From 1167560cee05a428c03cfb0ffedb83eefaac55ed Mon Sep 17 00:00:00 2001
From: Lars-Peter Clausen <lars@metafoo.de>
Date: Mon, 9 Jul 2012 10:00:00 +0100
Subject: [PATCH] --- yaml --- r: 317877 b: refs/heads/master c:
 81636632057cc1bece2531220dd5803036f95ea9 h: refs/heads/master i:   317875:
 6426ee9814e365533e416ff9aa85ac87771255a9 v: v3

---
 [refs]                                  |  2 +-
 trunk/drivers/iio/industrialio-buffer.c | 16 ++++++++++++++++
 trunk/include/linux/iio/buffer.h        |  3 +++
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index 0b31175457f9..765ae66257b3 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 939546d1a9f47ed169554c711e1e05965b84ffe1
+refs/heads/master: 81636632057cc1bece2531220dd5803036f95ea9
diff --git a/trunk/drivers/iio/industrialio-buffer.c b/trunk/drivers/iio/industrialio-buffer.c
index cc5db36fb75a..8c1dc9a683fb 100644
--- a/trunk/drivers/iio/industrialio-buffer.c
+++ b/trunk/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/trunk/include/linux/iio/buffer.h b/trunk/include/linux/iio/buffer.h
index 2a2b6b4d8d05..8ba516fc2ec6 100644
--- a/trunk/include/linux/iio/buffer.h
+++ b/trunk/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,