[PATCH] usb: dwc2: add "u-boot,force-vbus-detection" for stm32

[Patrick DELAUNAY]

Hi Marek,

On 12/9/20 5:22 PM, Patrick DELAUNAY wrote:
> -----Original Message-----
> From: Marek Vasut <marex at denx.de>
> Sent: mardi 20 octobre 2020 12:21
>
> On 10/16/20 6:32 PM, Patrick DELAUNAY wrote:
>> Hi Marek,
> Hi,
>
> [...]
>
>>>>> On 10/15/20 2:49 PM, Patrick Delaunay wrote:
>>>>>> On some board, the ID pin is not connected so the B session must
>>>>>> be overridden with "u-boot,force_b_session_valid" but the VBus
>>>>>> sensing must continue to be handle.
>>>>>>
>>>>>> To managed it, this patch adds a new DT field
>>>>>> "u-boot,force-vbus-detection" to use with "u-boot,force_b_session_valid"
>>>>> How is this solved in Linux ?
>>>> It is managed by Linux DWC2 driver: it is a real OTG driver, with
>>>> dual mode support and by usb framework
>>>>
>>>> Throught the properties
>>>> &usbotg_hs {
>>>> 	usb-role-switch;
>>>> };
>>>>
>>>> a glue treat the session and the sensing management see
>>>> linux/drivers/usb/dwc2/drd.c in linux-next
>>>>
>>>> PS: activate_stm_id_vb_detection is also used in driver = hsotg->params.
>>>>
>>>> As ID pin / vbus is completly managed by the USB TYPE driver C
>>>> (STUSB1600 for STMicroelectronics board) and DWC2 driver with dual
>>>> role stack (host/gadget).
>>>>
>>>> I don't found a better solution than device tree property for this
>>>> task in U-Boot as DWC2 driver don't support dual role and U-Boot
>>>> don't have
>>> framework for USB type C controller.
>>>>> btw can you do something about that huge change in indent ? Is it necessary ?
>>>> I move all this code under activate_stm_id_vb_detection (linked to
>>>> compatible "st,stm32mp1-hsotg") to avoid impact on other platform as
>>>> this "sensing" properties are only support for STM32MP15X (it is
>>>> linked to USB block detection integrated in SOC)
>>>>
>>>> And after I need to check the
>>>> 1/ The usb33d-supply is required of vbus or IDPIN sensing 2/ manage
>>>> Vbus sensing or override (according dt) 3/ manage IDPIN or override
>>>> (according dt)
>>>>
>>>> I add a new property to be backward compatible (even it the
>>>> combinaison is less clear) I protect regulator function call to
>>>> avoid compilation
>>> issue for other platform.
>>>> PS: after reading the refmanual, I also split VALOEN and VALOVAL bit
>>>> update
>>> as it is required.
>>>> So yes I think it is needed but I can split the patch to simplify the review.
>>> I presume you don't feel like implementing proper OTG support, right ?
>> Yes, I am afraid of this task.
> Can you take a look ?
>
> I will pick this patch into next for now.

I check this topic, I think I don't need to support OTG in dwc2

but I need to support USB port and connector as it is done in linux kernel.

and I think that I can propose a plan (6 month-1 year)

- Add a new u-class for USB connector based on 
linux/drivers/usb/typec/class.c

     => Allow to detect cable connection and USB mode (device / host)

- Add a new driver for USB type C connector (compatible "usb-c-connector")

- Migrate stusb1600 driver to use this new driver

- Update driver (dwc2 or usbphyc or directly in uclass ?) to use 
connector when present in device tree 
(devicetree/bindings/connector/usb-connector.yaml)

With these modifcations, I hope to have the same hooks than Linux.


And for future

- Add a USB typeC connector driver based on UCSI 
(linux/drivers/usb/typec/ucsi)

https://www.intel.com/content/dam/www/public/us/en/documents/technical-specifications/usb-type-c-ucsi-spec.pdf

- Adapt other driver to use USB connector..... (as DWC3 for example to 
manage dual role with type-c)

Patrick