diff options
Diffstat (limited to 'Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt')
-rw-r--r-- | Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt new file mode 100644 index 000000000..c57e11b8d --- /dev/null +++ b/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt @@ -0,0 +1,76 @@ +Tegra SoC PWFM controller + +Required properties: +- compatible: Must be: + - "nvidia,tegra20-pwm": for Tegra20 + - "nvidia,tegra30-pwm", "nvidia,tegra20-pwm": for Tegra30 + - "nvidia,tegra114-pwm", "nvidia,tegra20-pwm": for Tegra114 + - "nvidia,tegra124-pwm", "nvidia,tegra20-pwm": for Tegra124 + - "nvidia,tegra132-pwm", "nvidia,tegra20-pwm": for Tegra132 + - "nvidia,tegra210-pwm", "nvidia,tegra20-pwm": for Tegra210 + - "nvidia,tegra186-pwm": for Tegra186 +- reg: physical base address and length of the controller's registers +- #pwm-cells: should be 2. See pwm.txt in this directory for a description of + the cells format. +- clocks: Must contain one entry, for the module clock. + See ../clocks/clock-bindings.txt for details. +- resets: Must contain an entry for each entry in reset-names. + See ../reset/reset.txt for details. +- reset-names: Must include the following entries: + - pwm + +Optional properties: +============================ +In some of the interface like PWM based regulator device, it is required +to configure the pins differently in different states, especially in suspend +state of the system. The configuration of pin is provided via the pinctrl +DT node as detailed in the pinctrl DT binding document + Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt + +The PWM node will have following optional properties. +pinctrl-names: Pin state names. Must be "default" and "sleep". +pinctrl-0: phandle for the default/active state of pin configurations. +pinctrl-1: phandle for the sleep state of pin configurations. + +Example: + + pwm: pwm@7000a000 { + compatible = "nvidia,tegra20-pwm"; + reg = <0x7000a000 0x100>; + #pwm-cells = <2>; + clocks = <&tegra_car 17>; + resets = <&tegra_car 17>; + reset-names = "pwm"; + }; + + +Example with the pin configuration for suspend and resume: +========================================================= +Suppose pin PE7 (On Tegra210) interfaced with the regulator device and +it requires PWM output to be tristated when system enters suspend. +Following will be DT binding to achieve this: + +#include <dt-bindings/pinctrl/pinctrl-tegra.h> + + pinmux@700008d4 { + pwm_active_state: pwm_active_state { + pe7 { + nvidia,pins = "pe7"; + nvidia,tristate = <TEGRA_PIN_DISABLE>; + }; + }; + + pwm_sleep_state: pwm_sleep_state { + pe7 { + nvidia,pins = "pe7"; + nvidia,tristate = <TEGRA_PIN_ENABLE>; + }; + }; + }; + + pwm@7000a000 { + /* Mandatory PWM properties */ + pinctrl-names = "default", "sleep"; + pinctrl-0 = <&pwm_active_state>; + pinctrl-1 = <&pwm_sleep_state>; + }; |