On Mon, Oct 7, 2019 at 7:09 PM Maxime Ripard <mrip...@kernel.org> wrote:
>
> Hi,
>
> On Fri, Oct 04, 2019 at 02:33:41PM +0800, Chen-Yu Tsai wrote:
> > On Fri, Oct 4, 2019 at 12:37 AM Maxime Ripard <mrip...@kernel.org> wrote:
> > > On Thu, Oct 03, 2019 at 11:51:05PM +0800, Chen-Yu Tsai wrote:
> > > > On Thu, Oct 3, 2019 at 11:48 PM Maxime Ripard <mrip...@kernel.org>
> > > > wrote:
> > > > >
> > > > > It turns out that what was thought to be the module clock was
> > > > > actually the
> > > > > clock meant to be used by the sensor, and isn't playing any role with
> > > > > the
> > > > > CSI controller itself. Let's drop that clock from our binding.
> > > > >
> > > > > Fixes: c5e8f4ccd775 ("media: dt-bindings: media: Add Allwinner A10
> > > > > CSI binding")
> > > > > Reported-by: Chen-Yu Tsai <w...@csie.org>
> > > > > Signed-off-by: Maxime Ripard <mrip...@kernel.org>
> > > > > ---
> > > > > .../devicetree/bindings/media/allwinner,sun4i-a10-csi.yaml | 7
> > > > > ++-----
> > > > > 1 file changed, 2 insertions(+), 5 deletions(-)
> > > > >
> > > > > diff --git
> > > > > a/Documentation/devicetree/bindings/media/allwinner,sun4i-a10-csi.yaml
> > > > >
> > > > > b/Documentation/devicetree/bindings/media/allwinner,sun4i-a10-csi.yaml
> > > > > index 5dd1cf490cd9..d3e423fcb6c2 100644
> > > > > ---
> > > > > a/Documentation/devicetree/bindings/media/allwinner,sun4i-a10-csi.yaml
> > > > > +++
> > > > > b/Documentation/devicetree/bindings/media/allwinner,sun4i-a10-csi.yaml
> > > > > @@ -27,14 +27,12 @@ properties:
> > > > > clocks:
> > > > > items:
> > > > > - description: The CSI interface clock
> > > > > - - description: The CSI module clock
> > > > > - description: The CSI ISP clock
> > > > > - description: The CSI DRAM clock
> > > > >
> > > > > clock-names:
> > > > > items:
> > > > > - const: bus
> > > > > - - const: mod
> > > > > - const: isp
> > > > > - const: ram
> > > > >
> > > > > @@ -89,9 +87,8 @@ examples:
> > > > > compatible = "allwinner,sun7i-a20-csi0";
> > > > > reg = <0x01c09000 0x1000>;
> > > > > interrupts = <GIC_SPI 42 IRQ_TYPE_LEVEL_HIGH>;
> > > > > - clocks = <&ccu CLK_AHB_CSI0>, <&ccu CLK_CSI0>,
> > > > > - <&ccu CLK_CSI_SCLK>, <&ccu CLK_DRAM_CSI0>;
> > > > > - clock-names = "bus", "mod", "isp", "ram";
> > > > > + clocks = <&ccu CLK_AHB_CSI0>, <&ccu CLK_CSI_SCLK>, <&ccu
> > > > > CLK_DRAM_CSI0>;
> > > > > + clock-names = "bus", "isp", "ram";
> > > >
> > > > I believe what we thought was the ISP clock is actually the module clock
> > > > for the whole CSI subsystem. So we should still use the module clock
> > > > entry,
> > > > and remove the ISP entry.
> > >
> > > I'm really not sure it is. CSI1 on the A20 (possibly the A10 as well,
> > > I haven't checked), and the one on the A13 don't have any ISP embedded
> > > in the CSI controller.
> > >
> > > It makes some difference, because according to the BSP, you can see
> > > that the ISP clock is taken for CSI0:
> > > https://github.com/linux-sunxi/linux-sunxi/blob/sunxi-3.4/drivers/media/video/sun4i_csi/csi0/sun4i_drv_csi.c#L389
> > >
> > > While for CSI1, that block is commented out, and the ISP clock never
> > > used:
> > > https://github.com/linux-sunxi/linux-sunxi/blob/sunxi-3.4/drivers/media/video/sun4i_csi/csi1/sun4i_drv_csi.c#L396
> > >
> > > So I really believe that the ISP clock is here to feed the ISP block
> > > within the CSI controller if there's any. But it's far from always the
> > > case, as opposed to a module clock for the whole CSI controller that
> > > would be here in both cases.
> >
> > I guess we should try to test this with CSI1 one, either on a Cubieboard
> > or OlinuXino with a simple camera like the OV7670?
> >
> > Do you have any hardware on hand for this? I have the Cubieboard but I
> > need to get some proper 2.0mm connector blocks.
>
> I've tested it with the A13 before, and it doesn't need the ISP clock
OK! That clears things up!
ChenYu
