iio:inkern: Add function to read the processed value

Add a function to read a processed value from a channel. The function will first
attempt to read the IIO_CHAN_INFO_PROCESSED attribute. If that fails it will
read the IIO_CHAN_INFO_RAW attribute and convert the result from a raw value to
a processed value.

The patch also introduces a function to convert raw value to a processed value
and exports it, in case a user needs or wants to do the conversion by itself.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 109 insertions, 9 deletions

diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index d539e1e297ba..25b00761005a 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -238,9 +238,21 @@ void iio_channel_release_all(struct iio_channel *channels)
 }
 EXPORT_SYMBOL_GPL(iio_channel_release_all);
 
+static int iio_channel_read(struct iio_channel *chan, int *val, int *val2,
+        enum iio_chan_info_enum info)
+{
+        int unused;
+
+        if (val2 == NULL)
+                val2 = &unused;
+
+        return chan->indio_dev->info->read_raw(chan->indio_dev, chan->channel,
+                                                val, val2, info);
+}
+
 int iio_read_channel_raw(struct iio_channel *chan, int *val)
 {
-        int val2, ret;
+        int ret;
 
         mutex_lock(&chan->indio_dev->info_exist_lock);
         if (chan->indio_dev->info == NULL) {
@@ -248,10 +260,7 @@ int iio_read_channel_raw(struct iio_channel *chan, int *val)
                 goto err_unlock;
         }
 
-        ret = chan->indio_dev->info->read_raw(chan->indio_dev,
-                                              chan->channel,
-                                              val, &val2,
-                                              IIO_CHAN_INFO_RAW);
+        ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
 err_unlock:
         mutex_unlock(&chan->indio_dev->info_exist_lock);
 
@@ -259,6 +268,100 @@ err_unlock:
 }
 EXPORT_SYMBOL_GPL(iio_read_channel_raw);
 
+static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan,
+        int raw, int *processed, unsigned int scale)
+{
+        int scale_type, scale_val, scale_val2, offset;
+        s64 raw64 = raw;
+        int ret;
+
+        ret = iio_channel_read(chan, &offset, NULL, IIO_CHAN_INFO_SCALE);
+        if (ret == 0)
+                raw64 += offset;
+
+        scale_type = iio_channel_read(chan, &scale_val, &scale_val2,
+                                        IIO_CHAN_INFO_SCALE);
+        if (scale_type < 0)
+                return scale_type;
+
+        switch (scale_type) {
+        case IIO_VAL_INT:
+                *processed = raw64 * scale_val;
+                break;
+        case IIO_VAL_INT_PLUS_MICRO:
+                if (scale_val2 < 0)
+                        *processed = -raw64 * scale_val;
+                else
+                        *processed = raw64 * scale_val;
+                *processed += div_s64(raw64 * (s64)scale_val2 * scale,
+                                      1000000LL);
+                break;
+        case IIO_VAL_INT_PLUS_NANO:
+                if (scale_val2 < 0)
+                        *processed = -raw64 * scale_val;
+                else
+                        *processed = raw64 * scale_val;
+                *processed += div_s64(raw64 * (s64)scale_val2 * scale,
+                                      1000000000LL);
+                break;
+        case IIO_VAL_FRACTIONAL:
+                *processed = div_s64(raw64 * (s64)scale_val * scale,
+                                     scale_val2);
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
+        int *processed, unsigned int scale)
+{
+        int ret;
+
+        mutex_lock(&chan->indio_dev->info_exist_lock);
+        if (chan->indio_dev->info == NULL) {
+                ret = -ENODEV;
+                goto err_unlock;
+        }
+
+        ret = iio_convert_raw_to_processed_unlocked(chan, raw, processed,
+                                                        scale);
+err_unlock:
+        mutex_unlock(&chan->indio_dev->info_exist_lock);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(iio_convert_raw_to_processed);
+
+int iio_read_channel_processed(struct iio_channel *chan, int *val)
+{
+        int ret;
+
+        mutex_lock(&chan->indio_dev->info_exist_lock);
+        if (chan->indio_dev->info == NULL) {
+                ret = -ENODEV;
+                goto err_unlock;
+        }
+
+        if (iio_channel_has_info(chan->channel, IIO_CHAN_INFO_PROCESSED)) {
+                ret = iio_channel_read(chan, val, NULL,
+                                       IIO_CHAN_INFO_PROCESSED);
+        } else {
+                ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
+                if (ret < 0)
+                        goto err_unlock;
+                ret = iio_convert_raw_to_processed_unlocked(chan, *val, val, 1);
+        }
+
+err_unlock:
+        mutex_unlock(&chan->indio_dev->info_exist_lock);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(iio_read_channel_processed);
+
 int iio_read_channel_scale(struct iio_channel *chan, int *val, int *val2)
 {
         int ret;
@@ -269,10 +372,7 @@ int iio_read_channel_scale(struct iio_channel *chan, int *val, int *val2)
                 goto err_unlock;
         }
 
-        ret = chan->indio_dev->info->read_raw(chan->indio_dev,
-                                              chan->channel,
-                                              val, val2,
-                                              IIO_CHAN_INFO_SCALE);
+        ret = iio_channel_read(chan, val, val2, IIO_CHAN_INFO_SCALE);
 err_unlock:
         mutex_unlock(&chan->indio_dev->info_exist_lock);