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 8
  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 };
  33
  34 static inline void lirc_buffer_clear(struct lirc_buffer *buf)
  35 {
  36         unsigned long flags;
  37
  38         if (kfifo_initialized(&buf->fifo)) {
  39                 spin_lock_irqsave(&buf->fifo_lock, flags);
  40                 kfifo_reset(&buf->fifo);
  41                 spin_unlock_irqrestore(&buf->fifo_lock, flags);
  42         } else
  43                 WARN(1, "calling %s on an uninitialized lirc_buffer\n",
  44                      __func__);
  45 }
  46
  47 static inline int lirc_buffer_init(struct lirc_buffer *buf,
  48                                     unsigned int chunk_size,
  49                                     unsigned int size)
  50 {
  51         int ret;
  52
  53         init_waitqueue_head(&buf->wait_poll);
  54         spin_lock_init(&buf->fifo_lock);
  55         buf->chunk_size = chunk_size;
  56         buf->size = size;
  57         ret = kfifo_alloc(&buf->fifo, size * chunk_size, GFP_KERNEL);
  58
  59         return ret;
  60 }
  61
  62 static inline void lirc_buffer_free(struct lirc_buffer *buf)
  63 {
  64         if (kfifo_initialized(&buf->fifo)) {
  65                 kfifo_free(&buf->fifo);
  66         } else
  67                 WARN(1, "calling %s on an uninitialized lirc_buffer\n",
  68                      __func__);
  69 }
  70
  71 static inline int lirc_buffer_len(struct lirc_buffer *buf)
  72 {
  73         int len;
  74         unsigned long flags;
  75
  76         spin_lock_irqsave(&buf->fifo_lock, flags);
  77         len = kfifo_len(&buf->fifo);
  78         spin_unlock_irqrestore(&buf->fifo_lock, flags);
  79
  80         return len;
  81 }
  82
  83 static inline int lirc_buffer_full(struct lirc_buffer *buf)
  84 {
  85         return lirc_buffer_len(buf) == buf->size * buf->chunk_size;
  86 }
  87
  88 static inline int lirc_buffer_empty(struct lirc_buffer *buf)
  89 {
  90         return !lirc_buffer_len(buf);
  91 }
  92
  93 static inline int lirc_buffer_available(struct lirc_buffer *buf)
  94 {
  95         return buf->size - (lirc_buffer_len(buf) / buf->chunk_size);
  96 }
  97
  98 static inline unsigned int lirc_buffer_read(struct lirc_buffer *buf,
  99                                             unsigned char *dest)
 100 {
 101         unsigned int ret = 0;
 102
 103         if (lirc_buffer_len(buf) >= buf->chunk_size)
 104                 ret = kfifo_out_locked(&buf->fifo, dest, buf->chunk_size,
 105                                        &buf->fifo_lock);
 106         return ret;
 107
 108 }
 109
 110 static inline unsigned int lirc_buffer_write(struct lirc_buffer *buf,
 111                                              unsigned char *orig)
 112 {
 113         unsigned int ret;
 114
 115         ret = kfifo_in_locked(&buf->fifo, orig, buf->chunk_size,
 116                               &buf->fifo_lock);
 117
 118         return ret;
 119 }
 120
 121 /**
 122  * struct lirc_driver - Defines the parameters on a LIRC driver
 123  *
 124  * @name:               this string will be used for logs
 125  *
 126  * @minor:              indicates minor device (/dev/lirc) number for
 127  *                      registered driver if caller fills it with negative
 128  *                      value, then the first free minor number will be used
 129  *                      (if available).
 130  *
 131  * @code_length:        length of the remote control key code expressed in bits.
 132  *
 133  * @buffer_size:        Number of FIFO buffers with @chunk_size size. If zero,
 134  *                      creates a buffer with BUFLEN size (16 bytes).
 135  *
 136  * @sample_rate:        if zero, the device will wait for an event with a new
 137  *                      code to be parsed. Otherwise, specifies the sample
 138  *                      rate for polling. Value should be between 0
 139  *                      and HZ. If equal to HZ, it would mean one polling per
 140  *                      second.
 141  *
 142  * @features:           lirc compatible hardware features, like LIRC_MODE_RAW,
 143  *                      LIRC_CAN\_\*, as defined at include/media/lirc.h.
 144  *
 145  * @chunk_size:         Size of each FIFO buffer.
 146  *
 147  * @data:               it may point to any driver data and this pointer will
 148  *                      be passed to all callback functions.
 149  *
 150  * @min_timeout:        Minimum timeout for record. Valid only if
 151  *                      LIRC_CAN_SET_REC_TIMEOUT is defined.
 152  *
 153  * @max_timeout:        Maximum timeout for record. Valid only if
 154  *                      LIRC_CAN_SET_REC_TIMEOUT is defined.
 155  *
 156  * @add_to_buf:         add_to_buf will be called after specified period of the
 157  *                      time or triggered by the external event, this behavior
 158  *                      depends on value of the sample_rate this function will
 159  *                      be called in user context. This routine should return
 160  *                      0 if data was added to the buffer and -ENODATA if none
 161  *                      was available. This should add some number of bits
 162  *                      evenly divisible by code_length to the buffer.
 163  *
 164  * @rbuf:               if not NULL, it will be used as a read buffer, you will
 165  *                      have to write to the buffer by other means, like irq's
 166  *                      (see also lirc_serial.c).
 167  *
 168  * @set_use_inc:        set_use_inc will be called after device is opened
 169  *
 170  * @set_use_dec:        set_use_dec will be called after device is closed
 171  *
 172  * @rdev:               Pointed to struct rc_dev associated with the LIRC
 173  *                      device.
 174  *
 175  * @fops:               file_operations for drivers which don't fit the current
 176  *                      driver model.
 177  *                      Some ioctl's can be directly handled by lirc_dev if the
 178  *                      driver's ioctl function is NULL or if it returns
 179  *                      -ENOIOCTLCMD (see also lirc_serial.c).
 180  *
 181  * @dev:                pointer to the struct device associated with the LIRC
 182  *                      device.
 183  *
 184  * @owner:              the module owning this struct
 185  */
 186 struct lirc_driver {
 187         char name[40];
 188         int minor;
 189         __u32 code_length;
 190         unsigned int buffer_size; /* in chunks holding one code each */
 191         int sample_rate;
 192         __u32 features;
 193
 194         unsigned int chunk_size;
 195
 196         void *data;
 197         int min_timeout;
 198         int max_timeout;
 199         int (*add_to_buf)(void *data, struct lirc_buffer *buf);
 200         struct lirc_buffer *rbuf;
 201         int (*set_use_inc)(void *data);
 202         void (*set_use_dec)(void *data);
 203         struct rc_dev *rdev;
 204         const struct file_operations *fops;
 205         struct device *dev;
 206         struct module *owner;
 207 };
 208
 209 /* following functions can be called ONLY from user context
 210  *
 211  * returns negative value on error or minor number
 212  * of the registered device if success
 213  * contents of the structure pointed by p is copied
 214  */
 215 extern int lirc_register_driver(struct lirc_driver *d);
 216
 217 /* returns negative value on error or 0 if success
 218 */
 219 extern int lirc_unregister_driver(int minor);
 220
 221 /* Returns the private data stored in the lirc_driver
 222  * associated with the given device file pointer.
 223  */
 224 void *lirc_get_pdata(struct file *file);
 225
 226 /* default file operations
 227  * used by drivers if they override only some operations
 228  */
 229 int lirc_dev_fop_open(struct inode *inode, struct file *file);
 230 int lirc_dev_fop_close(struct inode *inode, struct file *file);
 231 unsigned int lirc_dev_fop_poll(struct file *file, poll_table *wait);
 232 long lirc_dev_fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 233 ssize_t lirc_dev_fop_read(struct file *file, char __user *buffer, size_t length,
 234                           loff_t *ppos);
 235 ssize_t lirc_dev_fop_write(struct file *file, const char __user *buffer,
 236                            size_t length, loff_t *ppos);
 237
 238 #endif