gpio: fix probe() error return in gpio driver probes
A number of drivers in drivers/gpio return -ENODEV when confronted with
missing setup parameters such as the platform data. However, returning
-ENODEV causes the driver layer to silently ignore the driver as it
assumes the probe did not find anything and was only speculative.
To make life easier to discern why a driver is not being attached, change
to returning -EINVAL, which is a better description of the fact that the
driver data was not valid.
Also add a set of dev_dbg() statements to the error paths to provide an
better explanation of the error as there may be more that one point in the
driver.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/gpio/pcf857x.c b/drivers/gpio/pcf857x.c
index 4bc2070..9525724 100644
--- a/drivers/gpio/pcf857x.c
+++ b/drivers/gpio/pcf857x.c
@@ -188,8 +188,10 @@
int status;
pdata = client->dev.platform_data;
- if (!pdata)
- return -ENODEV;
+ if (!pdata) {
+ dev_dbg(&client->dev, "no platform data\n");
+ return -EINVAL;
+ }
/* Allocate, initialize, and register this gpio_chip. */
gpio = kzalloc(sizeof *gpio, GFP_KERNEL);
@@ -248,8 +250,10 @@
else
status = i2c_read_le16(client);
- } else
- status = -ENODEV;
+ } else {
+ dev_dbg(&client->dev, "unsupported number of gpios\n");
+ status = -EINVAL;
+ }
if (status < 0)
goto fail;