Re: [PATCH] pwm-backlight: add regulator and GPIO support

From: Alex Courbot
Date: Wed Jul 04 2012 - 11:03:16 EST

On Wed 04 Jul 2012 10:00:56 PM JST, Sascha Hauer wrote:
That's very bad indeed. I assumed that the kernel would free
devm-allocated resources after probe returned -EPROBE_DEFER,

It indeed does free devm allocated resources, but neither the gpio nor
the pwm are devm allocated.

As far as I can tell the gpio is allocated through devm as well:

> + ret = devm_gpio_request_one(&pdev->dev, data->enable_gpio,
> + GPIOF_OUT_INIT_HIGH, "backlight_enable");

Thus if it is not reclaimed with probe returns with -EPROBE_DEFER, then I guess something is going wrong elsewhere. You are right that the PWM should be freed by the driver thought.

Also please be aware that using a regulator in the pwm backlight will
instantly break all existing users. That's hardly your fault though.

Sorry, I don't see why. Could you elaborate on this?


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