Some ADC devices allow averaging/downsampling. The minimal parameter
set for this will be the number of taps used for computing a mean value.
In some cases the ratio will hold discrete values for instance "1, 4, 16"
hence an averaging_ratio_available property is useful. The possible ratio
values are less likely to changing with the device settings, so this patch
only provides a CONST version of the definition helper.
Tested with ina226:
# ls /sys/bus/iio/devices/iio\:device0/
averaging_ratio_available in_voltage0_raw
dev in_voltage1_raw
in_averaging_ratio name
in_calibscale power
in_current2_raw sampling_frequency_available
in_power3_raw subsystem
in_sampling_frequency uevent
# cat averaging_ratio_available
1, 4, 16, 64, 128, 256, 512, 1024
Signed-off-by: Marc Titinger <mtitinger@xxxxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-bus-iio | 13 +++++++++++++
drivers/iio/industrialio-core.c | 1 +
include/linux/iio/iio.h | 1 +
include/linux/iio/sysfs.h | 9 +++++++++
4 files changed, 24 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index 42d360f..a208dfe 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -56,6 +56,19 @@ Description:
When the internal sampling clock can only take a small
discrete set of values, this file lists those available.
+What: /sys/bus/iio/devices/iio:deviceX/averaging_ratio
+KernelVersion: 4.x.x
+Contact: linux-iio@xxxxxxxxxxxxxxx
+Description:
+ Hardware dependent ADC averaging. Controls the averaging ratio
+ of the digital filter if available.
+
+What: /sys/bus/iio/devices/iio:deviceX/averaging_ratio_available
+KernelVersion: 4.x.x
+Contact: linux-iio@xxxxxxxxxxxxxxx
+Description:
+ Hardware dependent values supported by the averaging filter.
+
What: /sys/bus/iio/devices/iio:deviceX/oversampling_ratio
KernelVersion: 2.6.38
Contact: linux-iio@xxxxxxxxxxxxxxx
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index b3fcc2c..e4745f0 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -142,6 +142,7 @@ static const char * const iio_chan_info_postfix[] = {
[IIO_CHAN_INFO_DEBOUNCE_TIME] = "debounce_time",
[IIO_CHAN_INFO_CALIBEMISSIVITY] = "calibemissivity",
[IIO_CHAN_INFO_OVERSAMPLING_RATIO] = "oversampling_ratio",
+ [IIO_CHAN_INFO_AVERAGING_RATIO] = "averaging_ratio",
};
/**
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 7bb7f67..4c84de5 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -46,6 +46,7 @@ enum iio_chan_info_enum {
IIO_CHAN_INFO_DEBOUNCE_TIME,
IIO_CHAN_INFO_CALIBEMISSIVITY,
IIO_CHAN_INFO_OVERSAMPLING_RATIO,
+ IIO_CHAN_INFO_AVERAGING_RATIO,
};
enum iio_shared_by {
diff --git a/include/linux/iio/sysfs.h b/include/linux/iio/sysfs.h
index 9cd8f74..4478ba1 100644
--- a/include/linux/iio/sysfs.h
+++ b/include/linux/iio/sysfs.h
@@ -76,6 +76,15 @@ struct iio_const_attr {
/* Generic attributes of onetype or another */
/**
+ * IIO_CONST_ATTR_AVERAGING_RATIO_AVAIL - list available averaging ratios
+ * @_string: ratio string for the attribute
+ *
+ * Constant version
+ **/
+#define IIO_CONST_ATTR_AVERAGING_RATIO_AVAIL(_string) \
+ IIO_CONST_ATTR(averaging_ratio_available, _string)
+
+/**
* IIO_DEV_ATTR_SAMP_FREQ - sets any internal clock frequency
* @_mode: sysfs file mode/permissions
* @_show: output method for the attribute
--
1.9.1
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