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Commit | Line | Data |
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e41f6432 AJ |
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: | |
4d7e47bc | 59 | Degree Celsius = 1 / (t1 + 1/298)- 273 |
e41f6432 AJ |
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. |