diff options
Diffstat (limited to 'Documentation/gpio.txt')
-rw-r--r-- | Documentation/gpio.txt | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt index 218a8650f48d..6bc2ba215df9 100644 --- a/Documentation/gpio.txt +++ b/Documentation/gpio.txt | |||
@@ -148,7 +148,7 @@ pin ... that won't always match the specified output value, because of | |||
148 | issues including wire-OR and output latencies. | 148 | issues including wire-OR and output latencies. |
149 | 149 | ||
150 | The get/set calls have no error returns because "invalid GPIO" should have | 150 | The get/set calls have no error returns because "invalid GPIO" should have |
151 | been reported earlier in gpio_set_direction(). However, note that not all | 151 | been reported earlier from gpio_direction_*(). However, note that not all |
152 | platforms can read the value of output pins; those that can't should always | 152 | platforms can read the value of output pins; those that can't should always |
153 | return zero. Also, using these calls for GPIOs that can't safely be accessed | 153 | return zero. Also, using these calls for GPIOs that can't safely be accessed |
154 | without sleeping (see below) is an error. | 154 | without sleeping (see below) is an error. |
@@ -239,7 +239,7 @@ map between them using calls like: | |||
239 | Those return either the corresponding number in the other namespace, or | 239 | Those return either the corresponding number in the other namespace, or |
240 | else a negative errno code if the mapping can't be done. (For example, | 240 | else a negative errno code if the mapping can't be done. (For example, |
241 | some GPIOs can't used as IRQs.) It is an unchecked error to use a GPIO | 241 | some GPIOs can't used as IRQs.) It is an unchecked error to use a GPIO |
242 | number that hasn't been marked as an input using gpio_set_direction(), or | 242 | number that wasn't set up as an input using gpio_direction_input(), or |
243 | to use an IRQ number that didn't originally come from gpio_to_irq(). | 243 | to use an IRQ number that didn't originally come from gpio_to_irq(). |
244 | 244 | ||
245 | These two mapping calls are expected to cost on the order of a single | 245 | These two mapping calls are expected to cost on the order of a single |