linux_dsm_epyc7002/Documentation/devicetree/bindings/pwm/nvidia,tegra20-pwm.txt
Laxman Dewangan 0dafdd168b pwm: tegra: Add DT binding details to configure pin in suspends/resume
In some of NVIDIA Tegra's platform, PWM controller is used to
control the PWM controlled regulators. PWM signal is connected to
the VID pin of the regulator where duty cycle of PWM signal decide
the voltage level of the regulator output.

When system enters suspend, some PWM client/slave regulator devices
require the PWM output to be tristated.

Add DT binding details to provide the pin configuration state
from PWM and pinctrl DT node in suspend and active state of
the system.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2017-04-12 16:09:49 +02:00

77 lines
2.6 KiB
Plaintext

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>;
};