Commit 4d8440b9 authored Mar 10, 2015 by Rafael J. Wysocki Committed by Linus Walleij Mar 19, 2015

gpio / ACPI: Avoid unnecessary checks in __gpiod_get_index()



If dev is NULL in __gpiod_get_index() and both ACPI and OF are
enabled, it will be checked twice before the code decides to give
up with DT/ACPI lookup, so avoid that.

Also use the observation that ACPI_COMPANION() is much more efficient
than ACPI_HANDLE(), because the latter uses the former and carries out
a check and a pointer dereference on top of it, so replace the
ACPI_HANDLE() check with an ACPI_COMPANION() one which does not
require the additional IS_ENABLED(CONFIG_ACPI) check too.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

parent 964cb341

drivers/gpio/gpiolib.c

+9 −7

Original line number	Diff line number	Diff line
		@@ -1971,14 +1971,16 @@ struct gpio_desc __must_check __gpiod_get_index(struct device dev,

		dev_dbg(dev, "GPIO lookup for consumer %s\n", con_id);

		if (dev) {
		/* Using device tree? */
		if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) {
		if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
		dev_dbg(dev, "using device tree for GPIO lookup\n");
		desc = of_find_gpio(dev, con_id, idx, &lookupflags);
		} else if (IS_ENABLED(CONFIG_ACPI) && dev && ACPI_HANDLE(dev)) {
		} else if (ACPI_COMPANION(dev)) {
		dev_dbg(dev, "using ACPI for GPIO lookup\n");
		desc = acpi_find_gpio(dev, con_id, idx, &lookupflags);
		}
		}

		/*
		* Either we are not using DT or ACPI, or their lookup did not return