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authorRichard Leitner <richard.leitner@linux.dev>2025-12-09 23:44:38 +0100
committerHans Verkuil <hverkuil+cisco@kernel.org>2026-01-16 14:08:53 +0100
commitfa0e06f2fe00fa9e283a15d85e7542a4b72a14a7 (patch)
treef04e83a7293103d64cbb9fc74bf269f0bb0bc222 /Documentation/userspace-api
parent5be4154f6255d92d9d2ad5da658d7d33a655386f (diff)
Documentation: uAPI: media: add V4L2_CID_FLASH_{DURATION,STROBE_OE}
Add the new strobe duration and hardware strobe output enable to v4l uAPI documentation. Additionally add labels for cross-referencing v4l controls. Signed-off-by: Richard Leitner <richard.leitner@linux.dev> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
Diffstat (limited to 'Documentation/userspace-api')
-rw-r--r--Documentation/userspace-api/media/v4l/ext-ctrls-flash.rst42
1 files changed, 42 insertions, 0 deletions
diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-flash.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-flash.rst
index bd024ab461a4..b7f45fc0a797 100644
--- a/Documentation/userspace-api/media/v4l/ext-ctrls-flash.rst
+++ b/Documentation/userspace-api/media/v4l/ext-ctrls-flash.rst
@@ -58,6 +58,8 @@ Flash Control IDs
``V4L2_CID_FLASH_CLASS (class)``
The FLASH class descriptor.
+.. _v4l2-cid-flash-led-mode:
+
``V4L2_CID_FLASH_LED_MODE (menu)``
Defines the mode of the flash LED, the high-power white LED attached
to the flash controller. Setting this control may not be possible in
@@ -81,6 +83,8 @@ Flash Control IDs
+.. _v4l2-cid-flash-strobe-source:
+
``V4L2_CID_FLASH_STROBE_SOURCE (menu)``
Defines the source of the flash LED strobe.
@@ -97,6 +101,12 @@ Flash Control IDs
- The flash strobe is triggered by an external source. Typically
this is a sensor, which makes it possible to synchronise the
flash strobe start to exposure start.
+ This method of controlling flash LED strobe has two additional
+ prerequisites: the strobe source's :ref:`strobe output
+ <v4l2-cid-flash-strobe-oe>` must be enabled (if available)
+ and the flash controller's :ref:`flash LED mode
+ <v4l2-cid-flash-led-mode>` must be set to
+ ``V4L2_FLASH_LED_MODE_FLASH``.
@@ -187,3 +197,35 @@ Flash Control IDs
charged before strobing. LED flashes often require a cooldown period
after strobe during which another strobe will not be possible. This
is a read-only control.
+
+.. _v4l2-cid-flash-duration:
+
+``V4L2_CID_FLASH_DURATION (integer)``
+ Duration of the flash strobe pulse generated by the strobe source, when
+ using external strobe. This control shall be implemented by the device
+ generating the hardware flash strobe signal, typically a camera sensor,
+ connected to a flash controller.
+
+ The flash controllers :ref:`strobe source <v4l2-cid-flash-strobe-source>`
+ must be configured to ``V4L2_FLASH_STROBE_SOURCE_EXTERNAL`` for this
+ mode of operation. For more details please also take a look at the
+ documentation there.
+
+ The unit should be microseconds (µs) if possible.
+
+.. _v4l2-cid-flash-strobe-oe:
+
+``V4L2_CID_FLASH_STROBE_OE (boolean)``
+ Enables the output of a hardware strobe signal from the strobe source,
+ when using external strobe. This control shall be implemented by the device
+ generating the hardware flash strobe signal, typically a camera sensor,
+ connected to a flash controller.
+
+ Provided the signal generating device driver supports it, the length of the
+ strobe signal can be configured by adjusting its
+ :ref:`flash duration <v4l2-cid-flash-duration>`.
+
+ The flash controllers :ref:`strobe source <v4l2-cid-flash-strobe-source>`
+ must be configured to ``V4L2_FLASH_STROBE_SOURCE_EXTERNAL`` for this
+ mode of operation. For more details please also take a look at the
+ documentation there.