Searched hist:"60 befd2e" (Results 1 – 1 of 1) sorted by relevance
| /openbmc/linux/include/linux/gpio/ |
| H A D | driver.h | 60befd2e Tue Dec 22 08:37:28 CST 2015 Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com> 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>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
60befd2e Tue Dec 22 08:37:28 CST 2015 Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com> 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>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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