Re: [PATCH v3 2/3] dt-bindings: phy: Add constants for lan966x serdes

From: Horatiu Vultur <horatiu.vultur@microchip.com>
To: Rob Herring <robh@kernel.org>
Cc: <kishon@ti.com>, <vkoul@kernel.org>, <andrew@lunn.ch>,
	<alexandre.belloni@bootlin.com>, <linux-phy@lists.infradead.org>,
	<devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 2/3] dt-bindings: phy: Add constants for lan966x serdes
Date: Tue, 19 Oct 2021 11:12:58 +0200	[thread overview]
Message-ID: <20211019091258.3uet6lp3mxaoliqt@soft-dev3-1.localhost> (raw)
In-Reply-To: <YW3K2GX+hmkwt3EE@robh.at.kernel.org>

The 10/18/2021 14:28, Rob Herring wrote:
> 
> On Fri, Oct 15, 2021 at 02:39:19PM +0200, Horatiu Vultur wrote:
> > Lan966x has: 2 integrated PHYs, 3 SerDes and 2 RGMII interfaces. Which
> > requires to be muxed based on the HW representation.
> >
> > So add constants for each interface to be able to distinguish them.
> >
> > Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
> > ---
> >  include/dt-bindings/phy/phy-lan966x-serdes.h | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> >  create mode 100644 include/dt-bindings/phy/phy-lan966x-serdes.h
> >
> > diff --git a/include/dt-bindings/phy/phy-lan966x-serdes.h b/include/dt-bindings/phy/phy-lan966x-serdes.h
> > new file mode 100644
> > index 000000000000..8a05f93ecf41
> > --- /dev/null
> > +++ b/include/dt-bindings/phy/phy-lan966x-serdes.h
> > @@ -0,0 +1,14 @@
> > +/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
> > +
> > +#ifndef __PHY_LAN966X_SERDES_H__
> > +#define __PHY_LAN966X_SERDES_H__
> > +
> > +#define PHY(x)               (x)
> > +#define PHY_MAX              PHY(2)
> > +#define SERDES6G(x)  (PHY_MAX + 1 + (x))
> > +#define SERDES6G_MAX SERDES6G(3)
> > +#define RGMII(x)     (SERDES6G_MAX + 1 + (x))
> > +#define RGMII_MAX    RGMII(2)
> > +#define SERDES_MAX   (RGMII_MAX + 1)
> 
> I still don't understand. #phy-cells description says we have:
> 
> <port idx> <serdes idx>
> 
> But here it's 3 numbers. How are these defines used to fill in the 2
> cells?

Actually they are still only a number. Or maybe I am missing something.

Maybe an example will help:

---
serdes: serdes@e2004010 {
    compatible = "microchip,lan966x-serdes";
    reg = <0xe202c000 0x9c>, <0xe2004010 0x4>;
    #phy-cells = <2>;
};

&port0 {
    ...
    phys = <&serdes 0 SERDES6G(1)>;
    ...
};

&port1 {
    ...
    phys = <&serdes 1 PHY(0)>;
    ...
}

...
---

Here are some existing examples based on which I have created this patch
series:
https://elixir.bootlin.com/linux/v5.15-rc6/source/arch/mips/boot/dts/mscc/ocelot_pcb120.dts#L99
https://elixir.bootlin.com/linux/v5.15-rc6/source/arch/mips/boot/dts/mscc/ocelot.dtsi#L274

> 
> Rob

-- 
/Horatiu