Hi Tony,
On 11/14/2013 04:35 AM, Tony Lindgren wrote:
> 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.
Thanks for catching this. I have a recollection that I have tested the GPIO
and it appeared to be working fine..
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> Cc: Linus Walleij <linus.walleij@xxxxxxxxxx>
> Cc: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> Cc: linux-gpio@xxxxxxxxxxxxxxx
> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
> ---
>
> If this looks OK, I'd like to merge this as a fix via arm-soc tree
> along with the other patches in this series as my later patches
> depend on patches in this series.
>
> ---
> drivers/gpio/gpio-twl4030.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpio/gpio-twl4030.c b/drivers/gpio/gpio-twl4030.c
> index 0c7e891..5738d5a 100644
> --- a/drivers/gpio/gpio-twl4030.c
> +++ b/drivers/gpio/gpio-twl4030.c
> @@ -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)
>
--
Péter
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