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    Subject[PATCH 3.10 031/173] gpio: twl4030: Fix regression for twl gpio output
    Date
    3.10-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Tony Lindgren <tony@atomide.com>

    commit 0b2aa8bed3e13892fcac77e4f50ec6e80125469d upstream.

    Commit c111feabe2e2 (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
    Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
    Acked-by: Linus Walleij <linus.walleij@linaro.org>
    Signed-off-by: Tony Lindgren <tony@atomide.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/gpio/gpio-twl4030.c | 5 +++--
    1 file changed, 3 insertions(+), 2 deletions(-)

    --- a/drivers/gpio/gpio-twl4030.c
    +++ b/drivers/gpio/gpio-twl4030.c
    @@ -354,17 +354,18 @@ static void twl_set(struct gpio_chip *ch
    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)



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