linux/include/media/lirc_dev.h
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   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        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 */
 202extern int lirc_register_driver(struct lirc_driver *d);
 203
 204/* returns negative value on error or 0 if success
 205*/
 206extern 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 */
 211void *lirc_get_pdata(struct file *file);
 212
 213/* default file operations
 214 * used by drivers if they override only some operations
 215 */
 216int lirc_dev_fop_open(struct inode *inode, struct file *file);
 217int lirc_dev_fop_close(struct inode *inode, struct file *file);
 218unsigned int lirc_dev_fop_poll(struct file *file, poll_table *wait);
 219long lirc_dev_fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 220ssize_t lirc_dev_fop_read(struct file *file, char __user *buffer, size_t length,
 221                          loff_t *ppos);
 222ssize_t lirc_dev_fop_write(struct file *file, const char __user *buffer,
 223                           size_t length, loff_t *ppos);
 224
 225#endif
 226
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