linux-kernel - Re: [PATCH v4 09/13] ARM: dts: sun8i: r40: add sata node

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Message-ID: <20180831120804.GA11340@Red>
Date:   Fri, 31 Aug 2018 14:08:04 +0200
From:   Corentin Labbe <clabbe.montjoie@...il.com>
To:     Chen-Yu Tsai <wens@...e.org>
Cc:     Maxime Ripard <maxime.ripard@...tlin.com>, axboe@...nel.dk,
        Hans de Goede <hdegoede@...hat.com>,
        Kishon Vijay Abraham I <kishon@...com>,
        Mark Rutland <mark.rutland@....com>,
        Rob Herring <robh+dt@...nel.org>,
        devicetree <devicetree@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-ide@...r.kernel.org,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-sunxi <linux-sunxi@...glegroups.com>,
        Icenowy Zheng <icenowy@...c.io>
Subject: Re: [PATCH v4 09/13] ARM: dts: sun8i: r40: add sata node

On Fri, Aug 31, 2018 at 07:31:37PM +0800, Chen-Yu Tsai wrote:
> On Fri, Aug 31, 2018 at 6:54 PM Corentin Labbe
> <clabbe.montjoie@...il.com> wrote:
> >
> > On Fri, Aug 31, 2018 at 12:20:21PM +0200, maxime.ripard@...tlin.com wrote:
> > > On Fri, Aug 31, 2018 at 09:56:31AM +0200, Corentin Labbe wrote:
> > > > On Fri, Aug 31, 2018 at 09:35:00AM +0200, Maxime Ripard wrote:
> > > > > On Thu, Aug 30, 2018 at 09:01:16PM +0200, Corentin Labbe wrote:
> > > > > > R40 have a sata controller which is the same as A20.
> > > > > > This patch adds a DT node for it.
> > > > > >
> > > > > > Signed-off-by: Icenowy Zheng <icenowy@...c.io>
> > > > > > Signed-off-by: Corentin Labbe <clabbe.montjoie@...il.com>
> > > > > > ---
> > > > > >  arch/arm/boot/dts/sun8i-r40.dtsi | 23 +++++++++++++++++++++++
> > > > > >  1 file changed, 23 insertions(+)
> > > > > >
> > > > > > diff --git a/arch/arm/boot/dts/sun8i-r40.dtsi b/arch/arm/boot/dts/sun8i-r40.dtsi
> > > > > > index 852c2ccc3268..d6b5820da850 100644
> > > > > > --- a/arch/arm/boot/dts/sun8i-r40.dtsi
> > > > > > +++ b/arch/arm/boot/dts/sun8i-r40.dtsi
> > > > > > @@ -550,6 +550,29 @@
> > > > > >                         #size-cells = <0>;
> > > > > >                 };
> > > > > >
> > > > > > +               ahci: sata@...8000 {
> > > > > > +                       compatible = "allwinner,sun8i-r40-ahci";
> > > > > > +                       reg = <0x01c18000 0x1000>;
> > > > > > +                       interrupts = <GIC_SPI 56 IRQ_TYPE_LEVEL_HIGH>;
> > > > > > +                       clocks = <&ccu CLK_BUS_SATA>, <&ccu CLK_SATA>;
> > > > > > +                       resets = <&ccu RST_BUS_SATA>;
> > > > > > +                       resets-name = "ahci";
> > > > > > +                       #address-cells = <1>;
> > > > > > +                       #size-cells = <0>;
> > > > > > +                       status = "disabled";
> > > > > > +
> > > > > > +                       sata_port: sata-port@0 {
> > > > > > +                               reg = <0>;
> > > > > > +                               phys = <&sata_phy>;
> > > > > > +                       };
> > > > > > +               };
> > > > > > +
> > > > > > +               sata_phy: sata-phy@...80c0  {
> > > > > > +                       compatible = "allwinner,sun8i-r40-sata-phy";
> > > > > > +                       reg = <0x1c180c0 0x200>;
> > > > >
> > > > > Overlapping devices in the DTS is not ok.
> > > > >
> > > >
> > > > I do the same than arch/arm/boot/dts/berlin2.dtsi (sata@...000
> > > > phy@...0a0)
> > > >
> > > > But since it is not a good justification, it seems that regmap is my
> > > > only solution ?
> > >
> > > I'm not even sure why you are moving the phy out of its original node
> > > (and driver).
> > >
> >
> > For using the phy-supply already handled by the code.
> > The other choice is to add another xxx-supply to ahci_platform.
> > Or to use hackily port_regulator for this regulator.
> 
> The PHY registers are in the AHCI's "vendor specific registers"
> region. Following that are the per-port registers, which the ahci
> driver will need access to. This doesn't look like it should
> deserve a separate device node.
> 
> What's wrong with handling the regulator directly in the ahci-sunxi
> PHY init code?
> 

The reason are that I didnt wanted to use the port-regulator, and I didnt want to add new code to ahci_platform.
I tried to place a phy-supply in the ahci node, but it doesnt work (with or without a phy subnode).

Moving PHy code in a dedicated driver seemed to be good, but with all your comments and Maxime's one, it seems not.

I will keep ahci_sunxi as-is and will try to found how to add the needed phy-supply.

Regards