From: Vladimir Zapolskiy Date: Mon, 12 Oct 2015 12:29:03 +0000 (+0300) Subject: backlight: pwm: Reject legacy PWM request for device defined in DT X-Git-Tag: firefly_0821_release~176^2~770^2~2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=dc881123aa1aeff02ce2dc94c2b810d37173aa90;p=firefly-linux-kernel-4.4.55.git backlight: pwm: Reject legacy PWM request for device defined in DT 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 Signed-off-by: Vladimir Zapolskiy Acked-by: Thierry Reding Acked-by: Nicolas Ferre Tested-by: Robert Jarzmik Signed-off-by: Lee Jones --- diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index eff379b234cc..ae3c6b6fd5db 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");