Re: [PATCH v7] usb: common: usb-conn-gpio: Set last role to unknown before initial detection

Heikki Krogerus
2023-06-13T11:21:48Z

Hi,

On Wed, May 31, 2023 at 08:11:14PM +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.

So why can't you fix this by just always setting the role
unconditionally to USB_ROLE_NONE in your probe function before the
initial detection?

> While at it, also handle default case for the usb_role switch
> in cdns3, intel-xhci-usb-role-switch & musb/jz4740 to avoid
> build warnings.
>
> Fixes: 4602f3bff266 ("usb: common: add USB GPIO based connection detection driver")
> Signed-off-by: Prashanth K <quic_prashk@quicinc.com>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---
> v7: Added default case in musb/jz4740.c & intel-xhci-usb-role-switch.c to
> avoid build warnings.
> v6: Moved USB_ROLE_UNKNOWN towards the end of enum usb_role.
> 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 +++
> drivers/usb/musb/jz4740.c | 2 ++
> drivers/usb/roles/intel-xhci-usb-role-switch.c | 2 ++
> include/linux/usb/role.h | 1 +
> 5 files changed, 10 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;
> }
>
> 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;
> +
> /* Perform initial detection */
> usb_conn_queue_dwork(info, 0);
>
> diff --git a/drivers/usb/musb/jz4740.c b/drivers/usb/musb/jz4740.c
> index 5aabdd7..6d880c4 100644
> --- a/drivers/usb/musb/jz4740.c
> +++ b/drivers/usb/musb/jz4740.c
> @@ -95,6 +95,8 @@ static int jz4740_musb_role_switch_set(struct usb_role_switch *sw,
> case USB_ROLE_HOST:
> atomic_notifier_call_chain(&phy->notifier, USB_EVENT_ID, phy);
> break;
> + default:
> + break;
> }
>
> return 0;
> diff --git a/drivers/usb/roles/intel-xhci-usb-role-switch.c b/drivers/usb/roles/intel-xhci-usb-role-switch.c
> index 5c96e92..4d6a3dd 100644
> --- a/drivers/usb/roles/intel-xhci-usb-role-switch.c
> +++ b/drivers/usb/roles/intel-xhci-usb-role-switch.c
> @@ -97,6 +97,8 @@ static int intel_xhci_usb_set_role(struct usb_role_switch *sw,
> val |= SW_VBUS_VALID;
> drd_config = DRD_CONFIG_STATIC_DEVICE;
> break;
> + default:
> + break;
> }
> val |= SW_IDPIN_EN;
> if (data->enable_sw_switch) {
> diff --git a/include/linux/usb/role.h b/include/linux/usb/role.h
> index b5deafd..65e790a 100644
> --- a/include/linux/usb/role.h
> +++ b/include/linux/usb/role.h
> @@ -11,6 +11,7 @@ enum usb_role {
> USB_ROLE_NONE,
> USB_ROLE_HOST,
> USB_ROLE_DEVICE,
> + USB_ROLE_UNKNOWN,
> };
>
> typedef int (*usb_role_switch_set_t)(struct usb_role_switch *sw,
> --
> 2.7.4

--
heikki