[PATCH v5 3/5] counter: Introduce the Count capture component

[William Breathitt Gray <william.gray@linaro.org>]

Some devices provide a latch function to save historic Count values.
This patch standardizes exposure of such functionality as Count capture
components. A COUNTER_COMP_CAPTURE macro is provided for driver authors
to define a capture component. A new event COUNTER_EVENT_CAPTURE is
introduced to represent Count value capture events.

Cc: Julien Panis <jpanis@baylibre.com>
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
---
 Documentation/ABI/testing/sysfs-bus-counter | 6 ++++++
 include/linux/counter.h                     | 3 +++
 include/uapi/linux/counter.h                | 2 ++
 3 files changed, 11 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
index a234022f9add..30b6e1faa6f6 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter
+++ b/Documentation/ABI/testing/sysfs-bus-counter
@@ -4,6 +4,12 @@ Contact:	linux-iio@vger.kernel.org
 Description:
 		Count data of Count Y represented as a string.
 
+What:		/sys/bus/counter/devices/counterX/countY/capture
+KernelVersion:	6.1
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Historical capture of the Count Y count data.
+
 What:		/sys/bus/counter/devices/counterX/countY/ceiling
 KernelVersion:	5.2
 Contact:	linux-iio@vger.kernel.org
diff --git a/include/linux/counter.h b/include/linux/counter.h
index 60428d06915d..2c6594c240d4 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -453,6 +453,9 @@ struct counter_available {
 	.priv = &(_available), \
 }
 
+#define COUNTER_COMP_CAPTURE(_read, _write) \
+	COUNTER_COMP_COUNT_U64("capture", _read, _write)
+
 #define COUNTER_COMP_CEILING(_read, _write) \
 	COUNTER_COMP_COUNT_U64("ceiling", _read, _write)
 
diff --git a/include/uapi/linux/counter.h b/include/uapi/linux/counter.h
index e9610e1944dc..8ab12d731e3b 100644
--- a/include/uapi/linux/counter.h
+++ b/include/uapi/linux/counter.h
@@ -63,6 +63,8 @@ enum counter_event_type {
 	COUNTER_EVENT_INDEX,
 	/* State of counter is changed */
 	COUNTER_EVENT_CHANGE_OF_STATE,
+	/* Count value captured */
+	COUNTER_EVENT_CAPTURE,
 };
 
 /**
-- 
2.37.3