Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 188 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
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+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+
+.. _flash-controls:
+
+***********************
+Flash Control Reference
+***********************
+
+The V4L2 flash controls are intended to provide generic access to flash
+controller devices. Flash controller devices are typically used in
+digital cameras.
+
+The interface can support both LED and xenon flash devices. As of
+writing this, there is no xenon flash driver using this interface.
+
+
+.. _flash-controls-use-cases:
+
+Supported use cases
+===================
+
+
+Unsynchronised LED flash (software strobe)
+------------------------------------------
+
+Unsynchronised LED flash is controlled directly by the host as the
+sensor. The flash must be enabled by the host before the exposure of the
+image starts and disabled once it ends. The host is fully responsible
+for the timing of the flash.
+
+Example of such device: Nokia N900.
+
+
+Synchronised LED flash (hardware strobe)
+----------------------------------------
+
+The synchronised LED flash is pre-programmed by the host (power and
+timeout) but controlled by the sensor through a strobe signal from the
+sensor to the flash.
+
+The sensor controls the flash duration and timing. This information
+typically must be made available to the sensor.
+
+
+LED flash as torch
+------------------
+
+LED flash may be used as torch in conjunction with another use case
+involving camera or individually.
+
+
+.. _flash-control-id:
+
+Flash Control IDs
+-----------------
+
+``V4L2_CID_FLASH_CLASS (class)``
+    The FLASH class descriptor.
+
+``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
+    presence of some faults. See V4L2_CID_FLASH_FAULT.
+
+
+.. tabularcolumns:: |p{5.7cm}|p{11.8cm}|
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+
+    * - ``V4L2_FLASH_LED_MODE_NONE``
+      - Off.
+    * - ``V4L2_FLASH_LED_MODE_FLASH``
+      - Flash mode.
+    * - ``V4L2_FLASH_LED_MODE_TORCH``
+      - Torch mode.
+
+        See V4L2_CID_FLASH_TORCH_INTENSITY.
+
+
+
+``V4L2_CID_FLASH_STROBE_SOURCE (menu)``
+    Defines the source of the flash LED strobe.
+
+.. tabularcolumns:: |p{7.5cm}|p{7.5cm}|
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+
+    * - ``V4L2_FLASH_STROBE_SOURCE_SOFTWARE``
+      - The flash strobe is triggered by using the
+	V4L2_CID_FLASH_STROBE control.
+    * - ``V4L2_FLASH_STROBE_SOURCE_EXTERNAL``
+      - 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.
+
+
+
+``V4L2_CID_FLASH_STROBE (button)``
+    Strobe flash. Valid when V4L2_CID_FLASH_LED_MODE is set to
+    V4L2_FLASH_LED_MODE_FLASH and V4L2_CID_FLASH_STROBE_SOURCE
+    is set to V4L2_FLASH_STROBE_SOURCE_SOFTWARE. Setting this
+    control may not be possible in presence of some faults. See
+    V4L2_CID_FLASH_FAULT.
+
+``V4L2_CID_FLASH_STROBE_STOP (button)``
+    Stop flash strobe immediately.
+
+``V4L2_CID_FLASH_STROBE_STATUS (boolean)``
+    Strobe status: whether the flash is strobing at the moment or not.
+    This is a read-only control.
+
+``V4L2_CID_FLASH_TIMEOUT (integer)``
+    Hardware timeout for flash. The flash strobe is stopped after this
+    period of time has passed from the start of the strobe.
+
+``V4L2_CID_FLASH_INTENSITY (integer)``
+    Intensity of the flash strobe when the flash LED is in flash mode
+    (V4L2_FLASH_LED_MODE_FLASH). The unit should be milliamps (mA)
+    if possible.
+
+``V4L2_CID_FLASH_TORCH_INTENSITY (integer)``
+    Intensity of the flash LED in torch mode
+    (V4L2_FLASH_LED_MODE_TORCH). The unit should be milliamps (mA)
+    if possible. Setting this control may not be possible in presence of
+    some faults. See V4L2_CID_FLASH_FAULT.
+
+``V4L2_CID_FLASH_INDICATOR_INTENSITY (integer)``
+    Intensity of the indicator LED. The indicator LED may be fully
+    independent of the flash LED. The unit should be microamps (uA) if
+    possible.
+
+``V4L2_CID_FLASH_FAULT (bitmask)``
+    Faults related to the flash. The faults tell about specific problems
+    in the flash chip itself or the LEDs attached to it. Faults may
+    prevent further use of some of the flash controls. In particular,
+    V4L2_CID_FLASH_LED_MODE is set to V4L2_FLASH_LED_MODE_NONE
+    if the fault affects the flash LED. Exactly which faults have such
+    an effect is chip dependent. Reading the faults resets the control
+    and returns the chip to a usable state if possible.
+
+.. tabularcolumns:: |p{8.4cm}|p{9.1cm}|
+
+.. flat-table::
+    :header-rows:  0
+    :stub-columns: 0
+
+    * - ``V4L2_FLASH_FAULT_OVER_VOLTAGE``
+      - Flash controller voltage to the flash LED has exceeded the limit
+	specific to the flash controller.
+    * - ``V4L2_FLASH_FAULT_TIMEOUT``
+      - The flash strobe was still on when the timeout set by the user ---
+	V4L2_CID_FLASH_TIMEOUT control --- has expired. Not all flash
+	controllers may set this in all such conditions.
+    * - ``V4L2_FLASH_FAULT_OVER_TEMPERATURE``
+      - The flash controller has overheated.
+    * - ``V4L2_FLASH_FAULT_SHORT_CIRCUIT``
+      - The short circuit protection of the flash controller has been
+	triggered.
+    * - ``V4L2_FLASH_FAULT_OVER_CURRENT``
+      - Current in the LED power supply has exceeded the limit specific to
+	the flash controller.
+    * - ``V4L2_FLASH_FAULT_INDICATOR``
+      - The flash controller has detected a short or open circuit
+	condition on the indicator LED.
+    * - ``V4L2_FLASH_FAULT_UNDER_VOLTAGE``
+      - Flash controller voltage to the flash LED has been below the
+	minimum limit specific to the flash controller.
+    * - ``V4L2_FLASH_FAULT_INPUT_VOLTAGE``
+      - The input voltage of the flash controller is below the limit under
+	which strobing the flash at full current will not be possible.The
+	condition persists until this flag is no longer set.
+    * - ``V4L2_FLASH_FAULT_LED_OVER_TEMPERATURE``
+      - The temperature of the LED has exceeded its allowed upper limit.
+
+
+
+``V4L2_CID_FLASH_CHARGE (boolean)``
+    Enable or disable charging of the xenon flash capacitor.
+
+``V4L2_CID_FLASH_READY (boolean)``
+    Is the flash ready to strobe? Xenon flashes require their capacitors
+    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.