[PATCH] usb: cdns3: imx: Rework system PM to avoid duplicated operations

[PATCH] usb: cdns3: imx: Rework system PM to avoid duplicated operations

[Shenwei Wang]

The current implementation uses the same callbacks for system PM and
runtime PM suspend/resume without any state checking. This can cause the
clocks to be prepared/unprepared twice, leading to kernel warning issues.

This patch resolves the double prepare/unprepare issues by separating the
runtime PM and system PM handling.

Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
Reviewed-by: Frank Li <frank.li@nxp.com>
---
 drivers/usb/cdns3/cdns3-imx.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/cdns3/cdns3-imx.c b/drivers/usb/cdns3/cdns3-imx.c
index 59860d1753fd..1c6bc6036c15 100644
--- a/drivers/usb/cdns3/cdns3-imx.c
+++ b/drivers/usb/cdns3/cdns3-imx.c
@@ -375,14 +375,22 @@ static inline bool cdns_imx_is_power_lost(struct cdns_imx *data)
 		return false;
 }
 
+static int __maybe_unused cdns_imx_system_suspend(struct device *dev)
+{
+	pm_runtime_put_sync(dev);
+	return 0;
+}
+
 static int __maybe_unused cdns_imx_system_resume(struct device *dev)
 {
 	struct cdns_imx *data = dev_get_drvdata(dev);
 	int ret;
 
-	ret = cdns_imx_resume(dev);
-	if (ret)
+	ret = pm_runtime_resume_and_get(dev);
+	if (ret < 0) {
+		dev_err(dev, "Could not get runtime PM.\n");
 		return ret;
+	}
 
 	if (cdns_imx_is_power_lost(data)) {
 		dev_dbg(dev, "resume from power lost\n");
@@ -405,7 +413,7 @@ static int cdns_imx_platform_suspend(struct device *dev,
 
 static const struct dev_pm_ops cdns_imx_pm_ops = {
 	SET_RUNTIME_PM_OPS(cdns_imx_suspend, cdns_imx_resume, NULL)
-	SET_SYSTEM_SLEEP_PM_OPS(cdns_imx_suspend, cdns_imx_system_resume)
+	SET_SYSTEM_SLEEP_PM_OPS(cdns_imx_system_suspend, cdns_imx_system_resume)
 };
 
 static const struct of_device_id cdns_imx_of_match[] = {
-- 
2.34.1

Re: [PATCH] usb: cdns3: imx: Rework system PM to avoid duplicated operations

[Peter Chen]

On 23-05-23 13:44:12, Shenwei Wang wrote:
> The current implementation uses the same callbacks for system PM and
> runtime PM suspend/resume without any state checking. This can cause the
> clocks to be prepared/unprepared twice, leading to kernel warning issues.
> 
> This patch resolves the double prepare/unprepare issues by separating the
> runtime PM and system PM handling.
> 
> Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
> Reviewed-by: Frank Li <frank.li@nxp.com>
> ---
>  drivers/usb/cdns3/cdns3-imx.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/cdns3/cdns3-imx.c b/drivers/usb/cdns3/cdns3-imx.c
> index 59860d1753fd..1c6bc6036c15 100644
> --- a/drivers/usb/cdns3/cdns3-imx.c
> +++ b/drivers/usb/cdns3/cdns3-imx.c
> @@ -375,14 +375,22 @@ static inline bool cdns_imx_is_power_lost(struct cdns_imx *data)
>  		return false;
>  }
>  
> +static int __maybe_unused cdns_imx_system_suspend(struct device *dev)
> +{
> +	pm_runtime_put_sync(dev);
> +	return 0;
> +}
> +
>  static int __maybe_unused cdns_imx_system_resume(struct device *dev)
>  {
>  	struct cdns_imx *data = dev_get_drvdata(dev);
>  	int ret;
>  
> -	ret = cdns_imx_resume(dev);
> -	if (ret)
> +	ret = pm_runtime_resume_and_get(dev);
> +	if (ret < 0) {
> +		dev_err(dev, "Could not get runtime PM.\n");
>  		return ret;
> +	}
>  
>  	if (cdns_imx_is_power_lost(data)) {
>  		dev_dbg(dev, "resume from power lost\n");
> @@ -405,7 +413,7 @@ static int cdns_imx_platform_suspend(struct device *dev,
>  
>  static const struct dev_pm_ops cdns_imx_pm_ops = {
>  	SET_RUNTIME_PM_OPS(cdns_imx_suspend, cdns_imx_resume, NULL)
> -	SET_SYSTEM_SLEEP_PM_OPS(cdns_imx_suspend, cdns_imx_system_resume)
> +	SET_SYSTEM_SLEEP_PM_OPS(cdns_imx_system_suspend, cdns_imx_system_resume)
>  };
>  
>  static const struct of_device_id cdns_imx_of_match[] = {
> -- 
> 2.34.1
> 

Acked-by: Peter Chen <peter.chen@kernel.org>

-- 

Thanks,
Peter Chen