diff mbox series

[v5,6/9] dt/bindings: drm/bridge: it6505: Add mode-switch support

Message ID 20220622173605.1168416-7-pmalani@chromium.org
State New
Headers show
Series usb: typec: Introduce typec-switch binding | expand

Commit Message

Prashant Malani June 22, 2022, 5:34 p.m. UTC 
From: Pin-Yen Lin <treapking@chromium.org>

ITE IT6505 can be used in systems to switch USB Type-C DisplayPort
alternate mode lane traffic between 2 Type-C ports.

Update the binding to accommodate this usage by introducing a switch
property.

Signed-off-by: Pin-Yen Lin <treapking@chromium.org>
Signed-off-by: Prashant Malani <pmalani@chromium.org>
---

v5 is the first version for this patch.

 .../bindings/display/bridge/ite,it6505.yaml   | 97 ++++++++++++++++++-
 1 file changed, 96 insertions(+), 1 deletion(-)

Comments

Stephen Boyd June 23, 2022, 6:24 p.m. UTC | #1 
Quoting Prashant Malani (2022-06-22 10:34:35)
> From: Pin-Yen Lin <treapking@chromium.org>
>
> ITE IT6505 can be used in systems to switch USB Type-C DisplayPort
> alternate mode lane traffic between 2 Type-C ports.

How does it work? From what I can tell from the information I find when
googling this part[1] and looking at the existing binding doc is that
this device is a DPI to DP bridge, and it outputs DP (probably 4 lanes
of it?). Does the 2 type-c port design work by transmitting DP on two
lanes of DP for one type-c port and another two lanes of DP for the
other type-c port?

DP could be one lane, so if this device is able to output one lane on
any output differential pair then I suspect it could support 4 type-c
ports if the hardware engineer connected it that way. Can you confirm my
suspicion?

[1] https://www.ite.com.tw/en/product/view?mid=45
Prashant Malani June 23, 2022, 6:37 p.m. UTC | #2 
On Thu, Jun 23, 2022 at 11:24 AM Stephen Boyd <swboyd@chromium.org> wrote:
>
> Quoting Prashant Malani (2022-06-22 10:34:35)
> > From: Pin-Yen Lin <treapking@chromium.org>
> >
> > ITE IT6505 can be used in systems to switch USB Type-C DisplayPort
> > alternate mode lane traffic between 2 Type-C ports.
>
> How does it work? From what I can tell from the information I find when
> googling this part[1] and looking at the existing binding doc is that
> this device is a DPI to DP bridge, and it outputs DP (probably 4 lanes
> of it?). Does the 2 type-c port design work by transmitting DP on two
> lanes of DP for one type-c port and another two lanes of DP for the
> other type-c port?
>
> DP could be one lane, so if this device is able to output one lane on
> any output differential pair then I suspect it could support 4 type-c
> ports if the hardware engineer connected it that way. Can you confirm my
> suspicion?

I will let Pin-Yen comment re: this hardware, but 1-lane DP is not a
supported Type-C Pin assignment
(as per VESA DP Alternate Mode Spec version 2.0 [2]), so the H/W
configuration you are suggesting shouldn't be possible.

>
> [1] https://www.ite.com.tw/en/product/view?mid=45
Stephen Boyd June 23, 2022, 7:08 p.m. UTC | #3 
Quoting Prashant Malani (2022-06-23 11:37:08)
> On Thu, Jun 23, 2022 at 11:24 AM Stephen Boyd <swboyd@chromium.org> wrote:
> >
> > Quoting Prashant Malani (2022-06-22 10:34:35)
> > > From: Pin-Yen Lin <treapking@chromium.org>
> > >
> > > ITE IT6505 can be used in systems to switch USB Type-C DisplayPort
> > > alternate mode lane traffic between 2 Type-C ports.
> >
> > How does it work? From what I can tell from the information I find when
> > googling this part[1] and looking at the existing binding doc is that
> > this device is a DPI to DP bridge, and it outputs DP (probably 4 lanes
> > of it?). Does the 2 type-c port design work by transmitting DP on two
> > lanes of DP for one type-c port and another two lanes of DP for the
> > other type-c port?
> >
> > DP could be one lane, so if this device is able to output one lane on
> > any output differential pair then I suspect it could support 4 type-c
> > ports if the hardware engineer connected it that way. Can you confirm my
> > suspicion?
>
> I will let Pin-Yen comment re: this hardware, but 1-lane DP is not a
> supported Type-C Pin assignment
> (as per VESA DP Alternate Mode Spec version 2.0 [2]), so the H/W

Some missing link?

> configuration you are suggesting shouldn't be possible.
>

Alright, cool. But it is possible in the DP spec. So it seems like if
this is connected to 4 DP connectors it could be used to mux between DP
on 4 DP ports.
Prashant Malani June 23, 2022, 7:15 p.m. UTC | #4 
On Thu, Jun 23, 2022 at 12:08 PM Stephen Boyd <swboyd@chromium.org> wrote:
>
> Quoting Prashant Malani (2022-06-23 11:37:08)
> > On Thu, Jun 23, 2022 at 11:24 AM Stephen Boyd <swboyd@chromium.org> wrote:
> > >
> > > Quoting Prashant Malani (2022-06-22 10:34:35)
> > > > From: Pin-Yen Lin <treapking@chromium.org>
> > > >
> > > > ITE IT6505 can be used in systems to switch USB Type-C DisplayPort
> > > > alternate mode lane traffic between 2 Type-C ports.
> > >
> > > How does it work? From what I can tell from the information I find when
> > > googling this part[1] and looking at the existing binding doc is that
> > > this device is a DPI to DP bridge, and it outputs DP (probably 4 lanes
> > > of it?). Does the 2 type-c port design work by transmitting DP on two
> > > lanes of DP for one type-c port and another two lanes of DP for the
> > > other type-c port?
> > >
> > > DP could be one lane, so if this device is able to output one lane on
> > > any output differential pair then I suspect it could support 4 type-c
> > > ports if the hardware engineer connected it that way. Can you confirm my
> > > suspicion?
> >
> > I will let Pin-Yen comment re: this hardware, but 1-lane DP is not a
> > supported Type-C Pin assignment
> > (as per VESA DP Alternate Mode Spec version 2.0 [2]), so the H/W
>
> Some missing link?

My bad. I tried to find a publicly accessible link to the DP altmode
spec, but it
seems like one needs to be a VESA member to access it :/

>
> > configuration you are suggesting shouldn't be possible.
> >
>
> Alright, cool. But it is possible in the DP spec. So it seems like if
> this is connected to 4 DP connectors it could be used to mux between DP
> on 4 DP ports.

Ack. In that case, no "typec-switches" should be added to the DT.
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml b/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
index 833d11b2303a..86bb6dc5ae6f 100644
--- a/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
+++ b/Documentation/devicetree/bindings/display/bridge/ite,it6505.yaml
@@ -56,13 +56,46 @@  properties:
     $ref: /schemas/graph.yaml#/properties/port
     description: A port node pointing to DPI host port node
 
+  switches:
+    type: object
+    description: Set of switches controlling DisplayPort traffic on
+      outgoing RX/TX lanes to Type C ports.
+    additionalProperties: false
+
+    properties:
+      '#address-cells':
+        const: 1
+
+      '#size-cells':
+        const: 0
+
+    patternProperties:
+      '^switch@[01]$':
+        $ref: /schemas/usb/typec-switch.yaml#
+        unevaluatedProperties: false
+
+        properties:
+          reg:
+            maxItems: 1
+
+        required:
+          - reg
+
+    required:
+      - switch@0
+
 required:
   - compatible
   - ovdd-supply
   - pwr18-supply
   - interrupts
   - reset-gpios
-  - extcon
+
+oneOf:
+  - required:
+      - extcon
+  - required:
+      - switches
 
 additionalProperties: false
 
@@ -92,3 +125,65 @@  examples:
             };
         };
     };
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c3 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        it6505dptx: it6505dptx@5c {
+            compatible = "ite,it6505";
+            interrupts = <8 IRQ_TYPE_LEVEL_LOW 8 0>;
+            reg = <0x5c>;
+            pinctrl-names = "default";
+            pinctrl-0 = <&it6505_pins>;
+            ovdd-supply = <&mt6366_vsim2_reg>;
+            pwr18-supply = <&pp1800_dpbrdg_dx>;
+            reset-gpios = <&pio 177 0>;
+
+            port {
+                it6505_dp_in: endpoint {
+                    remote-endpoint = <&dpi_out>;
+                };
+            };
+
+            switches {
+                #address-cells = <1>;
+                #size-cells = <0>;
+                switch@0 {
+                    compatible = "typec-switch";
+                    reg = <0>;
+                    mode-switch;
+
+                    ports {
+                        #address-cells = <1>;
+                        #size-cells = <0>;
+                        port@0 {
+                            reg = <0>;
+                            ite_typec0: endpoint {
+                                remote-endpoint = <&typec_port0>;
+                            };
+                        };
+                    };
+                };
+
+                switch@1 {
+                    compatible = "typec-switch";
+                    reg = <1>;
+                    mode-switch;
+
+                    ports {
+                        #address-cells = <1>;
+                        #size-cells = <0>;
+                        port@0 {
+                            reg = <0>;
+                            ite_typec1: endpoint {
+                                remote-endpoint = <&typec_port1>;
+                            };
+                        };
+                    };
+                };
+            };
+        };
+    };