Re: [PATCH v5 3/5] dt-bindings: phy: tegra: Add Tegra194 support

[Rob Herring <robh@kernel.org>]

On Fri, Jan 03, 2020 at 04:18:12PM +0800, JC Kuo wrote:
> Extend the bindings to cover the set of features found in Tegra194.
> Note that, technically, there are four more supplies connected to the
> XUSB pad controller (DVDD_PEX, DVDD_PEX_PLL, HVDD_PEX and HVDD_PEX_PLL)
> , but the power sequencing requirements of Tegra194 require these to be
> under the control of the PMIC.
> 
> Tegra194 XUSB PADCTL supports up to USB 3.1 Gen 2 speed, however, it
> is possible for some platforms have long signal trace that could not
> provide sufficient electrical environment for Gen 2 speed. This patch
> adds a "maximum-speed" property to usb3 ports which can be used to
> specify the maximum supported speed for any particular USB 3.1 port.
> For a port that is not capable of SuperSpeedPlus, "maximum-speed"
> property should carry "super-speed".
> 
> Signed-off-by: JC Kuo <jckuo@nvidia.com>
> ---
> Changes in v5:
> - re-use "maximum-speed" instead of adding "nvidia,disable-gen2"
> Changes in v4: none
> Changes in v3: none
> Changes in v2:
> - fix a typo
> 
>  .../phy/nvidia,tegra124-xusb-padctl.txt        | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/phy/nvidia,tegra124-xusb-padctl.txt b/Documentation/devicetree/bindings/phy/nvidia,tegra124-xusb-padctl.txt
> index 9fb682e47c29..7d0089006e67 100644
> --- a/Documentation/devicetree/bindings/phy/nvidia,tegra124-xusb-padctl.txt
> +++ b/Documentation/devicetree/bindings/phy/nvidia,tegra124-xusb-padctl.txt
> @@ -37,6 +37,7 @@ Required properties:
>    - Tegra132: "nvidia,tegra132-xusb-padctl", "nvidia,tegra124-xusb-padctl"
>    - Tegra210: "nvidia,tegra210-xusb-padctl"
>    - Tegra186: "nvidia,tegra186-xusb-padctl"
> +  - Tegra194: "nvidia,tegra194-xusb-padctl"
>  - reg: Physical base address and length of the controller's registers.
>  - resets: Must contain an entry for each entry in reset-names.
>  - reset-names: Must include the following entries:
> @@ -62,6 +63,10 @@ For Tegra186:
>  - vclamp-usb-supply: Bias rail for USB pad. Must supply 1.8 V.
>  - vddio-hsic-supply: HSIC PHY power supply. Must supply 1.2 V.
>  
> +For Tegra194:
> +- avdd-usb-supply: USB I/Os, VBUS, ID, REXT, D+/D- power supply. Must supply
> +  3.3 V.
> +- vclamp-usb-supply: Bias rail for USB pad. Must supply 1.8 V.
>  
>  Pad nodes:
>  ==========
> @@ -154,6 +159,11 @@ For Tegra210, the list of valid PHY nodes is given below:
>  - sata: sata-0
>    - functions: "usb3-ss", "sata"
>  
> +For Tegra194, the list of valid PHY nodes is given below:
> +- usb2: usb2-0, usb2-1, usb2-2, usb2-3
> +  - functions: "xusb"
> +- usb3: usb3-0, usb3-1, usb3-2, usb3-3
> +  - functions: "xusb"
>  
>  Port nodes:
>  ===========
> @@ -221,6 +231,11 @@ Optional properties:
>    is internal. In the absence of this property the port is considered to be
>    external.
>  
> +- maximum-speed: Only for Tegra194. A string property that specifies maximum
> +  supported speed of a usb3 port. Valid values are:
> +  - "super-speed-plus": default, the usb3 port supports USB 3.1 Gen 2 speed.

Not defined as a valid value in usb/generic.txt. '-gen2' instead of 
'-plus' would be clearer IMO. However, is there any need to define the 
maximum speed possible? The purpose of this property is to limit the 
speed below the max.

> +  - "super-speed": the usb3 port supports USB 3.1 Gen 1 speed only.
> +
>  For Tegra124 and Tegra132, the XUSB pad controller exposes the following
>  ports:
>  - 3x USB2: usb2-0, usb2-1, usb2-2
> @@ -233,6 +248,9 @@ For Tegra210, the XUSB pad controller exposes the following ports:
>  - 2x HSIC: hsic-0, hsic-1
>  - 4x super-speed USB: usb3-0, usb3-1, usb3-2, usb3-3
>  
> +For Tegra194, the XUSB pad controller exposes the following ports:
> +- 4x USB2: usb2-0, usb2-1, usb2-2, usb2-3
> +- 4x super-speed USB: usb3-0, usb3-1, usb3-2, usb3-3
>  
>  Examples:
>  =========
> -- 
> 2.17.1
>