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@xxxxxxxxxx>
---
drivers/iio/inkern.c | 114 ++++++++++++++++++++++++++++++++++++++----
include/linux/iio/consumer.h | 38 ++++++++++++++
include/linux/iio/iio.h | 17 +++++++
3 files changed, 160 insertions(+), 9 deletions(-)
diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index a14e55d..37299bf 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -229,9 +229,21 @@ void iio_channel_release_all(struct iio_channel *channels)
}
EXPORT_SYMBOL_GPL(iio_channel_release_all);
+static 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) {
@@ -239,10 +251,7 @@ 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);
@@ -250,6 +259,96 @@ 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 = raw * scale_val;
+ break;
+ case IIO_VAL_INT_PLUS_MICRO:
+ if (scale_val2 < 0)
+ *processed = -raw * scale_val;
+ else
+ *processed = raw * scale_val;
+ *processed += div_s64(raw * (s64)scale_val2 * scale, 1000000LL);
+ break;
+ case IIO_VAL_INT_PLUS_NANO:
+ if (scale_val2 < 0)
+ *processed = -raw * scale_val;
+ else
+ *processed = raw * scale_val;
+ *processed += div_s64(raw * (s64)scale_val2 * scale, 1000000000LL);
+ break;
+ case IIO_VAL_FRACTIONAL:
+ *processed = div_s64(raw * (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 unused, 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;
@@ -260,10 +359,7 @@ 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_read_channel(chan, val, val2, IIO_CHAN_INFO_SCALE);
err_unlock:
mutex_unlock(&chan->indio_dev->info_exist_lock);
diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
index 27759ac3..3f66304 100644
--- a/include/linux/iio/consumer.h
+++ b/include/linux/iio/consumer.h
@@ -71,6 +71,21 @@ int iio_read_channel_raw(struct iio_channel *channel,
int *val);
/**
+ * iio_read_channel_processed() - read processed value from a given channel
+ * @channel: The channel being queried.
+ * @val: Value read back.
+ *
+ * Returns an error code or 0.
+ *
+ * This function will read a processed value from a channel. A processed value
+ * means that this value will have the correct unit and not some device internal
+ * representation. If the device does not support reporting a processed value
+ * the function will query the raw value and the channels scale and offset and
+ * do the appropriate transformation.
+ */
+int iio_read_channel_processed(const struct iio_channel *channel, int *val);
+
+/**
* iio_get_channel_type() - get the type of a channel
* @channel: The channel being queried.
* @type: The type of the channel.
@@ -93,4 +108,27 @@ int iio_get_channel_type(struct iio_channel *channel,
int iio_read_channel_scale(struct iio_channel *channel, int *val,
int *val2);
+/**
+ * iio_convert_raw_to_processed() - Converts a raw value to a processed value
+ * @channel: The channel being queried
+ * @raw: The raw IIO to convert
+ * @processed: The result of the conversion
+ * @scale: Scale factor to apply during the conversion
+ *
+ * Returns an error code or 0.
+ *
+ * This function converts a raw value to processed value for a specific channel.
+ * A raw value is the device internal representation of a sample and the value
+ * returned by iio_read_channel_raw, so the unit of that value is device
+ * depended. A processed value on the other hand is value has a normed unit
+ * according with the IIO specification.
+ *
+ * The scale factor allows to increase the precession of the returned value. For
+ * a scale factor of 1 the function will return the result in the normal IIO
+ * unit for the channel type. E.g. millivolt for voltage channels, if you want
+ * nanovolts instead pass 1000 as the scale factor.
+ */
+int iio_convert_raw_to_processed(const struct iio_channel *channel, int raw,
+ int *processed, unsigned int scale);
+
#endif
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 30affa5..c0ae76a 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -40,6 +40,8 @@ enum iio_chan_info_enum {
#define IIO_CHAN_INFO_SHARED_BIT(type) BIT(type*2)
#define IIO_CHAN_INFO_SEPARATE_BIT(type) BIT(type*2 + 1)
+#define IIO_CHAN_INFO_BITS(type) (IIO_CHAN_INFO_SHARED_BIT(type) | \
+ IIO_CHAN_INFO_SEPARATE_BIT(type))
#define IIO_CHAN_INFO_RAW_SEPARATE_BIT \
IIO_CHAN_INFO_SEPARATE_BIT(IIO_CHAN_INFO_RAW)
@@ -261,6 +263,21 @@ struct iio_chan_spec {
unsigned differential:1;
};
+
+/**
+ * iio_channel_has_info() - Checks whether a channel supports a info attribute
+ * @chan: The channel to be queried
+ * @type: Type of the info attribute to be checked
+ *
+ * Returns true if the channels supports reporting values for the given info
+ * attribute type, false otherwise.
+ */
+static inline bool iio_channel_has_info(const struct iio_chan_spec *chan,
+ enum iio_chan_info_enum type)
+{
+ return chan->info_mask & IIO_CHAN_INFO_BITS(type);
+}
+
#define IIO_ST(si, rb, sb, sh) \
{ .sign = si, .realbits = rb, .storagebits = sb, .shift = sh }
--
1.7.10.4
--
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