diff options
Diffstat (limited to 'Documentation/gpio')
| -rw-r--r-- | Documentation/gpio/board.txt | 25 |
1 files changed, 13 insertions, 12 deletions
diff --git a/Documentation/gpio/board.txt b/Documentation/gpio/board.txt index b80606de545a..9edd5af31b3a 100644 --- a/Documentation/gpio/board.txt +++ b/Documentation/gpio/board.txt @@ -39,11 +39,11 @@ This property will make GPIOs 15, 16 and 17 available to the driver under the struct gpio_desc *red, *green, *blue, *power; - red = gpiod_get_index(dev, "led", 0); - green = gpiod_get_index(dev, "led", 1); - blue = gpiod_get_index(dev, "led", 2); + red = gpiod_get_index(dev, "led", 0, GPIOD_OUT_HIGH); + green = gpiod_get_index(dev, "led", 1, GPIOD_OUT_HIGH); + blue = gpiod_get_index(dev, "led", 2, GPIOD_OUT_HIGH); - power = gpiod_get(dev, "power"); + power = gpiod_get(dev, "power", GPIOD_OUT_HIGH); The led GPIOs will be active-high, while the power GPIO will be active-low (i.e. gpiod_is_active_low(power) will be true). @@ -142,13 +142,14 @@ The driver controlling "foo.0" will then be able to obtain its GPIOs as follows: struct gpio_desc *red, *green, *blue, *power; - red = gpiod_get_index(dev, "led", 0); - green = gpiod_get_index(dev, "led", 1); - blue = gpiod_get_index(dev, "led", 2); + red = gpiod_get_index(dev, "led", 0, GPIOD_OUT_HIGH); + green = gpiod_get_index(dev, "led", 1, GPIOD_OUT_HIGH); + blue = gpiod_get_index(dev, "led", 2, GPIOD_OUT_HIGH); - power = gpiod_get(dev, "power"); - gpiod_direction_output(power, 1); + power = gpiod_get(dev, "power", GPIOD_OUT_HIGH); -Since the "power" GPIO is mapped as active-low, its actual signal will be 0 -after this code. Contrary to the legacy integer GPIO interface, the active-low -property is handled during mapping and is thus transparent to GPIO consumers. +Since the "led" GPIOs are mapped as active-high, this example will switch their +signals to 1, i.e. enabling the LEDs. And for the "power" GPIO, which is mapped +as active-low, its actual signal will be 0 after this code. Contrary to the legacy +integer GPIO interface, the active-low property is handled during mapping and is +thus transparent to GPIO consumers. |