pwm: pwm-qti-lpg: Add LUT mode to support modulated PWM output

- reg:

	Usage: required

	Value type: <prop-encoded-array>

	Definition: Register base and length for LPG modules. The length

		      varies based on the number of channels available in

		      the PMIC chips.

	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 be "lpg-base".

		      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: See Documentation/devicetree/bindings/pwm/pwm.txt;

	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>;

		reg-names = "lpg-base";

		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;

		};

	};