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.
It is the backport of linux commit ede033e1e863c ('dt-bindings: gpio: document the new pull-up/pull-down flags') from Thomas Petazzoni thomas.petazzoni@bootlin.com and integrated in v5.1-rc1 https://github.com/torvalds/linux/commit/ede033e1e863c
Signed-off-by: Patrick Delaunay patrick.delaunay@st.com ---
Changes in v2: None
doc/device-tree-bindings/gpio/gpio.txt | 24 ++++++++++++++++++++++++ include/dt-bindings/gpio/gpio.h | 6 ++++++ 2 files changed, 30 insertions(+)
diff --git a/doc/device-tree-bindings/gpio/gpio.txt b/doc/device-tree-bindings/gpio/gpio.txt index e146917ff3..e9ef0212af 100644 --- a/doc/device-tree-bindings/gpio/gpio.txt +++ b/doc/device-tree-bindings/gpio/gpio.txt @@ -65,6 +65,30 @@ Example of a node using GPIOs: GPIO_ACTIVE_HIGH is 0, so in this example gpio-specifier is "18 0" and encodes GPIO pin number, and GPIO flags as accepted by the "qe_pio_e" gpio-controller.
+Optional standard bitfield specifiers for the last cell: + +- Bit 0: 0 means active high, 1 means active low +- Bit 1: 0 mean push-pull wiring, see: + https://en.wikipedia.org/wiki/Push-pull_output + 1 means single-ended wiring, see: + https://en.wikipedia.org/wiki/Single-ended_triode +- Bit 2: 0 means open-source, 1 means open drain, see: + https://en.wikipedia.org/wiki/Open_collector +- Bit 3: 0 means the output should be maintained during sleep/low-power mode + 1 means the output state can be lost during sleep/low-power mode +- Bit 4: 0 means no pull-up resistor should be enabled + 1 means a pull-up resistor should be enabled + This setting only applies to hardware with a simple on/off + control for pull-up configuration. If the hardware has more + elaborate pull-up configuration, it should be represented + using a pin control binding. +- Bit 5: 0 means no pull-down resistor should be enabled + 1 means a pull-down resistor should be enabled + This setting only applies to hardware with a simple on/off + control for pull-down configuration. If the hardware has more + elaborate pull-down configuration, it should be represented + using a pin control binding. + 1.1) GPIO specifier best practices ----------------------------------
diff --git a/include/dt-bindings/gpio/gpio.h b/include/dt-bindings/gpio/gpio.h index 2cc10ae4bb..c029467e82 100644 --- a/include/dt-bindings/gpio/gpio.h +++ b/include/dt-bindings/gpio/gpio.h @@ -33,4 +33,10 @@ #define GPIO_PERSISTENT 0 #define GPIO_TRANSITORY 8
+/* Bit 4 express pull up */ +#define GPIO_PULL_UP 16 + +/* Bit 5 express pull down */ +#define GPIO_PULL_DOWN 32 + #endif