Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.
1 Supported chips: 2 * Dialog Semiconductors DA9052-BC and DA9053-AA/Bx PMICs 3 Prefix: 'da9052' 4 Datasheet: Datasheet is not publicly available. 5 6 Authors: David Dajun Chen <dchen@diasemi.com> 7 8 Description 9 ----------- 10 11 The DA9052/53 provides an Analogue to Digital Converter (ADC) with 10 bits 12 resolution and track and hold circuitry combined with an analogue input 13 multiplexer. The analogue input multiplexer will allow conversion of up to 10 14 different inputs. The track and hold circuit ensures stable input voltages at 15 the input of the ADC during the conversion. 16 17 The ADC is used to measure the following inputs: 18 Channel 0: VDDOUT - measurement of the system voltage 19 Channel 1: ICH - internal battery charger current measurement 20 Channel 2: TBAT - output from the battery NTC 21 Channel 3: VBAT - measurement of the battery voltage 22 Channel 4: ADC_IN4 - high impedance input (0 - 2.5V) 23 Channel 5: ADC_IN5 - high impedance input (0 - 2.5V) 24 Channel 6: ADC_IN6 - high impedance input (0 - 2.5V) 25 Channel 7: XY - TSI interface to measure the X and Y voltage of the touch 26 screen resistive potentiometers 27 Channel 8: Internal Tjunc. - sense (internal temp. sensor) 28 Channel 9: VBBAT - measurement of the backup battery voltage 29 30 By using sysfs attributes we can measure the system voltage VDDOUT, the battery 31 charging current ICH, battery temperature TBAT, battery junction temperature 32 TJUNC, battery voltage VBAT and the back up battery voltage VBBAT. 33 34 Voltage Monitoring 35 ------------------ 36 37 Voltages are sampled by a 10 bit ADC. 38 39 The battery voltage is calculated as: 40 Milli volt = ((ADC value * 1000) / 512) + 2500 41 42 The backup battery voltage is calculated as: 43 Milli volt = (ADC value * 2500) / 512; 44 45 The voltages on ADC channels 4, 5 and 6 are calculated as: 46 Milli volt = (ADC value * 2500) / 1023 47 48 Temperature Monitoring 49 ---------------------- 50 51 Temperatures are sampled by a 10 bit ADC. Junction and battery temperatures 52 are monitored by the ADC channels. 53 54 The junction temperature is calculated: 55 Degrees celsius = 1.708 * (TJUNC_RES - T_OFFSET) - 108.8 56 The junction temperature attribute is supported by the driver. 57 58 The battery temperature is calculated: 59 Degree Celsius = 1 / (t1 + 1/298)- 273 60 where t1 = (1/B)* ln(( ADCval * 2.5)/(R25*ITBAT*255)) 61 Default values of R25, B, ITBAT are 10e3, 3380 and 50e-6 respectively.