diff mbox series

[v4,1/4] pwm: dwc: Fix PM regression

Message ID 20240219033835.11369-2-raag.jadav@intel.com
State New
Headers
Series DesignWare PWM improvements |

Commit Message

Raag Jadav Feb. 19, 2024, 3:38 a.m. UTC 
  While preparing dwc driver for devm_pwmchip_alloc() usage, commit
df41cd8bbcad ("pwm: dwc: Prepare removing pwm_chip from driver data")
modified ->suspend() handle to use the pwm_chip as driver_data for
accessing struct dwc_pwm, but didn't modify ->resume() handle with
relevant changes. This results into illegal memory access during
device wakeup and causes a PM regression.

Fix this by correctly accessing struct dwc_pwm in ->resume() handle.

Fixes: df41cd8bbcad ("pwm: dwc: Prepare removing pwm_chip from driver data")
Signed-off-by: Raag Jadav <raag.jadav@intel.com>
---
 drivers/pwm/pwm-dwc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Uwe Kleine-König Feb. 19, 2024, 7:22 a.m. UTC | #1 
Hello Raag,

On Mon, Feb 19, 2024 at 09:08:32AM +0530, Raag Jadav wrote:
> While preparing dwc driver for devm_pwmchip_alloc() usage, commit
> df41cd8bbcad ("pwm: dwc: Prepare removing pwm_chip from driver data")
> modified ->suspend() handle to use the pwm_chip as driver_data for
> accessing struct dwc_pwm, but didn't modify ->resume() handle with
> relevant changes. This results into illegal memory access during
> device wakeup and causes a PM regression.
> 
> Fix this by correctly accessing struct dwc_pwm in ->resume() handle.
> 
> Fixes: df41cd8bbcad ("pwm: dwc: Prepare removing pwm_chip from driver data")
> Signed-off-by: Raag Jadav <raag.jadav@intel.com>
> ---
>  drivers/pwm/pwm-dwc.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pwm/pwm-dwc.c b/drivers/pwm/pwm-dwc.c
> index 8ca1c20a6aaf..c0e586688e57 100644
> --- a/drivers/pwm/pwm-dwc.c
> +++ b/drivers/pwm/pwm-dwc.c
> @@ -95,7 +95,8 @@ static int dwc_pwm_suspend(struct device *dev)
>  
>  static int dwc_pwm_resume(struct device *dev)
>  {
> -	struct dwc_pwm *dwc = dev_get_drvdata(dev);
> +	struct pwm_chip *chip = dev_get_drvdata(dev);
> +	struct dwc_pwm *dwc = to_dwc_pwm(chip);
>  	int i;
>  
>  	for (i = 0; i < DWC_TIMERS_TOTAL; i++) {

If you're ok I'd squash this into df41cd8bbcad adding

	Thanks to Raag Jadav for providing a hunk of this patch that Uwe
	missed during creation of this patch.

to the commit log.

Best regards
Uwe
Raag Jadav Feb. 19, 2024, 9:05 a.m. UTC | #2 
On Mon, Feb 19, 2024 at 08:22:15AM +0100, Uwe Kleine-König wrote:
> Hello Raag,
> 
> On Mon, Feb 19, 2024 at 09:08:32AM +0530, Raag Jadav wrote:
> > While preparing dwc driver for devm_pwmchip_alloc() usage, commit
> > df41cd8bbcad ("pwm: dwc: Prepare removing pwm_chip from driver data")
> > modified ->suspend() handle to use the pwm_chip as driver_data for
> > accessing struct dwc_pwm, but didn't modify ->resume() handle with
> > relevant changes. This results into illegal memory access during
> > device wakeup and causes a PM regression.
> > 
> > Fix this by correctly accessing struct dwc_pwm in ->resume() handle.
> > 
> > Fixes: df41cd8bbcad ("pwm: dwc: Prepare removing pwm_chip from driver data")
> > Signed-off-by: Raag Jadav <raag.jadav@intel.com>
> > ---
> >  drivers/pwm/pwm-dwc.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/pwm/pwm-dwc.c b/drivers/pwm/pwm-dwc.c
> > index 8ca1c20a6aaf..c0e586688e57 100644
> > --- a/drivers/pwm/pwm-dwc.c
> > +++ b/drivers/pwm/pwm-dwc.c
> > @@ -95,7 +95,8 @@ static int dwc_pwm_suspend(struct device *dev)
> >  
> >  static int dwc_pwm_resume(struct device *dev)
> >  {
> > -	struct dwc_pwm *dwc = dev_get_drvdata(dev);
> > +	struct pwm_chip *chip = dev_get_drvdata(dev);
> > +	struct dwc_pwm *dwc = to_dwc_pwm(chip);
> >  	int i;
> >  
> >  	for (i = 0; i < DWC_TIMERS_TOTAL; i++) {
> 
> If you're ok I'd squash this into df41cd8bbcad adding
> 
> 	Thanks to Raag Jadav for providing a hunk of this patch that Uwe
> 	missed during creation of this patch.
> 
> to the commit log.

Works for me.

Raag
diff mbox series

Patch

diff --git a/drivers/pwm/pwm-dwc.c b/drivers/pwm/pwm-dwc.c
index 8ca1c20a6aaf..c0e586688e57 100644
--- a/drivers/pwm/pwm-dwc.c
+++ b/drivers/pwm/pwm-dwc.c
@@ -95,7 +95,8 @@  static int dwc_pwm_suspend(struct device *dev)
 
 static int dwc_pwm_resume(struct device *dev)
 {
-	struct dwc_pwm *dwc = dev_get_drvdata(dev);
+	struct pwm_chip *chip = dev_get_drvdata(dev);
+	struct dwc_pwm *dwc = to_dwc_pwm(chip);
 	int i;
 
 	for (i = 0; i < DWC_TIMERS_TOTAL; i++) {