RE: [PATCH v2 04/15] dt-bindings: rcar-gen3-phy-usb2: Document use of usb_x1

From: Chris Brandt <Chris.Brandt@renesas.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Simon Horman <horms@verge.net.au>,
	Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-renesas-soc@vger.kernel.org"
	<linux-renesas-soc@vger.kernel.org>
Subject: RE: [PATCH v2 04/15] dt-bindings: rcar-gen3-phy-usb2: Document use of usb_x1
Date: Mon, 13 May 2019 21:07:04 +0000	[thread overview]
Message-ID: <TY1PR01MB15620F606FDE4AF0C446213E8A0F0@TY1PR01MB1562.jpnprd01.prod.outlook.com> (raw)
In-Reply-To: <CAMuHMdVVoYak4FGEOYK_dGLCLEQ7avVCv5AcY43BPkDnt7OZ4w@mail.gmail.com>

Hi Geert and Shimoda-san,

On Fri, May 10, 2019, Geert Uytterhoeven wrote:
> > I think we can reuse it like below:
> >
> > - clock-names: Name of the clocks. This property is model-dependent.
> >   - R-Car Gen3 SoCs use a single functional clock. The clock doesn't
> need to be
> >     named.
> >   - RZ/A2 uses a single functional clock as a separate dedicated 48MHz
> 
> and a separate?
> 
> >     USB_X1 input. So, the functional clock must be named "???" and
> >     the USB_X1 input must be named as "usb_x1".
> >
> > What do you think? I'm not sure how to be named the functional clock so
> that
> > the sample is named as "???".
> 
> We typically use "fclk" for the functional clock's name.

Just to make sure I'm following this, here is what you are asking for:

[r7s9210.dtsi]

	usb2_phy1: usb-phy@e821a200 {
		compatible = "renesas,usb2-phy-r7s9210", "renesas,rcar-gen3-usb2-phy";
		reg = <0xe821a200 0x10>;
		interrupts = <GIC_SPI 36 IRQ_TYPE_LEVEL_HIGH>;
+		clocks = <&cpg CPG_MOD 60>, <&usb_x1_clk>;
+		clock-names = "fclk", "usb_x1";
		power-domains = <&cpg>;
		#phy-cells = <0>;
		status = "disabled";

[phy-rcar-gen3-usb2.c]
	usb_x1_clk = devm_clk_get(dev, "usb_x1");
	if (!IS_ERR(usb_x1_clk))
		if (clk_get_rate(usb_x1_clk))
			channel->uses_usb_x1 = true;

And then document this in the bindings, saying that clock-names is 
option if there is only 1 clock (to be backward compatible with existing 
Device Trees.

Is this correct?

Thanks,
Chris