add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/sound/core/device.c
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@@ -1,22 +1,7 @@
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+// SPDX-License-Identifier: GPL-2.0-or-later
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 /*
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  *  Device management routines
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  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
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- *
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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/slab.h>
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@@ -42,7 +27,7 @@
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  * Return: Zero if successful, or a negative error code on failure.
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  */
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 int snd_device_new(struct snd_card *card, enum snd_device_type type,
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-		   void *device_data, struct snd_device_ops *ops)
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+		   void *device_data, const struct snd_device_ops *ops)
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 {
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 	struct snd_device *dev;
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 	struct list_head *p;
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@@ -252,3 +237,24 @@
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 	list_for_each_entry_safe_reverse(dev, next, &card->devices, list)
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 		__snd_device_free(dev);
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 }
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+
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+/**
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+ * snd_device_get_state - Get the current state of the given device
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+ * @card: the card instance
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+ * @device_data: the data pointer to release
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+ *
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+ * Returns the current state of the given device object.  For the valid
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+ * device, either @SNDRV_DEV_BUILD, @SNDRV_DEV_REGISTERED or
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+ * @SNDRV_DEV_DISCONNECTED is returned.
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+ * Or for a non-existing device, -1 is returned as an error.
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+ */
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+int snd_device_get_state(struct snd_card *card, void *device_data)
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+{
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+	struct snd_device *dev;
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+
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+	dev = look_for_dev(card, device_data);
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+	if (dev)
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+		return dev->state;
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+	return -1;
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+}
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+EXPORT_SYMBOL_GPL(snd_device_get_state);