@@ -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;
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> --- ChangeLog v2->v3: - Reverse logic on raw+rescale vs processed channels. - Make sure to not announce .read_avail() when using a processed channel. ChangeLog v1->v2: - Deny calls to .read_avail() for processed channels, and insert a comment. - Move an assignment of IIO_VAL_FRACTIONAL down to the end of the block for better readability. --- drivers/iio/afe/iio-rescale.c | 41 ++++++++++++++++++++++++++++++----- 1 file changed, 35 insertions(+), 6 deletions(-)