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-rw-r--r--Documentation/gpio/board.txt11
1 files changed, 5 insertions, 6 deletions
diff --git a/Documentation/gpio/board.txt b/Documentation/gpio/board.txt
index 3092178628c4..86d3fa95fd12 100644
--- a/Documentation/gpio/board.txt
+++ b/Documentation/gpio/board.txt
@@ -111,16 +111,13 @@ files that desire to do so need to include the following header:
GPIOs are mapped by the means of tables of lookups, containing instances of the
gpiod_lookup structure. Two macros are defined to help declaring such mappings:
- GPIO_LOOKUP(chip_label, chip_hwnum, dev_id, con_id, flags)
- GPIO_LOOKUP_IDX(chip_label, chip_hwnum, dev_id, con_id, idx, flags)
+ GPIO_LOOKUP(chip_label, chip_hwnum, con_id, flags)
+ GPIO_LOOKUP_IDX(chip_label, chip_hwnum, con_id, idx, flags)
where
- chip_label is the label of the gpiod_chip instance providing the GPIO
- chip_hwnum is the hardware number of the GPIO within the chip
- - dev_id is the identifier of the device that will make use of this GPIO. It
- can be NULL, in which case it will be matched for calls to gpiod_get()
- with a NULL device.
- con_id is the name of the GPIO function from the device point of view. It
can be NULL, in which case it will match any function.
- idx is the index of the GPIO within the function.
@@ -134,7 +131,9 @@ In the future, these flags might be extended to support more properties.
Note that GPIO_LOOKUP() is just a shortcut to GPIO_LOOKUP_IDX() where idx = 0.
A lookup table can then be defined as follows, with an empty entry defining its
-end:
+end. The 'dev_id' field of the table is the identifier of the device that will
+make use of these GPIOs. It can be NULL, in which case it will be matched for
+calls to gpiod_get() with a NULL device.
struct gpiod_lookup_table gpios_table = {
.dev_id = "foo.0",