1Kernel driver da9055 2==================== 3 4Supported chips: 5 * Dialog Semiconductors DA9055 PMIC 6 7 Prefix: 'da9055' 8 9 Datasheet: Datasheet is not publicly available. 10 11Authors: David Dajun Chen <dchen@diasemi.com> 12 13Description 14----------- 15 16The DA9055 provides an Analogue to Digital Converter (ADC) with 10 bits 17resolution and track and hold circuitry combined with an analogue input 18multiplexer. The analogue input multiplexer will allow conversion of up to 5 19different inputs. The track and hold circuit ensures stable input voltages at 20the input of the ADC during the conversion. 21 22The ADC is used to measure the following inputs: 23 24- Channel 0: VDDOUT - measurement of the system voltage 25- Channel 1: ADC_IN1 - high impedance input (0 - 2.5V) 26- Channel 2: ADC_IN2 - high impedance input (0 - 2.5V) 27- Channel 3: ADC_IN3 - high impedance input (0 - 2.5V) 28- Channel 4: Internal Tjunc. - sense (internal temp. sensor) 29 30By using sysfs attributes we can measure the system voltage VDDOUT, 31chip junction temperature and auxiliary channels voltages. 32 33Voltage Monitoring 34------------------ 35 36Voltages are sampled in a AUTO mode it can be manually sampled too and results 37are stored in a 10 bit ADC. 38 39The system voltage is calculated as: 40 41 Milli volt = ((ADC value * 1000) / 85) + 2500 42 43The voltages on ADC channels 1, 2 and 3 are calculated as: 44 45 Milli volt = (ADC value * 1000) / 102 46 47Temperature Monitoring 48---------------------- 49 50Temperatures are sampled by a 10 bit ADC. Junction temperatures 51are monitored by the ADC channels. 52 53The junction temperature is calculated: 54 55 Degrees celsius = -0.4084 * (ADC_RES - T_OFFSET) + 307.6332 56 57The junction temperature attribute is supported by the driver. 58