Re: [PATCH/RFC 00/19] arm64: dts: renesas: Initial support for R-Car M3-W+

From: Eugeniu Rosca <erosca@de.adit-jv.com>
To: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: <linux-renesas-soc@vger.kernel.org>,
	Magnus Damm <magnus.damm@gmail.com>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	Eugeniu Rosca <erosca@de.adit-jv.com>,
	Eugeniu Rosca <roscaeugeniu@gmail.com>
Subject: Re: [PATCH/RFC 00/19] arm64: dts: renesas: Initial support for R-Car M3-W+
Date: Mon, 14 Oct 2019 21:58:42 +0200	[thread overview]
Message-ID: <20191014195842.GB10366@vmlxhi-102.adit-jv.com> (raw)
In-Reply-To: <20191007102332.12196-1-geert+renesas@glider.be>

Hi Geert,

On Mon, Oct 07, 2019 at 12:23:13PM +0200, Geert Uytterhoeven wrote:
> 	Hi all,
> 
> This RFC patch series adds support for the R-Car M3-W+ (R8A77961) SoC
> and the Salvator-XS board with R-Car M3-W+.  This SoC is a derivative of
> R-Car M3-W (R8A77960), and also known as R-Car M3-W ES3.0.
> As this is an RFC, I'm sending it to a limited audience.
> 
> Based on experience with previous SoCs in the R-Car Gen3 family, the
> following design decisions were made:
>   - Use different compatible values (r8a77961-based),

Given that a potentially incomplete list of M3-W compatible strings
counts 40 occurrences [1] and this series adds only 7 [2], current RFC
looks like the first step in a multi-phase approach. Do you plan to add
the missing r8a77961 compatibles in the next revision or do you expect
other people to contribute those later?

>   - Use different clock and SYSC DT binding definitions
>     (R8A77961-based), but the same numerical values, to allow sharing
>     drivers,
>   - Share the pin control driver,
>   - Share the clock driver,
>   - Share the system controller driver.
> 
> While the DT ABI is stable (hence we cannot s/r8a7796/r8a77960/ in DTS),
> kernel source code and kernel config symbols can be changed at any
> time.  As changing kernel config symbols impacts the user, they weren't
> renamed yet.
> 
> Questions:
>   - What's the board part number of Salvator-XS with R-Car M3-W+?

I guess my board is an exception, since it got the SiP simply upgraded
from SoC ES1.x to ES3.0 by resoldering. IOW the board carries the same
serial number as M3-ES1.1 Salvator-XS.

[..]

>   - Should the R8A77961 config symbols be dropped?
>       - CONFIG_ARCH_R8A77961
>       - CONFIG_CLK_R8A77961
>       - CONFIG_PINCTRL_PFC_R8A77961
>       - CONFIG_SYSC_R8A77961
> 
>   - If not, should the R8A7796 config symbols be renamed?
>       - CONFIG_ARCH_R8A7796 to CONFIG_ARCH_R8A77960?
>       - CONFIG_CLK_R8A7796 to CONFIG_CLK_R8A77960?
>       - CONFIG_PINCTRL_PFC_R8A7796 to CONFIG_PINCTRL_PFC_R8A77960?
>       - CONFIG_SYSC_R8A7796 to CONFIG_SYSC_R8A77960?
>     Due to dependencies on CONFIG_ARCH_R8A7796, this should be a single
>     commit.

[2 cents] Both adding CONFIG_*_R8A77961 and renaming CONFIG_*_R8A7796 to
CONFIG_*_R8A77960 make sense to me.

> Related questions for old R-Car H3 ES1.x support:
>   - Should CONFIG_PINCTRL_PFC_R8A77950 be added, to allow compiling out
>     R-Car H3 ES1.x pin control support?

[2 cents] Adding CONFIG_*_R8A77950 makes sense in spite of the fact that
R8A77950 is not documented in R-Car HW man. In fact, it is quite clear
why R8A77950 is _not_ documented while R8A77960 _is_ documented. The
former is obsolete (the community is nice by not obliterating its
support) while the latter is expected to hit the market.

>     If yes, should CONFIG_PINCTRL_PFC_R8A7795 be renamed to
>     CONFIG_PINCTRL_PFC_R8A77951?

In a perfect/ideal world, I would say yes.

> This patch series is based on renesas-drivers-2019-10-01-v5.4-rc1).  For
> your convenience, it is available in the topic/r8a77961-v1 branch of my
> renesas-drivers git repository at
> git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git.
> 
> This has been tested using remote access.
> 
> Thanks for your comments!

Thanks for the bring-up!

[..]

[1] linux (geert-renesas-drivers/topic/r8a77961-v1) \
git grep -o "\"renesas[^\ ]*r8a7796\b[^\"]*\"" | cut -f2 -d: | sort -u
"renesas,can-r8a7796"
"renesas,dmac-r8a7796"
"renesas,du-r8a7796"
"renesas,etheravb-r8a7796"
"renesas,gpio-r8a7796"
"renesas,hscif-r8a7796"
"renesas,i2c-r8a7796"
"renesas,iic-r8a7796"
"renesas,intc-ex-r8a7796"
"renesas,ipmmu-r8a7796"
"renesas,msiof-r8a7796"
"renesas,pcie-r8a7796"
"renesas,pfc-r8a7796"
"renesas,pwm-r8a7796"
"renesas,r8a7796"
"renesas,r8a7796-canfd"
"renesas,r8a7796-cmt0"
"renesas,r8a7796-cmt1"
"renesas,r8a7796-cpg-mssr"
"renesas,r8a7796-csi2"
"renesas,r8a7796-drif"
"renesas,r8a7796-hdmi"
"renesas,r8a7796-imr-lx4"
"renesas,r8a7796-lvds"
"renesas,r8a7796-rcar-usb2-clock-sel"
"renesas,r8a7796-rst"
"renesas,r8a7796-sysc"
"renesas,r8a7796-thermal"
"renesas,r8a7796-usb3-peri"
"renesas,r8a7796-usb3-phy"
"renesas,r8a7796-usb-dmac"
"renesas,r8a7796-wdt"
"renesas,rcar_sound-r8a7796"
"renesas,scif-r8a7796"
"renesas,sdhi-r8a7796"
"renesas,tpu-r8a7796"
"renesas,usb2-phy-r8a7796"
"renesas,usbhs-r8a7796"
"renesas,vin-r8a7796"
"renesas,xhci-r8a7796"

[2] linux (geert-renesas-drivers/topic/r8a77961-v1) \
git grep -o "\"renesas[^\ ]*r8a77961\b[^\"]*\"" | cut -f2 -d: | sort -u
"renesas,hscif-r8a77961"
"renesas,pfc-r8a77961"
"renesas,r8a77961"
"renesas,r8a77961-cpg-mssr"
"renesas,r8a77961-rst"
"renesas,r8a77961-sysc"
"renesas,scif-r8a77961"

-- 
Best Regards,
Eugeniu