leds-lm3532.txt

  1* Texas Instruments - lm3532 White LED driver with ambient light sensing
  2capability.
  3
  4The LM3532 provides the 3 high-voltage, low-side current sinks. The device is
  5programmable over an I2C-compatible interface and has independent
  6current control for all three channels. The adaptive current regulation
  7method allows for different LED currents in each current sink thus allowing
  8for a wide variety of backlight and keypad applications.
  9
 10The main features of the LM3532 include dual ambient light sensor inputs
 11each with 32 internal voltage setting resistors, 8-bit logarithmic and linear
 12brightness control, dual external PWM brightness control inputs, and up to
 131000:1 dimming ratio with programmable fade in and fade out settings.
 14
 15Required properties:
 16	- compatible : "ti,lm3532"
 17	- reg : I2C slave address
 18	- #address-cells : 1
 19	- #size-cells : 0
 20
 21Optional properties:
 22	- enable-gpios : gpio pin to enable (active high)/disable the device.
 23	- ramp-up-us - The Run time ramp rates/step are from one current
 24		       set-point to another after the device has reached its
 25		       initial target set point from turn-on
 26	- ramp-down-us - The Run time ramp rates/step are from one current
 27			 set-point to another after the device has reached its
 28			 initial target set point from turn-on
 29	Range for ramp settings: 8us - 65536us
 30
 31Optional properties if ALS mode is used:
 32	- ti,als-vmin - Minimum ALS voltage defined in Volts
 33	- ti,als-vmax - Maximum ALS voltage defined in Volts
 34	Per the data sheet the max ALS voltage is 2V and the min is 0V
 35
 36	- ti,als1-imp-sel - ALS1 impedance resistor selection in Ohms
 37	- ti,als2-imp-sel - ALS2 impedance resistor selection in Ohms
 38	Range for impedance select: 37000 Ohms - 1190 Ohms
 39	Values above 37kohms will be set to the "High Impedance" setting
 40
 41	- ti,als-avrg-time-us - Determines the length of time the device needs to
 42			  average the two ALS inputs.  This is only used if
 43			  the input mode is LM3532_ALS_INPUT_AVRG.
 44			     Range: 17920us - 2293760us
 45	- ti,als-input-mode - Determines how the device uses the attached ALS
 46			   devices.
 47			   0x00 - ALS1 and ALS2 input average
 48			   0x01 - ALS1 Input
 49			   0x02 - ALS2 Input
 50			   0x03 - Max of ALS1 and ALS2
 51
 52Required child properties:
 53	- reg : Indicates control bank the LED string is controlled by
 54	- led-sources : see Documentation/devicetree/bindings/leds/common.txt
 55	- ti,led-mode : Defines if the LED strings are manually controlled or
 56			if the LED strings are controlled by the ALS.
 57			0x00 - LED strings are I2C controlled via full scale
 58			       brightness control register
 59			0x01 - LED strings are ALS controlled
 60
 61Optional LED child properties:
 62	- label : see Documentation/devicetree/bindings/leds/common.txt
 63	- linux,default-trigger :
 64	   see Documentation/devicetree/bindings/leds/common.txt
 65	- led-max-microamp : Defines the full scale current value for each control
 66			  bank.  The range is from 5000uA-29800uA in increments
 67			  of 800uA.
 68
 69Example:
 70led-controller@38 {
 71	compatible = "ti,lm3532";
 72	#address-cells = <1>;
 73	#size-cells = <0>;
 74	reg = <0x38>;
 75
 76	enable-gpios = <&gpio6 12 GPIO_ACTIVE_HIGH>;
 77	ramp-up-us = <1024>;
 78	ramp-down-us = <65536>;
 79
 80	ti,als-vmin = <0>;
 81	ti,als-vmax = <2000>;
 82	ti,als1-imp-sel = <4110>;
 83	ti,als2-imp-sel = <2180>;
 84	ti,als-avrg-time-us = <17920>;
 85	ti,als-input-mode = <0x00>;
 86
 87	led@0 {
 88		reg = <0>;
 89		led-sources = <2>;
 90		ti,led-mode = <1>;
 91		led-max-microamp = <21800>;
 92		label = ":backlight";
 93		linux,default-trigger = "backlight";
 94	};
 95
 96	led@1 {
 97		reg = <1>;
 98		led-sources = <1>;
 99		ti,led-mode = <0>;
100		label = ":kbd_backlight";
101	};
102};
103
104For more product information please see the links below:
105https://www.ti.com/product/LM3532