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