patch "iio: chemical: ccs811: Fix output of IIO_CONCENTRATION channels" added to staging-next

patch "iio: chemical: ccs811: Fix output of IIO_CONCENTRATION channels" added to staging-next

[gregkh]

This is a note to let you know that I've just added the patch titled

    iio: chemical: ccs811: Fix output of IIO_CONCENTRATION channels

to my staging git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-next branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will also be merged in the next major kernel release
during the merge window.

If you have any questions about this process, please let me know.


>From 8f114acd4e1a9cfa05b70bcc4219bc88197b5c9b Mon Sep 17 00:00:00 2001
From: Narcisa Ana Maria Vasile <narcisaanamaria12@gmail.com>
Date: Wed, 6 Dec 2017 18:57:58 +0200
Subject: 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>
---
 drivers/iio/chemical/ccs811.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/chemical/ccs811.c b/drivers/iio/chemical/ccs811.c
index 97bce8345c6a..fbe2431f5b81 100644
--- a/drivers/iio/chemical/ccs811.c
+++ b/drivers/iio/chemical/ccs811.c
@@ -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;
 	}
-- 
2.15.1