Re: [PATCH v4 2/5] dt-bindings: Add a binding for Mediatek xHCI host controller

[chunfeng yun <chunfeng.yun-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>]

hi,

On Fri, 2015-07-31 at 14:45 +0100, Mark Rutland wrote:
> Hi,
> 
> Sorry for my late reply to a prior version of this series, but I still
> have concerns with some of the properties.
> 
> I'll repeat those below.
> 
> On Fri, Jul 31, 2015 at 02:03:53PM +0100, Chunfeng Yun wrote:
> > add a DT binding documentation of xHCI host controller for the
> > MT8173 SoC from Mediatek.
> > 
> > Signed-off-by: Chunfeng Yun <chunfeng.yun-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
> > ---
> >  .../devicetree/bindings/usb/mt8173-xhci.txt        | 51 ++++++++++++++++++++++
> >  1 file changed, 51 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/usb/mt8173-xhci.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/usb/mt8173-xhci.txt b/Documentation/devicetree/bindings/usb/mt8173-xhci.txt
> > new file mode 100644
> > index 0000000..364be5a
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/usb/mt8173-xhci.txt
> > @@ -0,0 +1,51 @@
> > +MT65XX xhci
> > +
> > +The device node for Mediatek SOC usb3.0 host controller
> > +
> > +Required properties:
> > + - compatible : Supports "mediatek,mt8173-xhci"
> 
> s/Supports/should contain/
> 
done
> > + - reg : Specifies physical base address and size of the registers,
> > +	the first one for MAC, the second for IPPC
> > + - interrupts : Interrupt mode, number and trigger mode
> 
> Just specify what this logically corresponds to; the format of the
> interrupts proeprty depends on the interrupt controller.
> 
done
> > + - power-domains : To enable usb's mtcmos
> 
> Please describe what this contains. I assume you exped a single power
> domain to be described, covering the whole xHCI controller?
> 
> > + - vusb33-supply : Regulator of usb avdd3.3v
> > + - clocks : Must support all clocks that xhci needs
> 
> - clocks: a list of phandle + clock-specifier pairs, one for each entry
>   in clock-names.
> 
> > + - clock-names : Should be "sys_mac" for sys and mac clocks, and
> > +	"wakeup_deb_p0", "wakeup_deb_p1" for wakeup debounce control
> > +	clocks
> 
> This would be better as a list, e.g.
> 
> - clock-names: should contain:
>   * "sys_mac" <description here if necessary>
>   * "wakeup_deb_p0" <description here if necessary>
>   * "wakeup_deb_p1" <description here if necessary>
> 
done
> Is sys_mac a single clock input line? Or is it jsut the case that a
> single line feeds two inputs currently? if the latter they should be
> separate entries.
> 
It is a single clock for usb MAC, already rename it

> > + - phys : List of PHY specifiers (used by generic PHY framework).
> 
> The bracketed part should go. The bidnigns should know nothing of Linux
> internals.
> 
remove it
> > + - phy-names : Must be "usb-phy0", "usb-phy1",.., "usb-phyN", based on
> > +	the number of PHYs as specified in @phys property.
> 
> This is useless.
> 
> You either don't need names, and can acquire the phys by index, or you
> need names which correspond to those on the data sheet for the xHCI
> controller.
> 
Ok, re-write the phy driver, and here also make use of the new format.

> > + - mediatek,usb-wakeup : To access usb wakeup control register
> 
> Please describe what this points to (I guess it's a syscon)/
> 
> > + - mediatek,wakeup-src : 1: Ip sleep wakeup mode; 2: line state wakeup
> > +	mode; others means don't enable wakeup source of usb
> 
> This sounds like a runtime decision.
> 
No, the driver do not know whether to enable wakeup function or not and
also don't know enable which one, except tell it. 
And it will set different registers of @mediatek,usb-wakeup to enable
the selected wakeup mode when system enter suspend.

> _why_ do you think this needs to be in the DT?
> 
> > + - mediatek,u2port-num : The number should not greater than the number
> > +	of phys
> 
> This is useless. Either this is implied by the entries in the phys
> property, or it should be a runtime decision.
> 
Yes, it can be calculated from @phys, already remove it.

Thanks a lot for your suggestion
 
> Thanks,
> Mark.
> 
> > +
> > +Optional properties:
> > + - vbus-supply : Reference to the VBUS regulator;
> > +
> > +Example:
> > +usb: usb@11270000 {
> > +	compatible = "mediatek,mt8173-xhci";
> > +	reg = <0 0x11270000 0 0x4000>,
> > +	      <0 0x11280000 0 0x0800>;
> > +	interrupts = <GIC_SPI 115 IRQ_TYPE_LEVEL_LOW>;
> > +	power-domains = <&scpsys MT8173_POWER_DOMAIN_USB>;
> > +	clocks = <&topckgen CLK_TOP_USB30_SEL>,
> > +		 <&pericfg CLK_PERI_USB0>,
> > +		 <&pericfg CLK_PERI_USB1>;
> > +	clock-names = "sys_mac",
> > +		      "wakeup_deb_p0",
> > +		      "wakeup_deb_p1";
> > +	phys = <&u3phy 0>, <&u3phy 1>;
> > +	phy-names = "usb-phy0", "usb-phy1";
> > +	vusb33-supply = <&mt6397_vusb_reg>;
> > +	vbus-supply = <&usb_p1_vbus>;
> > +	usb3-lpm-capable;
> > +	mediatek,usb-wakeup = <&pericfg>;
> > +	mediatek,wakeup-src = <1>;
> > +	mediatek,u2port-num = <2>;
> > +	status = "okay";
> > +};
> > -- 
> > 1.8.1.1.dirty
> > 


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