linux-kernel - Re: [RESEND PATCH] leds: leds-gpio: set devm_gpio_request

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Message-ID: <CALF0-+XM4EZJHU360AUAUFBPctwO81JQ7kUiH12V2n6x7wCXfA@mail.gmail.com>
Date:	Fri, 21 Dec 2012 14:06:15 -0300
From:	Ezequiel Garcia <elezegarcia@...il.com>
To:	Javier Martinez Canillas <javier.martinez@...labora.co.uk>
Cc:	linux-leds@...r.kernel.org, linux-omap@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [RESEND PATCH] leds: leds-gpio: set devm_gpio_request_one() flags correctly

On Fri, Dec 21, 2012 at 12:07 PM, Javier Martinez Canillas
<javier.martinez@...labora.co.uk> wrote:
> commit a99d76f leds: leds-gpio: use gpio_request_one
>
> changed the leds-gpio driver to use gpio_request_one() instead
> of gpio_request() + gpio_direction_output()
>
> Unfortunately, it also made a semantic change that breaks the
> leds-gpio driver.
>
> The gpio_request_one() flags parameter was set to:
>
> GPIOF_DIR_OUT | (led_dat->active_low ^ state)
>
> Since GPIOF_DIR_OUT is 0, the final flags value will just be the
> XOR'ed value of led_dat->active_low and state.
>
> This value were used to distinguish between HIGH/LOW output initial
> level and call gpio_direction_output() accordingly.
>
> With this new semantic gpio_request_one() will take the flags value
> of 1 as a configuration of input direction (GPIOF_DIR_IN) and will
> call gpio_direction_input() instead of gpio_direction_output().
>
> int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
> {
> ..
>         if (flags & GPIOF_DIR_IN)
>                 err = gpio_direction_input(gpio);
>         else
>                 err = gpio_direction_output(gpio,
>                                 (flags & GPIOF_INIT_HIGH) ? 1 : 0);
> ..
> }
>
> The right semantic is to evaluate led_dat->active_low ^ state and
> set the output initial level explicitly.
>
> Signed-off-by: Javier Martinez Canillas <javier.martinez@...labora.co.uk>
> ---
>
> This makes LEDs to work again on my IGEPv2 board (TI OMAP3 based SoC).
>
> I sent this patch before but then realized that I only cc'ed to linux-leds.
> So, I'm resending the patch cc'ing linux-omap,linux-arm-kernel and LKML to
> reach a broader audience and have more people review/test the patch.
>
> Sorry for the noise if someone got it twice.
>
>  drivers/leds/leds-gpio.c |    5 +++--
>  1 files changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/leds/leds-gpio.c b/drivers/leds/leds-gpio.c
> index 1885a26..a0d931b 100644
> --- a/drivers/leds/leds-gpio.c
> +++ b/drivers/leds/leds-gpio.c
> @@ -127,8 +127,9 @@ static int create_gpio_led(const struct gpio_led *template,
>                 led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
>
>         ret = devm_gpio_request_one(parent, template->gpio,
> -                       GPIOF_DIR_OUT | (led_dat->active_low ^ state),
> -                       template->name);
> +                                   (led_dat->active_low ^ state) ?
> +                                   GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW,
> +                                   template->name);
>         if (ret < 0)
>                 return ret;
>
> --
> 1.7.7.6
>

Without this patch my IGEP v2 LEDs were dead,
and this patch brings them back.

Tested-by: Ezequiel Garcia <ezequiel.garcia@...e-electrons.com>

Thanks,

    Ezequiel
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