On Thu, May 25, 2023 at 02:23:45PM +0530, Prashanth K wrote:
> 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
> initialised 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.
>
> While at it, also handle default case for the usb_role switch
> in cdns3 to avoid build warnings.
>
> Fixes: 4602f3bff266 ("usb: common: add USB GPIO based connection detection driver")
> Signed-off-by: Prashanth K <quic_prashk@xxxxxxxxxxx>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
> ---
> v5: Update commit text to mention the changes made in cdns3 driver.
> v4: Added Reviewed-by tag.
> v3: Added a default case in drivers/usb/cdns3/core.c as pointed out by
> the test robot.
> v2: Added USB_ROLE_UNKNWON to enum usb_role.
>
> drivers/usb/cdns3/core.c | 2 ++
> drivers/usb/common/usb-conn-gpio.c | 3 +++
> include/linux/usb/role.h | 1 +
> 3 files changed, 6 insertions(+)
>
> diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
> index dbcdf3b..69d2921 100644
> --- a/drivers/usb/cdns3/core.c
> +++ b/drivers/usb/cdns3/core.c
> @@ -252,6 +252,8 @@ static enum usb_role cdns_hw_role_state_machine(struct cdns *cdns)
> if (!vbus)
> role = USB_ROLE_NONE;
> break;
> + default:
> + break;
No error if this happens?
> }
>
> dev_dbg(cdns->dev, "role %d -> %d\n", cdns->role, role);
> 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;
Shouldn't last_role have already been set to 0? If so, why not just
have this enum value be 0?
> +
> /* 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,
Why is this explicitly set to a value? What is magic about -1? Why not
0x42? Or something else? Or as I mention above, 0?
thanks,
greg k-h
