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1* Texas Instruments - lm3532 White LED driver with ambient light sensing2capability.3 4The LM3532 provides the 3 high-voltage, low-side current sinks. The device is5programmable over an I2C-compatible interface and has independent6current control for all three channels. The adaptive current regulation7method allows for different LED currents in each current sink thus allowing8for a wide variety of backlight and keypad applications.9 10The main features of the LM3532 include dual ambient light sensor inputs11each with 32 internal voltage setting resistors, 8-bit logarithmic and linear12brightness control, dual external PWM brightness control inputs, and up to131000:1 dimming ratio with programmable fade in and fade out settings.14 15Required properties:16 - compatible : "ti,lm3532"17 - reg : I2C slave address18 - #address-cells : 119 - #size-cells : 020 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 current24 set-point to another after the device has reached its25 initial target set point from turn-on26 - ramp-down-us - The Run time ramp rates/step are from one current27 set-point to another after the device has reached its28 initial target set point from turn-on29 Range for ramp settings: 8us - 65536us30 31Optional properties if ALS mode is used:32 - ti,als-vmin - Minimum ALS voltage defined in Volts33 - ti,als-vmax - Maximum ALS voltage defined in Volts34 Per the data sheet the max ALS voltage is 2V and the min is 0V35 36 - ti,als1-imp-sel - ALS1 impedance resistor selection in Ohms37 - ti,als2-imp-sel - ALS2 impedance resistor selection in Ohms38 Range for impedance select: 37000 Ohms - 1190 Ohms39 Values above 37kohms will be set to the "High Impedance" setting40 41 - ti,als-avrg-time-us - Determines the length of time the device needs to42 average the two ALS inputs. This is only used if43 the input mode is LM3532_ALS_INPUT_AVRG.44 Range: 17920us - 2293760us45 - ti,als-input-mode - Determines how the device uses the attached ALS46 devices.47 0x00 - ALS1 and ALS2 input average48 0x01 - ALS1 Input49 0x02 - ALS2 Input50 0x03 - Max of ALS1 and ALS251 52Required child properties:53 - reg : Indicates control bank the LED string is controlled by54 - led-sources : see Documentation/devicetree/bindings/leds/common.txt55 - ti,led-mode : Defines if the LED strings are manually controlled or56 if the LED strings are controlled by the ALS.57 0x00 - LED strings are I2C controlled via full scale58 brightness control register59 0x01 - LED strings are ALS controlled60 61Optional LED child properties:62 - label : see Documentation/devicetree/bindings/leds/common.txt63 - linux,default-trigger :64 see Documentation/devicetree/bindings/leds/common.txt65 - led-max-microamp : Defines the full scale current value for each control66 bank. The range is from 5000uA-29800uA in increments67 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/LM3532106