On 29/04/16 13:31, Laxman Dewangan wrote:
> Implement gpio_get_direction() callback for Tegra GPIO.
> The direction is only valid if the pin is configured as
> GPIO. If pin is not configured in GPIO mode then this
> function return error.
>
> This makes debugfs and initial reading of the state of
> the lines more accurate.
>
> Signed-off-by: Laxman Dewangan <[email protected]>
> ---
> This patch is based on discussion on series
> Re: [PATCH V5 0/4] gpio: tegra: Cleanups and support for debounce
> From Linus W:
> It would be nice if you also implement .get_direction() which makes
> debugfs and initial reading of the state of the lines more accurate.
>
> drivers/gpio/gpio-tegra.c | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/drivers/gpio/gpio-tegra.c b/drivers/gpio/gpio-tegra.c
> index b3ddd92..6f2292b 100644
> --- a/drivers/gpio/gpio-tegra.c
> +++ b/drivers/gpio/gpio-tegra.c
> @@ -191,6 +191,24 @@ static int tegra_gpio_direction_output(struct gpio_chip
> *chip, unsigned offset,
> return 0;
> }
>
> +static int tegra_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
> +{
> + struct tegra_gpio_info *tgi = gpiochip_get_data(chip);
> + u32 pin_mask = BIT(GPIO_BIT(offset));
> + u32 cnf, oe;
> +
> + cnf = tegra_gpio_readl(tgi, GPIO_CNF(tgi, offset));
> + oe = tegra_gpio_readl(tgi, GPIO_OE(tgi, offset));
> + if (cnf & pin_mask) {
Nit ... does not look like there is any point in reading GPIO_OE if cnf
& pin_mask == 0, so you could move the test before reading GPIO_OE and
then ...
> + if (oe & pin_mask)
> + return GPIOF_DIR_OUT;
> +
> + return GPIOF_DIR_IN;
You could ...
return (oe & mask) ? GPIOF_DIR_OUT : GPIOF_DIR_IN;
Cheers
Jon
