@@ -29,6 +29,20 @@ used in the system. Using another frequency may cause harmful effects
elsewhere. Therefore only the pre-determined frequencies are configurable by the
user.
+On choosing link frequencies
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Choosing link frequencies for a board is generally a part of the hardware design
+process as one needs to ensure an EMC-safe frequency the sensor supports with
+the given external clock frequency exists. On development systems this may be
+less than an immediate concern, so more or less anything that sensor and the
+rest of the applicable hardware supports can be used.
+
+If the sensor's PLL tree is not documented and all that is available are
+register lists, even knowing the frequency a driver uses may be difficult. This
+could still be :ref:`calculated from the number of lanes, sensor's output image
+size, blanking values and frame rate <media_camera_raw_frame_interval>`.
+
ACPI
~~~~
@@ -54,6 +54,8 @@ less all modern raw camera sensors.
The frame interval is calculated using the following equation::
+.. _media_camera_raw_frame_interval:
+
frame interval = (analogue crop width + horizontal blanking) *
(analogue crop height + vertical blanking) / pixel rate
Document how link frequencies can be selected for the link-frequencies property. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> --- Documentation/driver-api/media/camera-sensor.rst | 14 ++++++++++++++ .../userspace-api/media/drivers/camera-sensor.rst | 2 ++ 2 files changed, 16 insertions(+)