1 * Texas Instruments - lm3532 White LED driver 1 * Texas Instruments - lm3532 White LED driver with ambient light sensing
2 capability. 2 capability.
3 3
4 The LM3532 provides the 3 high-voltage, low-si 4 The LM3532 provides the 3 high-voltage, low-side current sinks. The device is
5 programmable over an I2C-compatible interface 5 programmable over an I2C-compatible interface and has independent
6 current control for all three channels. The ad 6 current control for all three channels. The adaptive current regulation
7 method allows for different LED currents in ea 7 method allows for different LED currents in each current sink thus allowing
8 for a wide variety of backlight and keypad app 8 for a wide variety of backlight and keypad applications.
9 9
10 The main features of the LM3532 include dual a 10 The main features of the LM3532 include dual ambient light sensor inputs
11 each with 32 internal voltage setting resistor 11 each with 32 internal voltage setting resistors, 8-bit logarithmic and linear
12 brightness control, dual external PWM brightne 12 brightness control, dual external PWM brightness control inputs, and up to
13 1000:1 dimming ratio with programmable fade in 13 1000:1 dimming ratio with programmable fade in and fade out settings.
14 14
15 Required properties: 15 Required properties:
16 - compatible : "ti,lm3532" 16 - compatible : "ti,lm3532"
17 - reg : I2C slave address 17 - reg : I2C slave address
18 - #address-cells : 1 18 - #address-cells : 1
19 - #size-cells : 0 19 - #size-cells : 0
20 20
21 Optional properties: 21 Optional properties:
22 - enable-gpios : gpio pin to enable (a 22 - enable-gpios : gpio pin to enable (active high)/disable the device.
23 - ramp-up-us - The Run time ramp rates 23 - ramp-up-us - The Run time ramp rates/step are from one current
24 set-point to another af 24 set-point to another after the device has reached its
25 initial target set poin 25 initial target set point from turn-on
26 - ramp-down-us - The Run time ramp rat 26 - ramp-down-us - The Run time ramp rates/step are from one current
27 set-point to another 27 set-point to another after the device has reached its
28 initial target set po 28 initial target set point from turn-on
29 Range for ramp settings: 8us - 65536us 29 Range for ramp settings: 8us - 65536us
30 30
31 Optional properties if ALS mode is used: 31 Optional properties if ALS mode is used:
32 - ti,als-vmin - Minimum ALS voltage de 32 - ti,als-vmin - Minimum ALS voltage defined in Volts
33 - ti,als-vmax - Maximum ALS voltage de 33 - ti,als-vmax - Maximum ALS voltage defined in Volts
34 Per the data sheet the max ALS voltage 34 Per the data sheet the max ALS voltage is 2V and the min is 0V
35 35
36 - ti,als1-imp-sel - ALS1 impedance res 36 - ti,als1-imp-sel - ALS1 impedance resistor selection in Ohms
37 - ti,als2-imp-sel - ALS2 impedance res 37 - ti,als2-imp-sel - ALS2 impedance resistor selection in Ohms
38 Range for impedance select: 37000 Ohms 38 Range for impedance select: 37000 Ohms - 1190 Ohms
39 Values above 37kohms will be set to th 39 Values above 37kohms will be set to the "High Impedance" setting
40 40
41 - ti,als-avrg-time-us - Determines the 41 - ti,als-avrg-time-us - Determines the length of time the device needs to
42 average the two ALS 42 average the two ALS inputs. This is only used if
43 the input mode is LM 43 the input mode is LM3532_ALS_INPUT_AVRG.
44 Range: 17920us - 44 Range: 17920us - 2293760us
45 - ti,als-input-mode - Determines how t 45 - ti,als-input-mode - Determines how the device uses the attached ALS
46 devices. 46 devices.
47 0x00 - ALS1 and ALS 47 0x00 - ALS1 and ALS2 input average
48 0x01 - ALS1 Input 48 0x01 - ALS1 Input
49 0x02 - ALS2 Input 49 0x02 - ALS2 Input
50 0x03 - Max of ALS1 50 0x03 - Max of ALS1 and ALS2
51 51
52 Required child properties: 52 Required child properties:
53 - reg : Indicates control bank the LED 53 - reg : Indicates control bank the LED string is controlled by
54 - led-sources : see Documentation/devi 54 - led-sources : see Documentation/devicetree/bindings/leds/common.txt
55 - ti,led-mode : Defines if the LED str 55 - ti,led-mode : Defines if the LED strings are manually controlled or
56 if the LED strings are 56 if the LED strings are controlled by the ALS.
57 0x00 - LED strings are 57 0x00 - LED strings are I2C controlled via full scale
58 brightness cont 58 brightness control register
59 0x01 - LED strings are 59 0x01 - LED strings are ALS controlled
60 60
61 Optional LED child properties: 61 Optional LED child properties:
62 - label : see Documentation/devicetree 62 - label : see Documentation/devicetree/bindings/leds/common.txt
63 - linux,default-trigger : 63 - linux,default-trigger :
64 see Documentation/devicetree/bindin 64 see Documentation/devicetree/bindings/leds/common.txt
65 - led-max-microamp : Defines the full 65 - led-max-microamp : Defines the full scale current value for each control
66 bank. The range is 66 bank. The range is from 5000uA-29800uA in increments
67 of 800uA. 67 of 800uA.
68 68
69 Example: 69 Example:
70 led-controller@38 { 70 led-controller@38 {
71 compatible = "ti,lm3532"; 71 compatible = "ti,lm3532";
72 #address-cells = <1>; 72 #address-cells = <1>;
73 #size-cells = <0>; 73 #size-cells = <0>;
74 reg = <0x38>; 74 reg = <0x38>;
75 75
76 enable-gpios = <&gpio6 12 GPIO_ACTIVE_ 76 enable-gpios = <&gpio6 12 GPIO_ACTIVE_HIGH>;
77 ramp-up-us = <1024>; 77 ramp-up-us = <1024>;
78 ramp-down-us = <65536>; 78 ramp-down-us = <65536>;
79 79
80 ti,als-vmin = <0>; 80 ti,als-vmin = <0>;
81 ti,als-vmax = <2000>; 81 ti,als-vmax = <2000>;
82 ti,als1-imp-sel = <4110>; 82 ti,als1-imp-sel = <4110>;
83 ti,als2-imp-sel = <2180>; 83 ti,als2-imp-sel = <2180>;
84 ti,als-avrg-time-us = <17920>; 84 ti,als-avrg-time-us = <17920>;
85 ti,als-input-mode = <0x00>; 85 ti,als-input-mode = <0x00>;
86 86
87 led@0 { 87 led@0 {
88 reg = <0>; 88 reg = <0>;
89 led-sources = <2>; 89 led-sources = <2>;
90 ti,led-mode = <1>; 90 ti,led-mode = <1>;
91 led-max-microamp = <21800>; 91 led-max-microamp = <21800>;
92 label = ":backlight"; 92 label = ":backlight";
93 linux,default-trigger = "backl 93 linux,default-trigger = "backlight";
94 }; 94 };
95 95
96 led@1 { 96 led@1 {
97 reg = <1>; 97 reg = <1>;
98 led-sources = <1>; 98 led-sources = <1>;
99 ti,led-mode = <0>; 99 ti,led-mode = <0>;
100 label = ":kbd_backlight"; 100 label = ":kbd_backlight";
101 }; 101 };
102 }; 102 };
103 103
104 For more product information please see the li 104 For more product information please see the links below:
105 https://www.ti.com/product/LM3532 105 https://www.ti.com/product/LM3532
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