On Fri, Nov 6, 2020 at 5:07 AM Jun Li [off-list ref] wrote:

quoted

-----Original Message-----
From: Rob Herring <robh@kernel.org>
Sent: Friday, November 6, 2020 6:26 AM
To: Jun Li <redacted>
Cc: heikki.krogerus@linux.intel.com; rafael@kernel.org;
gregkh@linuxfoundation.org; andriy.shevchenko@linux.intel.com;
hdegoede@redhat.com; lee.jones@linaro.org;
mika.westerberg@linux.intel.com; dmitry.torokhov@gmail.com;
prabhakar.mahadev-lad.rj@bp.renesas.com;
laurent.pinchart+renesas@ideasonboard.com; linux-usb@vger.kernel.org;
devicetree@vger.kernel.org; dl-linux-imx [off-list ref]; Peter Chen
[off-list ref]
Subject: Re: [PATCH v5 1/4] dt-bindings: usb: add documentation for typec
switch simple driver

On Tue, Nov 03, 2020 at 07:40:07PM +0800, Li Jun wrote:

quoted

Some platforms need a simple driver to do some controls according to
typec orientation, this can be extended to be a generic driver with
compatible with "typec-orientation-switch".

Signed-off-by: Li Jun <redacted>
---
No changes for v5.

changes on v4:
- Use compatible instead of bool property for switch matching.
- Change switch GPIO to be switch simple.
- Change the active channel selection GPIO to be optional.

previous discussion:

https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fpatch

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work.ozlabs.org%2Fpatch%2F1054342%2F&data=04%7C01%7Cjun.li%40nxp.c

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om%7C78ca5205695149e2743208d881d9c753%7C686ea1d3bc2b4c6fa92cd99c5c3016

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35%7C0%7C0%7C637402119664101856%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLj

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AwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=

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8TY%2BPRIui6HhxhYE1%2BLmwWL38Vp7SY1Ceb5rGG%2B4DUo%3D&reserved=0

 .../bindings/usb/typec-switch-simple.yaml          | 69

++++++++++++++++++++++

quoted

 1 file changed, 69 insertions(+)

diff --git
a/Documentation/devicetree/bindings/usb/typec-switch-simple.yaml
b/Documentation/devicetree/bindings/usb/typec-switch-simple.yaml
new file mode 100644
index 0000000..244162d

--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/typec-switch-simple.yaml

@@ -0,0 +1,69 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) %YAML 1.2
+---
+$id:

+https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevi

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+cetree.org%2Fschemas%2Fusb%2Ftypec-switch-simple.yaml%23&data=04%

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+7C01%7Cjun.li%40nxp.com%7C78ca5205695149e2743208d881d9c753%7C686ea1d3

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+bc2b4c6fa92cd99c5c301635%7C0%7C0%7C637402119664111854%7CUnknown%7CTWF

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+pbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6

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+Mn0%3D%7C1000&sdata=HjWfKlDLyqb%2FKLlL6vdnyPe%2BnB8pSllhokIXQ%2Bw

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+yyw8%3D&reserved=0
+$schema:

+https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevi

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+cetree.org%2Fmeta-schemas%2Fcore.yaml%23&data=04%7C01%7Cjun.li%40

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+nxp.com%7C78ca5205695149e2743208d881d9c753%7C686ea1d3bc2b4c6fa92cd99c

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+5c301635%7C0%7C0%7C637402119664111854%7CUnknown%7CTWFpbGZsb3d8eyJWIjo

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+iMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&am

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+p;sdata=z0bO47QVl5gw0UE%2Bx3a5E27ALgz568zp%2Bf4suGlch%2Fo%3D&rese

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+rved=0
+
+title: Typec Orientation Switch Simple Solution Bindings
+
+maintainers:
+  - Li Jun [off-list ref]
+
+description: |-
+  USB SuperSpeed (SS) lanes routing to which side of typec connector
+is
+  decided by orientation, this maybe achieved by some simple control
+like
+  GPIO toggle.
+
+properties:
+  compatible:
+    const: typec-orientation-switch
+
+  switch-gpios:
+    description: |
+      gpio specifier to switch the super speed active channel,
+      GPIO_ACTIVE_HIGH: GPIO state high for cc1;
+      GPIO_ACTIVE_LOW:  GPIO state low for cc1.

What does active mean? There isn't really an active and inactive state, right?
It's more a mux selecting 0 or 1 input?

Yes, I will change the description:
gpio specifier to select the target channel of mux.

I wonder if the existing mux bindings should be used here.

quoted

I think you want flags 0 (aka GPIO_ACTIVE_HIGH) unless there's an inverter
in the middle.

This depends on the switch IC design and board design, leave 2 flags
(GPIO_ACTIVE_HIGH and GPIO_ACTIVE_LOW) can cover all possible cases.

NXP has 2 diff IC parts for this:
1. PTN36043(used on iMX8MQ)
Output selection control
When SEL=0, RX_AP_*/TX_AP_* are connected to RX_CON_2*/TX_CON_2*, and
RX_CON_1*/TX_CON_1* are connected to VDD thru low ohmic resistor.
When SEL=1, RX_AP_*/TX_AP_* are connected to RX_CON_1*/TX_CON_1*, and
RX_CON_2*/TX_CON_2* are connected to VDD thru low ohmic resistor.

Board design connects RX_CON_1*/TX_CON_1* to typec connector CC1,
so GPIO_ACTIVE_HIGH

2. CBTU02043(used on iMX8MP)
SEL        Function
--------------------------------------
Low        A to B ports and vice versa
High       A to C ports and vice versa

Board design connects B to typec connector CC1, so GPIO_ACTIVE_LOW

Therefore, we need 2 flags.

I'm not saying you don't. Just that the description is a bit odd.
Please expand the description for how one decides how to set the
flags.

quoted

quoted

+    maxItems: 1
+
+  port:
+    type: object
+    additionalProperties: false
+    description: -|
+      Connection to the remote endpoint using OF graph bindings that model

SS

quoted

+      data bus to typec connector.
+
+    properties:
+      endpoint:
+        type: object
+        additionalProperties: false
+
+        properties:
+          remote-endpoint: true
+
+        required:
+          - remote-endpoint
+
+    required:
+      - endpoint
+
+required:
+  - compatible
+  - port
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    ptn36043 {
+        compatible = "typec-orientation-switch";
+        pinctrl-names = "default";
+        pinctrl-0 = <&pinctrl_ss_sel>;
+        switch-gpios = <&gpio3 15 GPIO_ACTIVE_HIGH>;
+
+        port {
+                usb3_data_ss: endpoint {
+                        remote-endpoint = <&typec_con_ss>;

The data goes from the connector to here and then where? You need a connection
to the USB host controller.

The orientation switch only need interact with type-c, no any interaction
with USB controller, do we still need a connection to it?

If you have 2 USB hosts and 2 connectors (and 2 muxes), how would you
describe which connector goes with which host?

Rob