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authorGeert Uytterhoeven <geert+renesas@glider.be>2020-05-11 17:52:54 +0300
committerLinus Walleij <linus.walleij@linaro.org>2020-05-18 11:12:42 +0300
commit4c033b549912bc301c5e2adfb7b6ca007c11bf31 (patch)
tree82a28f20edfb2d106fcb6062bb8114e27a9d5416 /include/linux/gpio
parent7b67b836625d9b8350aaec7ecd8347b0336f3f92 (diff)
downloadlinux-4c033b549912bc301c5e2adfb7b6ca007c11bf31.tar.xz
gpiolib: Add support for GPIO lookup by line name
Currently a GPIO lookup table can only refer to a specific GPIO by a tuple, consisting of a GPIO controller label and a GPIO offset inside the controller. However, a GPIO may also carry a line name, defined by DT or ACPI. If present, the line name is the most use-centric way to refer to a GPIO. Hence add support for looking up GPIOs by line name. Note that there is no guarantee that GPIO line names are globally unique, so this will use the first match found. Implement this by reusing the existing gpiod_lookup infrastructure. Rename gpiod_lookup.chip_label to gpiod_lookup.key, to make it clear that this field can have two meanings, and update the kerneldoc and GPIO_LOOKUP*() macros. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com> Reviewed-by: Ulrich Hecht <uli+renesas@fpond.eu> Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com> Link: https://lore.kernel.org/r/20200511145257.22970-4-geert+renesas@glider.be Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'include/linux/gpio')
-rw-r--r--include/linux/gpio/machine.h17
1 files changed, 10 insertions, 7 deletions
diff --git a/include/linux/gpio/machine.h b/include/linux/gpio/machine.h
index 1ebe5be05d5f..781a053abbb9 100644
--- a/include/linux/gpio/machine.h
+++ b/include/linux/gpio/machine.h
@@ -20,8 +20,11 @@ enum gpio_lookup_flags {
/**
* struct gpiod_lookup - lookup table
- * @chip_label: name of the chip the GPIO belongs to
- * @chip_hwnum: hardware number (i.e. relative to the chip) of the GPIO
+ * @key: either the name of the chip the GPIO belongs to, or the GPIO line name
+ * Note that GPIO line names are not guaranteed to be globally unique,
+ * so this will use the first match found!
+ * @chip_hwnum: hardware number (i.e. relative to the chip) of the GPIO, or
+ * U16_MAX to indicate that @key is a GPIO line name
* @con_id: name of the GPIO from the device's point of view
* @idx: index of the GPIO in case several GPIOs share the same name
* @flags: bitmask of gpio_lookup_flags GPIO_* values
@@ -30,7 +33,7 @@ enum gpio_lookup_flags {
* functions using platform data.
*/
struct gpiod_lookup {
- const char *chip_label;
+ const char *key;
u16 chip_hwnum;
const char *con_id;
unsigned int idx;
@@ -63,17 +66,17 @@ struct gpiod_hog {
/*
* Simple definition of a single GPIO under a con_id
*/
-#define GPIO_LOOKUP(_chip_label, _chip_hwnum, _con_id, _flags) \
- GPIO_LOOKUP_IDX(_chip_label, _chip_hwnum, _con_id, 0, _flags)
+#define GPIO_LOOKUP(_key, _chip_hwnum, _con_id, _flags) \
+ GPIO_LOOKUP_IDX(_key, _chip_hwnum, _con_id, 0, _flags)
/*
* Use this macro if you need to have several GPIOs under the same con_id.
* Each GPIO needs to use a different index and can be accessed using
* gpiod_get_index()
*/
-#define GPIO_LOOKUP_IDX(_chip_label, _chip_hwnum, _con_id, _idx, _flags) \
+#define GPIO_LOOKUP_IDX(_key, _chip_hwnum, _con_id, _idx, _flags) \
{ \
- .chip_label = _chip_label, \
+ .key = _key, \
.chip_hwnum = _chip_hwnum, \
.con_id = _con_id, \
.idx = _idx, \