hwmon: (ina2xx) Make calibration register value fixed

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Calibration register is used for calculating current register in
hardware according to datasheet:
current = shunt_volt * calib_register / 2048 (ina 226)
current = shunt_volt * calib_register / 4096 (ina 219)

Fix calib_register value to 2048 for ina226 and 4096 for ina 219 in
order to avoid truncation error and provide best precision allowed
by shunt_voltage measurement. Make current scale value follow changes
of shunt_resistor from sysfs as calib_register value is now fixed.

Power_lsb value should also follow shunt_resistor changes as stated in
datasheet:
power_lsb = 25 * current_lsb (ina 226)
power_lsb = 20 * current_lsb (ina 219)

Signed-off-by: Maciej Purski <m.purski@samsung.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

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This commit is contained in:

Maciej Purski 2017-11-22 16:32:15 +01:00 • committed by Guenter Roeck

parent cf583b4275

commit 5d389b1251

1 changed files with 50 additions and 37 deletions

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drivers/hwmon/ina2xx.c

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