[PATCH] memory: renesas-rpc-if: Fix IO state based on flash type

[Biju Das]

Hi Geert,

Thanks for the feedback.

> Subject: Re: [PATCH] memory: renesas-rpc-if: Fix IO state based on flash
> type
> 
> Hi Miquel,
> 
> On Thu, Sep 14, 2023 at 11:12 AM Miquel Raynal <miquel.raynal at bootlin.com>
> wrote:
> > geert at linux-m68k.org wrote on Thu, 14 Sep 2023 11:04:01 +0200:
> > > On Thu, Sep 14, 2023 at 10:59 AM Miquel Raynal
> > > <miquel.raynal at bootlin.com> wrote:
> > > > geert at linux-m68k.org wrote on Thu, 14 Sep 2023 10:34:50 +0200:
> > > > > On Thu, Sep 14, 2023 at 10:08 AM Krzysztof Kozlowski
> > > > > <krzysztof.kozlowski at linaro.org> wrote:
> > > > > > On 30/08/2023 17:18, Biju Das wrote:
> > > > > > >>>                 regmap_update_bits(rpc->regmap,
> > > > > > >>> RPCIF_CMNCR, @@ -774,6
> > > > > > >>> +776,12 @@ static int rpcif_probe(struct platform_device
> > > > > > >>> +*pdev)
> > > > > > >>>                 return ret;
> > > > > > >>>         }
> > > > > > >>>
> > > > > > >>> +       if (rpc->info->type == RPCIF_RZ_G2L &&
> > > > > > >>
> > > > > > >> Wouldn't this apply to non-RZ/G2L systems, too?
> > > > > > >
> > > > > > > It applies, if the device uses the flash[1] or [2] and it
> > > > > > > needs 4-bit tx support.
> > > > > > >
> > > > > >
> > > > > > Geert,
> > > > > >
> > > > > > Does it answer your comment or do you expect here some changes?
> > > > >
> > > > > Well, now it has been confirmed this applies to non-RZ/G2L
> > > > > systems, too, the check for RPCIF_RZ_G2L should probably be
> > > > > removed.  In upstream, only
> > > > > arch/arm64/boot/dts/renesas/rzg2l{,c}-smarc-som.dtsi have
> > > > > devices that are compatible with "micron,mt25qu512a", but obviously
> they can appear elsewhere, too.
> > > > >
> > > > > Now, the presence of that compatible value in
> > > > > rzg2l{,c}-smarc-som.dtsi currently causes a dtbs_check warning, as
> it is not documented.
> > > > > However, there has been some pushback against adding more
> > > > > compatible values, cfr. my patch to add mt25qu512a[1], and Miquel's
> commit [2].
> > > >
> > > > Just FYI, I sent [2] after an unsuccessful attempt to update that
> > > > list too, see [3]. The idea is: if you don't have anything useful
> > > > to add,
> > >
> > > Oh, I didn't know that.
> > >
> > > > just use the generic compatible. If you need specific changes, you
> > > > can add an entry.
> > >
> > > The problem is that usually these things are discovered too late, so
> > > the only prudent way is to be proactive, and always add them.
> > > Initially I thought that the different handling on RZ/G2L was due to
> > > a difference in the RPC-IF block.  But now we know it's due to the
> > > type of FLASH attached.
> >
> > Actually what I say is wrong, we are not supposed to touch that list
> > anymore and prefer to handle the issues in the drivers by
> > auto-discovery. Can't we do that in your case?
> 
> I'm not sure we can do that, as this code is part of the hardware
> initialization during probing.
> Biju: is this needed that early, or can it be done later, after the
> connected device has been identified?

I need to check that. 

You mean patch drivers/spi/spi-rpc-if.c 
to identify the flash type from sfdp info and pass as a parameter to rpcif_hw_init??

Cheers,
Biju