Hi Guennadi, On Tuesday 31 July 2012 13:29:55 Guennadi Liakhovetski wrote: > On Tue, 31 Jul 2012, Laurent Pinchart wrote: > > On Tuesday 31 July 2012 13:14:13 Guennadi Liakhovetski wrote: > > > On Tue, 31 Jul 2012, Laurent Pinchart wrote: > > > > On Tuesday 31 July 2012 11:56:44 Guennadi Liakhovetski wrote: > > > > > On Thu, 26 Jul 2012, Laurent Pinchart wrote: > > > > > > On Wednesday 18 July 2012 11:18:33 Sylwester Nawrocki wrote: > > > > > > > On 07/16/2012 11:42 AM, Guennadi Liakhovetski wrote: > > > > > > > > On Fri, 25 May 2012, Sylwester Nawrocki wrote: > > > > > > > >> The driver initializes all board related properties except > > > > > > > >> the s_power() callback to board code. The platforms that > > > > > > > >> require this callback are not supported by this driver yet > > > > > > > >> for CONFIG_OF=y. > > > > > > > >> > > > > > > > >> Signed-off-by: Sylwester Nawrocki<s.nawrocki@xxxxxxxxxxx> > > > > > > > >> Signed-off-by: Bartlomiej > > > > > > > >> Zolnierkiewicz<b.zolnierkie@xxxxxxxxxxx> > > > > > > > >> Signed-off-by: Kyungmin Park<kyungmin.park@xxxxxxxxxxx> > > > > > > > >> --- > > > > > > > >> > > > > > > > >> .../bindings/camera/samsung-s5k6aafx.txt | 57 > > > > > > > >> +++++++++ > > > > > > > >> drivers/media/video/s5k6aa.c | 129 > > > > > > > >> ++++++++++++++------ 2 files changed, 146 insertions(+), 40 > > > > > > > >> deletions(-) > > > > > > > >> create mode 100644 > > > > > > > >> Documentation/devicetree/bindings/camera/samsung-s5k6aafx.t > > > > > > > >> xt>> > > > > > > > >> > > > > > > > >> diff --git > > > > > > > >> a/Documentation/devicetree/bindings/camera/samsung-s5k6aafx.t > > > > > > > >> xt > > > > > > > >> b/Documentation/devicetree/bindings/camera/samsung-s5k6aafx.t > > > > > > > >> xt > > > > > > > >> new > > > > > > > >> file > > > > > > > >> mode 100644 > > > > > > > >> index 0000000..6685a9c > > > > > > > >> --- /dev/null > > > > > > > >> +++ > > > > > > > >> b/Documentation/devicetree/bindings/camera/samsung-s5k6aafx.t > > > > > > > >> xt > > > > > > > >> @@ -0,0 +1,57 @@ > > > > > > > >> +Samsung S5K6AAFX camera sensor > > > > > > > >> +------------------------------ > > > > > > > >> + > > > > > > > >> +Required properties: > > > > > > > >> + > > > > > > > >> +- compatible : "samsung,s5k6aafx"; > > > > > > > >> +- reg : base address of the device on I2C bus; > > > > > > > > > > > > > > > > You said you ended up putting your sensors outside of I2C > > > > > > > > busses, is this one of changes, that are present in your git- > > > > > > > > tree but not in this series? > > > > > > > > > > > > > > No, I must have been not clear enough on that. Our idea was to > > > > > > > keep I2C slave device nodes as an I2C controller's child nodes, > > > > > > > according to the current convention. The 'sensor' nodes (the > > > > > > > 'camera''s children) would only contain a phandle to a > > > > > > > respective I2C slave node. > > > > > > > > > > > > > > This implies that we cannot access I2C bus in I2C client's > > > > > > > device probe() callback. An actual H/W access could begin only > > > > > > > from within and after invocation of v4l2_subdev .registered > > > > > > > callback.. > > > > > > > > > > > > That's how I've envisioned the DT bindings for sensors as well, > > > > > > this sounds good. The real challenge will be to get hold of the > > > > > > subdev to register it without race conditions. > > > > > > > > > > Hrm... That's how early pre-subdev versions of soc-camera used to > > > > > work, that's where all the <device>_video_probe() functions come > > > > > from. But then we switched to dynamic i2c device registration. Do we > > > > > want to switch all drivers back now?... Couldn't we "temporarily" > > > > > use references from subdevs to hosts until the clock API is > > > > > available? > > > > > > > > I don't think that requires a reference from subdevs to hosts in the > > > > DT. The subdev will need the host to be probed before a clock can be > > > > available so you won't be able to access the hardware in the probe() > > > > function in the generic case. You will need to wait until the > > > > registered() subdev operation is called, at which point the host can > > > > be accessed through the v4l2_device. > > > > > > Sure, I understand, but that's exactly what we wanted to avoid - > > > succeeding client's i2c .probe() without even touching the hardware. > > > > But should we allow host probe() to succeed if the sensor isn't present ? > > I think we should, yes. The host hardware is there and functional - > whether or not all or some of the clients are failing. Theoretically > clients can also be hot-plugged. Whether and how many video device nodes > we create, that's a different question. I think I can agree with you on this (although I could change my mind if this architecture turns out to result in unsolvable technical issues). That will involve a lot of work though. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
