Documentation/devicetree/bindings/pwm/pwm-qti-lpg.txt

Qualcomm Technologies, Inc. LPG driver specific bindings

This binding document describes the properties of LPG (Light Pulse Generator)
device module in Qualcomm Technologies, Inc. PMIC chips.

- compatible:
	Usage: required
	Value type: <string>
	Definition: Must be "qcom,pwm-lpg".

- reg:
	Usage: required
	Value type: <prop-encoded-array>
	Definition: Register base and length for LPG and LUT modules. LPG size
		      or length available per channel varies depending on the
		      number of channels in PMIC.

- reg-names:
	Usage: required
	Value type: <string>
	Definition: The name of the register defined in the reg property.
		      It must have "lpg-base", "lut-base" is optional but
		      it's required if any LPG channels support LUT mode.

- #pwm-cells:
	Usage: required
	Value type: <u32>
	Definition: The number of cells in "pwms" property specified in
		      PWM user nodes. It should be 2. The first cell is
		      the PWM channel ID indexed from 0, and the second
		      cell is the PWM default period in nanoseconds.

- qcom,lut-patterns:
	Usage: optional
	Value type: <prop-encoded-array>
	Definition: Duty ratios in percentages for LPG working at LUT mode.
		      These duty ratios will be translated into PWM values
		      and stored in LUT module. The LUT module has resource
		      to store 47 PWM values at max and shared for all LPG
		      channels. This property is required if any LPG channels
		      support LUT mode.

Subnode is optional if LUT mode is not required, it's required if any LPG
channels expected to be supported in LUT mode.

Subnode properties:
Subnodes for each LPG channel (lpg@X) can be defined if any of the following
parameters needs to be configured for that channel.

- qcom,lpg-chan-id:
	Usage: required
	Value type: <u32>
	Definition: The LPG channel's hardware ID indexed from 1. Allowed
		      range is 1 - 8. Maximum value depends on the number of
		      channels supported on PMIC.

- qcom,ramp-step-ms:
	Usage: required
	Value type: <u32>
	Definition: The step duration in milliseconds for LPG staying at each
		      duty specified in the LUT pattern. Allowed range is
		      1 - 511.

- qcom,ramp-high-index:
	Usage: required
	Value type: <u32>
	Definition: The high index of the LUT pattern where LPG ends up
		      ramping to. Allowed range is 1 - 47.

- qcom,ramp-low-index:
	Usage: required
	Value type: <u32>
	Definition: The low index of the LUT pattern from where LPG begins
		      ramping from. Allowed range is 0 - 46.

- qcom,ramp-from-low-to-high:
	Usage: optional
	Value type: <empty>
	Definition: The flag to specify the LPG ramping direction. The ramping
		      direction is from low index to high index of the LUT
		      pattern if it's specified.

- qcom,ramp-pattern-repeat:
	Usage: optional
	Value type: <empty>
	Definition: The flag to specify if LPG would be ramping with the LUT
		      pattern repeatedly.

- qcom,ramp-toggle:
	Usage: optional
	Value type: <empty>
	Definition: The flag to specify if LPG would toggle the LUT pattern
		      in ramping. If toggling enabled, LPG would return to the
		      low index when high index is reached, or return to the high
		      index when low index is reached.

- qcom,ramp-pause-hi-count:
	Usage: optional
	Value type: <u32>
	Definition: The step count that LPG stop the output when it ramped up
		      to the high index of the LUT.

- qcom,ramp-pause-lo-count:
	Usage: optional
	Value type: <u32>
	Definition: The step count that LPG stop the output when it ramped up
		      to the low index of the LUT.
Example:

	pmi8998_lpg: lpg@b100 {
		compatible = "qcom,pwm-lpg";
		reg = <0xb100 0x600>, <0xb000 0x100>;
		reg-names = "lpg-base", "lut-base";
		#pwm-cells = <2>;
		qcom,lut-patterns = <0 14 28 42 56 70 84 100
					100 84 70 56 42 28 14 0>;
		lpg@3 {
			qcom,lpg-chan-id = <3>;
			qcom,ramp-step-ms = <200>;
			qcom,ramp-pause-hi-count = <10>;
			qcom,ramp-pause-lo-count = <10>;
			qcom,ramp-low-index = <0>;
			qcom,ramp-high-index = <15>;
			qcom,ramp-from-low-to-high;
			qcom,ramp-pattern-repeat;
		};
		lpg@4 {
			qcom,lpg-chan-id = <4>;
			qcom,ramp-step-ms = <200>;
			qcom,ramp-pause-hi-count = <10>;
			qcom,ramp-pause-lo-count = <10>;
			qcom,ramp-low-index = <0>;
			qcom,ramp-high-index = <15>;
			qcom,ramp-from-low-to-high;
			qcom,ramp-pattern-repeat;
		};
		lpg@5 {
			qcom,lpg-chan-id = <5>;
			qcom,ramp-step-ms = <200>;
			qcom,ramp-pause-hi-count = <10>;
			qcom,ramp-pause-lo-count = <10>;
			qcom,ramp-low-index = <0>;
			qcom,ramp-high-index = <15>;
			qcom,ramp-from-low-to-high;
			qcom,ramp-pattern-repeat;
		};
	};