[PATCH 6/7] usb: dwc3: Add support for a role-switch notifier

Bryan O'Donoghue
2020-03-11T19:15:03Z

Role-switching is a 1:1 mapping between a producer and a consumer. For DWC3
we have some vendor specific wrappers, notably the qcom wrapper that want
to toggle some PHY related bits on a USB role switch.

This patch adds a role-switch notifier to the dwc3 drd code. When the USB
role-switch set() routine runs, the notifier will fire passing the notified
mode to the consumer, thus allowing vendor specific fix-ups to toggle from
the role-switching events.

Cc: Andy Gross <agross@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Jack Pham <jackp@codeaurora.org>
Cc: linux-arm-msm@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Jack Pham <jackp@codeaurora.org>
Tested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
---
drivers/usb/dwc3/core.h | 19 +++++++++++++++++++
drivers/usb/dwc3/drd.c | 17 +++++++++++++++++
2 files changed, 36 insertions(+)

diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index a99e57636172..c2e85f587674 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -955,6 +955,7 @@ struct dwc3_scratchpad_array {
* - USBPHY_INTERFACE_MODE_UTMI
* - USBPHY_INTERFACE_MODE_UTMIW
* @role_sw: usb_role_switch handle
+ * @role_sw_nl: role switch notifier list
* @usb2_phy: pointer to USB2 PHY
* @usb3_phy: pointer to USB3 PHY
* @usb2_generic_phy: pointer to USB2 PHY
@@ -1089,6 +1090,7 @@ struct dwc3 {
struct notifier_block edev_nb;
enum usb_phy_interface hsphy_mode;
struct usb_role_switch *role_sw;
+ struct raw_notifier_head role_sw_nl;

u32 fladj;
u32 irq_gadget;
@@ -1499,4 +1501,21 @@ static inline void dwc3_ulpi_exit(struct dwc3 *dwc)
{ }
#endif

+#if IS_ENABLED(CONFIG_USB_ROLE_SWITCH)
+int dwc3_role_switch_notifier_register(struct dwc3 *dwc,
+ struct notifier_block *nb);
+int dwc3_role_switch_notifier_unregister(struct dwc3 *dwc,
+ struct notifier_block *nb);
+#else
+static inline int
+dwc3_role_switch_notifier_register(struct dwc3 *dwc,
+ struct notifier_block *nb)
+{ return 0; }
+
+static inline int
+dwc3_role_switch_notifier_unregister(struct dwc3 *dwc,
+ struct notifier_block *nb)
+{ return 0; }
+#endif
+
#endif /* __DRIVERS_USB_DWC3_CORE_H */
diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
index 2705871ec95e..789e93dd93b4 100644
--- a/drivers/usb/dwc3/drd.c
+++ b/drivers/usb/dwc3/drd.c
@@ -497,6 +497,8 @@ static int dwc3_usb_role_switch_set(struct usb_role_switch *sw, enum usb_role ro
}

dwc3_set_mode(dwc, mode);
+ raw_notifier_call_chain(&dwc->role_sw_nl, mode, NULL);
+
return 0;
}

@@ -560,6 +562,18 @@ static int dwc3_register_gpio_usb_connector(struct dwc3 *dwc)
return ret;
}

+int dwc3_role_switch_notifier_register(struct dwc3 *dwc,
+ struct notifier_block *nb)
+{
+ return raw_notifier_chain_register(&dwc->role_sw_nl, nb);
+}
+
+int dwc3_role_switch_notifier_unregister(struct dwc3 *dwc,
+ struct notifier_block *nb)
+{
+ return raw_notifier_chain_unregister(&dwc->role_sw_nl, nb);
+}
+
#else
#define ROLE_SWITCH 0
#define dwc3_setup_role_switch(x) 0
@@ -582,6 +596,9 @@ int dwc3_drd_init(struct dwc3 *dwc)
ret = dwc3_register_gpio_usb_connector(dwc);
if (ret < 0)
return ret;
+
+ RAW_INIT_NOTIFIER_HEAD(&dwc->role_sw_nl);
+
} else if (dwc->edev) {
dwc->edev_nb.notifier_call = dwc3_drd_notifier;
ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
--
2.25.1