linux-kernel - Re: [PATCH 3/4] phy: rcar-gen3-usb2: add SoC-specific parameter for dedicated pins

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Date:   Thu, 31 Aug 2017 10:27:01 +0200
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Cc:     Kishon Vijay Abraham I <kishon@...com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH 3/4] phy: rcar-gen3-usb2: add SoC-specific parameter for
 dedicated pins

Hi Shimoda-san,

On Thu, Aug 31, 2017 at 10:15 AM, Yoshihiro Shimoda
<yoshihiro.shimoda.uh@...esas.com> wrote:
>> From: Geert Uytterhoeven
>> Sent: Thursday, August 31, 2017 4:51 PM
>> On Thu, Aug 31, 2017 at 9:31 AM, Yoshihiro Shimoda
>> <yoshihiro.shimoda.uh@...esas.com> wrote:
>> > This patch adds SoC-specific parameter to avoid reading/writing
>> > specific registers wronly if this driver runs on a SoC which doesn't
>> > have dedicated pins (e.g. R-Car D3).
>> >
>> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
>> > ---
>> >  drivers/phy/renesas/phy-rcar-gen3-usb2.c | 25 ++++++++++++++++++++-----
>> >  1 file changed, 20 insertions(+), 5 deletions(-)
>> >
>> > diff --git a/drivers/phy/renesas/phy-rcar-gen3-usb2.c b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
>> > index 4ea9902..28ebc98 100644
>> > --- a/drivers/phy/renesas/phy-rcar-gen3-usb2.c
>> > +++ b/drivers/phy/renesas/phy-rcar-gen3-usb2.c
>>
>> > @@ -400,9 +403,18 @@ static irqreturn_t rcar_gen3_phy_usb2_irq(int irq, void *_ch)
>> >  }
>> >
>> >  static const struct of_device_id rcar_gen3_phy_usb2_match_table[] = {
>> > -       { .compatible = "renesas,usb2-phy-r8a7795" },
>> > -       { .compatible = "renesas,usb2-phy-r8a7796" },
>> > -       { .compatible = "renesas,rcar-gen3-usb2-phy" },
>> > +       {
>> > +               .compatible = "renesas,usb2-phy-r8a7795",
>> > +               .data = (void *)RCAR_GEN3_PHY_HAS_DEDICATED_PINS,
>> > +       },
>> > +       {
>> > +               .compatible = "renesas,usb2-phy-r8a7796",
>> > +               .data = (void *)RCAR_GEN3_PHY_HAS_DEDICATED_PINS,
>> > +       },
>> > +       {
>> > +               .compatible = "renesas,rcar-gen3-usb2-phy",
>> > +               .data = (void *)RCAR_GEN3_PHY_HAS_DEDICATED_PINS,
>> > +       },
>> >         { }
>> >  };
>>
>> Given the generic R-Car Gen3 entry sets RCAR_GEN3_PHY_HAS_DEDICATED_PINS, you
>> cannot specify the fallback compatible value of "renesas,rcar-gen3-usb2-phy"
>> in the R-Car D3 .dtsi.
>
> I understood it.
>
>> So I'm wondering, does the USB2 PHY still work (with limitations) on R-Car H3
>> and M3-W if you drop RCAR_GEN3_PHY_HAS_DEDICATED_PINS?
>
> Yes, the USB PHY still work with limitation (otg capability channel works as
> peripheral mode only. Other channels are no limitation).

That's good to hear.

>> If yes, you can drop the flag from the generic entry, and R-Car D3 can specify
>> the generic fallback compatible value in its .dtsi, like H3 and M3-W.
>
> I got it. I will fix this patch set.

And you can drop the driver change from "[PATCH 4/4] phy: rcar-gen3-usb2: add
binding for r8a77995", as it will match against the generic fallback on D3.

Thanks.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-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