142 lines
5.1 KiB
Plaintext
142 lines
5.1 KiB
Plaintext
Qualcomm's QPNP PMIC thermal monitor ADC driver (VADC_TM)
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QPNP PMIC thermal monitoring (TM) provides interface to thermal clients
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to set temperature thresholds and receive notification when the thresholds
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are crossed. A 15 bit ADC is used for measurements. The driver is part
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of the sysfs thermal framework that provides support to read the trip
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points, set threshold for the trip points and enable the trip points.
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Seperate kernel api's are provided to usb_id and batt_therm
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to set thresholds and receive threshold notifications.
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VADC_TM node
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Required properties:
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- compatible : should be "qcom,qpnp-adc-tm" for thermal ADC driver.
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- reg : offset and length of the PMIC Aribter register map.
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- address-cells : Must be one.
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- size-cells : Must be zero.
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- interrupts : The thermal ADC bank peripheral interrupts for eoc, high and low interrupts.
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- interrupt-names : Should be "eoc-int-en-set", "high-thr-en-set" and "low-thr-en-set".
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- qcom,adc-bit-resolution : Bit resolution of the ADC.
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- qcom,adc-vdd-reference : Voltage reference used by the ADC.
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Optional properties:
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- qcom,thermal-node : If present a thermal node is created and the channel is registered as
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part of the thermal sysfs which allows clients to use the thermal framework
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to set temperature thresholds and receive notification when the temperature
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crosses a set threshold, read temperature and enable/set trip types supported
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by the thermal framework.
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Channel nodes
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NOTE: Atleast one Channel node is required.
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Required properties:
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- label : Channel name used for sysfs entry.
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- reg : AMUX channel number.
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- qcom,decimation : Sampling rate to use for the individual channel measurement.
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Select from the following unsigned int.
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0 : 512
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1 : 1K
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2 : 2K
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3 : 4K
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- qcom,pre-div-channel-scaling : Pre-div used for the channel before the signal is being measured.
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Select from the following unsigned int for the corresponding
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numerator/denominator pre-div ratio.
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0 : pre-div ratio of {1, 1}
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1 : pre-div ratio of {1, 3}
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2 : pre-div ratio of {1, 4}
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3 : pre-div ratio of {1, 6}
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4 : pre-div ratio of {1, 20}
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- qcom,calibration-type : Reference voltage to use for channel calibration.
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Channel calibration is dependendent on the channel.
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Certain channels like XO_THERM, BATT_THERM use ratiometric
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calibration. Most other channels fall under absolute calibration.
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Select from the following strings.
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"absolute" : Uses the 625mv and 1.25V reference channels.
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"ratiometric" : Uses the reference Voltage/GND for calibration.
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- qcom,scale-function : Scaling fuction used to convert raw ADC code to units specific to
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a given channel.
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Select from the following unsigned int.
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0 : Default scaling to convert raw adc code to voltage.
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1 : Conversion to temperature based on btm parameters.
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2 : Returns result in milli degree's Centigrade.
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3 : Returns current across 0.1 ohm resistor.
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4 : Returns XO thermistor voltage in degree's Centigrade.
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- qcom,hw-settle-time : Settling period for the channel before ADC read.
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Select from the following unsigned int.
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0 : 0us
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1 : 100us
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2 : 200us
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3 : 300us
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4 : 400us
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5 : 500us
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6 : 600us
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7 : 700us
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8 : 800us
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9 : 900us
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0xa : 1ms
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0xb : 2ms
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0xc : 4ms
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0xd : 6ms
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0xe : 8ms
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0xf : 10ms
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- qcom,fast-avg-setup : Average number of samples to be used for measurement. Fast averaging
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provides the option to obtain a single measurement from the ADC that
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is an average of multiple samples. The value selected is 2^(value)
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Select from
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0 : 1
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1 : 2
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2 : 4
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3 : 8
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4 : 16
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5 : 32
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6 : 64
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7 : 128
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8 : 256
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- qcom,btm-channel-number : There are 5 BTM channels. The BTM channel numbers are statically
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allocated to the corresponding channel node.
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Example:
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/* Main Node */
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qcom,vadc@3400 {
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compatible = "qcom,qpnp-adc-tm";
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reg = <0x3400 0x100>;
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#address-cells = <1>;
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#size-cells = <0>;
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interrupts = <0x0 0x34 0x0>,
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<0x0 0x34 0x3>,
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<0x0 0x34 0x4>;
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interrupt-names = "eoc-int-en-set",
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"high-thr-en-set",
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"low-thr-en-set";
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qcom,adc-bit-resolution = <15>;
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qcom,adc-vdd-reference = <1800>;
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/* Channel Node to be registered as part of thermal sysfs */
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chan@b5 {
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label = "pa_therm1";
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reg = <0xb5>;
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qcom,decimation = <0>;
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qcom,pre-div-channel-scaling = <0>;
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qcom,calibration-type = "absolute";
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qcom,scale-function = <2>;
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qcom,hw-settle-time = <0>;
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qcom,fast-avg-setup = <0>;
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qcom,btm-channel-number = <0x70>;
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qcom,thermal-node;
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};
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/* Channel Node */
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chan@6 {
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label = "vbat_sns";
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reg = <6>;
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qcom,decimation = <0>;
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qcom,pre-div-channel-scaling = <1>;
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qcom,calibration-type = "absolute";
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qcom,scale-function = <3>;
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qcom,hw-settle-time = <0>;
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qcom,fast-avg-setup = <0>;
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qcom,btm-channel-number = <0x78>;
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};
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};
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