gpiolib: return -ENOENT if no GPIO mapping exists

Some devices drivers make use of optional GPIO parameters. For such
drivers, it is important to discriminate between the case where no
GPIO mapping has been defined for the function they are requesting, and
the case where a mapping exists but an error occured while resolving it
or when acquiring the GPIO.

This patch changes the family of gpiod_get() functions such that they
will return -ENOENT if and only if no GPIO mapping is defined for the
requested function. Other error codes are used when an actual error
occured during the GPIO resolution.

Signed-off-by: Alexandre Courbot <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Reviewed-by: Mika Westerberg <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>
This commit is contained in:
Alexandre Courbot 2013-12-11 11:32:28 +09:00 • committed by Linus Walleij
commit 2a3cf6a359
2 changed files with 22 additions and 18 deletions

View file

@ -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: