From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Stultz Subject: [RFC][PATCH 2/3] usb: roles: Add usb role switch notifier. Date: Wed, 2 Oct 2019 23:16:16 +0000 Message-ID: <20191002231617.3670-3-john.stultz@linaro.org> References: <20191002231617.3670-1-john.stultz@linaro.org> Return-path: In-Reply-To: <20191002231617.3670-1-john.stultz@linaro.org> Sender: linux-kernel-owner@vger.kernel.org To: lkml Cc: Yu Chen , Greg Kroah-Hartman , Rob Herring , Mark Rutland , Heikki Krogerus , Suzuki K Poulose , Chunfeng Yun , Felipe Balbi , Hans de Goede , Andy Shevchenko , Jun Li , Valentin Schneider , linux-usb@vger.kernel.org, devicetree@vger.kernel.org, John Stultz List-Id: devicetree@vger.kernel.org From: Yu Chen This patch adds notifier for drivers want to be informed of the usb role switch. Cc: Greg Kroah-Hartman Cc: Rob Herring Cc: Mark Rutland Cc: Heikki Krogerus Cc: Suzuki K Poulose Cc: Chunfeng Yun Cc: Yu Chen Cc: Felipe Balbi Cc: Hans de Goede Cc: Andy Shevchenko Cc: Jun Li Cc: Valentin Schneider Cc: linux-usb@vger.kernel.org Cc: devicetree@vger.kernel.org Suggested-by: Heikki Krogerus Signed-off-by: Yu Chen Signed-off-by: John Stultz --- drivers/usb/roles/class.c | 35 ++++++++++++++++++++++++++++++++++- include/linux/usb/role.h | 16 ++++++++++++++++ 2 files changed, 50 insertions(+), 1 deletion(-) diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c index 94b4e7db2b94..418e762d5d72 100644 --- a/drivers/usb/roles/class.c +++ b/drivers/usb/roles/class.c @@ -20,6 +20,7 @@ struct usb_role_switch { struct device dev; struct mutex lock; /* device lock*/ enum usb_role role; + struct blocking_notifier_head nh; /* From descriptor */ struct device *usb2_port; @@ -49,8 +50,10 @@ int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role) mutex_lock(&sw->lock); ret = sw->set(sw->dev.parent, role); - if (!ret) + if (!ret) { sw->role = role; + blocking_notifier_call_chain(&sw->nh, role, NULL); + } mutex_unlock(&sw->lock); @@ -58,6 +61,35 @@ int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role) } EXPORT_SYMBOL_GPL(usb_role_switch_set_role); +int usb_role_switch_register_notifier(struct usb_role_switch *sw, + struct notifier_block *nb) +{ + int ret = blocking_notifier_chain_register(&sw->nh, nb); + enum usb_role role; + + if (ret) + return ret; + + /* Initialize the notifier that was just registered */ + mutex_lock(&sw->lock); + if (sw->get) + role = sw->get(sw->dev.parent); + else + role = sw->role; + blocking_notifier_call_chain(&sw->nh, role, NULL); + mutex_unlock(&sw->lock); + + return 0; +} +EXPORT_SYMBOL_GPL(usb_role_switch_register_notifier); + +int usb_role_switch_unregister_notifier(struct usb_role_switch *sw, + struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&sw->nh, nb); +} +EXPORT_SYMBOL_GPL(usb_role_switch_unregister_notifier); + /** * usb_role_switch_get_role - Get the USB role for a switch * @sw: USB role switch @@ -296,6 +328,7 @@ usb_role_switch_register(struct device *parent, return ERR_PTR(-ENOMEM); mutex_init(&sw->lock); + BLOCKING_INIT_NOTIFIER_HEAD(&sw->nh); sw->allow_userspace_control = desc->allow_userspace_control; sw->usb2_port = desc->usb2_port; diff --git a/include/linux/usb/role.h b/include/linux/usb/role.h index 2d77f97df72d..8dbf7940b7da 100644 --- a/include/linux/usb/role.h +++ b/include/linux/usb/role.h @@ -54,6 +54,10 @@ struct usb_role_switch * usb_role_switch_register(struct device *parent, const struct usb_role_switch_desc *desc); void usb_role_switch_unregister(struct usb_role_switch *sw); +int usb_role_switch_register_notifier(struct usb_role_switch *sw, + struct notifier_block *nb); +int usb_role_switch_unregister_notifier(struct usb_role_switch *sw, + struct notifier_block *nb); #else static inline int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role) @@ -87,6 +91,18 @@ usb_role_switch_register(struct device *parent, } static inline void usb_role_switch_unregister(struct usb_role_switch *sw) { } + +static int usb_role_switch_register_notifier(struct usb_role_switch *sw, + struct notifier_block *nb) +{ + return -ENODEV; +} + +static int usb_role_switch_unregister_notifier(struct usb_role_switch *sw, + struct notifier_block *nb) +{ + return -ENODEV; +} #endif #endif /* __LINUX_USB_ROLE_H */ -- 2.17.1