[V2,4/8] dt-bindings: usb: Add NVIDIA Tegra XUSB device mode controller binding

[Thierry Reding <thierry.reding@gmail.com>]

On Thu, Apr 25, 2019 at 05:14:01PM +0200, Thierry Reding wrote:
> On Mon, Mar 11, 2019 at 04:41:52PM +0530, Nagarjuna Kristam wrote:
> > Add device-tree binding documentation for the XUSB device mode controller
> > present on tegra210 SoC. This controller supports USB 3.0 specification
> 
> Tegra210, please. "... supports the USB 3.0 ...". Also end sentences
> with a fullstop.
> 
> > 
> > Based on work by Andrew Bresticker <abrestic@chromium.org>.
> > 
> > Signed-off-by: Nagarjuna Kristam <nkristam@nvidia.com>
> > ---
> >  .../devicetree/bindings/usb/nvidia,tegra-xudc.txt  | 105 +++++++++++++++++++++
> >  1 file changed, 105 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/usb/nvidia,tegra-xudc.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/usb/nvidia,tegra-xudc.txt b/Documentation/devicetree/bindings/usb/nvidia,tegra-xudc.txt
> > new file mode 100644
> > index 0000000..990655d
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/usb/nvidia,tegra-xudc.txt
> > @@ -0,0 +1,105 @@
> > +Device tree binding for NVIDIA Tegra XUSB device mode controller (XUDC)
> > +=======================================================================
> > +
> > +The Tegra XUDC controller supports both USB 2.0 HighSpeed/FullSpeed and
> > +USB 3.0 SuperSpeed protocols.
> > +
> > +Required properties:
> > +--------------------
> > +- compatible: For Tegra210, must contain "nvidia,tegra210-xudc".
> > +- reg: Must contain the base and length of the XUSB device registers, XUSB device
> > +  PCI Config registers and XUSB device controller registers.
> > +- interrupts: Must contain the XUSB device interrupt
> > +- clocks: Must contain an entry for ell clocks used.
> 
> s/ell/all/
> 
> > +  See ../clock/clock-bindings.txt for details.
> > +- clock-names: Must include the following entries:
> > +   - xusb_device
> > +   - xusb_ss
> > +   - xusb_ss_src
> > +   - xusb_hs_src
> > +   - xusb_fs_src
> 
> It'd be good to explain what each of these are.

Perhaps we should also drop the xusb_ prefix here. That's already
implied by this being the XUDC controller bindings.

> 
> > +- nvidia,xusb-padctl: phandle to the XUSB pad controller that is used to
> > +  configure the USB pads used by the XUDC controller
> > +- power-domains: A list of PM domain specifiers that reference each power-domain
> > +  used by the XUSB device mode controller. This list must comprise of a specifier
> > +  for the XUSBA and XUSBB power-domains. See ../power/power_domain.txt and
> > +  ../arm/tegra/nvidia,tegra20-pmc.txt for details.
> > +- power-domain-names: A list of names that represent each of the specifiers in
> > +  the 'power-domains' property. Must include 'xusb_ss' and 'xusb_device'

Same here, I'd drop the xusb_ prefix. I think the "device" power domain
is also usually referred to as "XUSB_DEV", so perhaps make that "dev"
instead?

Thierry

> > +
> > +For Tegra210:
> > +- avddio-usb-supply: PCIe/USB3 analog logic power supply. Must supply 1.05 V.
> > +- hvdd-usb-supply: USB controller power supply. Must supply 3.3 V.
> > +- avdd-pll-utmip-supply: UTMI PLL power supply. Must supply 1.8 V.
> 
> My understanding is that this last supply is really needed for the XUSB
> pad controller to bring up the PLL. In fact, I've just moved the same
> supply to the XUSB pad controller from the XUSB controller for all of
> the supported boards because having this in the XUSB controller would
> fail under some circumstances.
> 
> > +
> > +- phys: Must contain an entry for each entry in phy-names.
> > +  See ../phy/phy-bindings.txt for details.
> > +- extcon-usb: Must contains an extcon-usb entry which detects
> 
> In the example below, this is simply "extcon".
> 
> > +  USB VBUS pin. See ../extcon/extcon-usb-gpio.txt for details.
> > +
> > +Optional properties:
> > +--------------------
> > +- phy-names: Should include an entry for each PHY used by the controller.
> > +  Names must be "usb2", and "usb3" if support SuperSpeed device mode.
> > +  - "usb3" phy, SuperSpeed (SSTX+/SSTX-/SSRX+/SSRX-) data lines
> > +  - "usb2" phy, USB 2.0 (D+/D-) data lines
> 
> Why are these optional? phys is required and references phy-names
> explicitly, so I think that effectively makes these phy-names required
> as well.
> 
> > +
> > +Example:
> > +--------
> > +	pmc: pmc@7000e400 {
> > +		compatible = "nvidia,tegra210-pmc";
> > +		reg = <0x0 0x7000e400 0x0 0x400>;
> > +		clocks = <&tegra_car TEGRA210_CLK_PCLK>, <&clk32k_in>;
> > +		clock-names = "pclk", "clk32k_in";
> > +
> > +		powergates {
> > +			pd_xusbss: xusba {
> > +				clocks = <&tegra_car TEGRA210_CLK_XUSB_SS>;
> > +				resets = <&tegra_car TEGRA210_CLK_XUSB_SS>;
> > +				#power-domain-cells = <0>;
> > +			};
> > +
> > +			pd_xusbdev: xusbb {
> > +				clocks = <&tegra_car TEGRA210_CLK_XUSB_DEV>;
> > +				resets = <&tegra_car 95>;
> > +				#power-domain-cells = <0>;
> > +			};
> > +		};
> > +	};
> > +
> > +	xudc@700d0000 {
> > +		compatible = "nvidia,tegra210-xudc";
> > +		reg = <0x0 0x700d0000 0x0 0x8000>,
> > +			<0x0 0x700d8000 0x0 0x1000>,
> > +			<0x0 0x700d9000 0x0 0x1000>;
> > +
> > +		interrupts = <0 44 0x4>;
> 
> This should use symbolic names defined in the following includes:
> 
> 	dt-bindings/interrupt-controller/irq.h
> 	dt-bindings/interrupt-controller/arm-gic.h
> 
> Thierry
> 
> > +
> > +		clocks = <&tegra_car TEGRA210_CLK_XUSB_DEV>,
> > +			<&tegra_car TEGRA210_CLK_XUSB_SS>,
> > +			<&tegra_car TEGRA210_CLK_XUSB_SSP_SRC>,
> > +			<&tegra_car TEGRA210_CLK_XUSB_HS_SRC>,
> > +			<&tegra_car TEGRA210_CLK_XUSB_FS_SRC>;
> > +		clock-names = "xusb_device", "xusb_ss", "xusb_ss_src",
> > +			      "xusb_hs_src", "xusb_fs_src";
> > +
> > +		power-domains = <&pd_xusbdev>, <&pd_xusbss>;
> > +		power-domain-names = "xusb_device", "xusb_ss";
> > +
> > +		nvidia,xusb-padctl = <&padctl>;
> > +
> > +		phys = <&{/padctl@7009f000/pads/usb2/lanes/usb2-0}>;
> > +		phy-names = "usb2;
> > +
> > +		avddio-usb-supply = <&vdd_pex_1v05>;
> > +		hvdd-usb-supply = <&vdd_3v3_sys>;
> > +		avdd-pll-utmip-supply = <&vdd_1v8>;
> > +
> > +		extcon = <&extcon_usb>;
> > +	};
> > +
> > +	extcon_usb: extcon_vbus {
> > +		compatible = "linux,extcon-usb-gpio";
> > +		vbus-gpio = <&gpio TEGRA_GPIO(Z, 0) GPIO_ACTIVE_LOW>;
> > +	};
> > +
> > -- 
> > 2.7.4
> >