diff mbox series

[v3,1/3] dt-bindings: usb: dwc3: Add support for multiport related properties

Message ID 1654709787-23686-2-git-send-email-quic_harshq@quicinc.com
State New
Headers show
Series Add support for multiport controller | expand

Commit Message

Harsh Agarwal June 8, 2022, 5:36 p.m. UTC
Added support for multiport, mport, num_usb2_phy and num_usb3_phy
properties. These properties are used to support devices having
a multiport controller.

Signed-off-by: Harsh Agarwal <quic_harshq@quicinc.com>
---
 .../devicetree/bindings/usb/snps,dwc3.yaml         | 53 ++++++++++++++++++++++
 1 file changed, 53 insertions(+)

Comments

Rob Herring (Arm) June 8, 2022, 9:48 p.m. UTC | #1
On Wed, 08 Jun 2022 23:06:25 +0530, Harsh Agarwal wrote:
> Added support for multiport, mport, num_usb2_phy and num_usb3_phy
> properties. These properties are used to support devices having
> a multiport controller.
> 
> Signed-off-by: Harsh Agarwal <quic_harshq@quicinc.com>
> ---
>  .../devicetree/bindings/usb/snps,dwc3.yaml         | 53 ++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:
./Documentation/devicetree/bindings/usb/snps,dwc3.yaml:367:9: [warning] wrong indentation: expected 10 but found 8 (indentation)
./Documentation/devicetree/bindings/usb/snps,dwc3.yaml:369:9: [warning] wrong indentation: expected 10 but found 8 (indentation)

dtschema/dtc warnings/errors:

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/patch/

This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit.
Rob Herring (Arm) June 9, 2022, 3:38 p.m. UTC | #2
On Wed, Jun 08, 2022 at 11:06:25PM +0530, Harsh Agarwal wrote:
> Added support for multiport, mport, num_usb2_phy and num_usb3_phy
> properties. These properties are used to support devices having
> a multiport controller.
> 
> Signed-off-by: Harsh Agarwal <quic_harshq@quicinc.com>
> ---
>  .../devicetree/bindings/usb/snps,dwc3.yaml         | 53 ++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> index d41265b..9332fa2 100644
> --- a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> +++ b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> @@ -343,6 +343,32 @@ properties:
>        This port is used with the 'usb-role-switch' property  to connect the
>        dwc3 to type C connector.
>  
> +  multiport:

Again, I don't think this is going to play well if you need to describe 
USB devices in your DT. For example, a USB hub with additional DT 
properties.

> +    description:
> +      If a single USB controller supports multiple ports, then it's referred to as
> +      a multiport controller. Each port of the multiport controller can support
> +      either High Speed or Super Speed or both and have their own PHY phandles. Each
> +      port is represented by "mport" node and all the "mport" nodes are grouped
> +      together inside the "multiport" node where individual "mport" node defines the
> +      PHYs supported by that port.
> +
> +  num_usb2_phy:
> +    description: Total number of HS-PHYs defined by the multiport controller.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +
> +  num_usb3_phy:
> +    description: Total number of SS-PHYs defined by the multiport controller.
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +
> +  mport:
> +    description: Each mport node represents one port of the multiport controller.
> +    oneOf:
> +      - required:
> +        - usb-phy

This is deprecated. Why are you adding it?

> +      - required:
> +        - phys
> +        - phy-names

Other multi port USB hosts just have a list of phys. Why can't you just 
use phy-names to identify each phy:

phy-names = "port0-hs", "port0-ss", "port1-hs", "port1-ss", "port2-hs", 
  "port3-hs";

Rob
Harsh Agarwal June 10, 2022, 11:55 a.m. UTC | #3
On 6/9/2022 9:08 PM, Rob Herring wrote:
> On Wed, Jun 08, 2022 at 11:06:25PM +0530, Harsh Agarwal wrote:
>> Added support for multiport, mport, num_usb2_phy and num_usb3_phy
>> properties. These properties are used to support devices having
>> a multiport controller.
>>
>> Signed-off-by: Harsh Agarwal <quic_harshq@quicinc.com>
>> ---
>>   .../devicetree/bindings/usb/snps,dwc3.yaml         | 53 ++++++++++++++++++++++
>>   1 file changed, 53 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
>> index d41265b..9332fa2 100644
>> --- a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
>> +++ b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
>> @@ -343,6 +343,32 @@ properties:
>>         This port is used with the 'usb-role-switch' property  to connect the
>>         dwc3 to type C connector.
>>   
>> +  multiport:
> Again, I don't think this is going to play well if you need to describe
> USB devices in your DT. For example, a USB hub with additional DT
> properties.
Thanks for the review Rob.
Can you please explain why would one want to describe a USB hub in 
device tree ?
IF USB hub is attached to a root port , it would be enumerated by the 
SW. I am not clear how DT is coming
into picture. Even if there was a scenario to add DT properties for a 
hub, then this multiport node would be like a nop
as it just helps us to get the PHY phandles in a proper way.
Do you feel we still might have a problem with multiport node ?
>> +    description:
>> +      If a single USB controller supports multiple ports, then it's referred to as
>> +      a multiport controller. Each port of the multiport controller can support
>> +      either High Speed or Super Speed or both and have their own PHY phandles. Each
>> +      port is represented by "mport" node and all the "mport" nodes are grouped
>> +      together inside the "multiport" node where individual "mport" node defines the
>> +      PHYs supported by that port.
>> +
>> +  num_usb2_phy:
>> +    description: Total number of HS-PHYs defined by the multiport controller.
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +
>> +  num_usb3_phy:
>> +    description: Total number of SS-PHYs defined by the multiport controller.
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +
>> +  mport:
>> +    description: Each mport node represents one port of the multiport controller.
>> +    oneOf:
>> +      - required:
>> +        - usb-phy
> This is deprecated. Why are you adding it?
Do you mean "usb-phy" is deprecated ?
Internally we use usb-phy with our downstream GLUE driver
>
>> +      - required:
>> +        - phys
>> +        - phy-names
> Other multi port USB hosts just have a list of phys. Why can't you just
> use phy-names to identify each phy:
>
> phy-names = "port0-hs", "port0-ss", "port1-hs", "port1-ss", "port2-hs",
>    "port3-hs";
With the above method we would have to do some kind of string parsing on 
the phy-names to get the HS and SS PHYs as we need to cater to different 
combinations of Ports ( some support HS+SS , other supports SS only).
So one challenge here is with the "usb-phy". There we directly define 
the phy phandles and that might/might-not have proper sub-strings. eg 
USB_QMP_PHY . So extracting PHYS could be tricky if the phy-handle does 
not have proper substring like "SS" "HS" etc.
We cannot break existing implementation and so we thought of going with 
the "multiport" node approach, listing below some flexibility :

1. Better representation of the PHYs and it's relation with a port.
2. Here for each port we pick the first PHY as HS and 2nd PHY as SS as 
we have been doing traditionally.
So for "usb-phy" we need not care how the PHY handles are named.

3. It's future proof incase we need to add additional properties 
specific to a port. We can just add those properties inside MP_1 or MP_2 
etc.
Though nothing like this has yet been implemented.

Also agree that there are multiple ways to approach this problem and 
that's why we had RFC tag earlier to get feedback on the same.
> Rob
Rob Herring (Arm) June 10, 2022, 5:22 p.m. UTC | #4
On Fri, Jun 10, 2022 at 05:25:25PM +0530, Harsh Agarwal wrote:
> 
> On 6/9/2022 9:08 PM, Rob Herring wrote:
> > On Wed, Jun 08, 2022 at 11:06:25PM +0530, Harsh Agarwal wrote:
> > > Added support for multiport, mport, num_usb2_phy and num_usb3_phy
> > > properties. These properties are used to support devices having
> > > a multiport controller.
> > > 
> > > Signed-off-by: Harsh Agarwal <quic_harshq@quicinc.com>
> > > ---
> > >   .../devicetree/bindings/usb/snps,dwc3.yaml         | 53 ++++++++++++++++++++++
> > >   1 file changed, 53 insertions(+)
> > > 
> > > diff --git a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> > > index d41265b..9332fa2 100644
> > > --- a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> > > +++ b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> > > @@ -343,6 +343,32 @@ properties:
> > >         This port is used with the 'usb-role-switch' property  to connect the
> > >         dwc3 to type C connector.
> > > +  multiport:
> > Again, I don't think this is going to play well if you need to describe
> > USB devices in your DT. For example, a USB hub with additional DT
> > properties.
> Thanks for the review Rob.
> Can you please explain why would one want to describe a USB hub in device
> tree ?

Because someone soldered a hub on the board and then connected extra 
things like resets, GPIOs, supplies which are all outside of standard 
USB. It's quite common...

There's some flavors of Beagle boards that have a USB ethernet on board. 
Guess what, they skipped out on a eeprom and so the device and a MAC 
address has to be described in DT (if you want a stable MAC addr).

> IF USB hub is attached to a root port , it would be enumerated by the SW. I
> am not clear how DT is coming
> into picture. Even if there was a scenario to add DT properties for a hub,
> then this multiport node would be like a nop
> as it just helps us to get the PHY phandles in a proper way.

It won't be enumerated by the SW if it has to be powered on first using 
non-standard resources.

> Do you feel we still might have a problem with multiport node ?

A board design could have a hub or device on any or all your ports.

> > > +    description:
> > > +      If a single USB controller supports multiple ports, then it's referred to as
> > > +      a multiport controller. Each port of the multiport controller can support
> > > +      either High Speed or Super Speed or both and have their own PHY phandles. Each
> > > +      port is represented by "mport" node and all the "mport" nodes are grouped
> > > +      together inside the "multiport" node where individual "mport" node defines the
> > > +      PHYs supported by that port.
> > > +
> > > +  num_usb2_phy:
> > > +    description: Total number of HS-PHYs defined by the multiport controller.
> > > +    $ref: /schemas/types.yaml#/definitions/uint32
> > > +
> > > +  num_usb3_phy:
> > > +    description: Total number of SS-PHYs defined by the multiport controller.
> > > +    $ref: /schemas/types.yaml#/definitions/uint32
> > > +
> > > +  mport:
> > > +    description: Each mport node represents one port of the multiport controller.
> > > +    oneOf:
> > > +      - required:
> > > +        - usb-phy
> > This is deprecated. Why are you adding it?
> Do you mean "usb-phy" is deprecated ?

It is replaced by 'phys'. Any new user should use 'phys'.

> Internally we use usb-phy with our downstream GLUE driver

Upstream does not care about that.

> > 
> > > +      - required:
> > > +        - phys
> > > +        - phy-names
> > Other multi port USB hosts just have a list of phys. Why can't you just
> > use phy-names to identify each phy:
> > 
> > phy-names = "port0-hs", "port0-ss", "port1-hs", "port1-ss", "port2-hs",
> >    "port3-hs";
> With the above method we would have to do some kind of string parsing on the
> phy-names to get the HS and SS PHYs as we need to cater to different
> combinations of Ports ( some support HS+SS , other supports SS only).

You are doing string parsing anyways to get the child nodes and 
properties.

> So one challenge here is with the "usb-phy". There we directly define the
> phy phandles and that might/might-not have proper sub-strings. eg
> USB_QMP_PHY . So extracting PHYS could be tricky if the phy-handle does not
> have proper substring like "SS" "HS" etc.

The schema can and should enforce that you have the proper strings.

> We cannot break existing implementation and so we thought of going with the
> "multiport" node approach, listing below some flexibility :

How would this break?

> 1. Better representation of the PHYs and it's relation with a port.
> 2. Here for each port we pick the first PHY as HS and 2nd PHY as SS as we
> have been doing traditionally.
> So for "usb-phy" we need not care how the PHY handles are named.
> 
> 3. It's future proof incase we need to add additional properties specific to
> a port. We can just add those properties inside MP_1 or MP_2 etc.
> Though nothing like this has yet been implemented.

Then you have to consider how the standard USB device binding fits into 
this, and it needs to work for anyone with multiple ports. The 
usb-hcd.yaml schema already defines that child nodes represent a USB 
device attached to a port on the host. 'reg' is the port number.

Rob
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
index d41265b..9332fa2 100644
--- a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
+++ b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
@@ -343,6 +343,32 @@  properties:
       This port is used with the 'usb-role-switch' property  to connect the
       dwc3 to type C connector.
 
+  multiport:
+    description:
+      If a single USB controller supports multiple ports, then it's referred to as
+      a multiport controller. Each port of the multiport controller can support
+      either High Speed or Super Speed or both and have their own PHY phandles. Each
+      port is represented by "mport" node and all the "mport" nodes are grouped
+      together inside the "multiport" node where individual "mport" node defines the
+      PHYs supported by that port.
+
+  num_usb2_phy:
+    description: Total number of HS-PHYs defined by the multiport controller.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  num_usb3_phy:
+    description: Total number of SS-PHYs defined by the multiport controller.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  mport:
+    description: Each mport node represents one port of the multiport controller.
+    oneOf:
+      - required:
+        - usb-phy
+      - required:
+        - phys
+        - phy-names
+
 unevaluatedProperties: false
 
 required:
@@ -371,4 +397,31 @@  examples:
       snps,dis_u2_susphy_quirk;
       snps,dis_enblslpm_quirk;
     };
+  - |
+    usb@4a000000 {
+      compatible = "snps,dwc3";
+      reg = <0x4a000000 0xcfff>;
+      interrupts = <0 92 4>;
+
+      multiport {
+
+        MP_1: mport1 {
+          usb-phy = <&usb2_phy0>, <&usb3_phy0>;
+          /* Can define Generic PHYs also */
+        };
+
+        MP_2: mport2 {
+          usb-phy = <&usb2_phy1>, <&usb3_phy1>;
+        };
+
+        MP_3: mport3 {
+          usb-phy = <&usb2_phy2>;
+        };
+
+        MP_4: mport4 {
+          usb-phy = <&usb2_phy3>;
+        };
+
+      };
+    };
 ...