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Message-ID: <01e20726-ad01-2761-2546-c574bfb3ea88@axentia.se>
Date: Mon, 27 Jul 2020 11:22:45 +0200
From: Peter Rosin <peda@...ntia.se>
To: Paul Cercueil <paul@...pouillou.net>,
Jonathan Cameron <jic23@...nel.org>
Cc: od@...c.me, linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] iio: afe: rescale: Add support for converting scale
avail table
Hi!
On 2020-02-10 23:54, Paul Cercueil wrote:
> When the IIO channel has a scale_available attribute, we want the values
> contained to be properly converted the same way the scale value is.
>
> Signed-off-by: Paul Cercueil <paul@...pouillou.net>
> ---
> drivers/iio/afe/iio-rescale.c | 125 ++++++++++++++++++++++++++++------
> 1 file changed, 103 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c
> index e9ceee66d1e7..95802d9ee25e 100644
> --- a/drivers/iio/afe/iio-rescale.c
> +++ b/drivers/iio/afe/iio-rescale.c
> @@ -31,14 +31,45 @@ struct rescale {
> struct iio_chan_spec_ext_info *ext_info;
> s32 numerator;
> s32 denominator;
> + int scale_type, scale_len;
> + int *scale_data;
> };
>
> +static int rescale_convert(struct rescale *rescale, int type,
> + const int val, const int val2,
> + int *val_out, int *val2_out)
> +{
> + unsigned long long tmp;
> +
> + switch (type) {
> + case IIO_VAL_FRACTIONAL:
> + *val_out = val * rescale->numerator;
> + *val2_out = val2 * rescale->denominator;
> + return type;
> + case IIO_VAL_INT:
> + *val_out = val * rescale->numerator;
> + if (rescale->denominator == 1)
> + return type;
> + *val2_out = rescale->denominator;
> + return IIO_VAL_FRACTIONAL;
> + case IIO_VAL_FRACTIONAL_LOG2:
> + tmp = val * 1000000000LL;
> + do_div(tmp, rescale->denominator);
> + tmp *= rescale->numerator;
> + do_div(tmp, 1000000000LL);
> + *val_out = tmp;
> + *val2_out = val2;
> + return type;
> + 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);
> - unsigned long long tmp;
> int ret;
>
> switch (mask) {
> @@ -47,27 +78,7 @@ static int rescale_read_raw(struct iio_dev *indio_dev,
>
> case IIO_CHAN_INFO_SCALE:
> ret = iio_read_channel_scale(rescale->source, val, val2);
> - switch (ret) {
> - case IIO_VAL_FRACTIONAL:
> - *val *= rescale->numerator;
> - *val2 *= rescale->denominator;
> - return ret;
> - case IIO_VAL_INT:
> - *val *= rescale->numerator;
> - if (rescale->denominator == 1)
> - return ret;
> - *val2 = rescale->denominator;
> - return IIO_VAL_FRACTIONAL;
> - case IIO_VAL_FRACTIONAL_LOG2:
> - tmp = *val * 1000000000LL;
> - do_div(tmp, rescale->denominator);
> - tmp *= rescale->numerator;
> - do_div(tmp, 1000000000LL);
> - *val = tmp;
> - return ret;
> - default:
> - return -EOPNOTSUPP;
> - }
> + return rescale_convert(rescale, ret, *val, *val2, val, val2);
> default:
> return -EINVAL;
> }
> @@ -85,6 +96,14 @@ static int rescale_read_avail(struct iio_dev *indio_dev,
> *type = IIO_VAL_INT;
> return iio_read_avail_channel_raw(rescale->source,
> vals, length);
> + case IIO_CHAN_INFO_SCALE:
> + if (rescale->scale_len) {
> + *type = rescale->scale_type;
> + *length = rescale->scale_len;
> + *vals = rescale->scale_data;
> + return IIO_AVAIL_LIST;
> + }
> + /* fall-through */
> default:
> return -EINVAL;
> }
> @@ -119,11 +138,65 @@ static ssize_t rescale_write_ext_info(struct iio_dev *indio_dev,
> buf, len);
> }
>
> +static int rescale_init_scale_avail(struct device *dev, struct rescale *rescale)
> +{
> + const int *scale_raw;
> + unsigned int i;
> + int ret;
> +
> + ret = iio_read_avail_channel_attribute(rescale->source, &scale_raw,
> + &rescale->scale_type,
> + &rescale->scale_len,
> + IIO_CHAN_INFO_SCALE);
> + if (ret)
> + return ret;
> +
> + if (rescale->scale_type == IIO_VAL_INT && rescale->denominator > 1)
> + rescale->scale_len *= 2;
> +
> + rescale->scale_data = devm_kzalloc(dev,
> + sizeof(int) * rescale->scale_len,
> + GFP_KERNEL);
> + if (!rescale->scale_len)
> + return -ENOMEM;
> +
> + if (rescale->scale_type != IIO_VAL_INT) {
> + for (i = 0; i < rescale->scale_len; i += 2) {
> + ret = rescale_convert(rescale, rescale->scale_type,
> + scale_raw[i], scale_raw[i + 1],
> + &rescale->scale_data[i],
> + &rescale->scale_data[i + 1]);
> + if (ret < 0)
> + return ret;
> + }
> + } else if (rescale->denominator == 1) {
> + for (i = 0; i < rescale->scale_len; i++) {
> + ret = rescale_convert(rescale, IIO_VAL_INT,
> + scale_raw[i], 0,
> + &rescale->scale_data[i], NULL);
> + if (ret < 0)
> + return ret;
> + }
> + } else {
> + for (i = 0; i < rescale->scale_len / 2; i++) {
> + ret = rescale_convert(rescale, IIO_VAL_INT,
> + scale_raw[i], 0,
> + &rescale->scale_data[i * 2],
> + &rescale->scale_data[i * 2 + 1]);
> + if (ret < 0)
> + return ret;
> + }
> + }
> +
> + return 0;
> +}
> +
> static int rescale_configure_channel(struct device *dev,
> struct rescale *rescale)
> {
> struct iio_chan_spec *chan = &rescale->chan;
> struct iio_chan_spec const *schan = rescale->source->channel;
> + int ret;
>
> chan->indexed = 1;
> chan->output = schan->output;
> @@ -142,6 +215,14 @@ static int rescale_configure_channel(struct device *dev,
> if (iio_channel_has_available(schan, IIO_CHAN_INFO_RAW))
> chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW);
>
> + if (iio_channel_has_available(schan, IIO_CHAN_INFO_SCALE)) {
> + chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_SCALE);
> +
> + ret = rescale_init_scale_avail(dev, rescale);
> + if (ret)
> + return ret;
> + }
> +
You unconditionally add a channel that in some cases then always return
"not supported" if you try to use it. Is that "safe" or can it cause
trouble for some unsuspecting application?
Cheers,
Peter
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