Re: [PATCH v3 1/4] USB: Fix of_usb_get_dr_mode_by_phy with a shared phy block

[Bin Liu <b-liu-l0cyMroinI0@public.gmane.org>]

Hi,

On Thu, Jun 09, 2016 at 04:51:45PM +0200, Hans de Goede wrote:
> Hi,
> 
> On 09-06-16 16:30, Bin Liu wrote:
> >Hi,
> >
> >On Sun, Jun 05, 2016 at 04:59:33PM +0200, Hans de Goede wrote:
> >>Some SoCs have a single phy-hw-block with multiple phys, this is
> >>modelled by a single phy dts node, so we end up with multiple
> >>controller nodes with a phys property pointing to the phy-node
> >>of the otg-phy.
> >>
> >>Only one of these controllers typically is an otg controller, yet we
> >>were checking the first controller who uses a phy from the block and
> >>then end up looking for a dr_mode property in e.g. the ehci controller.
> >>
> >>This commit fixes this by adding an arg0 parameter to
> >>of_usb_get_dr_mode_by_phy and make of_usb_get_dr_mode_by_phy
> >>check that this matches the phandle args[0] value when looking for
> >>the otg controller.
> >>
> >>Signed-off-by: Hans de Goede <hdegoede-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> >>---
> >>Changes in v2:
> >>-Add a args0 parameter instead of looking for nodes with a dr_mode property
> >>Changes in v3:
> >>-No changes
> >>---
> >> drivers/usb/common/common.c  | 31 ++++++++++++++++++-------------
> >> drivers/usb/phy/phy-am335x.c |  2 +-
> >> include/linux/usb/of.h       |  4 ++--
> >> 3 files changed, 21 insertions(+), 16 deletions(-)
> >
> >This breaks am335x.
> >
> >[   17.433166] /ocp/usb@47400000/usb@47401000: could not get #phy-cells
> >for /ocp/usb@47400000/usb-phy@47401300
> >[   17.443627] /ocp/usb@47400000/usb@47401800: could not get #phy-cells
> >for /ocp/usb@47400000/usb-phy@47401b00
> >[   17.454005] am335x-phy-driver 47401300.usb-phy: dr_mode 0
> >[   17.460518] 47401300.usb-phy supply vcc not found, using dummy
> >regulator
> >[   17.469685] /ocp/usb@47400000/usb@47401000: could not get #phy-cells
> >for /ocp/usb@47400000/usb-phy@47401300
> >[   17.479998] /ocp/usb@47400000/usb@47401800: could not get #phy-cells
> >for /ocp/usb@47400000/usb-phy@47401b00
> >[   17.490342] am335x-phy-driver 47401b00.usb-phy: dr_mode 0
> 
> That is weird, quoting: drivers/phy/phy-core.c: _of_phy_get():
> 
>         ret = of_parse_phandle_with_args(np, "phys", "#phy-cells",
>                 index, &args);
>         if (ret)
>                 return ERR_PTR(-ENODEV);
> 
> So if #phy-cells is not defined, then the phy core should not
> be able to work with the dts files in question at all.

am335x phy does not use phy framework, so those phy core api is not
called.

> 
> All my patch does is make the way of_usb_get_dr_mode_by_phy parses
> phy-handles be identical to how phy-core.c does it.
> 
> I see that the usb0_phy node in arch/arm/boot/dts/am33xx.dtsi
> indeed lacks a "#phy-cells = <0>;" line.
> 
> Quoting: Documentation/devicetree/bindings/phy/phy-bindings.txt
> 
> PHY device node
> ===============
> 
> Required Properties:
> #phy-cells:     Number of cells in a PHY specifier;  The meaning of all those
>                 cells is defined by the binding for the phy node. The PHY
>                 provider can use the values in cells to find the appropriate
>                 PHY.
> 
> So not having #phy-cells defined for a phy-node clearly is a bug.

am335x phy does not follow the bindings in phy/, but usb/phy/.

> 
> A patch like the following should fix this:
> 
> diff --git a/arch/arm/boot/dts/am33xx.dtsi b/arch/arm/boot/dts/am33xx.dtsi
> index 52be48b..c4ff788d 100644
> --- a/arch/arm/boot/dts/am33xx.dtsi
> +++ b/arch/arm/boot/dts/am33xx.dtsi
> @@ -557,6 +557,7 @@
>  			};
> 
>  			usb0_phy: usb-phy@47401300 {
> +				#phy-cells = <0>;

This seems to be ok, but this patch would break the dt backward compatible.

>  				compatible = "ti,am335x-usb-phy";
>  				reg = <0x47401300 0x100>;
>  				reg-names = "phy";
> 
> Regards,
> 
> Hans

Regards,
-Bin.
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