Re: [PATCH v6 1/8] usb: dwc3: Registering a role switch in the DRD code.

[Bryan O'Donoghue]

On 28/11/2019 05:09, John Stultz wrote:
> From: Yu Chen <chenyu56@xxxxxxxxxx>
>
> The Type-C drivers use USB role switch API to inform the
> system about the negotiated data role, so registering a role
> switch in the DRD code in order to support platforms with
> USB Type-C connectors.
>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> CC: ShuFan Lee <shufan_lee@xxxxxxxxxxx>
> Cc: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> Cc: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
> Cc: Yu Chen <chenyu56@xxxxxxxxxx>
> Cc: Felipe Balbi <balbi@xxxxxxxxxx>
> Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
> Cc: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> Cc: Jun Li <lijun.kernel@xxxxxxxxx>
> Cc: Valentin Schneider <valentin.schneider@xxxxxxx>
> Cc: Jack Pham <jackp@xxxxxxxxxxxxxx>
> Cc: linux-usb@xxxxxxxxxxxxxxx
> Cc: devicetree@xxxxxxxxxxxxxxx
> Suggested-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> Signed-off-by: Yu Chen <chenyu56@xxxxxxxxxx>
> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
> Change-Id: Ibd89b7eb3e59688895a2d317f3515e6d2705c6f3
> ---
> v2: Fix role_sw and role_switch_default_mode descriptions as
>      reported by kbuild test robot <lkp@xxxxxxxxx>
>
> v3: Split out the role-switch-default-host logic into its own
>      patch
>
> v5: Drop selecting CONFIG_USB_ROLE_SWITCH & ifdef dependent code
>
> v6: Fix build issue Reported-by: kbuild test robot <lkp@xxxxxxxxx>
> ---
>   drivers/usb/dwc3/core.h |  3 ++
>   drivers/usb/dwc3/drd.c  | 77 ++++++++++++++++++++++++++++++++++++++++-
>   2 files changed, 79 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> index 1c8b349379af..6f19e9891767 100644
> --- a/drivers/usb/dwc3/core.h
> +++ b/drivers/usb/dwc3/core.h
> @@ -25,6 +25,7 @@
>   #include <linux/usb/ch9.h>
>   #include <linux/usb/gadget.h>
>   #include <linux/usb/otg.h>
> +#include <linux/usb/role.h>
>   #include <linux/ulpi/interface.h>
>   
>   #include <linux/phy/phy.h>
> @@ -951,6 +952,7 @@ struct dwc3_scratchpad_array {
>    * @hsphy_mode: UTMI phy mode, one of following:
>    *		- USBPHY_INTERFACE_MODE_UTMI
>    *		- USBPHY_INTERFACE_MODE_UTMIW
> + * @role_sw: usb_role_switch handle
>    * @usb2_phy: pointer to USB2 PHY
>    * @usb3_phy: pointer to USB3 PHY
>    * @usb2_generic_phy: pointer to USB2 PHY
> @@ -1084,6 +1086,7 @@ struct dwc3 {
>   	struct extcon_dev	*edev;
>   	struct notifier_block	edev_nb;
>   	enum usb_phy_interface	hsphy_mode;
> +	struct usb_role_switch	*role_sw;
>   
>   	u32			fladj;
>   	u32			irq_gadget;
> diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
> index c946d64142ad..3b57d2ddda93 100644
> --- a/drivers/usb/dwc3/drd.c
> +++ b/drivers/usb/dwc3/drd.c
> @@ -476,6 +476,73 @@ static struct extcon_dev *dwc3_get_extcon(struct dwc3 *dwc)
>   	return edev;
>   }
>   
> +#ifdef CONFIG_USB_ROLE_SWITCH
> +#define ROLE_SWITCH 1
> +static int dwc3_usb_role_switch_set(struct device *dev, enum usb_role role)
> +{
> +	struct dwc3 *dwc = dev_get_drvdata(dev);
> +	u32 mode;
> +
> +	switch (role) {
> +	case USB_ROLE_HOST:
> +		mode = DWC3_GCTL_PRTCAP_HOST;
> +		break;
> +	case USB_ROLE_DEVICE:
> +		mode = DWC3_GCTL_PRTCAP_DEVICE;
> +		break;
> +	default:
> +		mode = DWC3_GCTL_PRTCAP_DEVICE;
> +		break;
> +	}
> +
> +	dwc3_set_mode(dwc, mode);
> +	return 0;
> +}
> +
> +static enum usb_role dwc3_usb_role_switch_get(struct device *dev)
> +{
> +	struct dwc3 *dwc = dev_get_drvdata(dev);
> +	unsigned long flags;
> +	enum usb_role role;
> +
> +	spin_lock_irqsave(&dwc->lock, flags);
> +	switch (dwc->current_dr_role) {
> +	case DWC3_GCTL_PRTCAP_HOST:
> +		role = USB_ROLE_HOST;
> +		break;
> +	case DWC3_GCTL_PRTCAP_DEVICE:
> +		role = USB_ROLE_DEVICE;
> +		break;
> +	case DWC3_GCTL_PRTCAP_OTG:
> +		role = dwc->current_otg_role;
> +		break;
> +	default:
> +		role = USB_ROLE_DEVICE;
> +		break;
> +	}
> +	spin_unlock_irqrestore(&dwc->lock, flags);
> +	return role;
> +}
> +
> +static int dwc3_setup_role_switch(struct dwc3 *dwc)
> +{
> +	struct usb_role_switch_desc dwc3_role_switch = {NULL};
> +
> +	dwc3_role_switch.fwnode = dev_fwnode(dwc->dev);
> +	dwc3_role_switch.set = dwc3_usb_role_switch_set;
> +	dwc3_role_switch.get = dwc3_usb_role_switch_get;
> +	dwc->role_sw = usb_role_switch_register(dwc->dev, &dwc3_role_switch);
> +	if (IS_ERR(dwc->role_sw))
> +		return PTR_ERR(dwc->role_sw);
> +
> +	dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
> +	return 0;
> +}
> +#else
> +#define ROLE_SWITCH 0
> +#define dwc3_setup_role_switch(x) 0
> +#endif
> +
>   int dwc3_drd_init(struct dwc3 *dwc)
>   {
>   	int ret, irq;
> @@ -484,7 +551,12 @@ int dwc3_drd_init(struct dwc3 *dwc)
>   	if (IS_ERR(dwc->edev))
>   		return PTR_ERR(dwc->edev);
>   
> -	if (dwc->edev) {
> +	if (ROLE_SWITCH &&
> +	    device_property_read_bool(dwc->dev, "usb-role-switch")) {
> +		ret = dwc3_setup_role_switch(dwc);
> +		if (ret < 0)
> +			return ret;
> +	} else if (dwc->edev) {
>   		dwc->edev_nb.notifier_call = dwc3_drd_notifier;
>   		ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
>   					       &dwc->edev_nb);
> @@ -531,6 +603,9 @@ void dwc3_drd_exit(struct dwc3 *dwc)
>   {
>   	unsigned long flags;
>   
> +	if (dwc->role_sw)
> +		usb_role_switch_unregister(dwc->role_sw);
> +
>   	if (dwc->edev)
>   		extcon_unregister_notifier(dwc->edev, EXTCON_USB_HOST,
>   					   &dwc->edev_nb);

This again I've used on the qcs404 and it works nicely.

Tested-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>