diff options
Diffstat (limited to 'docs/zephyr/zephyr_gpio.md')
| -rw-r--r-- | docs/zephyr/zephyr_gpio.md | 32 |
1 files changed, 21 insertions, 11 deletions
diff --git a/docs/zephyr/zephyr_gpio.md b/docs/zephyr/zephyr_gpio.md index 5e70562ab9..5204e6107f 100644 --- a/docs/zephyr/zephyr_gpio.md +++ b/docs/zephyr/zephyr_gpio.md @@ -70,6 +70,15 @@ included from the main board DTS file. For platform specific features, other flags may be available in the Zephyr [dt-bindings/gpio/gpio.h] file, such as `GPIO_VOLTAGE_1P8`. +### Alternate functions + +All pins are configured as GPIO by default, so normally pinctrl configuration +for GPIO pins is not required. Note that on NPCX ECs some pins default to a +non-GPIO function after reset. These are explicitly set to GPIO during +initialization, based on the `def-io-conf-list` node in [npcx9.dtsi], so they +do not need to be set to GPIO usage, but they need an explicit `pinctrl-x` +entry to be set back to the specific function. + ### Legacy enum-name usage Only GPIOs that require referencing from legacy common code should have @@ -241,18 +250,18 @@ For example on the Volteer reference board: Low voltage pins configuration depends on the specific chip family. -For Nuvoton, this is done using a [nuvoton,npcx-lvolctrl-def] devicetree node, -with a `lvol-io-pads` property listing all the pins that have to be configured -for low-voltage operation. For example: +For Nuvoton, this is done using the `GPIO_VOLTAGE_1P8` flag in the `named-gpios` +child node. For example ``` -def-lvol-io-list { - compatible = "nuvoton,npcx-lvolctrl-def"; - lvol-io-pads = < - &lvol_iob3 /* EC_I2C_SENSOR_SCL */ - &lvol_iob2 /* EC_I2C_SENSOR_SDA */ - >; -}; +named-gpios { + compatible = "named-gpios"; + ... + ec-i2c-sensor-scl { + gpios = <&gpiob 5 (GPIO_INPUT | GPIO_VOLTAGE_1P8)>; + }; + ... +} ``` For ITE, this is done using the `GPIO_VOLTAGE_1P8` flag in the `named-gpios` @@ -456,4 +465,5 @@ project. [gpio.dts]: ../../zephyr/projects/volteer/volteer/gpio.dts [interrupts.dts]: ../../zephyr/projects/volteer/volteer/interrupts.dts [BUILD.py]: ../../zephyr/projects/volteer/volteer/BUILD.py -[*node label*]: https://docs.zephyrproject.org/latest/build/dts/intro.html#dt-node-labels
\ No newline at end of file +[*node label*]: https://docs.zephyrproject.org/latest/build/dts/intro.html#dt-node-labels +[npcx9.dtsi]: https://github.com/zephyrproject-rtos/zephyr/blob/main/dts/arm/nuvoton/npcx9.dtsi |