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    Subject[PATCH 4.14 152/156] iio: chemical: ccs811: Fix output of IIO_CONCENTRATION channels
    Date
    4.14-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Narcisa Ana Maria Vasile <narcisaanamaria12@gmail.com>

    commit 8f114acd4e1a9cfa05b70bcc4219bc88197b5c9b upstream.

    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>
    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>

    ---
    drivers/iio/chemical/ccs811.c | 13 +++----------
    1 file changed, 3 insertions(+), 10 deletions(-)

    --- a/drivers/iio/chemical/ccs811.c
    +++ b/drivers/iio/chemical/ccs811.c
    @@ -91,7 +91,6 @@ static const struct iio_chan_spec ccs811
    .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 = {
    @@ -245,24 +244,18 @@ static int ccs811_read_raw(struct iio_de
    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;
    }

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