AcoSail/kernel_optimize_test
8
0
Fork 0
forked from luck/tmp_suning_uos_patched
Code Pull Requests Activity

gpio: twl4030: Fix regression for twl gpio output

Browse Source 
Commit c111feabe2 (gpio: twl4030: Cache the direction and output
states in private data) improved things in general, but caused a
regression for setting the GPIO output direction.

The change reorganized twl_direction_out() and twl_set() and swapped
the function names around in the process. While doing that, a bug got
introduced that's not obvious while reading the patch as it appears
as no change to the code.

The bug is we now call function twl4030_set_gpio_dataout() twice in
both twl_direction_out() and twl_set(). Instead, we should first
call twl_direction_out() in twl_direction_out() followed by
twl4030_set_gpio_dataout() in twl_set().

This regression probably has gone unnoticed for a long time as the
bootloader may have set the GPIO direction properly in many cases.
This fixes at least the LCD panel not turning on omap3 LDP for
example.

Cc: linux-gpio@vger.kernel.org
Cc: stable@vger.kernel.org #v3.9+
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
This commit is contained in:
Tony Lindgren 2013-11-18 15:22:49 -08:00
parent cae26f3113
commit 0b2aa8bed3
1 changed files with 3 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/gpio/gpio-twl4030.c
View File

@ -354,17 +354,18 @@ static void twl_set(struct gpio_chip *chip, unsigned offset, int value)
static int twl_direction_out(struct gpio_chip *chip, unsigned offset, int value)
{
struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);
int ret = -EINVAL;
mutex_lock(&priv->mutex);
if (offset < TWL4030_GPIO_MAX)
twl4030_set_gpio_dataout(offset, value);
ret = twl4030_set_gpio_direction(offset, 0);
priv->direction |= BIT(offset);
mutex_unlock(&priv->mutex);
twl_set(chip, offset, value);
return 0;
return ret;
}
static int twl_to_irq(struct gpio_chip *chip, unsigned offset)