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SubjectRe: [PATCH v4 08/12] usb: roles: Add usb role switch notifier.
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Hi,

On 2019/3/19 19:56, Heikki Krogerus wrote:
> On Sat, Mar 16, 2019 at 11:53:38AM +0800, Yu Chen wrote:
>> This patch adds notifier for drivers want to be informed of the usb role switch.
>>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
>> Cc: Hans de Goede <hdegoede@redhat.com>
>> Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
>> Cc: John Stultz <john.stultz@linaro.org>
>> Suggested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
>> Signed-off-by: Yu Chen <chenyu56@huawei.com>
>> ---
>> drivers/usb/roles/class.c | 20 +++++++++++++++++++-
>> include/linux/usb/role.h | 46 ++++++++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 65 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
>> index f45d8df5cfb8..e2caaa665d6e 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 +61,20 @@ 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)
>> +{
>> + return blocking_notifier_chain_register(&sw->nh, nb);
>> +}
>> +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
>> @@ -271,6 +288,7 @@ 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 c05ffa6abda9..99d8b8e4fe61 100644
>> --- a/include/linux/usb/role.h
>> +++ b/include/linux/usb/role.h
>> @@ -42,6 +42,8 @@ struct usb_role_switch_desc {
>> bool allow_userspace_control;
>> };
>>
>> +
>> +#if IS_ENABLED(CONFIG_USB_ROLE_SWITCH)
>> int usb_role_switch_set_role(struct usb_role_switch *sw, enum usb_role role);
>> enum usb_role usb_role_switch_get_role(struct usb_role_switch *sw);
>> struct usb_role_switch *usb_role_switch_get(struct device *dev);
>> @@ -51,5 +53,49 @@ 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)
>> +{
>> + return 0;
>> +}
>> +
>> +static inline enum usb_role usb_role_switch_get_role(struct usb_role_switch *sw)
>> +{
>> + return USB_ROLE_NONE;
>> +}
>> +
>> +static inline struct usb_role_switch *usb_role_switch_get(struct device *dev)
>> +{
>> + return ERR_PTR(-ENODEV);
>> +}
>> +
>> +static inline void usb_role_switch_put(struct usb_role_switch *sw) { }
>> +
>> +static inline struct usb_role_switch *
>> +usb_role_switch_register(struct device *parent,
>> + const struct usb_role_switch_desc *desc)
>> +{
>> + return ERR_PTR(-ENODEV);
>> +}
>> +
>> +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 */
>
> Sorry for the late response, but since you are providing a stub for
> all the functions, not just the new ones, could you please introduce
> them in a separate patch.
>
> Add a patch where you introduce stubs for the exiting functions, and
> this patch can then add the stubs for just the new notifier functions.
>
>
> thanks,
>

OK.

Thanks
Yu Chen

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