Re: [PATCH 2/2] pwm-backlight: switch to gpiod interface

From: Thierry Reding
Date: Wed May 07 2014 - 04:20:53 EST


On Thu, Feb 27, 2014 at 02:53:34PM +0900, Alexandre Courbot wrote:
> Switch to the new gpiod interface, which allows to handle GPIO
> properties such as active low transparently and removes a whole bunch of
> code.
>
> There are still a couple of users of this driver that rely on passing
> the enable GPIO number through platform data, so a fallback mechanism
> using a GPIO number is still available to avoid breaking them. It will
> be removed once current users have switched to the GPIO lookup tables
> provided by the gpiod interface.
>
> Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
> ---
> drivers/video/backlight/pwm_bl.c | 72 +++++++++++++++++-----------------------
> include/linux/pwm_backlight.h | 5 +--
> 2 files changed, 32 insertions(+), 45 deletions(-)

I've applied this with two tiny changes, see below. Please shout if you
think that's a bad idea.

> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
[...]
> @@ -256,8 +238,6 @@ static int pwm_backlight_probe(struct platform_device *pdev)
[...]
> + pb->enable_gpio = devm_gpiod_get(&pdev->dev, "enable");
> + if (IS_ERR(pb->enable_gpio)) {
> + ret = PTR_ERR(pb->enable_gpio);
> + if (ret == -ENOENT) {
> + pb->enable_gpio = NULL;
> + ret = 0;
> + } else {
> + goto err_alloc;
> + }

I dropped the ret = 0 here because all error paths set it explicitly and
the non-error path never uses it. Now all branches have a single
statement and therefore the braces can be dropped.

> + /*
> + * Compatibility fallback for drivers still using the integer GPIO
> + * platform data. Must go away soon.
> + */
> + if (pb->enable_gpio == NULL && gpio_is_valid(data->enable_gpio)) {

Changed the first condition to !pb->enable_gpio for consistency.

Thierry

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