diff options
Diffstat (limited to 'Documentation/gpio/consumer.txt')
| -rw-r--r-- | Documentation/gpio/consumer.txt | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt index 07c74a3765a0..e42f77d8d4ca 100644 --- a/Documentation/gpio/consumer.txt +++ b/Documentation/gpio/consumer.txt @@ -38,7 +38,11 @@ device that displays digits), an additional index argument can be specified: const char *con_id, unsigned int idx) Both functions return either a valid GPIO descriptor, or an error code checkable -with IS_ERR(). They will never return a NULL pointer. +with IS_ERR() (they will never return a NULL pointer). -ENOENT will be returned +if and only if no GPIO has been assigned to the device/function/index triplet, +other error codes are used for cases where a GPIO has been assigned but an error +occured while trying to acquire it. This is useful to discriminate between mere +errors and an absence of GPIO for optional GPIO parameters. Device-managed variants of these functions are also defined: |