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Diffstat (limited to 'Documentation/gpio.txt')
| -rw-r--r-- | Documentation/gpio.txt | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt index 8a7c45956d24..b1b988701247 100644 --- a/Documentation/gpio.txt +++ b/Documentation/gpio.txt @@ -240,6 +240,10 @@ signal, or (b) something wrongly believes it's safe to remove drivers needed to manage a signal that's in active use. That is, requesting a GPIO can serve as a kind of lock. +Some platforms may also use knowledge about what GPIOs are active for +power management, such as by powering down unused chip sectors and, more +easily, gating off unused clocks. + These two calls are optional because not not all current Linux platforms offer such functionality in their GPIO support; a valid implementation could return success for all gpio_request() calls. Unlike the other calls, |