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