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Commit a67189ee authored by Subbaraman Narayanamurthy's avatar Subbaraman Narayanamurthy
Browse files

dt-bindings: pwm: Add DT bindings for QTI PWM LPG driver 



QTI PWM LPG driver supports configuring PWM/LPG channels on QTI
PMICs based on the client's request. Add snapshot of device tree
bindings for it.

This snapshot is taken as of msm-4.14
commit 9bb584ae ("msm/sde/rotator: Add rev checks for sdmmagpie").

Change-Id: I4640065c17cba28a64bcdca4646cbe2471e986cc
Signed-off-by: default avatarSubbaraman Narayanamurthy <subbaram@codeaurora.org>
parent 385fed9e

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

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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.



- qcom,sync-channel-ids:

	Usage: optional

	Value type: <prop-encoded-array>

	Definition: The hardware IDs of the LPG channel that required be

		      grouped together. These channels will share the same LUT

		      ramping configuration so that they will be enabled with a

		      synchronized pattern. If the LUT ramping configuration

		      differs for the channels grouped for synchronization,

		      configuration of the first channel will be applied for

		      all others.



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>;

		qcom,sync-channel-ids = <3 4 5>;

		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;

		};

	};