include/media/lirc_dev.h

   1 /*
   2  * LIRC base driver
   3  *
   4  * by Artur Lipowski <alipowski@interia.pl>
   5  *        This code is licensed under GNU GPL
   6  *
   7  */
   8
   9 #ifndef _LINUX_LIRC_DEV_H
  10 #define _LINUX_LIRC_DEV_H
  11
  12 #define MAX_IRCTL_DEVICES 4
  13 #define BUFLEN            16
  14
  15 #define mod(n, div) ((n) % (div))
  16
  17 #include <linux/slab.h>
  18 #include <linux/fs.h>
  19 #include <linux/ioctl.h>
  20 #include <linux/poll.h>
  21 #include <linux/kfifo.h>
  22 #include <media/lirc.h>
  23
  24 struct lirc_buffer {
  25         wait_queue_head_t wait_poll;
  26         spinlock_t fifo_lock;
  27         unsigned int chunk_size;
  28         unsigned int size; /* in chunks */
  29         /* Using chunks instead of bytes pretends to simplify boundary checking
  30          * And should allow for some performance fine tunning later */
  31         struct kfifo fifo;
  32         u8 fifo_initialized;
  33 };
  34
  35 static inline void lirc_buffer_clear(struct lirc_buffer *buf)
  36 {
  37         unsigned long flags;
  38
  39         if (buf->fifo_initialized) {
  40                 spin_lock_irqsave(&buf->fifo_lock, flags);
  41                 kfifo_reset(&buf->fifo);
  42                 spin_unlock_irqrestore(&buf->fifo_lock, flags);
  43         } else
  44                 WARN(1, "calling %s on an uninitialized lirc_buffer\n",
  45                      __func__);
  46 }
  47
  48 static inline int lirc_buffer_init(struct lirc_buffer *buf,
  49                                     unsigned int chunk_size,
  50                                     unsigned int size)
  51 {
  52         int ret;
  53
  54         init_waitqueue_head(&buf->wait_poll);
  55         spin_lock_init(&buf->fifo_lock);
  56         buf->chunk_size = chunk_size;
  57         buf->size = size;
  58         ret = kfifo_alloc(&buf->fifo, size * chunk_size, GFP_KERNEL);
  59         if (ret == 0)
  60                 buf->fifo_initialized = 1;
  61
  62         return ret;
  63 }
  64
  65 static inline void lirc_buffer_free(struct lirc_buffer *buf)
  66 {
  67         if (buf->fifo_initialized) {
  68                 kfifo_free(&buf->fifo);
  69                 buf->fifo_initialized = 0;
  70         } else
  71                 WARN(1, "calling %s on an uninitialized lirc_buffer\n",
  72                      __func__);
  73 }
  74
  75 static inline int lirc_buffer_len(struct lirc_buffer *buf)
  76 {
  77         int len;
  78         unsigned long flags;
  79
  80         spin_lock_irqsave(&buf->fifo_lock, flags);
  81         len = kfifo_len(&buf->fifo);
  82         spin_unlock_irqrestore(&buf->fifo_lock, flags);
  83
  84         return len;
  85 }
  86
  87 static inline int lirc_buffer_full(struct lirc_buffer *buf)
  88 {
  89         return lirc_buffer_len(buf) == buf->size * buf->chunk_size;
  90 }
  91
  92 static inline int lirc_buffer_empty(struct lirc_buffer *buf)
  93 {
  94         return !lirc_buffer_len(buf);
  95 }
  96
  97 static inline int lirc_buffer_available(struct lirc_buffer *buf)
  98 {
  99         return buf->size - (lirc_buffer_len(buf) / buf->chunk_size);
 100 }
 101
 102 static inline unsigned int lirc_buffer_read(struct lirc_buffer *buf,
 103                                             unsigned char *dest)
 104 {
 105         unsigned int ret = 0;
 106
 107         if (lirc_buffer_len(buf) >= buf->chunk_size)
 108                 ret = kfifo_out_locked(&buf->fifo, dest, buf->chunk_size,
 109                                        &buf->fifo_lock);
 110         return ret;
 111
 112 }
 113
 114 static inline unsigned int lirc_buffer_write(struct lirc_buffer *buf,
 115                                              unsigned char *orig)
 116 {
 117         unsigned int ret;
 118
 119         ret = kfifo_in_locked(&buf->fifo, orig, buf->chunk_size,
 120                               &buf->fifo_lock);
 121
 122         return ret;
 123 }
 124
 125 struct lirc_driver {
 126         char name[40];
 127         int minor;
 128         __u32 code_length;
 129         unsigned int buffer_size; /* in chunks holding one code each */
 130         int sample_rate;
 131         __u32 features;
 132
 133         unsigned int chunk_size;
 134
 135         void *data;
 136         int min_timeout;
 137         int max_timeout;
 138         int (*add_to_buf) (void *data, struct lirc_buffer *buf);
 139         struct lirc_buffer *rbuf;
 140         int (*set_use_inc) (void *data);
 141         void (*set_use_dec) (void *data);
 142         const struct file_operations *fops;
 143         struct device *dev;
 144         struct module *owner;
 145 };
 146
 147 /* name:
 148  * this string will be used for logs
 149  *
 150  * minor:
 151  * indicates minor device (/dev/lirc) number for registered driver
 152  * if caller fills it with negative value, then the first free minor
 153  * number will be used (if available)
 154  *
 155  * code_length:
 156  * length of the remote control key code expressed in bits
 157  *
 158  * sample_rate:
 159  *
 160  * data:
 161  * it may point to any driver data and this pointer will be passed to
 162  * all callback functions
 163  *
 164  * add_to_buf:
 165  * add_to_buf will be called after specified period of the time or
 166  * triggered by the external event, this behavior depends on value of
 167  * the sample_rate this function will be called in user context. This
 168  * routine should return 0 if data was added to the buffer and
 169  * -ENODATA if none was available. This should add some number of bits
 170  * evenly divisible by code_length to the buffer
 171  *
 172  * rbuf:
 173  * if not NULL, it will be used as a read buffer, you will have to
 174  * write to the buffer by other means, like irq's (see also
 175  * lirc_serial.c).
 176  *
 177  * set_use_inc:
 178  * set_use_inc will be called after device is opened
 179  *
 180  * set_use_dec:
 181  * set_use_dec will be called after device is closed
 182  *
 183  * fops:
 184  * file_operations for drivers which don't fit the current driver model.
 185  *
 186  * Some ioctl's can be directly handled by lirc_dev if the driver's
 187  * ioctl function is NULL or if it returns -ENOIOCTLCMD (see also
 188  * lirc_serial.c).
 189  *
 190  * owner:
 191  * the module owning this struct
 192  *
 193  */
 194
 195
 196 /* following functions can be called ONLY from user context
 197  *
 198  * returns negative value on error or minor number
 199  * of the registered device if success
 200  * contents of the structure pointed by p is copied
 201  */
 202 extern int lirc_register_driver(struct lirc_driver *d);
 203
 204 /* returns negative value on error or 0 if success
 205 */
 206 extern int lirc_unregister_driver(int minor);
 207
 208 /* Returns the private data stored in the lirc_driver
 209  * associated with the given device file pointer.
 210  */
 211 void *lirc_get_pdata(struct file *file);
 212
 213 /* default file operations
 214  * used by drivers if they override only some operations
 215  */
 216 int lirc_dev_fop_open(struct inode *inode, struct file *file);
 217 int lirc_dev_fop_close(struct inode *inode, struct file *file);
 218 unsigned int lirc_dev_fop_poll(struct file *file, poll_table *wait);
 219 long lirc_dev_fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 220 ssize_t lirc_dev_fop_read(struct file *file, char *buffer, size_t length,
 221                           loff_t *ppos);
 222 ssize_t lirc_dev_fop_write(struct file *file, const char *buffer, size_t length,
 223                            loff_t *ppos);
 224
 225 #endif