1 #include <linux/errno.h>
2 #include <linux/miscdevice.h> /* for misc_register, and SYNTH_MINOR */
3 #include <linux/types.h>
4 #include <linux/uaccess.h>
10 #define SYNTH_MINOR 25
13 static int misc_registered;
14 static int dev_opened;
16 static ssize_t speakup_file_write(struct file *fp, const char *buffer,
17 size_t nbytes, loff_t *ppos)
19 size_t count = nbytes;
20 const char *ptr = buffer;
28 bytes = min(count, sizeof(buf));
29 if (copy_from_user(buf, ptr, bytes))
34 synth_write(buf, bytes);
37 return (ssize_t) nbytes;
40 static ssize_t speakup_file_read(struct file *fp, char *buf, size_t nbytes,
46 static int speakup_file_open(struct inode *ip, struct file *fp)
50 if (xchg(&dev_opened, 1))
55 static int speakup_file_release(struct inode *ip, struct file *fp)
61 static const struct file_operations synth_fops = {
62 .read = speakup_file_read,
63 .write = speakup_file_write,
64 .open = speakup_file_open,
65 .release = speakup_file_release,
68 static struct miscdevice synth_device = {
74 void speakup_register_devsynth(void)
76 if (misc_registered != 0)
78 /* zero it so if register fails, deregister will not ref invalid ptrs */
79 if (misc_register(&synth_device))
80 pr_warn("Couldn't initialize miscdevice /dev/synth.\n");
82 pr_info("initialized device: /dev/synth, node (MAJOR %d, MINOR %d)\n",
83 MISC_MAJOR, SYNTH_MINOR);
88 void speakup_unregister_devsynth(void)
92 pr_info("speakup: unregistering synth device /dev/synth\n");
93 misc_deregister(&synth_device);