Commit Graph

5 Commits

Author SHA1 Message Date
Narcisa Ana Maria Vasile 8f114acd4e iio: chemical: ccs811: Fix output of IIO_CONCENTRATION channels
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>
2018-01-08 16:03:44 +01:00
Narcisa Ana Maria Vasile f1f065d7ac iio: chemical: ccs811: Add support for data ready trigger
Add data ready trigger for hardware interrupts that signal
new, available measurement samples.

Cc: Daniel Baluta <daniel.baluta@gmail.com>
Cc: Alison Schofield <amsfield22@gmail.com>
Signed-off-by: Narcisa Ana Maria Vasile <narcisaanamaria12@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2017-09-24 12:34:36 +01:00
Jonathan Cameron 254f3a6364 iio:chemical: drop assign iio_info.driver_module and iio_trigger_ops.owner
The equivalent of both of these are now done via macro magic when
the relevant register calls are made.  The actual structure
elements will shortly go away.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
2017-08-22 21:25:20 +01:00
Narcisa Ana Maria Vasile 283d26917a iio: chemical: ccs811: Add triggered buffer support
A software trigger such as hrtimer can be used to capture the data
that will be stored in the buffer.

Cc: Daniel Baluta <daniel.baluta@gmail.com>
Cc: Alison Schofield <amsfield22@gmail.com>
Signed-off-by: Narcisa Ana Maria Vasile <narcisaanamaria12@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2017-08-18 08:08:02 +01:00
Narcisa Ana Maria Vasile a94c24a712 iio: chemical: ccs811: Add support for AMS CCS811 VOC sensor
Add support for CCS811 VOC sensor. This patch adds support
for reading current and voltage across the sensor and TVOC
and equivalent CO2 values.

Scale and offset values have been computed according to datasheet:
    - For current: raw value is in microamps
        => 0.001 scale to convert to milliamps
    - For voltage: 1.65V = 1023, therefore 1650mV = 1023
        => 1650.0/1023 = 1.612903 scale to convert to millivolts
    - For eCO2: raw value range is from 400ppm to 8192ppm.
        => (val - 400) * (100 - 0) / (8192 - 400) + 0 =
           (val - 400) * 0.01283367 => offset: -400, scale = 0.012834
           to get a percentage value
    -For TVOC: raw value range is from 0ppb to 1187ppb.
        => (val - 0) * 100 / (1187 - 0) + 0 = val * 0.0842459 =>
            scale = 0.084246 for getting a percentage value

Cc: Daniel Baluta <daniel.baluta@gmail.com>
Cc: Alison Schofield <amsfield22@gmail.com>
Signed-off-by: Narcisa Ana Maria Vasile <narcisaanamaria12@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2017-07-22 21:16:37 +01:00