linux-kernel - RE: [PATCH 1/2] dt-bindings: phy: Document cadence Sierra PHY bindings

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Message-ID: <MWHPR07MB3502E5AD55EE63D83AA640E2D8F90@MWHPR07MB3502.namprd07.prod.outlook.com>
Date:   Fri, 19 Oct 2018 15:30:33 +0000
From:   Alan Douglas <adouglas@...ence.com>
To:     Rob Herring <robh@...nel.org>
CC:     "kishon@...com" <kishon@...com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: RE: [PATCH 1/2] dt-bindings: phy: Document cadence Sierra PHY
 bindings

On 15 October 2018 20:09, Rob Herring wrote:
> On Wed, Oct 03, 2018 at 05:02:25PM +0100, Alan Douglas wrote:
> > Add DT binding documentation for Sierra PHY.  The PHY supports
> > a number of different protocols, including PCIe and USB.
> >
> > The PHY lanes may be configured as single or multi-lane links.
> > Each link is treated as a separate sub-node.  For example, if
> > there are 4 lanes in total the first 2 might be configured as
> > a multi-lane PCIe link while the other two are single lane
> > USB links, and in this case there would be 3 sub-nodes.
> >
> > There are two resets for the PHY block (one for APB register
> > access, one for the PHY link) and separate resets for each
> > link.  For multi-lane links, the reset corresponds to the
> > reset line on the master lane, the resets on other lanes
> > have no effect.
> >
> > Signed-off-by: Alan Douglas <adouglas@...ence.com>
> > ---
> >  .../devicetree/bindings/phy/cdns-sierra-phy.txt    | 68 ++++++++++++++++++++++
> >  1 file changed, 68 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/phy/cdns-sierra-phy.txt
> >
> > diff --git a/Documentation/devicetree/bindings/phy/cdns-sierra-phy.txt b/Documentation/devicetree/bindings/phy/cdns-sierra-
> phy.txt
> > new file mode 100644
> > index 0000000..0e2f3e3
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/phy/cdns-sierra-phy.txt
> > @@ -0,0 +1,68 @@
> > +Cadence Sierra PHY
> > +-----------------------
> > +
> > +Required properties:
> > +- compatible:	cdns,sierra-phy-t0
> > +- clocks:	Must contain an entry in clock-names.
> > +		See ../clocks/clock-bindings.txt for details.
> > +- clock-names:	Must be "phy_clk"
> > +- resets:	Must contain an entry for each in reset-names.
> > +		See ../reset/reset.txt for details.
> > +- reset-names:	Must include "sierra_reset" and "sierra_apb" and one for each
> > +		sub-node.
> > +		"sierra_reset" must control the reset line to the PHY.
> > +		"sierra_apb" must control the reset line to the APB PHY
> > +		interface.
> > +		The name of the reset for each sub-node should match the full
> > +		name of the sub-node.  The sub-node resets must control the
> > +		reset line for the master lane of the sub-node.
> 
> Add a resets property to the sub-nodes instead.
> 
Will do.  As far as I can see it prevents me using devm_reset_control_get()
though, so I need to work out the best way to put these resets on remove()

> > +- reg:		register range for the PHY.
> > +- #address-cells: Must be 1
> > +- #size-cells:	Must be 0
> > +
> > +Optional properties:
> > +- cdns,autoconf:	A boolean property whose presence indicates that the
> > +			PHY registers will be configured by hardware. If not
> > +			present, all sub-node optional properties must be
> > +			provided.
> > +
> > +Sub-nodes:
> > +  Each group of PHY lanes with a single master lane should be represented as
> > +  a sub-node. Note that the actual configuration of each lane is determined by
> > +  hardware strapping, and must match the configuration specified here.
> > +
> > +Sub-node required properties:
> > +- #phy-cells:	Generic PHY binding; must be 0.
> > +
> > +Sub-node optional properties:
> > +- reg:			The master lane number.  This is the lowest numbered
> > +			lane in the lane group.
> 
> How do you name the nodes if this is optional?
> 
I'll change this to be required.

Thanks for your comments,
Alan

> > +- cdns,num-lanes:	Number of lanes in this group.  From 1 to 4.  The
> > +			group is made up of consecutive lanes.
> > +- cdns,phy-type:	Can be PHY_TYPE_PCIE or PHY_TYPE_USB3, depending on
> > +			configuration of lanes.
> > +
> > +Example:
> > +	pcie_phy4: pcie-phy@...40000 {
> > +		compatible = "cdns,sierra-phy-t0";
> > +		reg = <0x0 0xfd240000 0x0 0x40000>;
> > +		resets = <&phyrst 0>, <&phyrst 1>, <&phyrst 2>, <&phyrst 4>;
> > +		reset-names = "sierra_reset", "sierra_apb",
> > +				"pcie_phy@0", "pcie_phy@2";
> > +		clocks = <&phyclock>;
> > +		clock-names = "phy_clk";
> > +		#address-cells = <1>;
> > +		#size-cells = <0>;
> > +		pcie0_phy0: pcie-phy@0 {
> > +				reg = <0>;
> > +				cdns,num-lanes = <2>;
> > +				#phy-cells = <0>;
> > +				cdns,phy-type = <PHY_TYPE_PCIE>;
> > +		};
> > +		pcie0_phy1: pcie-phy@2 {
> > +				reg = <2>;
> > +				cdns,num-lanes = <1>;
> > +				#phy-cells = <0>;
> > +				cdns,phy-type = <PHY_TYPE_PCIE>;
> > +		};
> > +
> > --
> > 1.9.0
> >