On Mon, 12 Oct 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 <[email protected]>
> Signed-off-by: Vladimir Zapolskiy <[email protected]>
> Acked-by: Thierry Reding <[email protected]>
> Acked-by: Lee Jones <[email protected]>
> ---
> The change is based on lee-backlight/for-backlight-next
>
> Changes from v1 to v2:
> * rebased on top of Nicolas' commit
> 68feaca0b13 ("backlight: pwm: Handle EPROBE_DEFER while requesting the
> PWM")
>
> Links to previous discussions of the change:
> * https://patchwork.ozlabs.org/patch/483993/
> * https://patchwork.ozlabs.org/patch/398849/
>
> drivers/video/backlight/pwm_bl.c | 19 +++++++++----------
> 1 file changed, 9 insertions(+), 10 deletions(-)
Applied, thanks.
> diff --git a/drivers/video/backlight/pwm_bl.c
> b/drivers/video/backlight/pwm_bl.c
> index eff379b..ae3c6b6 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -271,19 +271,18 @@ 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;
> -
> + if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER
> + && !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)) {
> + ret = PTR_ERR(pb->pwm);
> + if (ret != -EPROBE_DEFER)
> + dev_err(&pdev->dev, "unable to request PWM\n");
> + 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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