projects / mirror_ubuntu-jammy-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 08fae079 MCC |
1 | Kernel driver da9052 |
| 2 | ==================== | |
| 3 | ||
| e41f6432 | 4 | Supported chips: |
| 08fae079 | 5 | |
| e41f6432 | 6 | * Dialog Semiconductors DA9052-BC and DA9053-AA/Bx PMICs |
| 08fae079 | 7 | |
| e41f6432 | 8 | Prefix: 'da9052' |
| 08fae079 | 9 | |
| e41f6432 AJ |
10 | Datasheet: Datasheet is not publicly available. |
| 11 | ||
| 12 | Authors: David Dajun Chen <dchen@diasemi.com> | |
| 13 | ||
| 14 | Description | |
| 15 | ----------- | |
| 16 | ||
| 17 | The DA9052/53 provides an Analogue to Digital Converter (ADC) with 10 bits | |
| 18 | resolution and track and hold circuitry combined with an analogue input | |
| 19 | multiplexer. The analogue input multiplexer will allow conversion of up to 10 | |
| 20 | different inputs. The track and hold circuit ensures stable input voltages at | |
| 21 | the input of the ADC during the conversion. | |
| 22 | ||
| 23 | The ADC is used to measure the following inputs: | |
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24 | |
| 25 | ========= =================================================================== | |
| 26 | Channel 0 VDDOUT - measurement of the system voltage | |
| 27 | Channel 1 ICH - internal battery charger current measurement | |
| 28 | Channel 2 TBAT - output from the battery NTC | |
| 29 | Channel 3 VBAT - measurement of the battery voltage | |
| 30 | Channel 4 ADC_IN4 - high impedance input (0 - 2.5V) | |
| 31 | Channel 5 ADC_IN5 - high impedance input (0 - 2.5V) | |
| 32 | Channel 6 ADC_IN6 - high impedance input (0 - 2.5V) | |
| 33 | Channel 7 XY - TSI interface to measure the X and Y voltage of the touch | |
| 34 | screen resistive potentiometers | |
| 35 | Channel 8 Internal Tjunc. - sense (internal temp. sensor) | |
| 36 | Channel 9 VBBAT - measurement of the backup battery voltage | |
| 37 | ========= =================================================================== | |
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38 | |
| 39 | By using sysfs attributes we can measure the system voltage VDDOUT, the battery | |
| 40 | charging current ICH, battery temperature TBAT, battery junction temperature | |
| 41 | TJUNC, battery voltage VBAT and the back up battery voltage VBBAT. | |
| 42 | ||
| 43 | Voltage Monitoring | |
| 44 | ------------------ | |
| 45 | ||
| 46 | Voltages are sampled by a 10 bit ADC. | |
| 47 | ||
| 48 | The battery voltage is calculated as: | |
| 08fae079 | 49 | |
| e41f6432 AJ |
50 | Milli volt = ((ADC value * 1000) / 512) + 2500 |
| 51 | ||
| 52 | The backup battery voltage is calculated as: | |
| 08fae079 | 53 | |
| e41f6432 AJ |
54 | Milli volt = (ADC value * 2500) / 512; |
| 55 | ||
| 56 | The voltages on ADC channels 4, 5 and 6 are calculated as: | |
| 08fae079 | 57 | |
| e41f6432 AJ |
58 | Milli volt = (ADC value * 2500) / 1023 |
| 59 | ||
| 60 | Temperature Monitoring | |
| 61 | ---------------------- | |
| 62 | ||
| 63 | Temperatures are sampled by a 10 bit ADC. Junction and battery temperatures | |
| 64 | are monitored by the ADC channels. | |
| 65 | ||
| 66 | The junction temperature is calculated: | |
| 08fae079 | 67 | |
| e41f6432 | 68 | Degrees celsius = 1.708 * (TJUNC_RES - T_OFFSET) - 108.8 |
| 08fae079 | 69 | |
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70 | The junction temperature attribute is supported by the driver. |
| 71 | ||
| 72 | The battery temperature is calculated: | |
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73 | |
| 74 | Degree Celsius = 1 / (t1 + 1/298) - 273 | |
| 75 | ||
| e41f6432 | 76 | where t1 = (1/B)* ln(( ADCval * 2.5)/(R25*ITBAT*255)) |
| 08fae079 | 77 | |
| e41f6432 | 78 | Default values of R25, B, ITBAT are 10e3, 3380 and 50e-6 respectively. |