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The ltc2947 is a high precision power and energy monitor with an internal sense resistor supporting up to +/- 30A. Three internal no Latency ADCs ensure accurate measurement of voltage and current, while high-bandwidth analog multiplication of voltage and current provides accurate power measurement in a wide range of applications. Internal or external clocking options enable precise charge and energy measurements. Signed-off-by: Nuno Sá <nuno.sa@analog.com> Link: https://lore.kernel.org/r/20191021154115.319073-1-nuno.sa@analog.com [groeck: Removed unnecessary checks when reading temperature and energy; PAGE{0,1} -> LTC2947_PAGE_{0,1}] Signed-off-by: Guenter Roeck <linux@roeck-us.net>
101 lines
3.5 KiB
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101 lines
3.5 KiB
ReStructuredText
Kernel drivers ltc2947-i2c and ltc2947-spi
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==========================================
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Supported chips:
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* Analog Devices LTC2947
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Prefix: 'ltc2947'
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Addresses scanned: -
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Datasheet:
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https://www.analog.com/media/en/technical-documentation/data-sheets/LTC2947.pdf
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Author: Nuno Sá <nuno.sa@analog.com>
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Description
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___________
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The LTC2947 is a high precision power and energy monitor that measures current,
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voltage, power, temperature, charge and energy. The device supports both SPI
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and I2C depending on the chip configuration.
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The device also measures accumulated quantities as energy. It has two banks of
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register's to read/set energy related values. These banks can be configured
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independently to have setups like: energy1 accumulates always and enrgy2 only
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accumulates if current is positive (to check battery charging efficiency for
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example). The device also supports a GPIO pin that can be configured as output
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to control a fan as a function of measured temperature. Then, the GPIO becomes
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active as soon as a temperature reading is higher than a defined threshold. The
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temp2 channel is used to control this thresholds and to read the respective
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alarms.
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Sysfs entries
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_____________
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The following attributes are supported. Limits are read-write, reset_history
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is write-only and all the other attributes are read-only.
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======================= ==========================================
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in0_input VP-VM voltage (mV).
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in0_min Undervoltage threshold
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in0_max Overvoltage threshold
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in0_lowest Lowest measured voltage
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in0_highest Highest measured voltage
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in0_reset_history Write 1 to reset in1 history
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in0_min_alarm Undervoltage alarm
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in0_max_alarm Overvoltage alarm
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in0_label Channel label (VP-VM)
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in1_input DVCC voltage (mV)
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in1_min Undervoltage threshold
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in1_max Overvoltage threshold
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in1_lowest Lowest measured voltage
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in1_highest Highest measured voltage
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in1_reset_history Write 1 to reset in2 history
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in1_min_alarm Undervoltage alarm
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in1_max_alarm Overvoltage alarm
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in1_label Channel label (DVCC)
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curr1_input IP-IM Sense current (mA)
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curr1_min Undercurrent threshold
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curr1_max Overcurrent threshold
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curr1_lowest Lowest measured current
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curr1_highest Highest measured current
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curr1_reset_history Write 1 to reset curr1 history
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curr1_min_alarm Undercurrent alarm
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curr1_max_alarm Overcurrent alarm
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curr1_label Channel label (IP-IM)
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power1_input Power (in uW)
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power1_min Low power threshold
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power1_max High power threshold
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power1_input_lowest Historical minimum power use
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power1_input_highest Historical maximum power use
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power1_reset_history Write 1 to reset power1 history
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power1_min_alarm Low power alarm
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power1_max_alarm High power alarm
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power1_label Channel label (Power)
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temp1_input Chip Temperature (in milliC)
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temp1_min Low temperature threshold
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temp1_max High temperature threshold
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temp1_input_lowest Historical minimum temperature use
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temp1_input_highest Historical maximum temperature use
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temp1_reset_history Write 1 to reset temp1 history
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temp1_min_alarm Low temperature alarm
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temp1_max_alarm High temperature alarm
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temp1_label Channel label (Ambient)
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temp2_min Low temperature threshold for fan control
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temp2_max High temperature threshold for fan control
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temp2_min_alarm Low temperature fan control alarm
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temp2_max_alarm High temperature fan control alarm
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temp2_label Channel label (TEMPFAN)
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energy1_input Measured energy over time (in microJoule)
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energy2_input Measured energy over time (in microJoule)
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======================= ==========================================
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