On Tue October 2 2012 12:13:20 Sylwester Nawrocki wrote:
> Hi Guennadi,
>
> On 10/02/2012 11:49 AM, Guennadi Liakhovetski wrote:
> >>> + if (!of_property_read_u32_array(node, "data-lanes", data_lanes,
> >>> + ARRAY_SIZE(data_lanes))) {
> >>> + int i;
> >>> + for (i = 0; i< ARRAY_SIZE(data_lanes); i++)
> >>> + link->mipi_csi_2.data_lanes[i] = data_lanes[i];
> >>
> >> It doesn't look like what we aimed for. The data-lanes array is supposed
> >> to be of variable length, thus I don't think it can be parsed like that.
> >> Or am I missing something ? I think we need more something like below
> >> (based on of_property_read_u32_array(), not tested):
> >
> > Ok, you're right, that my version only was suitable for fixed-size arrays,
> > which wasn't our goal. But I don't think we should go down to manually
> > parsing property data. How about (tested;-))
> >
> > data = of_find_property(node, "data-lanes", NULL);
> > if (data) {
> > int i = 0;
> > const __be32 *lane = NULL;
> > do {
> > lane = of_prop_next_u32(data, lane, &data_lanes[i]);
> > } while (lane && i++ < ARRAY_SIZE(data_lanes));
> > link->mipi_csi_2.num_data_lanes = i;
> > while (i--)
> > link->mipi_csi_2.data_lanes[i] = data_lanes[i];
> > }
>
> Yes, that looks neat and does what it is supposed to do. :) Thanks!
> For now, I'll trust you it works ;)
>
> With regards to the remaining patches, it looks a bit scary to me how
> complicated it got, perhaps mostly because of requirement to reference
> host devices from subdevs. And it seems to rely on the existing SoC
> camera infrastructure, which might imply lot's of work need to be done
> for non soc-camera drivers. But I'm going to take a closer look and
> comment more on the details at the corresponding patches.
I have to say that I agree with Sylwester here. It seems awfully complicated,
but I can't really put my finger on the actual cause. It would be really
interesting to see this implemented for a non-SoC device and to compare the
two.
One area that I do not yet completely understand is the i2c bus notifications
(or asynchronous loading or i2c modules).
I would have expected that using OF the i2c devices are still initialized
before the host/bridge driver is initialized. But I gather that's not the
case?
If this deferred probing is a general problem, then I think we need a general
solution as well that's part of the v4l2 core.
Regards,
Hans
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