48 lines
2 KiB
Text
48 lines
2 KiB
Text
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Kernel driver adc128d818
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========================
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Supported chips:
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* Texas Instruments ADC818D818
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Prefix: 'adc818d818'
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Addresses scanned: I2C 0x1d, 0x1e, 0x1f, 0x2d, 0x2e, 0x2f
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Datasheet: Publicly available at the TI website
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http://www.ti.com/
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Author: Guenter Roeck
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Description
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-----------
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This driver implements support for the Texas Instruments ADC128D818.
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It is described as 'ADC System Monitor with Temperature Sensor'.
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The ADC128D818 implements one temperature sensor and seven voltage sensors.
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Temperatures are measured in degrees Celsius. There is one set of limits.
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When the HOT Temperature Limit is crossed, this will cause an alarm that will
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be reasserted until the temperature drops below the HOT Hysteresis.
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Measurements are guaranteed between -55 and +125 degrees. The temperature
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measurement has a resolution of 0.5 degrees; the limits have a resolution
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of 1 degree.
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Voltage sensors (also known as IN sensors) report their values in volts.
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An alarm is triggered if the voltage has crossed a programmable minimum
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or maximum limit. Note that minimum in this case always means 'closest to
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zero'; this is important for negative voltage measurements. All voltage
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inputs can measure voltages between 0 and 2.55 volts, with a resolution
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of 0.625 mV.
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If an alarm triggers, it will remain triggered until the hardware register
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is read at least once. This means that the cause for the alarm may
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already have disappeared by the time the alarm is read. The driver
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caches the alarm status for each sensor until it is at least reported
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once, to ensure that alarms are reported to user space.
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The ADC128D818 only updates its values approximately once per second;
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reading it more often will do no harm, but will return 'old' values.
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In addition to the scanned address list, the chip can also be configured for
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addresses 0x35 to 0x37. Those addresses are not scanned. You have to instantiate
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the driver explicitly if the chip is configured for any of those addresses in
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your system.
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