counter: Introduce the Count capture component

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> Link: https://lore.kernel.org/r/c239572ab4208d0d6728136e82a88ad464369a7a.1664204990.git.william.gray@linaro.org/ Signed-off-by: William Breathitt Gray <william.gray@linaro.org> Link: https://lore.kernel.org/r/3cebaa0b807a225eb277d771504fe6dba7269ffd.1664318353.git.william.gray@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mariux64 · Sep 30, 2022 · 45d2918 · 45d2918
1 parent 9830288
commit 45d2918
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diff --git 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
@@ -203,6 +209,7 @@ Description:
 		both edges:
 			Any state transition.
 
+What:		/sys/bus/counter/devices/counterX/countY/capture_component_id
 What:		/sys/bus/counter/devices/counterX/countY/ceiling_component_id
 What:		/sys/bus/counter/devices/counterX/countY/floor_component_id
 What:		/sys/bus/counter/devices/counterX/countY/count_mode_component_id

diff --git 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
@@ -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,
 };
 
 /**