Re: [PATCH 1/1] PWM Backlight: Fix a bug which could cause the PWM backlight driver use the wrong PWM chip and fail the driver probing if multiple PWM chips exist. This defect could also cause the unintended PWM chip used and unaccessable by other drivers. The patch will check the error state first and allow a deferral PWM backlight probing if the intended PWM driver is not loaded at the probing moment.

[Lee Jones]

> I'm guessing this is your first patch.
> 
> Please read: Documentation/SubmittingPatches
> 
> A few notes for you search for and read about in the above document.
> 
>  - Subject line formatting (short, succinct) 
>  - Commit logs (present, descriptive [what changed and why], succinct)
>  - Authorship (full/real names only)

You also need to CC linux-kernel@xxxxxxxxxxxxxxx on all patches.

> > Signed-off-by: ryang <ryang@xxxxxxxx>
> > ---
> >  drivers/video/backlight/pwm_bl.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> > index b85983e..e0014a5 100644
> > --- a/drivers/video/backlight/pwm_bl.c
> > +++ b/drivers/video/backlight/pwm_bl.c
> > @@ -273,6 +273,9 @@ static int pwm_backlight_probe(struct platform_device *pdev)
> >  
> >  	pb->pwm = devm_pwm_get(&pdev->dev, NULL);
> >  	if (IS_ERR(pb->pwm)) {
> > +		ret = PTR_ERR(pb->pwm);
> > +		if (ret == -EPROBE_DEFER)
> > +			goto err_alloc;
> >  		dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
> >  
> >  		pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
> 

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org â Open source software for ARM SoCs
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