summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorLars-Peter Clausen <lars@metafoo.de>2012-07-09 10:00:00 +0100
committerJonathan Cameron <jic23@kernel.org>2012-07-09 18:18:15 +0100
commit81636632057cc1bece2531220dd5803036f95ea9 (patch)
tree6c1d73dbc88d32e49a2c5b44423a972a9b8da0c0
parent939546d1a9f47ed169554c711e1e05965b84ffe1 (diff)
downloadop-kernel-dev-81636632057cc1bece2531220dd5803036f95ea9.zip
op-kernel-dev-81636632057cc1bece2531220dd5803036f95ea9.tar.gz
iio: Introduce iio_validate_scan_mask_onehot
Add a helper function for validating a scan mask for devices where exactly one channel must be selected during sampling. This is a common case among devices which have scan mask restrictions so it makes sense to provide this function in the core. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
-rw-r--r--drivers/iio/industrialio-buffer.c16
-rw-r--r--include/linux/iio/buffer.h3
2 files changed, 19 insertions, 0 deletions
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index cc5db36..8c1dc9a 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -570,6 +570,22 @@ int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
}
EXPORT_SYMBOL(iio_sw_buffer_preenable);
+/**
+ * iio_validate_scan_mask_onehot() - Validates that exactly one channel is selected
+ * @indio_dev: the iio device
+ * @mask: scan mask to be checked
+ *
+ * Return true if exactly one bit is set in the scan mask, false otherwise. It
+ * can be used for devices where only one channel can be active for sampling at
+ * a time.
+ */
+bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
+ const unsigned long *mask)
+{
+ return bitmap_weight(mask, indio_dev->masklength) == 1;
+}
+EXPORT_SYMBOL_GPL(iio_validate_scan_mask_onehot);
+
static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
const unsigned long *mask)
{
diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h
index 2a2b6b4..8ba516f 100644
--- a/include/linux/iio/buffer.h
+++ b/include/linux/iio/buffer.h
@@ -177,6 +177,9 @@ ssize_t iio_buffer_show_enable(struct device *dev,
int iio_sw_buffer_preenable(struct iio_dev *indio_dev);
+bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
+ const unsigned long *mask);
+
#else /* CONFIG_IIO_BUFFER */
static inline int iio_buffer_register(struct iio_dev *indio_dev,
OpenPOWER on IntegriCloud