drivers/media/common/ir-functions.c

   1 /*
   2  *
   3  * some common structs and functions to handle infrared remotes via
   4  * input layer ...
   5  *
   6  * (c) 2003 Gerd Knorr <kraxel@bytesex.org> [SuSE Labs]
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or
  11  *  (at your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to the Free Software
  20  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/moduleparam.h>
  25 #include <linux/string.h>
  26 #include <media/ir-common.h>
  27
  28 /* -------------------------------------------------------------------------- */
  29
  30 MODULE_AUTHOR("Gerd Knorr <kraxel@bytesex.org> [SuSE Labs]");
  31 MODULE_LICENSE("GPL");
  32
  33 static int repeat = 1;
  34 module_param(repeat, int, 0444);
  35 MODULE_PARM_DESC(repeat,"auto-repeat for IR keys (default: on)");
  36
  37 static int debug = 0;    /* debug level (0,1,2) */
  38 module_param(debug, int, 0644);
  39
  40 #define dprintk(level, fmt, arg...)     if (debug >= level) \
  41         printk(KERN_DEBUG fmt , ## arg)
  42
  43 /* -------------------------------------------------------------------------- */
  44
  45 static void ir_input_key_event(struct input_dev *dev, struct ir_input_state *ir)
  46 {
  47         if (KEY_RESERVED == ir->keycode) {
  48                 printk(KERN_INFO "%s: unknown key: key=0x%02x raw=0x%02x down=%d\n",
  49                        dev->name,ir->ir_key,ir->ir_raw,ir->keypressed);
  50                 return;
  51         }
  52         dprintk(1,"%s: key event code=%d down=%d\n",
  53                 dev->name,ir->keycode,ir->keypressed);
  54         input_report_key(dev,ir->keycode,ir->keypressed);
  55         input_sync(dev);
  56 }
  57
  58 /* -------------------------------------------------------------------------- */
  59
  60 void ir_input_init(struct input_dev *dev, struct ir_input_state *ir,
  61                    int ir_type, IR_KEYTAB_TYPE *ir_codes)
  62 {
  63         int i;
  64
  65         ir->ir_type = ir_type;
  66         if (ir_codes)
  67                 memcpy(ir->ir_codes, ir_codes, sizeof(ir->ir_codes));
  68
  69
  70         dev->keycode     = ir->ir_codes;
  71         dev->keycodesize = sizeof(IR_KEYTAB_TYPE);
  72         dev->keycodemax  = IR_KEYTAB_SIZE;
  73         for (i = 0; i < IR_KEYTAB_SIZE; i++)
  74                 set_bit(ir->ir_codes[i], dev->keybit);
  75         clear_bit(0, dev->keybit);
  76
  77         set_bit(EV_KEY, dev->evbit);
  78         if (repeat)
  79                 set_bit(EV_REP, dev->evbit);
  80 }
  81
  82 void ir_input_nokey(struct input_dev *dev, struct ir_input_state *ir)
  83 {
  84         if (ir->keypressed) {
  85                 ir->keypressed = 0;
  86                 ir_input_key_event(dev,ir);
  87         }
  88 }
  89
  90 void ir_input_keydown(struct input_dev *dev, struct ir_input_state *ir,
  91                       u32 ir_key, u32 ir_raw)
  92 {
  93         u32 keycode = IR_KEYCODE(ir->ir_codes, ir_key);
  94
  95         if (ir->keypressed && ir->keycode != keycode) {
  96                 ir->keypressed = 0;
  97                 ir_input_key_event(dev,ir);
  98         }
  99         if (!ir->keypressed) {
 100                 ir->ir_key  = ir_key;
 101                 ir->ir_raw  = ir_raw;
 102                 ir->keycode = keycode;
 103                 ir->keypressed = 1;
 104                 ir_input_key_event(dev,ir);
 105         }
 106 }
 107
 108 /* -------------------------------------------------------------------------- */
 109
 110 u32 ir_extract_bits(u32 data, u32 mask)
 111 {
 112         int mbit, vbit;
 113         u32 value;
 114
 115         value = 0;
 116         vbit  = 0;
 117         for (mbit = 0; mbit < 32; mbit++) {
 118                 if (!(mask & ((u32)1 << mbit)))
 119                         continue;
 120                 if (data & ((u32)1 << mbit))
 121                         value |= (1 << vbit);
 122                 vbit++;
 123         }
 124         return value;
 125 }
 126
 127 static int inline getbit(u32 *samples, int bit)
 128 {
 129         return (samples[bit/32] & (1 << (31-(bit%32)))) ? 1 : 0;
 130 }
 131
 132 /* sump raw samples for visual debugging ;) */
 133 int ir_dump_samples(u32 *samples, int count)
 134 {
 135         int i, bit, start;
 136
 137         printk(KERN_DEBUG "ir samples: ");
 138         start = 0;
 139         for (i = 0; i < count * 32; i++) {
 140                 bit = getbit(samples,i);
 141                 if (bit)
 142                         start = 1;
 143                 if (0 == start)
 144                         continue;
 145                 printk("%s", bit ? "#" : "_");
 146         }
 147         printk("\n");
 148         return 0;
 149 }
 150
 151 /* decode raw samples, pulse distance coding used by NEC remotes */
 152 int ir_decode_pulsedistance(u32 *samples, int count, int low, int high)
 153 {
 154         int i,last,bit,len;
 155         u32 curBit;
 156         u32 value;
 157
 158         /* find start burst */
 159         for (i = len = 0; i < count * 32; i++) {
 160                 bit = getbit(samples,i);
 161                 if (bit) {
 162                         len++;
 163                 } else {
 164                         if (len >= 29)
 165                                 break;
 166                         len = 0;
 167                 }
 168         }
 169
 170         /* start burst to short */
 171         if (len < 29)
 172                 return 0xffffffff;
 173
 174         /* find start silence */
 175         for (len = 0; i < count * 32; i++) {
 176                 bit = getbit(samples,i);
 177                 if (bit) {
 178                         break;
 179                 } else {
 180                         len++;
 181                 }
 182         }
 183
 184         /* silence to short */
 185         if (len < 7)
 186                 return 0xffffffff;
 187
 188         /* go decoding */
 189         len   = 0;
 190         last = 1;
 191         value = 0; curBit = 1;
 192         for (; i < count * 32; i++) {
 193                 bit  = getbit(samples,i);
 194                 if (last) {
 195                         if(bit) {
 196                                 continue;
 197                         } else {
 198                                 len = 1;
 199                         }
 200                 } else {
 201                         if (bit) {
 202                                 if (len > (low + high) /2)
 203                                         value |= curBit;
 204                                 curBit <<= 1;
 205                                 if (curBit == 1)
 206                                         break;
 207                         } else {
 208                                 len++;
 209                         }
 210                 }
 211                 last = bit;
 212         }
 213
 214         return value;
 215 }
 216
 217 /* decode raw samples, biphase coding, used by rc5 for example */
 218 int ir_decode_biphase(u32 *samples, int count, int low, int high)
 219 {
 220         int i,last,bit,len,flips;
 221         u32 value;
 222
 223         /* find start bit (1) */
 224         for (i = 0; i < 32; i++) {
 225                 bit = getbit(samples,i);
 226                 if (bit)
 227                         break;
 228         }
 229
 230         /* go decoding */
 231         len   = 0;
 232         flips = 0;
 233         value = 1;
 234         for (; i < count * 32; i++) {
 235                 if (len > high)
 236                         break;
 237                 if (flips > 1)
 238                         break;
 239                 last = bit;
 240                 bit  = getbit(samples,i);
 241                 if (last == bit) {
 242                         len++;
 243                         continue;
 244                 }
 245                 if (len < low) {
 246                         len++;
 247                         flips++;
 248                         continue;
 249                 }
 250                 value <<= 1;
 251                 value |= bit;
 252                 flips = 0;
 253                 len   = 1;
 254         }
 255         return value;
 256 }
 257
 258 EXPORT_SYMBOL_GPL(ir_input_init);
 259 EXPORT_SYMBOL_GPL(ir_input_nokey);
 260 EXPORT_SYMBOL_GPL(ir_input_keydown);
 261
 262 EXPORT_SYMBOL_GPL(ir_extract_bits);
 263 EXPORT_SYMBOL_GPL(ir_dump_samples);
 264 EXPORT_SYMBOL_GPL(ir_decode_biphase);
 265 EXPORT_SYMBOL_GPL(ir_decode_pulsedistance);
 266
 267 /*
 268  * Local variables:
 269  * c-basic-offset: 8
 270  * End:
 271  */