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iio: chemical: ccs811: Fix output of IIO_CONCENTRATION channels

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in_concentration_raw should report, according to sysfs-bus-iio documentation,
a "Raw (unscaled no offset etc.) percentage reading of a substance."

Modify scale to convert from ppm/ppb to percentage:
1 ppm = 0.0001%
1 ppb = 0.0000001%

There is no offset needed to convert the ppm/ppb to percentage,
so remove offset from IIO_CONCENTRATION (IIO_MOD_CO2) channel.

Cc'd stable to reduce chance of userspace breakage in the long
run as we fix this wrong bit of ABI usage.

Signed-off-by: Narcisa Ana Maria Vasile <narcisaanamaria12@gmail.com>
Cc: <Stable@vger.kernel.org>
Reviewed-by: Matt Ranostay <matt.ranostay@konsulko.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Narcisa Ana Maria Vasile 2017-12-06 18:57:58 +02:00 committed by Greg Kroah-Hartman
parent 9bf94f836e
commit 8f114acd4e
1 changed files with 3 additions and 10 deletions
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13
drivers/iio/chemical/ccs811.c
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@ -96,7 +96,6 @@ static const struct iio_chan_spec ccs811_channels[] = {
.channel2 = IIO_MOD_CO2,
.modified = 1,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_OFFSET) |
BIT(IIO_CHAN_INFO_SCALE),
.scan_index = 0,
.scan_type = {
@ -255,24 +254,18 @@ static int ccs811_read_raw(struct iio_dev *indio_dev,
switch (chan->channel2) {
case IIO_MOD_CO2:
*val = 0;
*val2 = 12834;
*val2 = 100;
return IIO_VAL_INT_PLUS_MICRO;
case IIO_MOD_VOC:
*val = 0;
*val2 = 84246;
return IIO_VAL_INT_PLUS_MICRO;
*val2 = 100;
return IIO_VAL_INT_PLUS_NANO;
default:
return -EINVAL;
}
default:
return -EINVAL;
}
case IIO_CHAN_INFO_OFFSET:
if (!(chan->type == IIO_CONCENTRATION &&
chan->channel2 == IIO_MOD_CO2))
return -EINVAL;
*val = -400;
return IIO_VAL_INT;
default:
return -EINVAL;
}