On 06/14/2017 11:03 PM, Dave Stevenson wrote:
On 14 June 2017 at 18:38, Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
On 06/14/2017 06:29 PM, Dave Stevenson wrote:
Hi Hans.
On 14 June 2017 at 16:42, Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
Hi Dave,
How does this driver relate to this staging driver:
drivers/staging/vc04_services/bcm2835-camera/
It's not obvious to me.
drivers/staging/vc04_services/bcm2835-camera/ is using the VideoCore
firmware to control Unicam, ISP, and all the tuner algorithms. The ARM
gets delivered fully processed buffers from the VideoCore side. The
firmware only has drivers for the Omnivision OV5647 and Sony IMX219
(and an unsupported one for the Toshiba TC358743).
This driver is solely the Unicam block, reading the data in over
CSI2/CCP2 from the sensor and writing it to memory. No ISP or control
loops.
Other than power management, this driver is running solely on the ARM
with no involvement from the VideoCore firmware.
The sensor driver is whatever suitable V4L2 subdevice driver you fancy
attaching (as long as it supports CSI2, or eventually CCP2).
What is the interaction between these two drivers? Can they co-exist?
I would expect them to be mutually exclusive.
Mutually exclusive for the same Unicam instance, yes.
There are two Unicam instances on all BCM283x chips and both are
brought out on the Compute Modules. You could run bcm2835-unicam on
one and bcm2835-camera on the other if you so wished.
The firmware checks whether the csi nodes in the device tree are
active, and won't touch them if they are.
It would be good if this explanation is mentioned both in the driver code
and (I think) in the bindings document of *both* drivers. This setup is
unusual, so some extra documentation isn't amiss.
Regards,
Hans
