6b82151ce5
It is possible that while one driver has already suspended, another driver calls otg_id_notify() because it has not yet been suspended. It would then be possible for the suspended driver's detect callback to be called. This is undesirable. Introduce new otg_id_suspend/otg_id_resume functions that keep a suspended count, and if a notification happens while someone is suspended, that notification is deferred until all the drivers are resumed. If the notification happens before the last driver is suspended, that suspend will be aborted and once the final driver resumes through otg_id_resume, the notification will be delivered. Change-Id: I32fd32bec65e366e5f97a25c15255d94773b85b3 Signed-off-by: Dima Zavin <dima@android.com>
59 lines
1.9 KiB
C
59 lines
1.9 KiB
C
/*
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* Copyright (C) 2011 Google, Inc.
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*
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* Author:
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* Colin Cross <ccross@android.com>
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#ifndef __LINUX_USB_OTG_ID_H
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#define __LINUX_USB_OTG_ID_H
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#include <linux/notifier.h>
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#include <linux/plist.h>
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/**
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* otg_id_notifier_block
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*
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* @priority: Order the notifications will be called in. Higher numbers
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* get called first.
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* @detect: Called during otg_id_notify. Return OTG_ID_HANDLED if the USB cable
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* has been identified
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* @proxy_wait: Called during otg_id_notify if a previous handler returns
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* OTG_ID_PROXY_WAIT. This should wait on ID change then call otg_id_notify.
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* This is used when a handler knows what's connected but can't detect
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* the change itself.
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* @cancel: Called after detect has returned OTG_ID_HANDLED to ask it to
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* release detection resources to allow a new identification to occur.
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*/
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struct otg_id_notifier_block {
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int priority;
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int (*detect)(struct otg_id_notifier_block *otg_id_nb);
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int (*proxy_wait)(struct otg_id_notifier_block *otg_id_nb);
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void (*cancel)(struct otg_id_notifier_block *otg_id_nb);
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struct plist_node p;
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};
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#define OTG_ID_PROXY_WAIT 2
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#define OTG_ID_HANDLED 1
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#define OTG_ID_UNHANDLED 0
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int otg_id_register_notifier(struct otg_id_notifier_block *otg_id_nb);
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void otg_id_unregister_notifier(struct otg_id_notifier_block *otg_id_nb);
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void otg_id_notify(void);
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int otg_id_suspend(void);
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void otg_id_resume(void);
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#endif /* __LINUX_USB_OTG_ID_H */
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