[PATCH v10 01/11] usb: typec: Add notifier functions

[Chaoyi Chen <kernel@airkyi.com>]

From: Chaoyi Chen <chaoyi.chen@rock-chips.com>

Some other part of kernel may want to know the event of typec bus.

This patch add common notifier function to notify these event.

Signed-off-by: Chaoyi Chen <chaoyi.chen@rock-chips.com>
---

Changes in v10:
- Notify TYPEC_ALTMODE_UNREGISTERED when altmode removed. 

Changes in v9:
- Remove redundant header files.

Changes in v8:
- Fix coding style.

 drivers/usb/typec/Makefile        |  2 +-
 drivers/usb/typec/bus.h           |  2 ++
 drivers/usb/typec/class.c         |  3 +++
 drivers/usb/typec/notify.c        | 23 +++++++++++++++++++++++
 include/linux/usb/typec_altmode.h |  9 +++++++++
 5 files changed, 38 insertions(+), 1 deletion(-)
 create mode 100644 drivers/usb/typec/notify.c

diff --git a/drivers/usb/typec/Makefile b/drivers/usb/typec/Makefile
index 7a368fea61bc..20d09c5314d7 100644
--- a/drivers/usb/typec/Makefile
+++ b/drivers/usb/typec/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_TYPEC)		+= typec.o
-typec-y				:= class.o mux.o bus.o pd.o retimer.o
+typec-y				:= class.o mux.o notify.o bus.o pd.o retimer.o
 typec-$(CONFIG_ACPI)		+= port-mapper.o
 obj-$(CONFIG_TYPEC)		+= altmodes/
 obj-$(CONFIG_TYPEC_TCPM)	+= tcpm/
diff --git a/drivers/usb/typec/bus.h b/drivers/usb/typec/bus.h
index 643b8c81786d..820b59b6d434 100644
--- a/drivers/usb/typec/bus.h
+++ b/drivers/usb/typec/bus.h
@@ -26,6 +26,8 @@ struct altmode {
 	struct altmode			*plug[2];
 };
 
+void typec_notify_event(unsigned long event, void *data);
+
 #define to_altmode(d) container_of(d, struct altmode, adev)
 
 extern const struct bus_type typec_bus;
diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 9b2647cb199b..1ccf5385d559 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -600,6 +600,8 @@ typec_register_altmode(struct device *parent,
 		return ERR_PTR(ret);
 	}
 
+	typec_notify_event(TYPEC_ALTMODE_REGISTERED, &alt->adev);
+
 	return &alt->adev;
 }
 
@@ -614,6 +616,7 @@ void typec_unregister_altmode(struct typec_altmode *adev)
 {
 	if (IS_ERR_OR_NULL(adev))
 		return;
+	typec_notify_event(TYPEC_ALTMODE_UNREGISTERED, adev);
 	typec_retimer_put(to_altmode(adev)->retimer);
 	typec_mux_put(to_altmode(adev)->mux);
 	device_unregister(&adev->dev);
diff --git a/drivers/usb/typec/notify.c b/drivers/usb/typec/notify.c
new file mode 100644
index 000000000000..9e50b54da359
--- /dev/null
+++ b/drivers/usb/typec/notify.c
@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/notifier.h>
+
+#include "bus.h"
+
+static BLOCKING_NOTIFIER_HEAD(typec_notifier_list);
+
+int typec_altmode_register_notify(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&typec_notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(typec_altmode_register_notify);
+
+int typec_altmode_unregister_notify(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&typec_notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(typec_altmode_unregister_notify);
+
+void typec_notify_event(unsigned long event, void *data)
+{
+	blocking_notifier_call_chain(&typec_notifier_list, event, data);
+}
diff --git a/include/linux/usb/typec_altmode.h b/include/linux/usb/typec_altmode.h
index f7db3bd4c90e..59e20702504b 100644
--- a/include/linux/usb/typec_altmode.h
+++ b/include/linux/usb/typec_altmode.h
@@ -10,6 +10,7 @@
 #define MODE_DISCOVERY_MAX	6
 
 struct typec_altmode_ops;
+struct notifier_block;
 
 /**
  * struct typec_altmode - USB Type-C alternate mode device
@@ -77,6 +78,14 @@ int typec_altmode_notify(struct typec_altmode *altmode, unsigned long conf,
 const struct typec_altmode *
 typec_altmode_get_partner(struct typec_altmode *altmode);
 
+enum usb_typec_event {
+	TYPEC_ALTMODE_REGISTERED,
+	TYPEC_ALTMODE_UNREGISTERED,
+};
+
+int typec_altmode_register_notify(struct notifier_block *nb);
+int typec_altmode_unregister_notify(struct notifier_block *nb);
+
 /**
  * struct typec_cable_ops - Cable alternate mode operations vector
  * @enter: Operations to be executed with Enter Mode Command
-- 
2.51.1