tree 58db700d3703ef169ea3f9fffdd50a4d3f261be4
parent bc7ef0eeb792a965c07de2228760bc5574f0305a
author Thierry Reding <treding@nvidia.com> 1398438606 +0200
committer Mihai Serban <mihai.serban@intel.com> 1452182104 +0200

BACKPORT: gpio: Add helpers for optional GPIOs

Introduce gpiod_get_optional() and gpiod_get_index_optional() helpers
that make it easier for drivers to handle optional GPIOs.

Currently in order to handle optional GPIOs, a driver needs to special
case error handling for -ENOENT, such as this:

	gpio = gpiod_get(dev, "foo");
	if (IS_ERR(gpio)) {
		if (PTR_ERR(gpio) != -ENOENT)
			return PTR_ERR(gpio);

		gpio = NULL;
	}

	if (gpio) {
		/* set up GPIO */
	}

With these new helpers the above is reduced to:

	gpio = gpiod_get_optional(dev, "foo");
	if (IS_ERR(gpio))
		return PTR_ERR(gpio);

	if (gpio) {
		/* set up GPIO */
	}

While at it, device-managed variants of these functions are also
provided.

Change-Id: Ia62444ead2f07252a24462542dd8cd59f0cfced0
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bogdan Davidoaia <bogdan.m.davidoaia@intel.com>
Signed-off-by: Robert Dolca <robert.dolca@intel.com>