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

Message ID 20200311191501.8165-7-bryan.odonoghue@linaro.org
State Superseded
Headers show
Series None | expand

Commit Message

Bryan O'Donoghue March 11, 2020, 7:15 p.m. UTC 
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(+)

Comments

Vincent Whitchurch July 23, 2020, 8:13 a.m. UTC | #1 
On Wed, Mar 11, 2020 at 07:15:00PM +0000, Bryan O'Donoghue wrote:
> 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;

>  }


dwc3_set_mode() is called from a bunch of other places too, is it
sufficient to call the notifier only from here?  Also, dwc3_set_mode()
performs the mode set asynchronously so the mode switch can race with
this notifier call, is that OK?

Mike Looijmans proposed the control of a vbus regulator from
__dwc3_set_mode(), and that would take care of both the points above.
Perhaps this notifier call can be moved to the same place or perhaps
Mike's patch could even work for you?  The only problem is that your
switching code in dwc3-qcom.c would have to be modelled as a reulator:

 https://lore.kernel.org/linux-usb/20200619142512.19824-1-mike.looijmans@topic.nl/
diff mbox series

Patch

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,