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Date:   Fri, 13 Dec 2019 02:48:12 +0200
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Cc:     Simon Horman <horms@verge.net.au>,
        Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>,
        linux-renesas-soc@vger.kernel.org, David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        "open list:DRM DRIVERS FOR RENESAS" <dri-devel@lists.freedesktop.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] drm: rcar-du: Add r8a77980 support
Message-ID: <20191213004812.GA27328@pendragon.ideasonboard.com>
References: <20190911192502.16609-1-kieran.bingham+renesas@ideasonboard.com>
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 <20190913082129.lvusbp6pbcayqh5r@verge.net.au>
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Hi Kieran,

On Mon, Dec 09, 2019 at 12:41:07PM +0000, Kieran Bingham wrote:
> On 13/09/2019 10:03, Laurent Pinchart wrote:
> > On Fri, Sep 13, 2019 at 10:21:29AM +0200, Simon Horman wrote:
> >> On Thu, Sep 12, 2019 at 01:00:41PM +0300, Sergei Shtylyov wrote:
> >>> On 11.09.2019 22:25, Kieran Bingham wrote:
> >>>
> >>>> Add direct support for the r8a77980 (V3H).
> >>>>
> >>>> The V3H shares a common, compatible configuration with the r8a77970
> >>>> (V3M) so that device info structure is reused.
> >>>
> >>>    Do we really need to add yet another compatible in this case?
> >>> I just added r8a77970 to the compatible prop in the r8a77980 DT. That's why
> >>> a patch like this one didn't get posted by me.
> >>
> >> The reason for having per-SoC compat strings is that the IP blocks
> >> are not versioned and while we can observe that there are similarities
> >> between, f.e. the DU on the r8a77970 and r8a77980, we can't be certain that
> >> differences may not emerge at some point. By having per-SoC compat strings
> >> we have the flexibility for the driver to address any such differences as
> >> the need arises.
> >>
> >> My recollection is that this scheme has been adopted for non-versioned
> >> Renesas IP blocks since June 2015 and uses of this scheme well before that.
> > 
> > Sure, but we could use
> > 
> > 	compatible = "renesas,du-r8a77980", "renesas,du-r8a77970";
> > 
> > in DT without updating the driver. If the r8a77980 turns out to be
> > different, we'll then update the driver without a need to modify DT. I'm
> > fine either way, so
> > 
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> Thanks,
> 
> This patch has an RB tag from you, and Simon, but alas I don't believe
> it has been picked up in your drm/du/next branch.
> 
> Is this patch acceptable? Or do I need to repost?

Could you just confirm I should apply this patch, and not go for the
alternative proposal above ?

> >>>> Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
> >>
> >> Reviewed-by: Simon Horman <horms+renesas@verge.net.au>

-- 
Regards,

Laurent Pinchart