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authorIvan Zaentsev <ivan.zaentsev@wirenboard.ru>2020-09-04 19:00:03 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-10-02 11:49:50 +0200
commit021da53e65fdd0e1b8492c2670dd075c0ea910fc (patch)
tree1c13a1936d8f43a1d3b7804446b722296c69637b /fs/ceph/ioctl.h
parentb31de43c608ffaa83e67a410ba58d678ff405f55 (diff)
w1: w1_therm: Add sysfs entries to control conversion time and driver features
The conversion time of common DS18B20 clones deviates from datasheet specs. Allow adjustment and automatic measure of the conversion time. Add 'conv_time' sysfs attribute: *read*: Current conversion time in milliseconds. *write*: '0': Set default conversion time. '1': Measure and set the conversion time. Make a single temperature conversion, poll and measure an actual value. Measured value is increased by 20% for temperature drift. A new conversion time is returned by reading the same attribute. other positive value: Set the conversion time in milliseconds. The setting is active until a resolution change. Then it is reset to default conversion time for a new resolution. Add 'features' sysfs attribute to control optional driver settings per device. Bit masks to read/write (logical OR): 1: Enable check for conversion success. If byte 6 of scratchpad memory is 0xC after conversion, and temperature reads 85.00 (powerup value) or 127.94 (insufficient power) - return a conversion error. 2: Enable poll for conversion completion. Generate read cycles after the conversion start and wait for 1's. In parasite power mode this feature is not available. There are some clones of DS18B20 with fixed 12 bit resolution. Make the driver verify the resolution by reading back the device after resolution change. Signed-off-by: Ivan Zaentsev <ivan.zaentsev@wirenboard.ru> Acked-by: Evgeniy Polyakov <zbr@ioremap.net> Link: https://lore.kernel.org/r/20200904160004.87710-1-ivan.zaentsev@wirenboard.ru Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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