[U-Boot] [PATCH v2 5/7] tegra: Implement gpio_early_init() on Tamonten

[Stephen Warren]

On 05/25/2012 07:46 AM, Thierry Reding wrote:
> 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.

> +void gpio_early_init(void)
> +{
> +	gpio_request(GPIO_PI4, NULL);
> +	gpio_direction_output(GPIO_PI4, 1);
> +	gpio_free(GPIO_PI4);
> +}

Do you really mean to free the GPIO here?

While gpio_free() does not do this at present, it seems perfectly
reasonable for someone to modify gpio_free() so that instead of leaving
the HW in some random state when free, it actively reprograms the pin to
be an input instead, since that's the most conflict-free setting when
the pin is actively unused.