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path: root/drivers/telephony/phonedev.c
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Diffstat (limited to 'drivers/telephony/phonedev.c')
-rw-r--r--drivers/telephony/phonedev.c170
1 files changed, 170 insertions, 0 deletions
diff --git a/drivers/telephony/phonedev.c b/drivers/telephony/phonedev.c
new file mode 100644
index 000000000000..3c987f49f6b4
--- /dev/null
+++ b/drivers/telephony/phonedev.c
@@ -0,0 +1,170 @@
+/*
+ * Telephony registration for Linux
+ *
+ * (c) Copyright 1999 Red Hat Software Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * Author: Alan Cox, <alan@redhat.com>
+ *
+ * Fixes: Mar 01 2000 Thomas Sparr, <thomas.l.sparr@telia.com>
+ * phone_register_device now works with unit!=PHONE_UNIT_ANY
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/phonedev.h>
+#include <linux/init.h>
+#include <asm/uaccess.h>
+#include <asm/system.h>
+
+#include <linux/kmod.h>
+#include <linux/sem.h>
+#include <linux/devfs_fs_kernel.h>
+
+#define PHONE_NUM_DEVICES 256
+
+/*
+ * Active devices
+ */
+
+static struct phone_device *phone_device[PHONE_NUM_DEVICES];
+static DECLARE_MUTEX(phone_lock);
+
+/*
+ * Open a phone device.
+ */
+
+static int phone_open(struct inode *inode, struct file *file)
+{
+ unsigned int minor = iminor(inode);
+ int err = 0;
+ struct phone_device *p;
+ struct file_operations *old_fops, *new_fops = NULL;
+
+ if (minor >= PHONE_NUM_DEVICES)
+ return -ENODEV;
+
+ down(&phone_lock);
+ p = phone_device[minor];
+ if (p)
+ new_fops = fops_get(p->f_op);
+ if (!new_fops) {
+ up(&phone_lock);
+ request_module("char-major-%d-%d", PHONE_MAJOR, minor);
+ down(&phone_lock);
+ p = phone_device[minor];
+ if (p == NULL || (new_fops = fops_get(p->f_op)) == NULL)
+ {
+ err=-ENODEV;
+ goto end;
+ }
+ }
+ old_fops = file->f_op;
+ file->f_op = new_fops;
+ if (p->open)
+ err = p->open(p, file); /* Tell the device it is open */
+ if (err) {
+ fops_put(file->f_op);
+ file->f_op = fops_get(old_fops);
+ }
+ fops_put(old_fops);
+end:
+ up(&phone_lock);
+ return err;
+}
+
+/*
+ * Telephony For Linux device drivers request registration here.
+ */
+
+int phone_register_device(struct phone_device *p, int unit)
+{
+ int base;
+ int end;
+ int i;
+
+ base = 0;
+ end = PHONE_NUM_DEVICES - 1;
+
+ if (unit != PHONE_UNIT_ANY) {
+ base = unit;
+ end = unit + 1; /* enter the loop at least one time */
+ }
+
+ down(&phone_lock);
+ for (i = base; i < end; i++) {
+ if (phone_device[i] == NULL) {
+ phone_device[i] = p;
+ p->minor = i;
+ devfs_mk_cdev(MKDEV(PHONE_MAJOR,i),
+ S_IFCHR|S_IRUSR|S_IWUSR, "phone/%d", i);
+ up(&phone_lock);
+ return 0;
+ }
+ }
+ up(&phone_lock);
+ return -ENFILE;
+}
+
+/*
+ * Unregister an unused Telephony for linux device
+ */
+
+void phone_unregister_device(struct phone_device *pfd)
+{
+ down(&phone_lock);
+ if (phone_device[pfd->minor] != pfd)
+ panic("phone: bad unregister");
+ devfs_remove("phone/%d", pfd->minor);
+ phone_device[pfd->minor] = NULL;
+ up(&phone_lock);
+}
+
+
+static struct file_operations phone_fops =
+{
+ .owner = THIS_MODULE,
+ .open = phone_open,
+};
+
+/*
+ * Board init functions
+ */
+
+
+/*
+ * Initialise Telephony for linux
+ */
+
+static int __init telephony_init(void)
+{
+ printk(KERN_INFO "Linux telephony interface: v1.00\n");
+ if (register_chrdev(PHONE_MAJOR, "telephony", &phone_fops)) {
+ printk("phonedev: unable to get major %d\n", PHONE_MAJOR);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static void __exit telephony_exit(void)
+{
+ unregister_chrdev(PHONE_MAJOR, "telephony");
+}
+
+module_init(telephony_init);
+module_exit(telephony_exit);
+
+MODULE_LICENSE("GPL");
+
+EXPORT_SYMBOL(phone_register_device);
+EXPORT_SYMBOL(phone_unregister_device);