1Nuvoton NAU8824 audio codec 2 3This device supports I2C only. 4 5Required properties: 6 - compatible : Must be "nuvoton,nau8824" 7 8 - reg : the I2C address of the device. This is either 0x1a (CSB=0) or 0x1b (CSB=1). 9 10Optional properties: 11 - nuvoton,jkdet-polarity: JKDET pin polarity. 0 - active high, 1 - active low. 12 13 - nuvoton,vref-impedance: VREF Impedance selection 14 0 - Open 15 1 - 25 kOhm 16 2 - 125 kOhm 17 3 - 2.5 kOhm 18 19 - nuvoton,micbias-voltage: Micbias voltage level. 20 0 - VDDA 21 1 - VDDA 22 2 - VDDA * 1.1 23 3 - VDDA * 1.2 24 4 - VDDA * 1.3 25 5 - VDDA * 1.4 26 6 - VDDA * 1.53 27 7 - VDDA * 1.53 28 29 - nuvoton,sar-threshold-num: Number of buttons supported 30 - nuvoton,sar-threshold: Impedance threshold for each button. Array that contains up to 8 buttons configuration. SAR value is calculated as 31 SAR = 255 * MICBIAS / SAR_VOLTAGE * R / (2000 + R) 32 where MICBIAS is configured by 'nuvoton,micbias-voltage', SAR_VOLTAGE is configured by 'nuvoton,sar-voltage', R - button impedance. 33 Refer datasheet section 10.2 for more information about threshold calculation. 34 35 - nuvoton,sar-hysteresis: Button impedance measurement hysteresis. 36 37 - nuvoton,sar-voltage: Reference voltage for button impedance measurement. 38 0 - VDDA 39 1 - VDDA 40 2 - VDDA * 1.1 41 3 - VDDA * 1.2 42 4 - VDDA * 1.3 43 5 - VDDA * 1.4 44 6 - VDDA * 1.53 45 7 - VDDA * 1.53 46 47 - nuvoton,sar-compare-time: SAR compare time 48 0 - 500 ns 49 1 - 1 us 50 2 - 2 us 51 3 - 4 us 52 53 - nuvoton,sar-sampling-time: SAR sampling time 54 0 - 2 us 55 1 - 4 us 56 2 - 8 us 57 3 - 16 us 58 59 - nuvoton,short-key-debounce: Button short key press debounce time. 60 0 - 30 ms 61 1 - 50 ms 62 2 - 100 ms 63 64 - nuvoton,jack-eject-debounce: Jack ejection debounce time. 65 0 - 0 ms 66 1 - 1 ms 67 2 - 10 ms 68 69 70Example: 71 72 headset: nau8824@1a { 73 compatible = "nuvoton,nau8824"; 74 reg = <0x1a>; 75 interrupt-parent = <&gpio>; 76 interrupts = <TEGRA_GPIO(E, 6) IRQ_TYPE_LEVEL_LOW>; 77 nuvoton,vref-impedance = <2>; 78 nuvoton,micbias-voltage = <6>; 79 // Setup 4 buttons impedance according to Android specification 80 nuvoton,sar-threshold-num = <4>; 81 nuvoton,sar-threshold = <0xc 0x1e 0x38 0x60>; 82 nuvoton,sar-hysteresis = <0>; 83 nuvoton,sar-voltage = <6>; 84 nuvoton,sar-compare-time = <1>; 85 nuvoton,sar-sampling-time = <1>; 86 nuvoton,short-key-debounce = <0>; 87 nuvoton,jack-eject-debounce = <1>; 88 }; 89