Hi Fabrizio,

On Mon, Sep 24, 2018 at 11:30 AM Fabrizio Castro
[off-list ref] wrote:

quoted

-----Original Message-----
From: Simon Horman <horms@verge.net.au>
Sent: 24 September 2018 10:14
To: Fabrizio Castro <redacted>
Cc: Ulf Hansson <redacted>; Rob Herring <robh+dt@kernel.org>; Mark Rutland <mark.rutland@arm.com>; Laurent
Pinchart [off-list ref]; Geert Uytterhoeven [off-list ref]; Linus Walleij
[off-list ref]; Wolfram Sang [off-list ref]; Magnus Damm [off-list ref];
linux-mmc@vger.kernel.org; devicetree@vger.kernel.org; linux-renesas-soc@vger.kernel.org; linux-gpio@vger.kernel.org; Chris
Paterson [off-list ref]; Biju Das [off-list ref]
Subject: Re: [PATCH 4/4] ARM: dts: iwg23s-sbc: Add uSD card support

On Fri, Sep 21, 2018 at 12:55:11PM +0100, Fabrizio Castro wrote:

quoted

Add uSD card support to the iwg23s single board computer powered
by the RZ/G1C SoC (a.k.a. r8a77470).

Signed-off-by: Fabrizio Castro <redacted>
Reviewed-by: Biju Das <redacted>
---
Hello Simon,

this patch can only be taken after patch "pinctrl: sh-pfc: r8a77470:
Add SDHI2 voltage switch" from this series appears on a release candidate
or a release.

What is the nature of that dependency. Does adding this patch without
its dependency cause a regression?

Since the SDHI2 pins definition contain "power-source" property, adding this
patch without its dependency will cause an error at boot up as the kernel
would be looking for flag SH_PFC_PIN_CFG_IO_VOLTAGE for each pin contained
in sdhi2_pins and sdhi2_pins_uhs, and since that particular flag would be missing
(as such a definition comes from patch "pinctrl: sh-pfc: r8a77470: Add SDHI2 voltage
switch") the SD card would not be functional, but this won't have any impact on
the rest of the system.

But that won't be a regression, as currently there's no support for
SDHI2 anyway,
right? All pieces will start working when both the pinctrl and DTS support will
be merged together.

This is different from the case where you first add a device node to enable a
device (which makes it work), and later add pinctrl properties (which may
break it, if the pinctrl driver doesn't have support for it yet).

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds