| Ashish Jangam | e597022 | 2012-10-08 18:56:47 +0530 | [diff] [blame] | 1 | Supported chips: |
| 2 | * Dialog Semiconductors DA9055 PMIC |
| 3 | Prefix: 'da9055' |
| 4 | Datasheet: Datasheet is not publicly available. |
| 5 | |
| 6 | Authors: David Dajun Chen <dchen@diasemi.com> |
| 7 | |
| 8 | Description |
| 9 | ----------- |
| 10 | |
| 11 | The DA9055 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 5 |
| 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: ADC_IN1 - high impedance input (0 - 2.5V) |
| 20 | Channel 2: ADC_IN2 - high impedance input (0 - 2.5V) |
| 21 | Channel 3: ADC_IN3 - high impedance input (0 - 2.5V) |
| 22 | Channel 4: Internal Tjunc. - sense (internal temp. sensor) |
| 23 | |
| 24 | By using sysfs attributes we can measure the system voltage VDDOUT, |
| 25 | chip junction temperature and auxiliary channels voltages. |
| 26 | |
| 27 | Voltage Monitoring |
| 28 | ------------------ |
| 29 | |
| 30 | Voltages are sampled in a AUTO mode it can be manually sampled too and results |
| 31 | are stored in a 10 bit ADC. |
| 32 | |
| 33 | The system voltage is calculated as: |
| 34 | Milli volt = ((ADC value * 1000) / 85) + 2500 |
| 35 | |
| 36 | The voltages on ADC channels 1, 2 and 3 are calculated as: |
| 37 | Milli volt = (ADC value * 1000) / 102 |
| 38 | |
| 39 | Temperature Monitoring |
| 40 | ---------------------- |
| 41 | |
| 42 | Temperatures are sampled by a 10 bit ADC. Junction temperatures |
| 43 | are monitored by the ADC channels. |
| 44 | |
| 45 | The junction temperature is calculated: |
| 46 | Degrees celsius = -0.4084 * (ADC_RES - T_OFFSET) + 307.6332 |
| 47 | The junction temperature attribute is supported by the driver. |