Messages in this thread | | | From | Peter Rosin <> | Subject | RE: [PATCH] iio: max5487: Add support for Maxim digital potentiometers | Date | Fri, 25 Mar 2016 10:20:34 +0000 |
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Hi again,
Cristina Moraru wrote: > Add implementation for Maxim MAX5487, MAX5488, MAX5489 > digital potentiometers. > > Signed-off-by: Cristina Moraru <cristina.moraru09@gmail.com> > CC: Daniel Baluta <daniel.baluta@intel.com>
Some more comments, the mcp4531 chips have n**2 + 1 positions, therefore .max_pos in that driver isn't the number of wiper positions, it's the actual maximum value. So, in this driver, the corrent number for .max_pos would be 255, otherwise the reported scale is wrong (and then you also need to adjust the EINVAL check in max5487_write_raw to use > instead of >=).
Further comparison with the mcp4531 driver reveals that this driver does not support IIO_CHAN_INFO_RAW in max5487_read_raw. I assume the SPI interface does not support reading back the current value?
Cheers, Peter
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