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Commit e06193f4 authored by Jishnu Prakash's avatar Jishnu Prakash
Browse files

dt-bindings: qpnp-lcdb-regulator: Add LCDB regulator documentation 

Add documentation for QPNP LCDB regulator module. The driver
helps with controlling display bias voltage rails for LCD panels.

Change-Id: I526ae7553f5631e75b79114b386d10c1053e5453
parent 3ecfcb6d

bindings/regulator/qpnp-lcdb-regulator.txt

0 → 100644
+280 −0
Original line number Diff line number Diff line 
QPNP LCDB (LCD Bias) Regulator



QPNP LCDB module provides voltage bias to the LCD display panel. The biases

are positive (VDISP - supported by LDO) and negative (VDISN - supported by

NCP) voltage signals. The module also supports TTW (touch-to-wake) capability.



This document describes the bindings for QPNP LCDB module.



=======================

Required Node Structure

=======================



LCDB module must be described in two level of device nodes.



==============================

First Level Node - LCDB module

==============================



- compatible

	Usage:      required

	Value type: <string>

	Definition: must be one of:

			"qcom,qpnp-lcdb-regulator"

			"qcom,lcdb-pm660"

			"qcom,lcdb-pmi632"

			"qcom,lcdb-pm6150l"



- reg

	Usage:      required

	Value type: <prop-encoded-array>

	Definition:  Base address of the LCDB SPMI peripheral.



- qcom,pmic-revid

	Usage:      required

	Value type: <phandle>

	Definition:  Phandle to the PMIC's revid node



- qcom,voltage-step-ramp

	Usage:      optional

	Value type: <bool>

	Definition:  Required only if the voltage needs to be set in the

		     steps of 500 mV starting from the 4500 mV. This needs

		     to be enabled only on platforms where voltage needs to

		     be ramped up with multiple steps.



- qcom,pwrdn-delay-ms

	Usage:      optional

	Value type: <u32>

	Definition:  Required to control the LDO power down delay.

		     Possible values are 0, 1, 4, 8.



Touch-to-wake (TTW) properties:



TTW supports 2 modes of operation - HW and SW. In the HW mode the enable/disable

logic is controlled by an external signal (pin) where as in the SW mode it is

is controlled by a pre-configured timer (ton/toff) programmed in the TTW

register.



Properties below are specific to TTW mode only. They are sepecified in the

main node.



- qcom,ttw-enable

	Usage:      optional

	Value type:  <bool>

	Definition: Touch to wake-up support enabled.



- qcom,ttw-mode-sw

	Usage:      optional

	Value type:  <bool>

	Definition: Touch to wake supported in SW mode.

		    If not defined, ttw is enabled by HW pin.



- qcom,attw-toff-ms

	Usage:      required if 'qcom,ttw-mode-sw' is true.

	Value type:  <bool>

	Definition: Off time (in mS) for the VDISP/VDISN signals.

		    Possible values are 4, 8, 16, 32.



- qcom,attw-ton-ms

	Usage:      required if 'qcom,ttw-mode-sw' is true.

	Value type:  <bool>

	Definition: ON time (in mS) for the VDISP/VDISN signals.

		    Possible values are 4, 8, 16, 32.



========================================

Second Level Nodes - LDO/NCP/BOOST block

========================================



LDO / NCP subnode common properties:



Properties below are common to the LDO and NCP bias.



- label

	Usage:      required

	Value type: <string>

	Definition: A string used to describe the bias type.

		    Possible values are ldo, ncp, bst.



- regulator-name

	Usage:      required

	Value type: <string>

	Definition: A string used to describe the regulator.



- regulator-min-microvolt

	Usage:      required

	Value type: <u32>

	Definition: Minimum voltage (in uV) supported by the bias.



- regulator-max-microvolt

	Usage:      required

	Value type: <u32>

	Definition: Maximum voltage (in uV) supported by the bias.





LDO subnode properties:



Properties below are specific to LDO bias only.



- qcom,ldo-voltage-mv

	Usage:      optional

	Value type:  <u32>

	Definition: Voltage (in mV) progammed for the LDO (VDISP).

		    Possile values are 4000mV to 6000mV. The range

		    4000mV to 4900mV is in 100mV steps and 4900mV to

		    6000mV is in 50mV steps.



- qcom,ldo-pd

	Usage:      optional

	Value type:  <u32>

	Definition: Pull-down configuration of LDO. Possible values are:

		    1 - Enable pull-down

		    0 - Disable pull-down



- qcom,ldo-pd-strength

	Usage:      optional

	Value type:  <u32>

	Definition: Pull-down strength. Possible values are:

		    0 - Weak pull-down

		    1 - Strong pull-down



- qcom,ldo-ilim-ma

	Usage:      optional

	Value type:  <u32>

	Definition:  Current limit (in mA) of the LDO bias.

		     Possible values are 110, 160, 210, 260, 310, 360, 410, 460.



- qcom,ldo-soft-start-us

	Usage:      optional

	Value type:  <u32>

	Definition:  Soft-start time (in uS) of the LDO bias.

		     Possible values are 0, 500, 1000, 2000.





NCP subnode properties:



Properties below are specific to NCP bias only.



- qcom,ncp-voltage-mv

	Usage:      optional

	Value type:  <u32>

	Definition: Voltage (in mV) progammed for the NCP (VDISN).

		    Possile values are 4000mV to 6000mV. The range

		    4000mV to 4900mV is in 100mV steps and 4900mV to

		    6000mV is in 50mV steps.



- qcom,ncp-pd

	Usage:      optional

	Value type:  <u32>

	Definition: Pull-down configuration of NCP. Possible values are:

		    1 - Enable pull-down

		    0 - Disable pull-down



- qcom,ncp-pd-strength

	Usage:      optional

	Value type:  <u32>

	Definition: Pull-down strength. Possible values are:

		    0 - Weak pull-down

		    1 - Strong pull-down



- qcom,ncp-ilim-ma

	Usage:      optional

	Value type:  <u32>

	Definition:  Current limit (in mA) of the NCP bias.

		     Possible values are 260, 460, 640, 810.



- qcom,ncp-soft-start-us

	Usage:      optional

	Value type:  <u32>

	Definition:  Soft-start time (in uS) of the NCP bias.

		     Possible values are 0, 500, 1000, 2000.





BOOST subnode properties:



Properties below are specific to BOOST subnode only.



- qcom,bst-pd

	Usage:      optional

	Value type:  <bool>

	Definition: Pull-down configuration of BOOST. Possible values are:

		    1 - Enable pull-down

		    0 - Disable pull-down



- qcom,bst-pd-strength

	Usage:      optional

	Value type:  <u32>

	Definition: Pull-down strength. Possible values are:

		    0 - Weak pull-down

		    1 - Strong pull-down



- qcom,bst-ps

	Usage:      optional

	Value type:  <u32>

	Definition: Pulse-skip configuration for boost. Possible values are:

		    1 - Enable Pulse-skip

		    0 - Disable Pulse-skip



- qcom,bst-ps-threshold-ma

	Usage:      optional

	Value type:  <u32>

	Definition: Current threshold (in mA) at which pulse-skip is entered.

		    Possible values are 50, 60, 70, 80.



- qcom,bst-ilim-ma

	Usage:      optional

	Value type:  <u32>

	Definition:  Current limit (in mA) of the BOOST rail.

		     Possible values are 200 to 1600mA in 200mA steps.



- qcom,bst-headroom-mv

	Usage:      optional

	Value type:  <u16>

	Definition:  Headroom of the boost (in mV). If not specified, then the

		     default value is 200 mV (PM660L) or 150 mV (for PM8150L or

		     PMI632).



=======

Example

=======



pm660l_lcdb: qpnp-lcdb@ec00 {

	compatible = "qcom,qpnp-lcdb-regulator";

	#address-cells = <1>;

	#size-cells = <1>;

	reg = <0xec00 0x100>;



	qcom,ttw-enable;



	lcdb_ldo_vreg: ldo {

		label = "ldo";

		regulator-name = "lcdb_ldo";

		regulator-min-microvolt = <4000000>;

		regulator-max-microvolt = <6000000>;



		qcom,ldo-voltage-mv = <5400>;

		qcom,ldo-pd = <1>;

		qcom,ldo-pd-strength = <1>;

	};



	lcdb_ncp_vreg: ncp {

		label = "ncp";

		regulator-name = "lcdb_ncp";

		regulator-min-microvolt = <4000000>;

		regulator-max-microvolt = <6000000>;



		qcom,ncp-voltage-mv = <5400>;

		qcom,ncp-pd = <1>;

		qcom,ncp-pd-strength = <1>;

	};



	lcdb_bst: bst {

		label = "bst";



		qcom,bst-pd = <1>;

		qcom,bst-pd-strength = <1>;

		qcom,bst-ps = <1>;

		qcom,bst-ps-threshold-ma = <50>;

		qcom,bst-headroom-mv = <200>;

	};

};