[PATCH 4/5] gpiolib: handle deferral probe error

From: G, Manjunath Kondaiah
Date: Fri Oct 07 2011 - 01:10:18 EST

The gpio library should return -EPROBE_DEFER in gpio_request
if gpio driver is not ready. If drivers pass this error code through to
their caller (which they really should) then this will ensure that the
probe is retried later when further devices become available.

Signed-off-by: G, Manjunath Kondaiah <manjugk@xxxxxx>
Cc: linux-omap@xxxxxxxxxxxxxxx
Cc: linux-mmc@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: Grant Likely <grant.likely@xxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <greg@xxxxxxxxx>
Cc: Dilan Lee <dilee@xxxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Cc: Manjunath GKondaiah <manjunath.gkondaiah@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>

drivers/gpio/gpiolib.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index a971e3d..9081ef8 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1177,13 +1177,15 @@ int gpio_request(unsigned gpio, const char *label)
struct gpio_desc *desc;
struct gpio_chip *chip;
- int status = -EINVAL;
+ int status = -EPROBE_DEFER;
unsigned long flags;

spin_lock_irqsave(&gpio_lock, flags);

- if (!gpio_is_valid(gpio))
+ if (!gpio_is_valid(gpio)) {
+ status = -EINVAL;
goto done;
+ }
desc = &gpio_desc[gpio];
chip = desc->chip;
if (chip == NULL)

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