On Fri, Jan 24, 2025 at 06:33:25PM +0100, Fabrice Gasnier wrote:
> In dwc2_hsotg_udc_start(), e.g. when binding composite driver, "of_node"
> is set to hsotg->dev->of_node.
>
> It causes errors when binding the gadget driver several times, on
> stm32mp157c-ev1 board. Below error is seen:
> "pin PA10 already requested by 49000000.usb-otg; cannot claim for gadget.0"
>
> The first time, no issue is seen as when registering the driver, of_node
> isn't NULL:
> -> gadget_dev_desc_UDC_store
> -> usb_gadget_register_driver_owner
> -> driver_register
> ...
> -> really_probe -> pinctrl_bind_pins (no effect)
>
> Then dwc2_hsotg_udc_start() sets of_node.
>
> The second time (stop the gadget, reconfigure it, then start it again),
> of_node has been set, so the probing code tries to acquire pins for the
> gadget. These pins are hold by the controller, hence the error.
>
> So clear gadget.dev.of_node in udc_stop() routine to avoid the issue.
>
> Fixes: 7d7b22928b90 ("usb: gadget: s3c-hsotg: Propagate devicetree to gadget drivers")
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx>
> ---
> Note: I'd have been tempted to remove of_node setting from udc_start:
> - hsotg->gadget.dev.of_node = hsotg->dev->of_node;
>
> I can't find the original code that parses the device node [1] from
> composite_bind() routine, originally part of the series that introduces
> this.
> I'm not sure if setting the gadget of_node is really useful, but I chose
> safe approach to simply clear it in udc_stop().
>
> [1] http://lore.kernel.org/lkml/1340720833-781-6-git-send-email-aletes.xgr@xxxxxxxxx/
> ---
> drivers/usb/dwc2/gadget.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
> index e7bf9cc635be..bd4c788f03bc 100644
> --- a/drivers/usb/dwc2/gadget.c
> +++ b/drivers/usb/dwc2/gadget.c
> @@ -4615,6 +4615,7 @@ static int dwc2_hsotg_udc_stop(struct usb_gadget *gadget)
> spin_lock_irqsave(&hsotg->lock, flags);
>
> hsotg->driver = NULL;
> + hsotg->gadget.dev.of_node = NULL;
> hsotg->gadget.speed = USB_SPEED_UNKNOWN;
> hsotg->enabled = 0;
>
> --
> 2.25.1
>
>
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