4d7e47bc83
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net> Signed-off-by: Jean Delvare <khali@linux-fr.org>
61 lines
2.3 KiB
Text
61 lines
2.3 KiB
Text
Supported chips:
|
|
* Dialog Semiconductors DA9052-BC and DA9053-AA/Bx PMICs
|
|
Prefix: 'da9052'
|
|
Datasheet: Datasheet is not publicly available.
|
|
|
|
Authors: David Dajun Chen <dchen@diasemi.com>
|
|
|
|
Description
|
|
-----------
|
|
|
|
The DA9052/53 provides an Analogue to Digital Converter (ADC) with 10 bits
|
|
resolution and track and hold circuitry combined with an analogue input
|
|
multiplexer. The analogue input multiplexer will allow conversion of up to 10
|
|
different inputs. The track and hold circuit ensures stable input voltages at
|
|
the input of the ADC during the conversion.
|
|
|
|
The ADC is used to measure the following inputs:
|
|
Channel 0: VDDOUT - measurement of the system voltage
|
|
Channel 1: ICH - internal battery charger current measurement
|
|
Channel 2: TBAT - output from the battery NTC
|
|
Channel 3: VBAT - measurement of the battery voltage
|
|
Channel 4: ADC_IN4 - high impedance input (0 - 2.5V)
|
|
Channel 5: ADC_IN5 - high impedance input (0 - 2.5V)
|
|
Channel 6: ADC_IN6 - high impedance input (0 - 2.5V)
|
|
Channel 7: XY - TSI interface to measure the X and Y voltage of the touch
|
|
screen resistive potentiometers
|
|
Channel 8: Internal Tjunc. - sense (internal temp. sensor)
|
|
Channel 9: VBBAT - measurement of the backup battery voltage
|
|
|
|
By using sysfs attributes we can measure the system voltage VDDOUT, the battery
|
|
charging current ICH, battery temperature TBAT, battery junction temperature
|
|
TJUNC, battery voltage VBAT and the back up battery voltage VBBAT.
|
|
|
|
Voltage Monitoring
|
|
------------------
|
|
|
|
Voltages are sampled by a 10 bit ADC.
|
|
|
|
The battery voltage is calculated as:
|
|
Milli volt = ((ADC value * 1000) / 512) + 2500
|
|
|
|
The backup battery voltage is calculated as:
|
|
Milli volt = (ADC value * 2500) / 512;
|
|
|
|
The voltages on ADC channels 4, 5 and 6 are calculated as:
|
|
Milli volt = (ADC value * 2500) / 1023
|
|
|
|
Temperature Monitoring
|
|
----------------------
|
|
|
|
Temperatures are sampled by a 10 bit ADC. Junction and battery temperatures
|
|
are monitored by the ADC channels.
|
|
|
|
The junction temperature is calculated:
|
|
Degrees celsius = 1.708 * (TJUNC_RES - T_OFFSET) - 108.8
|
|
The junction temperature attribute is supported by the driver.
|
|
|
|
The battery temperature is calculated:
|
|
Degree Celsius = 1 / (t1 + 1/298)- 273
|
|
where t1 = (1/B)* ln(( ADCval * 2.5)/(R25*ITBAT*255))
|
|
Default values of R25, B, ITBAT are 10e3, 3380 and 50e-6 respectively.
|