Re: [PATCH v2] usb: common: usb-conn-gpio: Set last role to unknown before initial detection

From: Chunfeng Yun (云春峰)
Date: Thu May 25 2023 - 02:57:29 EST


On Wed, 2023-05-24 at 19:20 +0530, Prashanth K wrote:
> External email : Please do not click links or open attachments until
> you have verified the sender or the content.
>
>
> Currently if we bootup a device without cable connected, then
> usb-conn-gpio won't call set_role() since last_role is same as
> current role. This happens because during probe last_role gets
> initialized to zero.
>
> To avoid this, added a new constant in enum usb_role, last_role
> is set to USB_ROLE_UNKNOWN before performing initial detection.
>
> Fixes: 4602f3bff266 ("usb: common: add USB GPIO based connection
> detection driver")
> Signed-off-by: Prashanth K <quic_prashk@xxxxxxxxxxx>
> ---
> v2: Added USB_ROLE_UNKNWON to enum usb_role
>
> drivers/usb/common/usb-conn-gpio.c | 3 +++
> include/linux/usb/role.h | 1 +
> 2 files changed, 4 insertions(+)
>
> diff --git a/drivers/usb/common/usb-conn-gpio.c
> b/drivers/usb/common/usb-conn-gpio.c
> index e20874c..30bdb81 100644
> --- a/drivers/usb/common/usb-conn-gpio.c
> +++ b/drivers/usb/common/usb-conn-gpio.c
> @@ -257,6 +257,9 @@ static int usb_conn_probe(struct platform_device
> *pdev)
> platform_set_drvdata(pdev, info);
> device_set_wakeup_capable(&pdev->dev, true);
>
> + /* Set last role to unknown before performing the initial
> detection */
> + info->last_role = USB_ROLE_UNKNOWN;

Do you only use vbus-pin?

This driver assumes that the gadget driver's default role is none.


> +
> /* Perform initial detection */
> usb_conn_queue_dwork(info, 0);
>
> diff --git a/include/linux/usb/role.h b/include/linux/usb/role.h
> index b5deafd..221d462 100644
> --- a/include/linux/usb/role.h
> +++ b/include/linux/usb/role.h
> @@ -8,6 +8,7 @@
> struct usb_role_switch;
>
> enum usb_role {
> + USB_ROLE_UNKNOWN = -1,
> USB_ROLE_NONE,
> USB_ROLE_HOST,
> USB_ROLE_DEVICE,
> --
> 2.7.4
>