Message ID | 567966EB.8060900@mentor.com |
---|---|
State | New |
Headers | show |
On Tue, Dec 22, 2015 at 4:06 PM, Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com> wrote: > From a19047b2131f73cdf494abd44d76de6f57ca81ff Mon Sep 17 00:00:00 2001 > From: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com> > Date: Tue, 22 Dec 2015 16:37:28 +0200 > Subject: [PATCH] gpio: update gpiochip .get() callback description > > Since gpiochip .get() callback may return a negative error value, it > strictly limits the range of possible non-error returned values to > a subset of [30:0] bitmask, however on practice on success all > gpiochip drivers return either 0 for low signal or 1 for high signal, > this is assured by "gpio: *: Be sure to clamp return value" series of > changes. To avoid any confusion, misinterpretation and potential > errors while developing gpiochip drivers in future convert this > implicit assumption to a mandatory rule. > > For output signals with unknown output signal state gpiochip drivers > should return a negative error instead of 0. > > Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com> Patch applied! Merry Christmas, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index b02c43b..9907975 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -32,8 +32,7 @@ struct seq_file; * (same as GPIOF_DIR_XXX), or negative error * @direction_input: configures signal "offset" as input, or returns error * @direction_output: configures signal "offset" as output, or returns error - * @get: returns value for signal "offset"; for output signals this - * returns either the value actually sensed, or zero + * @get: returns value for signal "offset", 0=low, 1=high, or negative error * @set: assigns output value for signal "offset" * @set_multiple: assigns output values for multiple signals defined by "mask" * @set_debounce: optional hook for setting debounce time for specified gpio in