diff options
Diffstat (limited to 'src/soc/nvidia/tegra/gpio.c')
| -rw-r--r-- | src/soc/nvidia/tegra/gpio.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/src/soc/nvidia/tegra/gpio.c b/src/soc/nvidia/tegra/gpio.c index 4cf6d5f43a..ac0fc3f986 100644 --- a/src/soc/nvidia/tegra/gpio.c +++ b/src/soc/nvidia/tegra/gpio.c @@ -22,6 +22,7 @@ #include <soc/addressmap.h> #include <stddef.h> #include <stdint.h> +#include <delay.h> #include "gpio.h" #include "pinmux.h" @@ -174,6 +175,58 @@ int gpio_get_in_value(gpio_t gpio) return (port & (1 << bit)) != 0; } +int gpio_get_in_tristate_values(gpio_t gpio[], int num_gpio, int value[]) +{ + /* + * GPIOs which are tied to stronger external pull up or pull down + * will stay there regardless of the internal pull up or pull + * down setting. + * + * GPIOs which are floating will go to whatever level they're + * internally pulled to. + */ + + int temp; + int index; + + /* Enable internal pull up */ + for (index = 0; index < num_gpio; ++index) + gpio_input_pullup(gpio[index]); + + /* Wait until signals become stable */ + udelay(10); + + /* Get gpio values at internal pull up */ + for (index = 0; index < num_gpio; ++index) + value[index] = gpio_get_in_value(gpio[index]); + + /* Enable internal pull down */ + for (index = 0; index < num_gpio; ++index) + gpio_input_pulldown(gpio[index]); + + /* Wait until signals become stable */ + udelay(10); + + /* + * Get gpio values at internal pull down. + * Compare with gpio pull up value and then + * determine a gpio final value/state: + * 0: pull down + * 1: pull up + * 2: floating + */ + for (index = 0; index < num_gpio; ++index) { + temp = gpio_get_in_value(gpio[index]); + value[index] = ((value[index] ^ temp) << 1) | temp; + } + + /* Disable pull up / pull down to conserve power */ + for (index = 0; index < num_gpio; ++index) + gpio_input(gpio[index]); + + return 0; +} + int gpio_get_int_status(gpio_t gpio) { int bit = gpio % GPIO_GPIOS_PER_PORT; |