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@xxxxxx> >>>>>>> --- >>>>>>> >>>>>>> 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@xxxxxx> >>>>>>> + >>>>>>> +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
