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

[Hans de Goede]

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 at redhat.com>
>> ---
>> 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 at 47400000/usb at 47401000: could not get #phy-cells
> for /ocp/usb at 47400000/usb-phy at 47401300
> [   17.443627] /ocp/usb at 47400000/usb at 47401800: could not get #phy-cells
> for /ocp/usb at 47400000/usb-phy at 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 at 47400000/usb at 47401000: could not get #phy-cells
> for /ocp/usb at 47400000/usb-phy at 47401300
> [   17.479998] /ocp/usb at 47400000/usb at 47401800: could not get #phy-cells
> for /ocp/usb at 47400000/usb-phy at 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.

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.

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 at 47401300 {
+				#phy-cells = <0>;
  				compatible = "ti,am335x-usb-phy";
  				reg = <0x47401300 0x100>;
  				reg-names = "phy";

Regards,

Hans