On Sat 03 Jul 20:33 CDT 2021, Bryan O'Donoghue wrote:
> Add the ability to relay a role switch message from the core to the parent
> device of the controller.
>
> This is useful for the qcom-dwc3 wrapper which wants to receive role-switch
> notifications in order to waggle internal SoC UTMI signals.
>
> Having the core trigger the parent wrapper has the advantage of keeping the
> connector mechanism agnostic from dwc3 wrapper code and means that any
> other wrapper implementation on any other SoC or architecture need not
> write custom code to find various types of Type-C role switch mechanisms.
>
> Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
> ---
> drivers/usb/dwc3/core.h | 2 ++
> drivers/usb/dwc3/drd.c | 10 ++++++++++
> 2 files changed, 12 insertions(+)
>
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index dccdf13b5f9e..974104cc16f7 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -993,6 +993,7 @@ struct dwc3_scratchpad_array {
> * - USBPHY_INTERFACE_MODE_UTMI
> * - USBPHY_INTERFACE_MODE_UTMIW
> * @role_sw: usb_role_switch handle
> + * @role_sw_relay: usb_role_switch relay handle
> * @role_switch_default_mode: default operation mode of controller while
> * usb role is USB_ROLE_NONE.
> * @usb_psy: pointer to power supply interface.
> @@ -1136,6 +1137,7 @@ struct dwc3 {
> struct notifier_block edev_nb;
> enum usb_phy_interface hsphy_mode;
> struct usb_role_switch *role_sw;
> + struct usb_role_switch *role_sw_relay;
> enum usb_dr_mode role_switch_default_mode;
>
> struct power_supply *usb_psy;
> diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
> index 8fcbac10510c..74293861bd8f 100644
> --- a/drivers/usb/dwc3/drd.c
> +++ b/drivers/usb/dwc3/drd.c
> @@ -507,6 +507,9 @@ static int dwc3_usb_role_switch_set(struct usb_role_switch *sw,
> }
>
> dwc3_set_mode(dwc, mode);
> + if (dwc->role_sw_relay)
> + usb_role_switch_set_role(dwc->role_sw_relay, role);
> +
> return 0;
> }
>
> @@ -563,6 +566,10 @@ static int dwc3_setup_role_switch(struct dwc3 *dwc)
> if (IS_ERR(dwc->role_sw))
> return PTR_ERR(dwc->role_sw);
>
> + dwc->role_sw_relay = usb_role_switch_get(dwc->dev);
So you're going to rely on DT to create a role-switch link between the
dwc3 core driver and the qcom wrapper?
As I said the other day, this is just a hack to get around the fact that
of_platform_populate() may return before the dwc3 core has probed.
Another such case can be seen in [1], where Wesley is patching the DT
node in runtime in order to pass a boolean parameter between the two
driver parts.
If we fix that we don't need these kinds of workarounds.
[1] https://lore.kernel.org/linux-arm-msm/1625218655-14180-6-git-send-email-wcheng@xxxxxxxxxxxxxx/
Regards,
Bjorn
> + if (IS_ERR(dwc->role_sw_relay))
> + return PTR_ERR(dwc->role_sw_relay);
> +
> dwc3_set_mode(dwc, mode);
> return 0;
> }
> @@ -630,6 +637,9 @@ void dwc3_drd_exit(struct dwc3 *dwc)
> {
> unsigned long flags;
>
> + if (dwc->role_sw_relay)
> + usb_role_switch_put(dwc->role_sw_relay);
> +
> if (dwc->role_sw)
> usb_role_switch_unregister(dwc->role_sw);
>
> --
> 2.30.1
>
