linux/include/dt-bindings/gpio
Thomas Petazzoni ede033e1e8 dt-bindings: gpio: document the new pull-up/pull-down flags
This commit extends the flags that can be used in GPIO specifiers to
indicate if a pull-up resistor or pull-down resistor should be
enabled.

While some pinctrl DT bindings already offer the capability of
configuring pull-up/pull-down resistors at the pin level, a number of
simple GPIO controllers don't have any pinmuxing capability, and
therefore do not rely on the pinctrl DT bindings.

Such simple GPIO controllers however sometimes allow to configure
pull-up and pull-down resistors on a per-pin basis, and whether such
resistors should be enabled or not is a highly board-specific HW
characteristic.

By using two additional bits of the GPIO flag specifier, we can easily
allow the Device Tree to describe which GPIOs should have their
pull-up or pull-down resistors enabled. Even though the two options
are mutually exclusive, we still need two bits to encode at least
three states: no pull-up/pull-down, pull-up, pull-down.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2019-02-13 09:07:43 +01:00
..
aspeed-gpio.h dt-bindings: gpio: Add ASPEED constants 2017-12-21 14:03:14 +10:30
gpio.h dt-bindings: gpio: document the new pull-up/pull-down flags 2019-02-13 09:07:43 +01:00
meson8-gpio.h pinctrl: add driver for Amlogic Meson SoCs 2015-01-26 09:13:00 +01:00
meson8b-gpio.h pinctrl: meson: meson8b: fix requesting GPIOs greater than GPIOZ_3 2018-03-02 10:46:42 +01:00
meson-axg-gpio.h pinctrl: meson-axg: Add new pinctrl driver for Meson AXG SoC 2017-11-30 14:29:38 +01:00
meson-g12a-gpio.h pinctrl: Add compatibles for Amlogic Meson G12A pin controllers 2018-08-29 10:34:53 +02:00
meson-gxbb-gpio.h pinctrl: meson-gx: TEST_N belongs to the AO controller 2017-10-05 23:11:02 +02:00
meson-gxl-gpio.h pinctrl: meson-gx: TEST_N belongs to the AO controller 2017-10-05 23:11:02 +02:00
tegra186-gpio.h dt-bindings: tegra186-gpio: Add Tegra186 specific prefix 2018-12-07 11:07:12 +01:00
tegra194-gpio.h arm64: tegra: Add Tegra194 chip device tree 2018-03-08 14:31:13 +01:00
tegra-gpio.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
uniphier-gpio.h dt-bindings: gpio: uniphier: add UniPhier GPIO binding 2017-10-23 10:36:58 +02:00