tpu.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/drivers/pwm/pwm-renesas-tpu.c b/drivers/pwm/pwm-renesas-tpu.c
index 4a855a2..3c2819b 100644
--- a/drivers/pwm/pwm-renesas-tpu.c
+++ b/drivers/pwm/pwm-renesas-tpu.c
@@ -366,6 +366,47 @@ static void tpu_pwm_disable(struct pwm_chip *chip, struct pwm_device *_pwm)
 	tpu_pwm_timer_stop(pwm);
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int tpu_pwm_suspend(struct device *dev)
+{
+	struct tpu_device *tpu = dev_get_drvdata(dev);
+	struct pwm_chip *chip = &tpu->chip;
+	struct pwm_device *pwm;
+	int i;
+
+	for (i = 0; i < TPU_CHANNEL_MAX; i++) {
+		pwm = &chip->pwms[i];
+		if (pwm_is_enabled(pwm)) {
+			if (!test_bit(PWMF_REQUESTED, &pwm->flags))
+				return 0;
+			tpu_pwm_disable(pwm->chip,pwm);
+		}
+	}
+
+	return 0;
+}
+
+static int tpu_pwm_resume(struct device *dev)
+{
+	struct tpu_device *tpu = dev_get_drvdata(dev);
+	struct pwm_chip *chip = &tpu->chip;
+	struct pwm_device *pwm;
+	int i;
+
+	for (i = 0; i < TPU_CHANNEL_MAX; i++) {
+		pwm = &chip->pwms[i];
+		if (pwm_is_enabled(pwm)) {
+			if (!test_bit(PWMF_REQUESTED, &pwm->flags))
+				return 0;
+			tpu_pwm_enable(pwm->chip,pwm);
+		}
+	}
+
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+static SIMPLE_DEV_PM_OPS(tpu_pwm_pm_ops, tpu_pwm_suspend, tpu_pwm_resume);
+
 static const struct pwm_ops tpu_pwm_ops = {
 	.request = tpu_pwm_request,
 	.free = tpu_pwm_free,
@@ -459,6 +500,7 @@ static struct platform_driver tpu_driver = {
 	.remove		= tpu_remove,
 	.driver		= {
 		.name	= "renesas-tpu-pwm",
+		.pm	= &tpu_pwm_pm_ops,
 		.of_match_table = of_match_ptr(tpu_of_table),
 	}
 };
-- 
2.7.4

Re: [PATCH v4] pwm: renesas-tpu: Add suspend/resume function

[Kuninori Morimoto]

Hi

> This patch adds suspend/resume function support for Renesas the 16-Bit Timer
> Pulse Unit (TPU) driver. This has been tested on the Salvator-XS board 
> with R-Car M3-N and H3 at renesas-drivers-2019-05-21-v5.2-rc1 tag.
> I expect this to work on other SoCs.
(snip)
> +#ifdef CONFIG_PM_SLEEP
> +static int tpu_pwm_suspend(struct device *dev)
> +{
> +	struct tpu_device *tpu = dev_get_drvdata(dev);
> +	struct pwm_chip *chip = &tpu->chip;
> +	struct pwm_device *pwm;
> +	int i;
> +
> +	for (i = 0; i < TPU_CHANNEL_MAX; i++) {
> +		pwm = &chip->pwms[i];
> +		if (pwm_is_enabled(pwm)) {
> +			if (!test_bit(PWMF_REQUESTED, &pwm->flags))
> +				return 0;
> +			tpu_pwm_disable(pwm->chip,pwm);
> +		}
> +	}

I'm not familiar with pwm driver, but pwm_is_enabled() and
if (!test_bit(PWMF_REQUESTED, &pwm->flags)) can be happen in the same time ?
In other words, can we enable pwm without PWMF_REQUESTED ?

> +static int tpu_pwm_resume(struct device *dev)
> +{
> +	struct tpu_device *tpu = dev_get_drvdata(dev);
> +	struct pwm_chip *chip = &tpu->chip;
> +	struct pwm_device *pwm;
> +	int i;
> +
> +	for (i = 0; i < TPU_CHANNEL_MAX; i++) {
> +		pwm = &chip->pwms[i];
> +		if (pwm_is_enabled(pwm)) {
> +			if (!test_bit(PWMF_REQUESTED, &pwm->flags))
> +				return 0;
> +			tpu_pwm_enable(pwm->chip,pwm);
> +		}
> +	}

Please use ${LINUX}/scripts/checkpatch.pl

Thank you for your help !!
Best regards
---
Kuninori Morimoto

Re: [PATCH v4] pwm: renesas-tpu: Add suspend/resume function

[Cao Van Dong]

Dear Morimoto-san,

Thank for your feedback!

On 2019/05/27 10:24, Kuninori Morimoto wrote:
> Hi
>
>> This patch adds suspend/resume function support for Renesas the 16-Bit Timer
>> Pulse Unit (TPU) driver. This has been tested on the Salvator-XS board
>> with R-Car M3-N and H3 at renesas-drivers-2019-05-21-v5.2-rc1 tag.
>> I expect this to work on other SoCs.
> (snip)
>> +#ifdef CONFIG_PM_SLEEP
>> +static int tpu_pwm_suspend(struct device *dev)
>> +{
>> +	struct tpu_device *tpu = dev_get_drvdata(dev);
>> +	struct pwm_chip *chip = &tpu->chip;
>> +	struct pwm_device *pwm;
>> +	int i;
>> +
>> +	for (i = 0; i < TPU_CHANNEL_MAX; i++) {
>> +		pwm = &chip->pwms[i];
>> +		if (pwm_is_enabled(pwm)) {
>> +			if (!test_bit(PWMF_REQUESTED, &pwm->flags))
>> +				return 0;
>> +			tpu_pwm_disable(pwm->chip,pwm);
>> +		}
>> +	}
> I'm not familiar with pwm driver, but pwm_is_enabled() and
> if (!test_bit(PWMF_REQUESTED, &pwm->flags)) can be happen in the same time ?
> In other words, can we enable pwm without PWMF_REQUESTED ?

Thank for your help!
Can. Perhaps the PWMF_REQUESTED check is not necessary. I will remove it.

>> +static int tpu_pwm_resume(struct device *dev)
>> +{
>> +	struct tpu_device *tpu = dev_get_drvdata(dev);
>> +	struct pwm_chip *chip = &tpu->chip;
>> +	struct pwm_device *pwm;
>> +	int i;
>> +
>> +	for (i = 0; i < TPU_CHANNEL_MAX; i++) {
>> +		pwm = &chip->pwms[i];
>> +		if (pwm_is_enabled(pwm)) {
>> +			if (!test_bit(PWMF_REQUESTED, &pwm->flags))
>> +				return 0;
>> +			tpu_pwm_enable(pwm->chip,pwm);
>> +		}
>> +	}
> Please use ${LINUX}/scripts/checkpatch.pl

Thanks for the prompt!

Thank you,
Dong

> Thank you for your help !!
> Best regards
> ---
> Kuninori Morimoto