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105 lines
3.6 KiB
105 lines
3.6 KiB
* Texas Instruments - lm3532 White LED driver with ambient light sensing |
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capability. |
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The LM3532 provides the 3 high-voltage, low-side current sinks. The device is |
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programmable over an I2C-compatible interface and has independent |
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current control for all three channels. The adaptive current regulation |
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method allows for different LED currents in each current sink thus allowing |
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for a wide variety of backlight and keypad applications. |
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The main features of the LM3532 include dual ambient light sensor inputs |
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each with 32 internal voltage setting resistors, 8-bit logarithmic and linear |
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brightness control, dual external PWM brightness control inputs, and up to |
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1000:1 dimming ratio with programmable fade in and fade out settings. |
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Required properties: |
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- compatible : "ti,lm3532" |
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- reg : I2C slave address |
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- #address-cells : 1 |
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- #size-cells : 0 |
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Optional properties: |
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- enable-gpios : gpio pin to enable (active high)/disable the device. |
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- ramp-up-us - The Run time ramp rates/step are from one current |
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set-point to another after the device has reached its |
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initial target set point from turn-on |
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- ramp-down-us - The Run time ramp rates/step are from one current |
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set-point to another after the device has reached its |
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initial target set point from turn-on |
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Range for ramp settings: 8us - 65536us |
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Optional properties if ALS mode is used: |
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- ti,als-vmin - Minimum ALS voltage defined in Volts |
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- ti,als-vmax - Maximum ALS voltage defined in Volts |
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Per the data sheet the max ALS voltage is 2V and the min is 0V |
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- ti,als1-imp-sel - ALS1 impedance resistor selection in Ohms |
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- ti,als2-imp-sel - ALS2 impedance resistor selection in Ohms |
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Range for impedance select: 37000 Ohms - 1190 Ohms |
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Values above 37kohms will be set to the "High Impedance" setting |
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- ti,als-avrg-time-us - Determines the length of time the device needs to |
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average the two ALS inputs. This is only used if |
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the input mode is LM3532_ALS_INPUT_AVRG. |
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Range: 17920us - 2293760us |
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- ti,als-input-mode - Determines how the device uses the attached ALS |
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devices. |
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0x00 - ALS1 and ALS2 input average |
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0x01 - ALS1 Input |
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0x02 - ALS2 Input |
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0x03 - Max of ALS1 and ALS2 |
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Required child properties: |
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- reg : Indicates control bank the LED string is controlled by |
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- led-sources : see Documentation/devicetree/bindings/leds/common.txt |
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- ti,led-mode : Defines if the LED strings are manually controlled or |
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if the LED strings are controlled by the ALS. |
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0x00 - LED strings are I2C controlled via full scale |
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brightness control register |
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0x01 - LED strings are ALS controlled |
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Optional LED child properties: |
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- label : see Documentation/devicetree/bindings/leds/common.txt |
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- linux,default-trigger : |
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see Documentation/devicetree/bindings/leds/common.txt |
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- led-max-microamp : Defines the full scale current value for each control |
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bank. The range is from 5000uA-29800uA in increments |
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of 800uA. |
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Example: |
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led-controller@38 { |
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compatible = "ti,lm3532"; |
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#address-cells = <1>; |
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#size-cells = <0>; |
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reg = <0x38>; |
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enable-gpios = <&gpio6 12 GPIO_ACTIVE_HIGH>; |
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ramp-up-us = <1024>; |
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ramp-down-us = <65536>; |
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ti,als-vmin = <0>; |
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ti,als-vmax = <2000>; |
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ti,als1-imp-sel = <4110>; |
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ti,als2-imp-sel = <2180>; |
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ti,als-avrg-time-us = <17920>; |
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ti,als-input-mode = <0x00>; |
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led@0 { |
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reg = <0>; |
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led-sources = <2>; |
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ti,led-mode = <1>; |
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led-max-microamp = <21800>; |
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label = ":backlight"; |
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linux,default-trigger = "backlight"; |
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}; |
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led@1 { |
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reg = <1>; |
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led-sources = <1>; |
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ti,led-mode = <0>; |
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label = ":kbd_backlight"; |
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}; |
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}; |
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For more product information please see the links below: |
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https://www.ti.com/product/LM3532
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