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SubjectRe: [GIT PULL] GPIO changes for v3.6
On Thu, 26 Jul 2012 00:48:57 +0200 Linus Walleij <linus.walleij@linaro.org>
wrote:

> Hi Linus,
>
> in Grants absence, these are my queued and -next-tested changes
> for v3.6, please pull them in. Grants "merge" branch prior to his
> absence was merged in as a base for this patch series.
>
> The following is the same information as found in the tag:
>
> GPIO changes for v3.6:
> - New driver for AMD-8111 southbridge GPIOs
> - New driver for Wolfson Micro Arizona devices
> - Propagate device tree parse errors
> - Probe deferral finalizations - all expected calls to
> GPIO will now hopefully request deferral where apropriate
> - Misc updates to TCA6424, WM8994, LPC32xx, PCF857x, Samsung
> MXC, OMAP and PCA953X drivers.
>
..
> Mark Brown (5):
> gpiolib: Defer failed gpio requests by default

Hi,
this doesn't look quite right to me.

it means that if !gpio_is_valid(gpio), the error returned is EPROBE_DEFER
which isn't right (an invalid gpio number will never become valid).
If a driver happened to use gpio_request to check the validity of the gpio
rather than doing it itself, it would defer the probe, rather than assume
that the GPIO doesn't exist.

I would suggest the following. Reasonable?

NeilBrown

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index de0213c..259233b 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1186,13 +1186,14 @@ int gpio_request(unsigned gpio, const char *label)
{
struct gpio_desc *desc;
struct gpio_chip *chip;
- int status = -EPROBE_DEFER;
+ int status = -EINVAL;
unsigned long flags;

spin_lock_irqsave(&gpio_lock, flags);

if (!gpio_is_valid(gpio))
goto done;
+ status = -EPROBE_DEFER;
desc = &gpio_desc[gpio];
chip = desc->chip;
if (chip == NULL)[unhandled content-type:application/pgp-signature]
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