LXR linux/include/media/lirc

   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
  24struct 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
  35static 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
  48static 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
  65static 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
  75static 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
  87static inline int lirc_buffer_full(struct lirc_buffer *buf)
  88{
  89        return lirc_buffer_len(buf) == buf->size * buf->chunk_size;
  90}
  91
  92static inline int lirc_buffer_empty(struct lirc_buffer *buf)
  93{
  94        return !lirc_buffer_len(buf);
  95}
  96
  97static inline int lirc_buffer_available(struct lirc_buffer *buf)
  98{
  99        return buf->size - (lirc_buffer_len(buf) / buf->chunk_size);
 100}
 101
 102static 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
 114static 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
 125struct 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        struct rc_dev *rdev;
 143        const struct file_operations *fops;
 144        struct device *dev;
 145        struct module *owner;
 146};
 147
 148/* name:
 149 * this string will be used for logs
 150 *
 151 * minor:
 152 * indicates minor device (/dev/lirc) number for registered driver
 153 * if caller fills it with negative value, then the first free minor
 154 * number will be used (if available)
 155 *
 156 * code_length:
 157 * length of the remote control key code expressed in bits
 158 *
 159 * sample_rate:
 160 *
 161 * data:
 162 * it may point to any driver data and this pointer will be passed to
 163 * all callback functions
 164 *
 165 * add_to_buf:
 166 * add_to_buf will be called after specified period of the time or
 167 * triggered by the external event, this behavior depends on value of
 168 * the sample_rate this function will be called in user context. This
 169 * routine should return 0 if data was added to the buffer and
 170 * -ENODATA if none was available. This should add some number of bits
 171 * evenly divisible by code_length to the buffer
 172 *
 173 * rbuf:
 174 * if not NULL, it will be used as a read buffer, you will have to
 175 * write to the buffer by other means, like irq's (see also
 176 * lirc_serial.c).
 177 *
 178 * set_use_inc:
 179 * set_use_inc will be called after device is opened
 180 *
 181 * set_use_dec:
 182 * set_use_dec will be called after device is closed
 183 *
 184 * fops:
 185 * file_operations for drivers which don't fit the current driver model.
 186 *
 187 * Some ioctl's can be directly handled by lirc_dev if the driver's
 188 * ioctl function is NULL or if it returns -ENOIOCTLCMD (see also
 189 * lirc_serial.c).
 190 *
 191 * owner:
 192 * the module owning this struct
 193 *
 194 */
 195
 196
 197/* following functions can be called ONLY from user context
 198 *
 199 * returns negative value on error or minor number
 200 * of the registered device if success
 201 * contents of the structure pointed by p is copied
 202 */
 203extern int lirc_register_driver(struct lirc_driver *d);
 204
 205/* returns negative value on error or 0 if success
 206*/
 207extern int lirc_unregister_driver(int minor);
 208
 209/* Returns the private data stored in the lirc_driver
 210 * associated with the given device file pointer.
 211 */
 212void *lirc_get_pdata(struct file *file);
 213
 214/* default file operations
 215 * used by drivers if they override only some operations
 216 */
 217int lirc_dev_fop_open(struct inode *inode, struct file *file);
 218int lirc_dev_fop_close(struct inode *inode, struct file *file);
 219unsigned int lirc_dev_fop_poll(struct file *file, poll_table *wait);
 220long lirc_dev_fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 221ssize_t lirc_dev_fop_read(struct file *file, char __user *buffer, size_t length,
 222                          loff_t *ppos);
 223ssize_t lirc_dev_fop_write(struct file *file, const char __user *buffer,
 224                           size_t length, loff_t *ppos);
 225
 226#endif
 227