forked from Minki/linux
ebb812cb8d
Some devices provide support for detection of a small number of buttons on their jacks. One common implementation provides a single button, implemented by shorting the microphone to ground and detected along with microphone presence detection by detecting varying current draws on the microphone bias signal. Provide support for up to three buttons via the jack interface. These default to reporting BTN_n but an API is provided to allow these to be remapped to other keys by the machine driver where it knows what the keys are. More keys can be added with ease if required. This is only intended to support simple accessory button designs. If the interface is limiting then either creating a child device for the accessory or accessing the input device in the jack directly is recommended. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
239 lines
6.1 KiB
C
239 lines
6.1 KiB
C
/*
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* Jack abstraction layer
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*
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* Copyright 2008 Wolfson Microelectronics
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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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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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <linux/input.h>
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#include <sound/jack.h>
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#include <sound/core.h>
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static int jack_switch_types[] = {
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SW_HEADPHONE_INSERT,
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SW_MICROPHONE_INSERT,
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SW_LINEOUT_INSERT,
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SW_JACK_PHYSICAL_INSERT,
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SW_VIDEOOUT_INSERT,
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};
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static int snd_jack_dev_free(struct snd_device *device)
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{
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struct snd_jack *jack = device->device_data;
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if (jack->private_free)
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jack->private_free(jack);
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/* If the input device is registered with the input subsystem
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* then we need to use a different deallocator. */
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if (jack->registered)
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input_unregister_device(jack->input_dev);
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else
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input_free_device(jack->input_dev);
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kfree(jack->id);
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kfree(jack);
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return 0;
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}
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static int snd_jack_dev_register(struct snd_device *device)
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{
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struct snd_jack *jack = device->device_data;
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struct snd_card *card = device->card;
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int err, i;
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snprintf(jack->name, sizeof(jack->name), "%s %s",
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card->shortname, jack->id);
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jack->input_dev->name = jack->name;
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/* Default to the sound card device. */
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if (!jack->input_dev->dev.parent)
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jack->input_dev->dev.parent = snd_card_get_device_link(card);
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/* Add capabilities for any keys that are enabled */
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for (i = 0; i < ARRAY_SIZE(jack->key); i++) {
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int testbit = SND_JACK_BTN_0 >> i;
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if (!(jack->type & testbit))
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continue;
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if (!jack->key[i])
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jack->key[i] = BTN_0 + i;
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input_set_capability(jack->input_dev, EV_KEY, jack->key[i]);
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}
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err = input_register_device(jack->input_dev);
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if (err == 0)
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jack->registered = 1;
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return err;
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}
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/**
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* snd_jack_new - Create a new jack
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* @card: the card instance
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* @id: an identifying string for this jack
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* @type: a bitmask of enum snd_jack_type values that can be detected by
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* this jack
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* @jjack: Used to provide the allocated jack object to the caller.
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*
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* Creates a new jack object.
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*
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* Returns zero if successful, or a negative error code on failure.
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* On success jjack will be initialised.
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*/
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int snd_jack_new(struct snd_card *card, const char *id, int type,
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struct snd_jack **jjack)
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{
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struct snd_jack *jack;
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int err;
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int i;
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static struct snd_device_ops ops = {
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.dev_free = snd_jack_dev_free,
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.dev_register = snd_jack_dev_register,
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};
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jack = kzalloc(sizeof(struct snd_jack), GFP_KERNEL);
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if (jack == NULL)
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return -ENOMEM;
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jack->id = kstrdup(id, GFP_KERNEL);
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jack->input_dev = input_allocate_device();
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if (jack->input_dev == NULL) {
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err = -ENOMEM;
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goto fail_input;
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}
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jack->input_dev->phys = "ALSA";
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jack->type = type;
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for (i = 0; i < ARRAY_SIZE(jack_switch_types); i++)
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if (type & (1 << i))
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input_set_capability(jack->input_dev, EV_SW,
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jack_switch_types[i]);
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err = snd_device_new(card, SNDRV_DEV_JACK, jack, &ops);
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if (err < 0)
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goto fail_input;
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*jjack = jack;
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return 0;
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fail_input:
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input_free_device(jack->input_dev);
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kfree(jack);
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return err;
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}
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EXPORT_SYMBOL(snd_jack_new);
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/**
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* snd_jack_set_parent - Set the parent device for a jack
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*
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* @jack: The jack to configure
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* @parent: The device to set as parent for the jack.
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*
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* Set the parent for the jack input device in the device tree. This
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* function is only valid prior to registration of the jack. If no
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* parent is configured then the parent device will be the sound card.
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*/
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void snd_jack_set_parent(struct snd_jack *jack, struct device *parent)
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{
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WARN_ON(jack->registered);
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jack->input_dev->dev.parent = parent;
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}
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EXPORT_SYMBOL(snd_jack_set_parent);
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/**
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* snd_jack_set_key - Set a key mapping on a jack
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*
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* @jack: The jack to configure
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* @type: Jack report type for this key
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* @keytype: Input layer key type to be reported
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*
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* Map a SND_JACK_BTN_ button type to an input layer key, allowing
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* reporting of keys on accessories via the jack abstraction. If no
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* mapping is provided but keys are enabled in the jack type then
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* BTN_n numeric buttons will be reported.
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*
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* Note that this is intended to be use by simple devices with small
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* numbers of keys that can be reported. It is also possible to
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* access the input device directly - devices with complex input
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* capabilities on accessories should consider doing this rather than
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* using this abstraction.
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*
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* This function may only be called prior to registration of the jack.
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*/
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int snd_jack_set_key(struct snd_jack *jack, enum snd_jack_types type,
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int keytype)
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{
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int key = fls(SND_JACK_BTN_0) - fls(type);
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WARN_ON(jack->registered);
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if (!keytype || key >= ARRAY_SIZE(jack->key))
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return -EINVAL;
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jack->type |= type;
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jack->key[key] = keytype;
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return 0;
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}
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EXPORT_SYMBOL(snd_jack_set_key);
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/**
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* snd_jack_report - Report the current status of a jack
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*
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* @jack: The jack to report status for
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* @status: The current status of the jack
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*/
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void snd_jack_report(struct snd_jack *jack, int status)
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{
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int i;
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if (!jack)
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return;
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for (i = 0; i < ARRAY_SIZE(jack->key); i++) {
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int testbit = SND_JACK_BTN_0 >> i;
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if (jack->type & testbit)
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input_report_key(jack->input_dev, jack->key[i],
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status & testbit);
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}
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for (i = 0; i < ARRAY_SIZE(jack_switch_types); i++) {
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int testbit = 1 << i;
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if (jack->type & testbit)
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input_report_switch(jack->input_dev,
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jack_switch_types[i],
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status & testbit);
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}
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input_sync(jack->input_dev);
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}
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EXPORT_SYMBOL(snd_jack_report);
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MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
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MODULE_DESCRIPTION("Jack detection support for ALSA");
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MODULE_LICENSE("GPL");
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