![Henrik Rydberg](/assets/img/avatar_default.png)
The MT slots devices all follow the same initialization pattern of creating slots and hinting about buffer size. Let drivers call an initialization function instead, and make sure it can be called repeatedly without side effects. Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
66 lines
1.8 KiB
C
66 lines
1.8 KiB
C
/*
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* Input Multitouch Library
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*
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* Copyright (c) 2008-2010 Henrik Rydberg
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/input/mt.h>
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#include <linux/slab.h>
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/**
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* input_mt_init_slots() - initialize MT input slots
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* @dev: input device supporting MT events and finger tracking
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* @num_slots: number of slots used by the device
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*
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* This function allocates all necessary memory for MT slot handling
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* in the input device, adds ABS_MT_SLOT to the device capabilities
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* and sets up appropriate event buffers. All slots are initially
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* marked as unused by setting ABS_MT_TRACKING_ID to -1. May be called
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* repeatedly. Returns -EINVAL if attempting to reinitialize with a
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* different number of slots.
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*/
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int input_mt_init_slots(struct input_dev *dev, unsigned int num_slots)
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{
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int i;
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if (!num_slots)
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return 0;
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if (dev->mt)
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return dev->mtsize != num_slots ? -EINVAL : 0;
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dev->mt = kcalloc(num_slots, sizeof(struct input_mt_slot), GFP_KERNEL);
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if (!dev->mt)
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return -ENOMEM;
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dev->mtsize = num_slots;
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input_set_abs_params(dev, ABS_MT_SLOT, 0, num_slots - 1, 0, 0);
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input_set_events_per_packet(dev, 6 * num_slots);
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/* Mark slots as 'unused' */
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for (i = 0; i < num_slots; i++)
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input_mt_set_value(&dev->mt[i], ABS_MT_TRACKING_ID, -1);
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return 0;
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}
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EXPORT_SYMBOL(input_mt_init_slots);
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/**
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* input_mt_destroy_slots() - frees the MT slots of the input device
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* @dev: input device with allocated MT slots
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*
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* This function is only needed in error path as the input core will
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* automatically free the MT slots when the device is destroyed.
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*/
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void input_mt_destroy_slots(struct input_dev *dev)
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{
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kfree(dev->mt);
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dev->mt = NULL;
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dev->mtsize = 0;
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dev->slot = 0;
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}
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EXPORT_SYMBOL(input_mt_destroy_slots);
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