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authorLars-Peter Clausen <lars@metafoo.de>2012-09-17 16:17:00 +0400
committerJonathan Cameron <jic23@kernel.org>2012-09-18 00:48:51 +0400
commit48e44ce0f8810b530fc83a4f5eb67149280d9b82 (patch)
treece32b7a0917edb95fe5b4c3de1edd33e8d0f7ed6 /include/linux/iio
parent45f010baa0292c367168b1f62d5494965b905b5d (diff)
downloadlinux-48e44ce0f8810b530fc83a4f5eb67149280d9b82.tar.xz
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>
Diffstat (limited to 'include/linux/iio')
-rw-r--r--include/linux/iio/consumer.h38
-rw-r--r--include/linux/iio/iio.h17
2 files changed, 55 insertions, 0 deletions
diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
index 62118dd707d7..e875bcf0478f 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 *chan,
int *val);
/**
+ * iio_read_channel_processed() - read processed value from a given channel
+ * @chan: 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(struct iio_channel *chan, 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 *chan, int *val,
int *val2);
+/**
+ * iio_convert_raw_to_processed() - Converts a raw value to a processed value
+ * @chan: 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(struct iio_channel *chan, int raw,
+ int *processed, unsigned int scale);
+
#endif
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 30affa533a1f..c0ae76ac4e0b 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 }