The tegra GPIO controller has two ways of reading the value of a GPIO. It can supply the 'input' value (which is the value read from the pin) and the 'output' value (which is the value being driven from the pin. With a GPIO set to output mode, the 'input' value is always low which is not very useful.
This has the unfortunate result that setting a GPIO high still leaves it showing as low in the 'gpio status' command.
Adjust the driver to check which direction the GPIO is set to, then read the value from the appropriate register: 'input' for input GPIOs, 'output' for output GPIOs.
Signed-off-by: Simon Glass sjg@chromium.org Reviewed-by: Joe Hershberger joe.hershberger@ni.com ---
Changes in v2: None
drivers/gpio/tegra_gpio.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpio/tegra_gpio.c b/drivers/gpio/tegra_gpio.c index 8e880e2..5a03115 100644 --- a/drivers/gpio/tegra_gpio.c +++ b/drivers/gpio/tegra_gpio.c @@ -177,7 +177,10 @@ static int tegra_gpio_get_value(struct udevice *dev, unsigned offset) debug("%s: pin = %d (port %d:bit %d)\n", __func__, gpio, GPIO_FULLPORT(gpio), GPIO_BIT(gpio));
- val = readl(&state->bank->gpio_in[GPIO_PORT(gpio)]); + if (get_direction(gpio) == DIRECTION_INPUT) + val = readl(&state->bank->gpio_in[GPIO_PORT(gpio)]); + else + val = readl(&state->bank->gpio_out[GPIO_PORT(gpio)]);
return (val >> GPIO_BIT(gpio)) & 1; }