91 lines
4.3 KiB
Plaintext
91 lines
4.3 KiB
Plaintext
Qualcomm Technologies QPNP WLED
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QPNP (Qualcomm Technologies Plug N Play) WLED (White Light
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Emitting Diode) driver is used for controlling display
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backlight that is part of PMIC on Qualcomm Technologies
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reference platforms. The PMIC is connected to the host
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processor via SPMI bus.
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Required properties:
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- compatible : should be "qcom,qpnp-wled"
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- reg : base address and size for wled modules
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- reg-names : names associated with base addresses. It
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should be "qpnp-wled-ctrl-base", "qpnp-wled-sink-base",
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"qpnp-wled-ibb-base", "qpnp-wled-lab-base".
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Optional properties for WLED:
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- interrupts : Specifies the interrupts associated with WLED. The available
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interrupts are over voltage protection(ovp) and short circuit(sc).
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The values for ovp and sc are <0x3 0xd8 0x1> and <0x3 0xd8 0x2>.
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- interrupt-names : Specify the interrupt names associated with interrupts. Must be
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one of "ovp-irq" or "sc-irq"
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- linux,name : name of the wled. default is "wled".
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- linux,default-trigger : trigger for the backlight. default is NONE.
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- qcom,fdbk-output : string feedback current output for wled module. The accepted values
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are "wled1", "wled2", "wled3", "wled4" and "auto". default is "auto".
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- qcom,vref-mv : maximum reference voltage in mv. default is 350.
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- qcom,switch-freq-khz : switch frequency in khz. default is 800.
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- qcom,ovp-mv : over voltage protection value in mv. default is 17800.
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- qcom,ilim-ma : maximum current limiter in ma. default is 980.
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- qcom,boost-duty-ns : maximum boost duty cycle in ns. default is 104.
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- qcom,mod-freq-khz : modulation frequency in khz. default is 9600.
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- qcom,dim-mode : dimming mode. supporting dimming modes are "analog",
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"digital", and "hybrid". default is "hybrid".
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- qcom,hyb-thres : threshold value when used in hybrid mode. It represents the
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percentage of brightntess at which dimming mode is switched
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from "digital" to "analog". the default value is 6.25%. as the
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floating point cannot be represented directly, the value is
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multiplied by 100. so the default is 625.
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- qcom,sync-dly-us : delay for current sync in us. default is 400.
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- qcom,fs-curr-ua : maximum full scale current in ua. default is 25000.
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- qcom,en-9b-dim-res : boolean, specify if 9-bit dim resultion is needed. otherwise 12-bit is used.
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- qcom,en-phase-stag : boolean, specify if phase staggering is needed.
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- qcom,en-cabc : boolean, specify if cabc (content adaptive backlight control) is needed.
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- qcom,disp-type-amoled : specify if the display is amoled
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- qcom,led-strings-list : Wled module has four strings of leds numbered from 0 to 3. each string of leds
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are operated individually. specify the list of strings used by the device.
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any combination of led strings can be used. default value is [00 01 02 03]
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- qcom,en-ext-pfet-sc-pro : Specify if external pfet short circuit protection is needed
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- qcom,cons-sync-write-delay-us : Specify in 'us' the duration of delay between two consecutive writes to
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SYNC register.
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Optional properties if 'qcom,disp-type-amoled' is mentioned in DT:
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- qcom,loop-ea-gm : control the gm for gm stage in control loop. default is 3.
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- qcom,loop-comp-res-kohm : control to select the compensation resistor in kohm. default is 320.
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- qcom,vref-psm-mv : reference psm voltage in mv. default for amoled is 450.
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- qcom,sc-deb-cycles : debounce time for short circuit detection
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- qcom,avdd-trim-steps-from-center : The number of steps to trim the OVP threshold voltage. The possible values can be between -7 to 8.
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Example:
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qcom,leds@d800 {
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compatible = "qcom,qpnp-wled";
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reg = <0xd800 0x100>,
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<0xd900 0x100>,
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<0xdc00 0x100>,
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<0xde00 0x100>;
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reg-names = "qpnp-wled-ctrl-base",
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"qpnp-wled-sink-base",
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"qpnp-wled-ibb-base",
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"qpnp-wled-lab-base";
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interrupts = <0x3 0xd8 0x2>;
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interrupt-names = "sc-irq";
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status = "okay";
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linux,name = "wled";
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linux,default-trigger = "bkl-trigger";
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qcom,fdbk-output = "auto";
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qcom,vref-mv = <350>;
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qcom,switch-freq-khz = <800>;
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qcom,ovp-mv = <29500>;
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qcom,ilim-ma = <980>;
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qcom,boost-duty-ns = <26>;
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qcom,mod-freq-khz = <9600>;
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qcom,dim-mode = "hybrid";
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qcom,dim-method = "linear";
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qcom,hyb-thres = <625>;
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qcom,sync-dly-us = <800>;
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qcom,fs-curr-ua = <16000>;
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qcom,en-phase-stag;
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qcom,led-strings-list = [00 01 02 03];
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qcom,en-ext-pfet-sc-pro;
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};
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