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From:   Tianling Shen <cnsztl@gmail.com>
Date:   Mon, 7 Jun 2021 20:48:34 +0800
Message-ID: <CAOP2_TiZYXWnDZ1-_K-EvHt3-=sV1k8cRaenW8xqr44KdLCQiw@mail.gmail.com>
Subject: Re: [PATCH] arm64: dts: rockchip: add EEPROM node for NanoPi R4S
To:     Chen-Yu Tsai <wens@kernel.org>
Cc:     Rob Herring <robh+dt@kernel.org>, Heiko Stuebner <heiko@sntech.de>,
        Marty Jones <mj8263788@gmail.com>, Pavel Machek <pavel@ucw.cz>,
        devicetree <devicetree@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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Hi Chen-Yu,

On Mon, Jun 7, 2021 at 4:36 PM Chen-Yu Tsai <wens@kernel.org> wrote:
>
> Hi,
>
> On Mon, Jun 7, 2021 at 4:19 PM Tianling Shen <cnsztl@gmail.com> wrote:
> >
> > NanoPi R4S has a EEPROM attached to the 2nd I2C bus (U92), which
> > stores the MAC address.
> >
> > Signed-off-by: Tianling Shen <cnsztl@gmail.com>
> > ---
> >  arch/arm64/boot/dts/rockchip/rk3399-nanopi-r4s.dts | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> >
> > diff --git a/arch/arm64/boot/dts/rockchip/rk3399-nanopi-r4s.dts b/arch/arm64/boot/dts/rockchip/rk3399-nanopi-r4s.dts
> > index cef4d18b599d..4a82f50a07c5 100644
> > --- a/arch/arm64/boot/dts/rockchip/rk3399-nanopi-r4s.dts
> > +++ b/arch/arm64/boot/dts/rockchip/rk3399-nanopi-r4s.dts
> > @@ -68,6 +68,15 @@
> >         status = "disabled";
> >  };
> >
> > +&i2c2 {
> > +       eeprom@51 {
> > +               compatible = "microchip,24c02", "atmel,24c02";
>
> The actual part number is Microchip 24AA025E48, but I don't think
> the way this device splits its storage area is easy to support
> without additional modifications to the driver.
>

On the face of it, it seems to work fine, and I can read the data correctly.
(built with at24 eeprom driver)

Thanks,
Tianling.

> > +               reg = <0x51>;
> > +               pagesize = <16>;
> > +               read-only; /* This holds our MAC */
>
> Please also add the size, as well as a cell defining the offset
> and length to the MAC address. The gmac node can then reference
> this with:
>
>     nvmem-cells = <&mac_address>;
>     nvmem-cells-names = "mac-address";
>
> which will actually pick up the MAC address.
>
>
> Regards
> ChenYu
>
> > +       };
> > +};
> > +
> >  &i2c4 {
> >         status = "disabled";
> >  };
> > --
> > 2.17.1
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel