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