diff mbox series

[v2,1/2] dt-bindings: usb: Add documentation for AM62 USB Wrapper module

Message ID 20220324073425.18607-2-a-govindraju@ti.com
State New
Headers show
Series AM62: Add support for AM62 USB wrapper driver | expand

Commit Message

Aswath Govindraju March 24, 2022, 7:34 a.m. UTC 
Add bindings for the TI's AM62 wrapper module for the Synopsys USBSS-DRD
controller.

Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
---

Changes since v1:
- made correction in grammer of clocks property description
  and added maxItems in the interrupts property based on comments
  received from Roger
- corrected the title, fixed the description of
  ti,syscon-phy-pll-refclk, added pattern properties and child node
  in the example based on the comments from Krzysztof.

 .../devicetree/bindings/usb/ti,am62-usb.yaml  | 117 ++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/usb/ti,am62-usb.yaml

Comments

Krzysztof Kozlowski March 24, 2022, 11:07 a.m. UTC | #1 
On 24/03/2022 08:34, Aswath Govindraju wrote:
> Add bindings for the TI's AM62 wrapper module for the Synopsys USBSS-DRD
> controller.
> 
> Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
> ---
> 
> Changes since v1:
> - made correction in grammer of clocks property description
>   and added maxItems in the interrupts property based on comments
>   received from Roger
> - corrected the title, fixed the description of
>   ti,syscon-phy-pll-refclk, added pattern properties and child node
>   in the example based on the comments from Krzysztof.
> 
>  .../devicetree/bindings/usb/ti,am62-usb.yaml  | 117 ++++++++++++++++++
>  1 file changed, 117 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/usb/ti,am62-usb.yaml
> 
> diff --git a/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml b/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml
> new file mode 100644
> index 000000000000..452bfdc6fb09
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml
> @@ -0,0 +1,117 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/usb/ti,am62-usb.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: TI's AM62 wrapper module for the Synopsys USBSS-DRD controller
> +
> +maintainers:
> +  - Aswath Govindraju <a-govindraju@ti.com>
> +
> +properties:
> +  compatible:
> +    const: ti,am62-usb
> +
> +  reg:
> +    maxItems: 1
> +
> +  ranges: true
> +
> +  power-domains:
> +    description:
> +      PM domain provider node and an args specifier containing
> +      the USB ISO device id value. See,
> +      Documentation/devicetree/bindings/soc/ti/sci-pm-domain.yaml
> +    maxItems: 1
> +
> +  clocks:
> +    description: Clock phandle to usb2_refclk
> +    maxItems: 1
> +
> +  clock-names:
> +    items:
> +      - const: ref
> +
> +  id-gpio:
> +    description:
> +      GPIO to be used as ID pin
> +    maxItems: 1

I have doubts about this. If you USB controller handles the ID pin, then
probably this should be moved to usb-connector.yaml. I did not see
id-gpio in any other USB controller blocks.


Best regards,
Krzysztof
Krzysztof Kozlowski March 24, 2022, 11:53 a.m. UTC | #2 
On 24/03/2022 12:40, Aswath Govindraju wrote:
> Hi Krzysztof,
> 
> On 24/03/22 16:37, Krzysztof Kozlowski wrote:
>> On 24/03/2022 08:34, Aswath Govindraju wrote:
>>> Add bindings for the TI's AM62 wrapper module for the Synopsys USBSS-DRD
>>> controller.
>>>
>>> Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
>>> ---
>>>
>>> Changes since v1:
>>> - made correction in grammer of clocks property description
>>>   and added maxItems in the interrupts property based on comments
>>>   received from Roger
>>> - corrected the title, fixed the description of
>>>   ti,syscon-phy-pll-refclk, added pattern properties and child node
>>>   in the example based on the comments from Krzysztof.
>>>
>>>  .../devicetree/bindings/usb/ti,am62-usb.yaml  | 117 ++++++++++++++++++
>>>  1 file changed, 117 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/usb/ti,am62-usb.yaml
>>>
>>> diff --git a/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml b/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml
>>> new file mode 100644
>>> index 000000000000..452bfdc6fb09
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml
>>> @@ -0,0 +1,117 @@
>>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/usb/ti,am62-usb.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: TI's AM62 wrapper module for the Synopsys USBSS-DRD controller
>>> +
>>> +maintainers:
>>> +  - Aswath Govindraju <a-govindraju@ti.com>
>>> +
>>> +properties:
>>> +  compatible:
>>> +    const: ti,am62-usb
>>> +
>>> +  reg:
>>> +    maxItems: 1
>>> +
>>> +  ranges: true
>>> +
>>> +  power-domains:
>>> +    description:
>>> +      PM domain provider node and an args specifier containing
>>> +      the USB ISO device id value. See,
>>> +      Documentation/devicetree/bindings/soc/ti/sci-pm-domain.yaml
>>> +    maxItems: 1
>>> +
>>> +  clocks:
>>> +    description: Clock phandle to usb2_refclk
>>> +    maxItems: 1
>>> +
>>> +  clock-names:
>>> +    items:
>>> +      - const: ref
>>> +
>>> +  id-gpio:
>>> +    description:
>>> +      GPIO to be used as ID pin
>>> +    maxItems: 1
>>
>> I have doubts about this. If you USB controller handles the ID pin, then
>> probably this should be moved to usb-connector.yaml. I did not see
>> id-gpio in any other USB controller blocks.
>>
> 
> Yes, the USB wrapper handles the ID pin operation only. It also reads
> the status of VBUS by reading a register from its MMR and not using a
> gpio. After evaluating the role the based on the states if id pin and
> VBUS, this role is communicated to the dwc3 core driver using extcon.
> There is no way for the dwc3 driver to detect the role on its own.
> 
> 
> The usb-connector(drivers/usb/common/usb-conn-gpio.c) driver, seems to
> be implemented for driving the VBUS, based on ID and VBUS pin status.
> However, in case of the above implementation we need to communicate the
> detected role to the dwc3 core driver. Also, the wrapper does not
> control VBUS but it is the dwc3 core driver that drives the VBUS.
> Therefore, I think the usb-connector implementation cannot be used here.

I don't think about usb-conn-gpio.c but using the binding generic
binding for usb-X-connector and define a connector with ID.

Actually Rob could help here.

Rob,
Should the id-gpio be modeled as a property in this glue/wrapper driver
or rather as part of usb-connector child node?


Best regards,
Krzysztof
Aswath Govindraju April 1, 2022, 8:05 a.m. UTC | #3 
Hi Krzysztof, Rob,

On 01/04/22 13:19, Krzysztof Kozlowski wrote:
> On 01/04/2022 07:04, Aswath Govindraju wrote:
>> Hi Rob,
>>
>> On 01/04/22 05:50, Rob Herring wrote:
>>> On Thu, Mar 24, 2022 at 12:53:08PM +0100, Krzysztof Kozlowski wrote:
>>>> On 24/03/2022 12:40, Aswath Govindraju wrote:
>>>>> Hi Krzysztof,
>>>>>
>>>>> On 24/03/22 16:37, Krzysztof Kozlowski wrote:
>>>>>> On 24/03/2022 08:34, Aswath Govindraju wrote:
>>>>>>> Add bindings for the TI's AM62 wrapper module for the Synopsys USBSS-DRD
>>>>>>> controller.
>>>>>>>
>>>>>>> Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
>>>>>>> ---
>>>>>>>
>>>>>>> Changes since v1:
>>>>>>> - made correction in grammer of clocks property description
>>>>>>>   and added maxItems in the interrupts property based on comments
>>>>>>>   received from Roger
>>>>>>> - corrected the title, fixed the description of
>>>>>>>   ti,syscon-phy-pll-refclk, added pattern properties and child node
>>>>>>>   in the example based on the comments from Krzysztof.
>>>>>>>
>>>>>>>  .../devicetree/bindings/usb/ti,am62-usb.yaml  | 117 ++++++++++++++++++
>>>>>>>  1 file changed, 117 insertions(+)
>>>>>>>  create mode 100644 Documentation/devicetree/bindings/usb/ti,am62-usb.yaml
>>>>>>>
>>>>>>> diff --git a/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml b/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml
>>>>>>> new file mode 100644
>>>>>>> index 000000000000..452bfdc6fb09
>>>>>>> --- /dev/null
>>>>>>> +++ b/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml
>>>>>>> @@ -0,0 +1,117 @@
>>>>>>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>>>>>>> +%YAML 1.2
>>>>>>> +---
>>>>>>> +$id: http://devicetree.org/schemas/usb/ti,am62-usb.yaml#
>>>>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>>>>> +
>>>>>>> +title: TI's AM62 wrapper module for the Synopsys USBSS-DRD controller
>>>>>>> +
>>>>>>> +maintainers:
>>>>>>> +  - Aswath Govindraju <a-govindraju@ti.com>
>>>>>>> +
>>>>>>> +properties:
>>>>>>> +  compatible:
>>>>>>> +    const: ti,am62-usb
>>>>>>> +
>>>>>>> +  reg:
>>>>>>> +    maxItems: 1
>>>>>>> +
>>>>>>> +  ranges: true
>>>>>>> +
>>>>>>> +  power-domains:
>>>>>>> +    description:
>>>>>>> +      PM domain provider node and an args specifier containing
>>>>>>> +      the USB ISO device id value. See,
>>>>>>> +      Documentation/devicetree/bindings/soc/ti/sci-pm-domain.yaml
>>>>>>> +    maxItems: 1
>>>>>>> +
>>>>>>> +  clocks:
>>>>>>> +    description: Clock phandle to usb2_refclk
>>>>>>> +    maxItems: 1
>>>>>>> +
>>>>>>> +  clock-names:
>>>>>>> +    items:
>>>>>>> +      - const: ref
>>>>>>> +
>>>>>>> +  id-gpio:
>>>>>>> +    description:
>>>>>>> +      GPIO to be used as ID pin
>>>>>>> +    maxItems: 1
>>>>>>
>>>>>> I have doubts about this. If you USB controller handles the ID pin, then
>>>>>> probably this should be moved to usb-connector.yaml. I did not see
>>>>>> id-gpio in any other USB controller blocks.
>>>>>>
>>>>>
>>>>> Yes, the USB wrapper handles the ID pin operation only. It also reads
>>>>> the status of VBUS by reading a register from its MMR and not using a
>>>>> gpio. After evaluating the role the based on the states if id pin and
>>>>> VBUS, this role is communicated to the dwc3 core driver using extcon.
>>>>> There is no way for the dwc3 driver to detect the role on its own.
>>>>>
>>>>>
>>>>> The usb-connector(drivers/usb/common/usb-conn-gpio.c) driver, seems to
>>>>> be implemented for driving the VBUS, based on ID and VBUS pin status.
>>>>> However, in case of the above implementation we need to communicate the
>>>>> detected role to the dwc3 core driver. Also, the wrapper does not
>>>>> control VBUS but it is the dwc3 core driver that drives the VBUS.
>>>>> Therefore, I think the usb-connector implementation cannot be used here.
>>>>
>>>> I don't think about usb-conn-gpio.c but using the binding generic
>>>> binding for usb-X-connector and define a connector with ID.
>>>>
>>>> Actually Rob could help here.
>>>>
>>>> Rob,
>>>> Should the id-gpio be modeled as a property in this glue/wrapper driver
>>>> or rather as part of usb-connector child node?
>>>
>>> That's a simple question. Where does the ID GPIO signal go to? The 
>>> connector, so it goes in the connector node.
>>>
>>
>> Thank you for the clarification. Here ID-gpio is directly read by the
>> wrapper and hence, I have modeled it as a property in the wrapper dt
>> node. May I know if this wrong and should the modelling be looked at
>> differently?
> 
> What do you mean here by "read"? If you refer to the driver reading the
> pin value, it is less related to the hardware, right?
> 
> 

Thank you for clarification. Now I understood, I was looking at it in
the wrong way and when looking at in in terms hardware I understood the
mistake that I have been doing. So, the id-gpio is actually not an
inherent part of the wrapper but rather something that it gets from the
connector. So, there needs to be different node describing this.

Thanks,
Aswath

> Best regards,
> Krzysztof
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml b/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml
new file mode 100644
index 000000000000..452bfdc6fb09
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/ti,am62-usb.yaml
@@ -0,0 +1,117 @@ 
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/usb/ti,am62-usb.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: TI's AM62 wrapper module for the Synopsys USBSS-DRD controller
+
+maintainers:
+  - Aswath Govindraju <a-govindraju@ti.com>
+
+properties:
+  compatible:
+    const: ti,am62-usb
+
+  reg:
+    maxItems: 1
+
+  ranges: true
+
+  power-domains:
+    description:
+      PM domain provider node and an args specifier containing
+      the USB ISO device id value. See,
+      Documentation/devicetree/bindings/soc/ti/sci-pm-domain.yaml
+    maxItems: 1
+
+  clocks:
+    description: Clock phandle to usb2_refclk
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: ref
+
+  id-gpio:
+    description:
+      GPIO to be used as ID pin
+    maxItems: 1
+
+  interrupts:
+    description:
+      interrupt line to be used for detecting changes in VBUS
+    maxItems: 1
+
+  ti,vbus-divider:
+    description:
+      Should be present if USB VBUS line is connected to the
+      VBUS pin of the SoC via a 1/3 voltage divider.
+    type: boolean
+
+  ti,syscon-phy-pll-refclk:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    items:
+      - items:
+          - description: Phandle to the SYSCON entry
+          - description: USB phy control register offset within SYSCON
+    description:
+      Specifier for conveying frequency of ref clock input, for the
+      operation of USB2PHY.
+
+  '#address-cells':
+    const: 2
+
+  '#size-cells':
+    const: 2
+
+patternProperties:
+  "^usb@[0-9a-f]+$":
+    $ref: snps,dwc3.yaml#
+    description: Required child node
+
+required:
+  - compatible
+  - reg
+  - power-domains
+  - clocks
+  - clock-names
+  - interrupts
+  - ti,syscon-phy-pll-refclk
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/soc/ti,sci_pm_domain.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/gpio/gpio.h>
+
+    bus {
+      #address-cells = <2>;
+      #size-cells = <2>;
+
+      usbss1: usb@f910000 {
+        compatible = "ti,am62-usb";
+        reg = <0x00 0x0f910000 0x00 0x800>;
+        interrupts = <GIC_SPI 234 IRQ_TYPE_LEVEL_HIGH>; /* MISC IRQ */
+        clocks = <&k3_clks 162 3>;
+        clock-names = "ref";
+        ti,syscon-phy-pll-refclk = <&wkup_conf 0x4018>;
+        power-domains = <&k3_pds 179 TI_SCI_PD_EXCLUSIVE>;
+        id-gpio = <&main_gpio1 51 GPIO_ACTIVE_LOW>;
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        usb@31100000 {
+          compatible = "snps,dwc3";
+          reg =<0x00 0x31100000 0x00 0x50000>;
+          interrupts = <GIC_SPI 226 IRQ_TYPE_LEVEL_HIGH>, /* irq.0 */
+                       <GIC_SPI 226 IRQ_TYPE_LEVEL_HIGH>; /* irq.0 */
+          interrupt-names = "host", "peripheral";
+          maximum-speed = "high-speed";
+          extcon = <&usbss1>;
+          dr_mode = "otg";
+        };
+      };
+    };