Re: [PATCH v2 2/3] media: rockchip: add driver for the rockchip mipi csi-2 receiver

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hello,

On Wed, Nov 26, 2025 at 09:57:31PM +0100, Michael Riesch wrote:
> On 11/18/25 23:08, Frank Li wrote:
> > On Tue, Nov 18, 2025 at 07:59:14PM +0100, Michael Riesch wrote:
> >> On 11/18/25 18:15, Frank Li wrote:
> >>> On Tue, Nov 18, 2025 at 12:12:26PM +0100, Michael Riesch via B4 Relay wrote:
> >>>> From: Michael Riesch <michael.riesch@collabora.com>
> >>>>
> >>>> [...]
> >>>> +#define CSI2HOST_N_LANES     0x04
> >>>> +#define CSI2HOST_CSI2_RESETN 0x10
> >>>> +#define CSI2HOST_PHY_STATE   0x14
> >>>> +#define CSI2HOST_ERR1	     0x20
> >>>> +#define CSI2HOST_ERR2	     0x24
> >>>> +#define CSI2HOST_MSK1	     0x28
> >>>> +#define CSI2HOST_MSK2	     0x2c
> >>>> +#define CSI2HOST_CONTROL     0x40
> >>>
> >>> Look like that is designware CSI2 controller, can we build common library
> >>> for all dwc csi2 controller, instead of every vendor create individual one.
> >>>
> >>> First try at
> >>> https://lore.kernel.org/linux-media/20250821-95_cam-v3-21-c9286fbb34b9@nxp.com/
> >>>
> >>> Toshiba have similar patch
> >>> https://lore.kernel.org/linux-media/aPZd39riAxqfw3mT@lizhi-Precision-Tower-5810/
> >>>
> >>> Frank
> >>
> >> This has been discussed already a while ago:
> >> https://lore.kernel.org/all/20250507083837.GA11152@pendragon.ideasonboard.com/
> > 
> > https://lore.kernel.org/all/20250702093806.GF16835@pendragon.ideasonboard.com/
> > 
> > Laurent Pinchart prevent imx93 DWC CSI2 driver at Jul, your discussion at
> > May, I think Laurent Pinchart change the mind.
> > 
> > We can choose not base on imx6, but we should create a standard dwc2 under
> > drivers/media/platform/synopsys/
> 
> In principle, I agree with refactoring out common code. However, I am
> not sure how similar these IP cores really are. Again, the answer I
> received from Rockchip states that this is *not* a Synopsys IP core.

That's what I based my opinion on. If we're dealing with different IP
cores from different vendors, we can have separate drivers. Even within
the family of CSI-2 receivers from Synopsys, I'm fine having different
drivers if the version differ significantly enough that using a single
driver would cause more pain than gain.

To explain this differently, for Synopsys CSI-2 receivers, I would like
to try and support multiple IP cores integrated in different SoCs in a
single driver. If, during that development, we find good reasons to use
separate drivers, then we can do so.

> Can you maybe test whether the Rockchip MIPI CSI-2 Receiver driver in
> this series works on your hardware? Then we will know if (and what)
> parts can be shared.
> 
> > Laurent Pinchart:
> > 
> > 	Can you provide direction?
> > 
> >> Bottom line from Laurent:
> >>
> >> "Let's keep this driver Rockchip-specific then. Thanks for checking."
> >>
> >>>  [...]

-- 
Regards,

Laurent Pinchart