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Subject[PATCH 1/2] gpio / ACPI: Avoid unnecessary checks in __gpiod_get_index()
Date
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

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>
---
drivers/gpio/gpiolib.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)

Index: linux-pm/drivers/gpio/gpiolib.c
===================================================================
--- linux-pm.orig/drivers/gpio/gpiolib.c
+++ linux-pm/drivers/gpio/gpiolib.c
@@ -1865,13 +1865,15 @@ struct gpio_desc *__must_check __gpiod_g

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

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

/*


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