The PI4 GPIO is used on Tamonten to reset carrier board peripherals. Power sequencing hardware on the carrier pulls the reset low before powering up the Tegra, and the CPU is supposed to signal readiness, and therefore bring peripherals out of reset by pulling PI4 high.
Signed-off-by: Thierry Reding thierry.reding@avionic-design.de --- Changes in v2: - new patch required for TEC support
board/avionic-design/common/tamonten.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/board/avionic-design/common/tamonten.c b/board/avionic-design/common/tamonten.c index d9ecd23..2b19d1e 100644 --- a/board/avionic-design/common/tamonten.c +++ b/board/avionic-design/common/tamonten.c @@ -49,6 +49,15 @@ void gpio_config_uart(void) { }
+#ifdef CONFIG_BOARD_EARLY_INIT_F +void gpio_early_init(void) +{ + gpio_request(GPIO_PI4, NULL); + gpio_direction_output(GPIO_PI4, 1); + gpio_free(GPIO_PI4); +} +#endif + #ifdef CONFIG_TEGRA2_MMC /* * Routine: pin_mux_mmc