Re: [PATCH] backlight: pwm: reject legacy pwm request for device defined in dt

[Lee Jones <lee.jones@linaro.org>]

On Sun, 14 Jun 2015, Vladimir Zapolskiy wrote:

> Platform PWM backlight data provided by board's device tree should be
> complete enough to successfully request a pwm device using pwm_get()
> API. This change fixes a bug, when an arbitrary (first found) PWM is
> connected to a "pwm-backlight" compatible device, when explicit PWM
> device reference is not given.
> 
> Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt
> already describes "pwms" as a required property, instead of blind
> selection of a potentially wrong PWM reject legacy PWM device
> registration request, leave legacy API only for non-dt cases.
> 
> Based on initial implementation done by Dmitry Eremin-Solenikov.
> 
> Reported-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
> Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
> Acked-by: Thierry Reding <thierry.reding@gmail.com>
> ---
>  drivers/video/backlight/pwm_bl.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)

Applied, thanks.

> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index 57cb9ec..9991cdb 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -271,15 +271,16 @@ static int pwm_backlight_probe(struct platform_device *pdev)
>  	}
>  
>  	pb->pwm = devm_pwm_get(&pdev->dev, NULL);
> -	if (IS_ERR(pb->pwm)) {
> +	if (IS_ERR(pb->pwm) && !pdev->dev.of_node) {
>  		dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
>  		pb->legacy = true;
>  		pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");
> -		if (IS_ERR(pb->pwm)) {
> -			dev_err(&pdev->dev, "unable to request legacy PWM\n");
> -			ret = PTR_ERR(pb->pwm);
> -			goto err_alloc;
> -		}
> +	}
> +
> +	if (IS_ERR(pb->pwm)) {
> +		dev_err(&pdev->dev, "unable to request PWM\n");
> +		ret = PTR_ERR(pb->pwm);
> +		goto err_alloc;
>  	}
>  
>  	dev_dbg(&pdev->dev, "got pwm for backlight\n");

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