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08fae079 MCC |
1 | Kernel driver da9055 |
2 | ==================== | |
3 | ||
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4 | Supported chips: |
5 | * Dialog Semiconductors DA9055 PMIC | |
08fae079 | 6 | |
e5970223 | 7 | Prefix: 'da9055' |
08fae079 | 8 | |
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9 | Datasheet: Datasheet is not publicly available. |
10 | ||
11 | Authors: David Dajun Chen <dchen@diasemi.com> | |
12 | ||
13 | Description | |
14 | ----------- | |
15 | ||
16 | The DA9055 provides an Analogue to Digital Converter (ADC) with 10 bits | |
17 | resolution and track and hold circuitry combined with an analogue input | |
18 | multiplexer. The analogue input multiplexer will allow conversion of up to 5 | |
19 | different inputs. The track and hold circuit ensures stable input voltages at | |
20 | the input of the ADC during the conversion. | |
21 | ||
22 | The ADC is used to measure the following inputs: | |
08fae079 MCC |
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) | |
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29 | |
30 | By using sysfs attributes we can measure the system voltage VDDOUT, | |
31 | chip junction temperature and auxiliary channels voltages. | |
32 | ||
33 | Voltage Monitoring | |
34 | ------------------ | |
35 | ||
36 | Voltages are sampled in a AUTO mode it can be manually sampled too and results | |
37 | are stored in a 10 bit ADC. | |
38 | ||
39 | The system voltage is calculated as: | |
08fae079 | 40 | |
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41 | Milli volt = ((ADC value * 1000) / 85) + 2500 |
42 | ||
43 | The voltages on ADC channels 1, 2 and 3 are calculated as: | |
08fae079 | 44 | |
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45 | Milli volt = (ADC value * 1000) / 102 |
46 | ||
47 | Temperature Monitoring | |
48 | ---------------------- | |
49 | ||
50 | Temperatures are sampled by a 10 bit ADC. Junction temperatures | |
51 | are monitored by the ADC channels. | |
52 | ||
53 | The junction temperature is calculated: | |
08fae079 | 54 | |
e5970223 | 55 | Degrees celsius = -0.4084 * (ADC_RES - T_OFFSET) + 307.6332 |
08fae079 | 56 | |
e5970223 | 57 | The junction temperature attribute is supported by the driver. |