Re: [PATCH 09/11] mmc: sdhci-cadence: Add Pensando Elba SoC support

From: Arnd Bergmann <arnd@arndb.de>
To: Brad Larson <brad@pensando.io>
Cc: Adrian Hunter <adrian.hunter@intel.com>,
	Arnd Bergmann <arnd@arndb.de>,
	 Linux ARM <linux-arm-kernel@lists.infradead.org>,
	 Linus Walleij <linus.walleij@linaro.org>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	 Mark Brown <broonie@kernel.org>,
	Serge Semin <fancer.lancer@gmail.com>,
	 Ulf Hansson <ulf.hansson@linaro.org>,
	Olof Johansson <olof@lixom.net>, David Clear <dac2@pensando.io>,
	 "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
	linux-spi <linux-spi@vger.kernel.org>,
	 linux-mmc <linux-mmc@vger.kernel.org>,
	DTML <devicetree@vger.kernel.org>,
	 Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 09/11] mmc: sdhci-cadence: Add Pensando Elba SoC support
Date: Thu, 7 Apr 2022 22:38:31 +0200	[thread overview]
Message-ID: <CAK8P3a28ef+DgcKrMG03b5Og-W+afieoqF1zvNkXdG22qA8i7g@mail.gmail.com> (raw)
In-Reply-To: <CAK9rFnwsMd1+oQ8cg8Biw7HM=R6aOudfK7Ja+E+iGVgfrvC9Gg@mail.gmail.com>

On Thu, Apr 7, 2022 at 7:06 PM Brad Larson <brad@pensando.io> wrote:
> On Thu, Apr 7, 2022 at 12:13 AM Adrian Hunter <adrian.hunter@intel.com> wrote:
> >
> > What is the relationship between cadence and pensando elba?
>
> Pensando licensed the cadence controller, its 100% cadence IP.  The
> integration issue we ran into was with the accessors where we have the
> workaround.  The initial patch added a separate Elba driver file but
> the feedback was the Elba support didn't justify doing that and to add
> to sdhci-cacence.c.

I looked back at the earlier reviews now, I think the main problem with
versions 1 and 2 was that it had the abstraction the wrong way around,
so you added the complexity of having multiple files, without the benefits.

I still think that the cleanest approach would be to have it the way I
suggested in my reply to v1, with an elba specific platform driver
that calls into the generic cadence code, but the generic code knowing
nothing about the front-end.

Then again, it sounds like there was already an agreement about
the approach you took here, so let's stay with that and hope we don't
get any other chips with the same IP block in the future.

         Arnd

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