RE: [PATCH] usb: gadget: udc: renesas_usb3: add suspend event support

[Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>]

Hi Veeraiyan,

Thank you very much for the patch! I didn't realize that using USB_INT_1_B2_SPND
can resolve such a behavior. I'd like to apply this patch into upstream, but
I have some comments below.

> From: Veeraiyan Chidambaram, Sent: Wednesday, September 4, 2019 6:24 PM
> 
> In RCAR3 USB 3.0 Function, if host is detached an interrupt

I'd like to replace "RCAR3" with "R-Car Gen3".

> will be generated and Suspended state bit is set in interrupt status
> register. Interrupt handler will call driver->suspend(composite_suspend)
> if suspended state bit is set. composite_suspend will call
> ffs_func_suspend which will post FUNCTIONFS_SUSPEND and will be consumed
> by user space application via /dev/ep0.
> 
> To be able to detect the host detach, USB_INT_1_B2_SPND to cover the
> Suspended bit of the B2_SPND_OUT[9] from the USB Status Register
> (USB_STA) register and perform appropriate action in the
> usb3_irq_epc_int_1 function.
> 
> Without this commit, disconnection of the phone from R-Car-H3 ES2.0

s/R-Car-H3/R-Car H3/

> Salvator-X CN11 port is not recognized and reverse role switch does
> not happen. If phone is connected again it does not enumerate.
> 
> With this commit, disconnection will be recognized and reverse role
> switch will happen. If phone is connected again it will enumerate

IIUC, reverse role switch will happen by a user space application.
Is it correct?

> properly and will become visible in the output of 'lsusb'.
> 
> Signed-off-by: Veeraiyan Chidambaram <veeraiyan.chidambaram@in.bosch.com>
> ---
>  drivers/usb/gadget/udc/renesas_usb3.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c
> index eaa3339b30a2..4ec703e302f5 100644
> --- a/drivers/usb/gadget/udc/renesas_usb3.c
> +++ b/drivers/usb/gadget/udc/renesas_usb3.c
> @@ -767,6 +767,19 @@ static void usb3_irq_epc_int_1_resume(struct renesas_usb3 *usb3)
>  	usb3_transition_to_default_state(usb3, false);
>  }
> 
> +static void usb3_irq_epc_int_1_suspend(struct renesas_usb3 *usb3)
> +{
> +	usb3_disable_irq_1(usb3, USB_INT_1_B2_SPND);
> +
> +	if (usb3->driver &&
> +	    usb3->driver->suspend &&
> +	    usb3->gadget.speed != USB_SPEED_UNKNOWN &&
> +	    usb3->gadget.state != USB_STATE_NOTATTACHED) {
> +		usb3->driver->suspend(&usb3->gadget);
> +		usb_gadget_set_state(&usb3->gadget, USB_STATE_SUSPENDED);

I'd like to change the conditions like below if it still works on your environment.
This is because I'd like to set the gadget state if other gadget driver except f_fs
is used anyway. After that, a user also can recognize the state by using
/sys/devices/platform/soc/ee020000.usb/udc/ee020000.usb/state even if the use
doesn't use f_fs driver.

	if (usb3->gadget.speed != USB_SPEED_UNKNOWN &&
	    usb3->gadget.state != USB_STATE_NOTATTACHED) {
		if (usb3->driver && usb3->driver->suspend)
			usb3->driver->suspend(&usb3->gadget);
		usb_gadget_set_state(&usb3->gadget, USB_STATE_SUSPENDED);
	}

Best regards,
Yoshihiro Shimoda