Received-SPF: pass (google.com: domain of linux-kernel+bounces-204081-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) client-ip=147.75.199.223;
Date: Thu, 6 Jun 2024 12:08:10 +0200
From: Wolfram Sang <wsa+renesas@sang-engineering.com>
To: Prabhakar <prabhakar.csengg@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>,
	Ulf Hansson <ulf.hansson@linaro.org>, Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Mark Brown <broonie@kernel.org>,
	Magnus Damm <magnus.damm@gmail.com>, linux-mmc@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	Fabrizio Castro <fabrizio.castro.jz@renesas.com>,
	Biju Das <biju.das.jz@bp.renesas.com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: Re: [RFC PATCH 4/4] mmc: renesas_sdhi: Add support for RZ/V2H(P) SoC
Message-ID: <20240606100810.eskr7bd3oqpphaxh@ninjato>
Mail-Followup-To: Wolfram Sang <wsa+renesas@sang-engineering.com>,
	Prabhakar <prabhakar.csengg@gmail.com>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Ulf Hansson <ulf.hansson@linaro.org>, Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Mark Brown <broonie@kernel.org>,
	Magnus Damm <magnus.damm@gmail.com>, linux-mmc@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org,
	Fabrizio Castro <fabrizio.castro.jz@renesas.com>,
	Biju Das <biju.das.jz@bp.renesas.com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
References: <20240605074936.578687-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
 <20240605074936.578687-5-prabhakar.mahadev-lad.rj@bp.renesas.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha512;
	protocol="application/pgp-signature"; boundary="c4wwgkhsymlp5fu6"
Content-Disposition: inline
In-Reply-To: <20240605074936.578687-5-prabhakar.mahadev-lad.rj@bp.renesas.com>


--c4wwgkhsymlp5fu6
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

Hi Prabhakar,

thanks for this series!

On Wed, Jun 05, 2024 at 08:49:36AM +0100, Prabhakar wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
>=20
> The SDHI/eMMC IPs found in the RZ/V2H(P) (a.k.a. r9a09g057) are very
> similar to those found in R-Car Gen3. However, they are not identical,
> necessitating an SoC-specific compatible string for fine-tuning driver
> support.
>=20
> Key features of the RZ/V2H(P) SDHI/eMMC IPs include:
> - Voltage level control via the IOVS bit.
> - PWEN pin support via SD_STATUS register.
> - Lack of HS400 support.
> - Fixed address mode operation.
>=20
> sd_iovs and sd_pwen quirks are introduced for SoCs supporting this bit
> to handle voltage level control and power enable via SD_STATUS register.

Two high-level questions:

- can't we use .enable/.disable in regulator_ops for handling pwen?
  Then we could simply use regulator_en/disable in the code and be future
  proof when other SDHI instances have other kinds of regulators (unless
  I am mising something)

- what about not using regmap and use set/get_voltage and friends? My
  concern is that other "new" registers might appear in the future and
  it will be cumbersome to handle the scattered IO regions.

That said, having a regulator is not a quirk in my book. I'd think
'struct renesas_sdhi' is the proper place. Or?

Looking forward to your comments,

   Wolfram


--c4wwgkhsymlp5fu6
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=trg3
-----END PGP SIGNATURE-----

--c4wwgkhsymlp5fu6--