5.15-stable review patch. If anyone has any objections, please let me know.
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From: Liam Beguin liambeguin@gmail.com
[ Upstream commit a29c3283653b80b916c5ca5292c5d36415e38e92 ]
This is a preparatory change required for the addition of temperature sensing front ends.
Signed-off-by: Liam Beguin liambeguin@gmail.com Reviewed-by: Peter Rosin peda@axentia.se Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com Link: https://lore.kernel.org/r/20220213025739.2561834-4-liambeguin@gmail.com Signed-off-by: Jonathan Cameron Jonathan.Cameron@huawei.com Stable-dep-of: bee448390e51 ("iio: afe: rescale: Accept only offset channels") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iio/afe/iio-rescale.c | 81 +++++++++++++++++++++++++++++++++ include/linux/iio/afe/rescale.h | 4 ++ 2 files changed, 85 insertions(+)
diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c index 6cc453ab9c685..84f21dc94a2f7 100644 --- a/drivers/iio/afe/iio-rescale.c +++ b/drivers/iio/afe/iio-rescale.c @@ -3,6 +3,7 @@ * IIO rescale driver * * Copyright (C) 2018 Axentia Technologies AB + * Copyright (C) 2022 Liam Beguin liambeguin@gmail.com * * Author: Peter Rosin peda@axentia.se */ @@ -47,11 +48,46 @@ int rescale_process_scale(struct rescale *rescale, int scale_type, } }
+int rescale_process_offset(struct rescale *rescale, int scale_type, + int scale, int scale2, int schan_off, + int *val, int *val2) +{ + s64 tmp, tmp2; + + switch (scale_type) { + case IIO_VAL_FRACTIONAL: + tmp = (s64)rescale->offset * scale2; + *val = div_s64(tmp, scale) + schan_off; + return IIO_VAL_INT; + case IIO_VAL_INT: + *val = div_s64(rescale->offset, scale) + schan_off; + return IIO_VAL_INT; + case IIO_VAL_FRACTIONAL_LOG2: + tmp = (s64)rescale->offset * (1 << scale2); + *val = div_s64(tmp, scale) + schan_off; + return IIO_VAL_INT; + case IIO_VAL_INT_PLUS_NANO: + tmp = (s64)rescale->offset * 1000000000LL; + tmp2 = ((s64)scale * 1000000000LL) + scale2; + *val = div64_s64(tmp, tmp2) + schan_off; + return IIO_VAL_INT; + case IIO_VAL_INT_PLUS_MICRO: + tmp = (s64)rescale->offset * 1000000LL; + tmp2 = ((s64)scale * 1000000LL) + scale2; + *val = div64_s64(tmp, tmp2) + schan_off; + return IIO_VAL_INT; + default: + return -EOPNOTSUPP; + } +} + static int rescale_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask) { struct rescale *rescale = iio_priv(indio_dev); + int scale, scale2; + int schan_off = 0; int ret;
switch (mask) { @@ -78,6 +114,47 @@ static int rescale_read_raw(struct iio_dev *indio_dev, ret = iio_read_channel_scale(rescale->source, val, val2); } return rescale_process_scale(rescale, ret, val, val2); + case IIO_CHAN_INFO_OFFSET: + /* + * Processed channels are scaled 1-to-1 and source offset is + * already taken into account. + * + * In other cases, real world measurement are expressed as: + * + * schan_scale * (raw + schan_offset) + * + * Given that the rescaler parameters are applied recursively: + * + * rescaler_scale * (schan_scale * (raw + schan_offset) + + * rescaler_offset) + * + * Or, + * + * (rescaler_scale * schan_scale) * (raw + + * (schan_offset + rescaler_offset / schan_scale) + * + * Thus, reusing the original expression the parameters exposed + * to userspace are: + * + * scale = schan_scale * rescaler_scale + * offset = schan_offset + rescaler_offset / schan_scale + */ + if (rescale->chan_processed) { + *val = rescale->offset; + return IIO_VAL_INT; + } + + if (iio_channel_has_info(rescale->source->channel, + IIO_CHAN_INFO_OFFSET)) { + ret = iio_read_channel_offset(rescale->source, + &schan_off, NULL); + if (ret != IIO_VAL_INT) + return ret < 0 ? ret : -EOPNOTSUPP; + } + + ret = iio_read_channel_scale(rescale->source, &scale, &scale2); + return rescale_process_offset(rescale, ret, scale, scale2, + schan_off, val, val2); default: return -EINVAL; } @@ -154,6 +231,9 @@ static int rescale_configure_channel(struct device *dev, chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE);
+ if (rescale->offset) + chan->info_mask_separate |= BIT(IIO_CHAN_INFO_OFFSET); + /* * Using .read_avail() is fringe to begin with and makes no sense * whatsoever for processed channels, so we make sure that this cannot @@ -318,6 +398,7 @@ static int rescale_probe(struct platform_device *pdev) rescale->cfg = of_device_get_match_data(dev); rescale->numerator = 1; rescale->denominator = 1; + rescale->offset = 0;
ret = rescale->cfg->props(dev, rescale); if (ret) diff --git a/include/linux/iio/afe/rescale.h b/include/linux/iio/afe/rescale.h index 8a2eb34af3271..6eecb435488f1 100644 --- a/include/linux/iio/afe/rescale.h +++ b/include/linux/iio/afe/rescale.h @@ -25,8 +25,12 @@ struct rescale { bool chan_processed; s32 numerator; s32 denominator; + s32 offset; };
int rescale_process_scale(struct rescale *rescale, int scale_type, int *val, int *val2); +int rescale_process_offset(struct rescale *rescale, int scale_type, + int scale, int scale2, int schan_off, + int *val, int *val2); #endif /* __IIO_RESCALE_H__ */