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

[Chunfeng Yun (云春峰)]

On Wed, 2023-05-24 at 19:20 +0530, Prashanth K wrote:
> External email : Please do not click links or open attachments until
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> 
> 
> 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
>