Hi, On Wed, Nov 14, 2018 at 11:24:48AM +0800, Chen-Yu Tsai wrote: > On Tue, Nov 13, 2018 at 4:24 PM Maxime Ripard <maxime.ripard@xxxxxxxxxxx> wrote: > > Here is a series introducing the support for the A10 (and SoCs of the same > > generation) CMOS Sensor Interface (called CSI, not to be confused with > > MIPI-CSI, which isn't support by that IP). > > > > That interface is pretty straightforward, but the driver has a few issues > > that I wanted to bring up: > > > > * The only board I've been testing this with has an ov5640 sensor > > attached, which doesn't work with the upstream driver. Copying the > > Allwinner init sequence works though, and this is how it has been > > tested. Testing with a second sensor would allow to see if it's an > > issue on the CSI side or the sensor side. > > * When starting a capture, the last buffer to capture will fail due to > > double buffering being used, and we don't have a next buffer for the > > last frame. I'm not sure how to deal with that though. It seems like > > some drivers use a scratch buffer in such a case, some don't care, so > > I'm not sure which solution should be preferred. > > * We don't have support for the ISP at the moment, but this can be added > > eventually. > > > > * How to model the CSI module clock isn't really clear to me. It looks > > like it goes through the CSI controller and then is muxed to one of the > > CSI pin so that it can clock the sensor. I'm not quite sure how to > > model it, if it should be a clock, the CSI driver being a clock > > provider, or if the sensor should just use the module clock directly. > > Which clock are you talking about? MCLK? This seems to be fed directly from > the CCU, as there doesn't seem to be controls for it within the CSI hardware > block, and the diagram doesn't list it either. IMO you don't have to model it. > The camera sensor device node would just take a reference to it directly. Yeah, that what I went for, I guess we agree :) > You would probably enable the (separate) pinmux setting in the CSI > controller node. I'll change that. Thanks! Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
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