61 lines
2.8 KiB
Plaintext
61 lines
2.8 KiB
Plaintext
* ROHM BH1730FVC ambient light sensor
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nvs_ drivers use the NVidia Sensor (NVS) framework.
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See the nvs.txt documentation for NVS DT capabilities.
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Required properties:
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- compatible: must be "rohm,bh1730fvc"
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- reg: i2c address of the device. It should be 0x29.
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Optional properties:
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- status: set to "ok" or "okay" for normal operation. Set to anything else
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to unload the driver without ever communicating with the device.
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Note: The "anything else" above is typically "disabled".
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Since the driver will unload without communicating with the device, the
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device will be left in its POR state.
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- vdd-supply: regulator supply for the chip vcc
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- vid-supply: regulator supply for the chip dvi
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Note: This is required if the driver is to control the regulator.
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- bh1730fvc-lux-coeff-size: array size of bh1730fvc-lux-coeff.
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- bh1730fvc-lux-coeff: Lux calculation coefficient table. See the note.
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- bh1730fvc-lux-resolution: See the note.
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- bh1730fvc-lux-multiplier: See the note.
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Note: If lux coefficient data is not present, default calculation table is used.
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If present, lux calculation is done with following equation.
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Let following is set in dt:
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bh1730fvc-lux-coeff-size = <5>;
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bh1730fvc-lux-coeff = < 500 5002 7502>,
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< 754 2250 2000>,
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<1029 1999 1667>,
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<1373 884 583>,
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<1879 309 165>;
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bh1730fvc-lux-resolution = <1000>;
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bh1730fvc-lux-multiplier = <360>;
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Then lux is calculated with this equation:
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if (data1 * 1000 / data0 < 500)
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lux = 5002 * data0 - 7502 * data1
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else if (data1 * 1000 / data0 < 754)
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lux = 2250 * data0 - 2000 * data1
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else if (data1 * 1000 / data0 < 1029)
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lux = 1999 * data0 - 1667 * data1
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else if (data1 * 1000 / data0 < 1373)
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lux = 884 * data0 - 583 * data1
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else if (data1 * 1000 / data0 < 1879)
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lux = 309 * data0 - 165 * data1
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lux = lux * 360 / (gain * itime_us)
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Example:
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bh1730fvc@29 {
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compatible = "rohm,bh1730fvc";
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reg = <0x29>;
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bh1730fvc-lux-coeff-size = <5>;
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bh1730fvc-lux-coeff = < 500 5002 7502>,
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< 754 2250 2000>,
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<1029 1999 1667>,
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<1373 884 583>,
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<1879 309 165>;
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bh1730fvc-lux-resolution = <1000>;
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bh1730fvc-lux-multiplier = <360>;
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};
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