Re: [PATCH v5] media: platform: Renesas IMR driver

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

Hi Geert,

On Wednesday 03 May 2017 09:22:00 Geert Uytterhoeven wrote:
> On Tue, May 2, 2017 at 11:17 PM, Laurent Pinchart wrote:
> > On Wednesday 22 Mar 2017 10:34:16 Geert Uytterhoeven wrote:
> >> On Thu, Mar 9, 2017 at 9:08 PM, Sergei Shtylyov wrote:
> >>> --- /dev/null
> >>> +++ media_tree/Documentation/devicetree/bindings/media/rcar_imr.txt
> >>> @@ -0,0 +1,27 @@
> >>> +Renesas R-Car Image Renderer (Distortion Correction Engine)
> >>> +-----------------------------------------------------------
> >>> +
> >>> +The image renderer, or the distortion correction engine, is a drawing
> >>> processor
> >>> +with a simple instruction system capable of referencing video capture
> >>> data or
> >>> +data in an external memory as 2D texture data and performing texture
> >>> mapping
> >>> +and drawing with respect to any shape that is split into triangular
> >>> objects.
> >>> +
> >>> +Required properties:
> >>> +
> >>> +- compatible: "renesas,<soctype>-imr-lx4", "renesas,imr-lx4" as a
> >>> fallback for
> >>> +  the image renderer light extended 4 (IMR-LX4) found in the R-Car
> >>> gen3 SoCs,
> >>> +  where the examples with <soctype> are:
> >>> +  - "renesas,r8a7795-imr-lx4" for R-Car H3,
> >>> +  - "renesas,r8a7796-imr-lx4" for R-Car M3-W.
> >> 
> >> Laurent: what do you think about the need for SoC-specific compatible
> >> values for the various IM* blocks?
> > 
> > There's no documented IP core version register, but when dumping all
> > configuration registers on H3 and M3-W I noticed that register 0x002c, not
> > documented in the datasheet, reads 0x14060514 on all four IMR instances in
> > H3, and 0x20150505 on both instances in M3-W.
> > 
> > This looks like a version register to me. If my assumption is correct, we
> > could do without any SoC-specific compatible string.
> 
> I read this assumed version registers on all R-Car SoCs, after writing
> zero to 0xe6150990 (SMSTPCR8).
> 
> IMR-X2 on R-Car H2:     0x12072009
> IMR-LSX2 on R-Car H2:   0x12072009
> IMR-LSX3 on R-Car V2H:  0x13052617
> IMR-LX2 on R-Car M2-W:  0x12072009
> IMR-LX2 on R-Car M2-N:  0x12072009
> IMR-LX2 on R-Car E2:    0x13091909
> IMR-LX3 on R-Car V2H:   0x13052617
> 
> Note that several IDs are the same, but you know the type from the
> compatible value.
> 
> It would be good to get confirmation from the hardware team that this is
> indeed a version register.

Thank you for checking.

Morimoto-san, do you think there are still people alive in the Gen2 hardware 
team who could provide the information ? :-) If not, information restricted to 
Gen3 would still be useful.

-- 
Regards,

Laurent Pinchart