[PATCH] phy: qcom-snps: Add runtime suspend and resume handlers

[PATCH] phy: qcom-snps: Add runtime suspend and resume handlers

[Wesley Cheng]

Allow for the PHY to be put into a powered down state when possible.
Add the required suspend and resume callbacks, which will determine
what resources can be turned off depending on the cable status.

Signed-off-by: Wesley Cheng <wcheng@codeaurora.org>
---
Depends-on: phy: qcom-snps: Add SNPS USB PHY driver for QCOM based SOCs
(https://patchwork.kernel.org/patch/11486171/)
---
 drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c | 93 +++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)

diff --git a/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c b/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c
index 20442a3..f48d877 100644
--- a/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c
+++ b/drivers/phy/qualcomm/phy-qcom-snps-femto-v2.c
@@ -76,7 +76,9 @@
  * @iface_clk: phy interface clock
  * @phy_reset: phy reset control
  * @vregs: regulator supplies bulk data
+ * @suspended: PHY is in the suspended state
  * @phy_initialized: if PHY has been initialized correctly
+ * @mode: contains the current mode the PHY is in
  */
 struct qcom_snps_hsphy {
 	struct phy *phy;
@@ -87,7 +89,9 @@ struct qcom_snps_hsphy {
 	struct reset_control *phy_reset;
 	struct regulator_bulk_data vregs[SNPS_HS_NUM_VREGS];
 
+	bool suspended;
 	bool phy_initialized;
+	enum phy_mode mode;
 };
 
 static inline void qcom_snps_hsphy_write_mask(void __iomem *base, u32 offset,
@@ -104,6 +108,77 @@ static inline void qcom_snps_hsphy_write_mask(void __iomem *base, u32 offset,
 	readl_relaxed(base + offset);
 }
 
+static int qcom_snps_hsphy_suspend(struct qcom_snps_hsphy *hsphy)
+{
+	if (hsphy->suspended)
+		return 0;
+
+	dev_dbg(&hsphy->phy->dev, "Suspend QCOM SNPS PHY, mode = %d \n", hsphy->mode);
+
+	if (hsphy->mode == PHY_MODE_USB_HOST) {
+		/* Enable auto-resume to meet remote wakeup timing */
+		qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_HS_PHY_CTRL2,
+										USB2_AUTO_RESUME, USB2_AUTO_RESUME);
+		usleep_range(500, 1000);
+		qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_HS_PHY_CTRL2,
+										0, USB2_AUTO_RESUME);
+	}
+
+	clk_disable_unprepare(hsphy->cfg_ahb_clk);
+	hsphy->suspended = true;
+
+	return 0;
+}
+
+static int qcom_snps_hsphy_resume(struct qcom_snps_hsphy *hsphy)
+{
+	int ret = 0;
+
+	if (!hsphy->suspended)
+		return 0;
+
+	dev_dbg(&hsphy->phy->dev, "Resume QCOM SNPS PHY, mode = %d \n", hsphy->mode);
+
+	ret = clk_prepare_enable(hsphy->cfg_ahb_clk);
+	if (ret) {
+		dev_err(&hsphy->phy->dev, "failed to enable cfg ahb clock, %d\n", ret);
+		return ret;
+	}
+
+	hsphy->suspended = false;
+	return 0;
+}
+
+static int __maybe_unused qcom_snps_hsphy_runtime_suspend(struct device *dev)
+{
+	struct qcom_snps_hsphy *hsphy = dev_get_drvdata(dev);
+
+	if (!hsphy->phy_initialized)
+		return 0;
+
+	qcom_snps_hsphy_suspend(hsphy);
+	return 0;
+}
+
+static int __maybe_unused qcom_snps_hsphy_runtime_resume(struct device *dev)
+{
+	struct qcom_snps_hsphy *hsphy = dev_get_drvdata(dev);
+
+	if (!hsphy->phy_initialized)
+		return 0;
+
+	qcom_snps_hsphy_resume(hsphy);
+	return 0;
+}
+
+static int qcom_snps_hsphy_set_mode(struct phy *phy, enum phy_mode mode, int submode)
+{
+	struct qcom_snps_hsphy *hsphy = phy_get_drvdata(phy);
+
+	hsphy->mode = mode;
+	return 0;
+}
+
 static int qcom_snps_hsphy_init(struct phy *phy)
 {
 	struct qcom_snps_hsphy *hsphy = phy_get_drvdata(phy);
@@ -171,6 +246,7 @@ static int qcom_snps_hsphy_init(struct phy *phy)
 					UTMI_PHY_CMN_CTRL_OVERRIDE_EN, 0);
 
 	hsphy->phy_initialized = true;
+	hsphy->suspended = false;
 
 	return 0;
 
@@ -197,6 +273,7 @@ static int qcom_snps_hsphy_exit(struct phy *phy)
 static const struct phy_ops qcom_snps_hsphy_gen_ops = {
 	.init		= qcom_snps_hsphy_init,
 	.exit		= qcom_snps_hsphy_exit,
+	.set_mode	= qcom_snps_hsphy_set_mode,
 	.owner		= THIS_MODULE,
 };
 
@@ -208,6 +285,11 @@ static int qcom_snps_hsphy_exit(struct phy *phy)
 };
 MODULE_DEVICE_TABLE(of, qcom_snps_hsphy_of_match_table);
 
+static const struct dev_pm_ops qcom_snps_hsphy_pm_ops = {
+	SET_RUNTIME_PM_OPS(qcom_snps_hsphy_runtime_suspend,
+			   qcom_snps_hsphy_runtime_resume, NULL)
+};
+
 static int qcom_snps_hsphy_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -251,6 +333,14 @@ static int qcom_snps_hsphy_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+	/*
+	 * Prevent runtime pm from being ON by default. Users can enable
+	 * it using power/control in sysfs.
+	 */
+	pm_runtime_forbid(dev);
+
 	generic_phy = devm_phy_create(dev, NULL, &qcom_snps_hsphy_gen_ops);
 	if (IS_ERR(generic_phy)) {
 		ret = PTR_ERR(generic_phy);
@@ -265,6 +355,8 @@ static int qcom_snps_hsphy_probe(struct platform_device *pdev)
 	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
 	if (!IS_ERR(phy_provider))
 		dev_dbg(dev, "Registered Qcom-SNPS HS phy\n");
+	else
+		pm_runtime_disable(dev);
 
 	return PTR_ERR_OR_ZERO(phy_provider);
 }
@@ -273,6 +365,7 @@ static int qcom_snps_hsphy_probe(struct platform_device *pdev)
 	.probe		= qcom_snps_hsphy_probe,
 	.driver = {
 		.name	= "qcom-snps-hs-femto-v2-phy",
+		.pm = &qcom_snps_hsphy_pm_ops,
 		.of_match_table = qcom_snps_hsphy_of_match_table,
 	},
 };
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH] phy: qcom-snps: Add runtime suspend and resume handlers

[Vinod Koul]

On 23-04-20, 10:26, Wesley Cheng wrote:

> +static int qcom_snps_hsphy_suspend(struct qcom_snps_hsphy *hsphy)
> +{
> +	if (hsphy->suspended)
> +		return 0;
> +
> +	dev_dbg(&hsphy->phy->dev, "Suspend QCOM SNPS PHY, mode = %d \n", hsphy->mode);
> +
> +	if (hsphy->mode == PHY_MODE_USB_HOST) {
> +		/* Enable auto-resume to meet remote wakeup timing */
> +		qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_HS_PHY_CTRL2,
> +										USB2_AUTO_RESUME, USB2_AUTO_RESUME);
> +		usleep_range(500, 1000);
> +		qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_HS_PHY_CTRL2,
> +										0, USB2_AUTO_RESUME);

Kernel has a coding guideline where we try to "stick" to 80 char limit
and is sometimes okay like debug logs. Above is not okay. Please fix it
and run ./scripts/checkpatch.pl --strict on your patch and fix all
errors. Warning and checks at your discretion using common sense. When
in doubt do ask :)

> +	}
> +
> +	clk_disable_unprepare(hsphy->cfg_ahb_clk);
> +	hsphy->suspended = true;

why do you need to track this?

> +
> +	return 0;
> +}
> +
> +static int qcom_snps_hsphy_resume(struct qcom_snps_hsphy *hsphy)
> +{
> +	int ret = 0;

superfluous init..

>  static int qcom_snps_hsphy_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -251,6 +333,14 @@ static int qcom_snps_hsphy_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> +	pm_runtime_set_active(dev);
> +	pm_runtime_enable(dev);

would it not make sense to enable this after pjy in initialized?

-- 
~Vinod

Re: [PATCH] phy: qcom-snps: Add runtime suspend and resume handlers

[Wesley Cheng]

On 4/27/2020 9:59 AM, Vinod Koul wrote:
> On 23-04-20, 10:26, Wesley Cheng wrote:
> 
>> +static int qcom_snps_hsphy_suspend(struct qcom_snps_hsphy *hsphy)
>> +{
>> +	if (hsphy->suspended)
>> +		return 0;
>> +
>> +	dev_dbg(&hsphy->phy->dev, "Suspend QCOM SNPS PHY, mode = %d \n", hsphy->mode);
>> +
>> +	if (hsphy->mode == PHY_MODE_USB_HOST) {
>> +		/* Enable auto-resume to meet remote wakeup timing */
>> +		qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_HS_PHY_CTRL2,
>> +										USB2_AUTO_RESUME, USB2_AUTO_RESUME);
>> +		usleep_range(500, 1000);
>> +		qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_HS_PHY_CTRL2,
>> +										0, USB2_AUTO_RESUME);
> 
> Kernel has a coding guideline where we try to "stick" to 80 char limit
> and is sometimes okay like debug logs. Above is not okay. Please fix it
> and run ./scripts/checkpatch.pl --strict on your patch and fix all
> errors. Warning and checks at your discretion using common sense. When
> in doubt do ask :)
> 

Hi Vinod,

Thanks for the input.  I do run the checkpatch script before sending
patches, and addressing the errors.  However, seems this was tagged as a
warning instead.  Will keep in mind to address as many warnings as I can
as well.

>> +	}
>> +
>> +	clk_disable_unprepare(hsphy->cfg_ahb_clk);
>> +	hsphy->suspended = true;
> 
> why do you need to track this?
> 

More for debug purposes in case the RPM state becomes out of sync with
the expected PHY state.  We've seen some situations during PM
suspend/resume testing where our RPM routines aren't executed, as PM
will disable RPM briefly.  It would be nice to be able to catch these
situations after collecting our crash dumps.

>> +
>> +	return 0;
>> +}
>> +
>> +static int qcom_snps_hsphy_resume(struct qcom_snps_hsphy *hsphy)
>> +{
>> +	int ret = 0;
> 
> superfluous init..
> 

Agreed.

>>  static int qcom_snps_hsphy_probe(struct platform_device *pdev)
>>  {
>>  	struct device *dev = &pdev->dev;
>> @@ -251,6 +333,14 @@ static int qcom_snps_hsphy_probe(struct platform_device *pdev)
>>  		return ret;
>>  	}
>>  
>> +	pm_runtime_set_active(dev);
>> +	pm_runtime_enable(dev);
> 
> would it not make sense to enable this after pjy in initialized?
> 

Not sure we want to put this in the phy_init() callback, as we can't
guarantee how the driver registering the PHY will use it. It'll put the
requirement of having to call phy_exit() for every phy_init() sequence,
in order to avoid unbalanced disable_depth warnings from the RPM driver.

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project