Hi Marek,
From: Marek Vasut marex@denx.de Sent: jeudi 15 octobre 2020 19:39
On 10/15/20 6:52 PM, Patrick DELAUNAY wrote:
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.
Patrick