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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1356102464-22234-1-git-send-email-javier.martinez@collabora.co.uk>
Date:	Fri, 21 Dec 2012 16:07:44 +0100
From:	Javier Martinez Canillas <javier.martinez@...labora.co.uk>
To:	linux-leds@...r.kernel.org
Cc:	linux-omap@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	Javier Martinez Canillas <javier.martinez@...labora.co.uk>
Subject: [RESEND PATCH] leds: leds-gpio: set devm_gpio_request_one() flags correctly

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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/