linux_dsm_epyc7002/Documentation/devicetree/bindings/leds/leds-pwm.txt
Russell King b0571e7e4e leds: leds-pwm: add DT support for LEDs wired to supply
The non-DT driver allowed an active low property to be specified, but DT
is missing this in its description.  Add the property to the DT binding
document, making it optional.  It defaults to active high, which retains
compatibility with existing descriptions.

This should only be used for causes where the LED is wired to supply,
and the PWM does not sensibly support its own inversion.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
2014-05-08 14:28:07 +08:00

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LED connected to PWM
Required properties:
- compatible : should be "pwm-leds".
Each LED is represented as a sub-node of the pwm-leds device. Each
node's name represents the name of the corresponding LED.
LED sub-node properties:
- pwms : PWM property to point to the PWM device (phandle)/port (id) and to
specify the period time to be used: <&phandle id period_ns>;
- pwm-names : (optional) Name to be used by the PWM subsystem for the PWM device
For the pwms and pwm-names property please refer to:
Documentation/devicetree/bindings/pwm/pwm.txt
- max-brightness : Maximum brightness possible for the LED
- active-low : (optional) For PWMs where the LED is wired to supply
rather than ground.
- label : (optional)
see Documentation/devicetree/bindings/leds/common.txt
- linux,default-trigger : (optional)
see Documentation/devicetree/bindings/leds/common.txt
Example:
twl_pwm: pwm {
/* provides two PWMs (id 0, 1 for PWM1 and PWM2) */
compatible = "ti,twl6030-pwm";
#pwm-cells = <2>;
};
twl_pwmled: pwmled {
/* provides one PWM (id 0 for Charing indicator LED) */
compatible = "ti,twl6030-pwmled";
#pwm-cells = <2>;
};
pwmleds {
compatible = "pwm-leds";
kpad {
label = "omap4::keypad";
pwms = <&twl_pwm 0 7812500>;
max-brightness = <127>;
};
charging {
label = "omap4:green:chrg";
pwms = <&twl_pwmled 0 7812500>;
max-brightness = <255>;
};
};