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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 <dbaryshkov@gmail.com>
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Vladimir Zapolskiy 2015-10-12 15:29:03 +03:00 committed by Lee Jones
parent f85de2d9e2
commit dc881123aa
1 changed files with 9 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/video/backlight/pwm_bl.c
View File

@ -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");