58 lines
1.7 KiB
ReStructuredText
58 lines
1.7 KiB
ReStructuredText
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Kernel driver da9055
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====================
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Supported chips:
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* Dialog Semiconductors DA9055 PMIC
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Prefix: 'da9055'
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Datasheet: Datasheet is not publicly available.
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Authors: David Dajun Chen <dchen@diasemi.com>
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Description
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-----------
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The DA9055 provides an Analogue to Digital Converter (ADC) with 10 bits
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resolution and track and hold circuitry combined with an analogue input
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multiplexer. The analogue input multiplexer will allow conversion of up to 5
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different inputs. The track and hold circuit ensures stable input voltages at
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the input of the ADC during the conversion.
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The ADC is used to measure the following inputs:
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- Channel 0: VDDOUT - measurement of the system voltage
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- Channel 1: ADC_IN1 - high impedance input (0 - 2.5V)
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- Channel 2: ADC_IN2 - high impedance input (0 - 2.5V)
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- Channel 3: ADC_IN3 - high impedance input (0 - 2.5V)
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- Channel 4: Internal Tjunc. - sense (internal temp. sensor)
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By using sysfs attributes we can measure the system voltage VDDOUT,
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chip junction temperature and auxiliary channels voltages.
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Voltage Monitoring
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------------------
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Voltages are sampled in a AUTO mode it can be manually sampled too and results
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are stored in a 10 bit ADC.
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The system voltage is calculated as:
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Milli volt = ((ADC value * 1000) / 85) + 2500
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The voltages on ADC channels 1, 2 and 3 are calculated as:
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Milli volt = (ADC value * 1000) / 102
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Temperature Monitoring
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----------------------
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Temperatures are sampled by a 10 bit ADC. Junction temperatures
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are monitored by the ADC channels.
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The junction temperature is calculated:
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Degrees celsius = -0.4084 * (ADC_RES - T_OFFSET) + 307.6332
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The junction temperature attribute is supported by the driver.
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