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iio: afe: iio-rescale: Support processed channels 

It happens that an ADC will only provide raw or processed
voltage conversion channels. (adc/ab8500-gpadc.c).
On the Samsung GT-I9070 this is used for a light sensor
and current sense amplifier so we need to think of something.

The idea is to allow processed channels and scale them
with 1/1 and then the rescaler can modify the result
on top.

Link: https://lore.kernel.org/linux-iio/20201101232211.1194304-1-linus.walleij@linaro.org/
Cc: Peter Rosin <peda@axentia.se>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Peter Rosin <peda@axentia.se>
Link: https://lore.kernel.org/r/20210518092741.403080-1-linus.walleij@linaro.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Linus Walleij 2021-05-18 11:27:41 +02:00 committed by Jonathan Cameron
parent 842b17223f
commit 53ebee9499
1 changed files with 35 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
drivers/iio/afe/iio-rescale.c
View File

@ -29,6 +29,7 @@ struct rescale {
struct iio_channel *source;
struct iio_chan_spec chan;
struct iio_chan_spec_ext_info *ext_info;
bool chan_processed;
s32 numerator;
s32 denominator;
};
@ -43,10 +44,27 @@ static int rescale_read_raw(struct iio_dev *indio_dev,
switch (mask) {
case IIO_CHAN_INFO_RAW:
return iio_read_channel_raw(rescale->source, val);
if (rescale->chan_processed)
/*
* When only processed channels are supported, we
* read the processed data and scale it by 1/1
* augmented with whatever the rescaler has calculated.
*/
return iio_read_channel_processed(rescale->source, val);
else
return iio_read_channel_raw(rescale->source, val);
case IIO_CHAN_INFO_SCALE:
ret = iio_read_channel_scale(rescale->source, val, val2);
if (rescale->chan_processed) {
/*
* Processed channels are scaled 1-to-1
*/
*val = 1;
*val2 = 1;
ret = IIO_VAL_FRACTIONAL;
} else {
ret = iio_read_channel_scale(rescale->source, val, val2);
}
switch (ret) {
case IIO_VAL_FRACTIONAL:
*val *= rescale->numerator;
@ -130,16 +148,27 @@ static int rescale_configure_channel(struct device *dev,
chan->ext_info = rescale->ext_info;
chan->type = rescale->cfg->type;
if (!iio_channel_has_info(schan, IIO_CHAN_INFO_RAW) ||
!iio_channel_has_info(schan, IIO_CHAN_INFO_SCALE)) {
dev_err(dev, "source channel does not support raw/scale\n");
if (iio_channel_has_info(schan, IIO_CHAN_INFO_RAW) ||
iio_channel_has_info(schan, IIO_CHAN_INFO_SCALE)) {
dev_info(dev, "using raw+scale source channel\n");
} else if (iio_channel_has_info(schan, IIO_CHAN_INFO_PROCESSED)) {
dev_info(dev, "using processed channel\n");
rescale->chan_processed = true;
} else {
dev_err(dev, "source channel is not supported\n");
return -EINVAL;
}
chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_SCALE);
if (iio_channel_has_available(schan, IIO_CHAN_INFO_RAW))
/*
* Using .read_avail() is fringe to begin with and makes no sense
* whatsoever for processed channels, so we make sure that this cannot
* be called on a processed channel.
*/
if (iio_channel_has_available(schan, IIO_CHAN_INFO_RAW) &&
!rescale->chan_processed)
chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW);
return 0;