RE: [PATCH v4 0/7] treewide: scsi: ufs: Add support for Renesas R-Car UFS controller

From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Alim Akhtar <alim.akhtar@samsung.com>,
	"avri.altman@wdc.com" <avri.altman@wdc.com>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	scsi <linux-scsi@vger.kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>
Subject: RE: [PATCH v4 0/7] treewide: scsi: ufs: Add support for Renesas R-Car UFS controller
Date: Mon, 25 Apr 2022 23:25:30 +0000	[thread overview]
Message-ID: <TYBPR01MB5341306C3F0C5F556C0623D6D8F89@TYBPR01MB5341.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <CAMuHMdWRQYLK49pMKJ6b-SVK91brrEJvD52cyyLWTwAT0z3Cmg@mail.gmail.com>

Hi Geert-san,

> From: Geert Uytterhoeven, Sent: Tuesday, April 26, 2022 12:32 AM
> 
> Hi Shimoda-san,
> 
> On Wed, Apr 20, 2022 at 8:17 AM Yoshihiro Shimoda
> <yoshihiro.shimoda.uh@renesas.com> wrote:
> > This patch series adds support Renesas R-Car S4-8 UFS controller.
> 
> Thanks for your series!
> 
> > This controller has some restrictions so adds some quirks for it.
> > Before using this driver, we have to initialize a clock generator
> > on the environment board (named "Spider") by using the commands of
> > U-Boot like below:
> >  => i2c dev 0
> >  => i2c mw 0x6c 0x26 0x05
> >  => i2c olen 0x6c 2
> >  => i2c mw 0x6c 0x26c 0x2e
> 
> You mean we need a driver for the RC21212 clock generator? ;-)

You're correct.
# JFYI, the Spider has RC21012 instead of RC21212 for some reasons.

> Or the boot loader should program the clock generator, like is done
> on other R-Car boards for e.g. the PCIe clock (BTW, RC21212 also
> generates the PCIe clock on Spider)?

I think so because the clock generator specification is complex.
The RC21012 also generates the PCIe clock and Ethernet on Spider.

Best regards,
Yoshihiro Shimoda