Re: [PATCH 1/2] dt-bindings: add MediaTek XS-PHY binding

[Rob Herring]

On Wed, Apr 25, 2018 at 03:45:28PM +0800, Chunfeng Yun wrote:
> Add a DT binding documentation of XS-PHY for MediaTek SoCs
> with USB3.1 GEN2 controller
> 
> Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
> ---
>  .../devicetree/bindings/phy/phy-mtk-xsphy.txt      |  127 ++++++++++++++++++++
>  1 file changed, 127 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/phy/phy-mtk-xsphy.txt
> 
> diff --git a/Documentation/devicetree/bindings/phy/phy-mtk-xsphy.txt b/Documentation/devicetree/bindings/phy/phy-mtk-xsphy.txt
> new file mode 100644
> index 0000000..23c51a0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/phy/phy-mtk-xsphy.txt
> @@ -0,0 +1,127 @@
> +MediaTek XS-PHY binding
> +--------------------------
> +
> +The XS-PHY controller supports physical layer functionality for USB3.1
> +GEN2 controller on MediaTek SoCs.
> +
> +Required properties (controller (parent) node):
> + - compatible	: should be "mediatek,<soc-model>-xsphy", "mediatek,xsphy",
> + 		  soc-model is the name of SoC, such as mt2712 etc;

Please list all valid SoCs.

> +		  when using "mediatek,xsphy" compatible string, you need SoC specific
> +		  ones in addition.
> +
> +Required nodes	: a sub-node is required for each port the controller
> +		  provides. Address range information including the usual
> +		  'reg' property is used inside these nodes to describe
> +		  the controller's topology.

This should go afer the parent optional properties.

> +
> +Optional properties (controller (parent) node):
> + - reg		: offset and length of register shared by multiple U3 ports,
> +		  exclude port's private register, if only U2 ports provided,
> +		  shouldn't use the property.
> + - mediatek,src-ref-clk-mhz	: u32, frequency of reference clock for slew rate
> +		  calibrate
> + - mediatek,src-coef	: u32, coefficient for slew rate calibrate, depends on
> +		  SoC process
> +
> +Required properties (port (child) node):
> +- reg		: address and length of the register set for the port.
> +- clocks	: a list of phandle + clock-specifier pairs, one for each
> +		  entry in clock-names
> +- clock-names	: must contain
> +		  "ref": 48M reference clock for HighSpeed analog phy; and 26M
> +			reference clock for SuperSpeedPlus analog phy, sometimes is
> +			24M, 25M or 27M, depended on platform.
> +- #phy-cells	: should be 1 (See second example)
> +		  cell after port phandle is phy type from:
> +			- PHY_TYPE_USB2
> +			- PHY_TYPE_USB3

Is the type a property of the connection to the host? If not, this 
shouldn't be part of the phy cells. I would add compatible strings to 
the child nodes to define this. I think that would simplify the driver 
too as then you can parse DT properties in probe rather than phy_init.

> +
> +The following optional properties are only for debug or HQA test
> +Optional properties (PHY_TYPE_USB2 port (child) node):
> +- mediatek,eye-src	: u32, the value of slew rate calibrate
> +- mediatek,eye-vrt	: u32, the selection of VRT reference voltage
> +- mediatek,eye-term	: u32, the selection of HS_TX TERM reference voltage
> +- mediatek,efuse-intr	: u32, the selection of Internal Resistor
> +
> +Optional properties (PHY_TYPE_USB3 port (child) node):
> +- mediatek,efuse-intr	: u32, the selection of Internal Resistor
> +- mediatek,efuse-tx-imp	: u32, the selection of TX Impedance
> +- mediatek,efuse-rx-imp	: u32, the selection of RX Impedance
> +
> +Example:
> +
> +u3phy: usb-phy@11c40000 {
> +	compatible = "mediatek,mt36xx-xsphy", "mediatek,xsphy";

Is mt36xx a specific SoC? Don't use wildcards in compatible strings.

> +	reg = <0 0x11c43000 0 0x0200>;
> +	mediatek,src-ref-clk-mhz = <26>;
> +	mediatek,src-coef = <17>;
> +	#address-cells = <2>;
> +	#size-cells = <2>;

Really need 64-bit sizes?

> +	ranges;

Limiting the range to only the phy addresses is preferred.

> +	status = "disabled";

Don't show status in examples.

> +
> +	u2port0: usb-phy@11c40000 {
> +		reg = <0 0x11c40000 0 0x0400>;
> +		clocks = <&clk48m>;
> +		clock-names = "ref";
> +		mediatek,eye-src = <4>;
> +		#phy-cells = <1>;
> +		status = "okay";
> +	};
> +
> +	u3port0: usb-phy@11c43000 {
> +		reg = <0 0x11c43400 0 0x0500>;
> +		clocks = <&clk26m>;
> +		clock-names = "ref";
> +		mediatek,efuse-intr = <28>;
> +		#phy-cells = <1>;
> +		status = "okay";
> +	};
> +};
> +

> +Specifying phy control of devices
> +---------------------------------
> +
> +Device nodes should specify the configuration required in their "phys"
> +property, containing a phandle to the phy port node and a device type;
> +phy-names for each port are optional.
> +
> +Example:
> +
> +#include <dt-bindings/phy/phy.h>
> +
> +ssusb: usb@112a0000 {
> +	...
> +	phys = <&u2port0 PHY_TYPE_USB2>, <&u3port0 PHY_TYPE_USB3>;
> +	phy-names = "usb2-0", "usb3-0";
> +	...
> +};

This section is not necessary. We've already explained how to use the 
phy binding elsewhere.

> +
> +
> +Banks layout of xsphy

Put this before the example.

> +-------------------------------------------------------------
> +port        offset    bank
> +u2 port0    0x0000    MISC
> +            0x0100    FMREG
> +            0x0300    U2PHY_COM
> +u2 port1    0x1000    MISC
> +            0x1100    FMREG
> +            0x1300    U2PHY_COM
> +u2 port2    0x2000    MISC
> +            ...
> +u31 common  0x3000    DIG_GLB
> +            0x3100    PHYA_GLB
> +u31 port0   0x3400    DIG_LN_TOP
> +            0x3500    DIG_LN_TX0
> +            0x3600    DIG_LN_RX0
> +            0x3700    DIG_LN_DAIF
> +            0x3800    PHYA_LN
> +u31 port1   0x3a00    DIG_LN_TOP
> +            0x3b00    DIG_LN_TX0
> +            0x3c00    DIG_LN_RX0
> +            0x3d00    DIG_LN_DAIF
> +            0x3e00    PHYA_LN
> +            ...
> +
> +DIG_GLB & PHYA_GLB are shared by U31 ports.
> -- 
> 1.7.9.5
>