Hi Laurent, Thank you for your review. On 15/04/2022 16:37, Laurent Pinchart wrote: > Hi Benjamin, > > Thank you for the patch. > > On Fri, Apr 15, 2022 at 01:18:42PM +0200, Benjamin Mugnier wrote: >> Add V4L2_CID_TEMPERATURE control to get temperature from sensor in >> celsius as a volatile and read-only control, and its documentation. >> Useful to monitor thermals from v4l controls for sensors that support >> this. >> >> Signed-off-by: Benjamin Mugnier <benjamin.mugnier@xxxxxxxxxxx> >> --- >> Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst | 3 +++ >> drivers/media/v4l2-core/v4l2-ctrls-defs.c | 4 ++++ >> include/uapi/linux/v4l2-controls.h | 2 ++ >> 3 files changed, 9 insertions(+) >> >> diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst >> index 4c5061aa9cd4..26fa21f5c45a 100644 >> --- a/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst >> +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-camera.rst >> @@ -661,3 +661,6 @@ enum v4l2_scene_mode - >> .. [#f1] >> This control may be changed to a menu control in the future, if more >> options are required. >> + >> +``V4L2_CID_TEMPERATURE (integer)`` >> + The temperature of the sensor in celsius. This is a read-only control. > > I've seen sensors where the temperature sensor has a 1/10th degree > precision. Should we standardize on that ? Anything more precise is > likely overkill. > This sensor also has a 1/10th degree precision, here I only display the integer part. Ok to standardize on that. > There are also sensors with multiple temperature sensors. If there are > too many of them I suppose the temperature would be reported in embedded > data, but perhaps not always. How can we prepare for this ? > > There are also a few details that I think should be documented. Is the > temperature always read on-demand when reading the control, or updated > periodically ? I would assume most drivers would implement the former, > which means no control notification events will be generated. This > should be documented. Furthermore, do drivers need to support reading > the temperature when the sensor isn't streaming ? If not, when should a > control read ioctl return, the last value, or an error ? >
