Re: [RFC PATCH 4/4] mmc: renesas_sdhi: Add support for RZ/V2H(P) SoC

Lad, Prabhakar
2024-06-06T12:15:57Z

Hi Wolfram,

On Thu, Jun 6, 2024 at 11:08 AM Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
>
> 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>
> >
> > 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.
> >
> > 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.
> >
> > 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)
>
Ok let me check on this and get back.

> - 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.
>
I'll have to do some reading on this. Can you please point me to any
example driver which does not use regmap.

> That said, having a regulator is not a quirk in my book. I'd think
> 'struct renesas_sdhi' is the proper place. Or?
>
Ok, I will move them out of quirks.

Cheers,
Prabhakar