tree 2f9831f33ac579dda2719ce5cc8bcbcd75c96f24
parent 0dac4d51f50e9252dbc00075cf65eeba57017926
author Simon Glass <sjg@chromium.org> 1420513529 -0700
committer Simon Glass <sjg@chromium.org> 1422576591 -0700

dm: gpio: Add better functions to request GPIOs

At present U-Boot sort-of supports the standard way of reading GPIOs from
device tree nodes, but the support is incomplete, a bit clunky and only
works for GPIO bindings where #gpio-cells is 2.

Add new functions to request GPIOs, taking full account of the device
tree binding. These permit requesting a GPIO with a simple call like:

   gpio_request_by_name(dev, "cd-gpios", 0, &desc, GPIOD_IS_IN);

This will request the GPIO, looking at the device's node which might be
this, for example:

   cd-gpios = <&gpio TEGRA_GPIO(B, 3) GPIO_ACTIVE_LOW>;

The GPIO will be set to input mode in this case and polarity will be
honoured by the GPIO calls.

It is also possible to request and free a list of GPIOs.

Signed-off-by: Simon Glass <sjg@chromium.org>