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@xxxxxxxxxx/ Cc: Peter Rosin <peda@xxxxxxxxxx> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> --- 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(-) diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c index e42ea2b1707d..774eb3044edd 100644 --- a/drivers/iio/afe/iio-rescale.c +++ b/drivers/iio/afe/iio-rescale.c @@ -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; -- 2.31.1
