drivers/media/IR/ir-jvc-decoder.c

   1 /* ir-jvc-decoder.c - handle JVC IR Pulse/Space protocol
   2  *
   3  * Copyright (C) 2010 by David Härdeman <david@hardeman.nu>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation version 2 of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <linux/bitrev.h>
  16 #include "ir-core-priv.h"
  17
  18 #define JVC_NBITS               16              /* dev(8) + func(8) */
  19 #define JVC_UNIT                525000          /* ns */
  20 #define JVC_HEADER_PULSE        (16 * JVC_UNIT) /* lack of header -> repeat */
  21 #define JVC_HEADER_SPACE        (8  * JVC_UNIT)
  22 #define JVC_BIT_PULSE           (1  * JVC_UNIT)
  23 #define JVC_BIT_0_SPACE         (1  * JVC_UNIT)
  24 #define JVC_BIT_1_SPACE         (3  * JVC_UNIT)
  25 #define JVC_TRAILER_PULSE       (1  * JVC_UNIT)
  26 #define JVC_TRAILER_SPACE       (35 * JVC_UNIT)
  27
  28 /* Used to register jvc_decoder clients */
  29 static LIST_HEAD(decoder_list);
  30 DEFINE_SPINLOCK(decoder_lock);
  31
  32 enum jvc_state {
  33         STATE_INACTIVE,
  34         STATE_HEADER_SPACE,
  35         STATE_BIT_PULSE,
  36         STATE_BIT_SPACE,
  37         STATE_TRAILER_PULSE,
  38         STATE_TRAILER_SPACE,
  39 };
  40
  41 struct decoder_data {
  42         struct list_head        list;
  43         struct ir_input_dev     *ir_dev;
  44         int                     enabled:1;
  45
  46         /* State machine control */
  47         enum jvc_state          state;
  48         u16                     jvc_bits;
  49         u16                     jvc_old_bits;
  50         unsigned                count;
  51         bool                    first;
  52         bool                    toggle;
  53 };
  54
  55
  56 /**
  57  * get_decoder_data()   - gets decoder data
  58  * @input_dev:  input device
  59  *
  60  * Returns the struct decoder_data that corresponds to a device
  61  */
  62 static struct decoder_data *get_decoder_data(struct  ir_input_dev *ir_dev)
  63 {
  64         struct decoder_data *data = NULL;
  65
  66         spin_lock(&decoder_lock);
  67         list_for_each_entry(data, &decoder_list, list) {
  68                 if (data->ir_dev == ir_dev)
  69                         break;
  70         }
  71         spin_unlock(&decoder_lock);
  72         return data;
  73 }
  74
  75 static ssize_t store_enabled(struct device *d,
  76                              struct device_attribute *mattr,
  77                              const char *buf,
  78                              size_t len)
  79 {
  80         unsigned long value;
  81         struct ir_input_dev *ir_dev = dev_get_drvdata(d);
  82         struct decoder_data *data = get_decoder_data(ir_dev);
  83
  84         if (!data)
  85                 return -EINVAL;
  86
  87         if (strict_strtoul(buf, 10, &value) || value > 1)
  88                 return -EINVAL;
  89
  90         data->enabled = value;
  91
  92         return len;
  93 }
  94
  95 static ssize_t show_enabled(struct device *d,
  96                              struct device_attribute *mattr, char *buf)
  97 {
  98         struct ir_input_dev *ir_dev = dev_get_drvdata(d);
  99         struct decoder_data *data = get_decoder_data(ir_dev);
 100
 101         if (!data)
 102                 return -EINVAL;
 103
 104         if (data->enabled)
 105                 return sprintf(buf, "1\n");
 106         else
 107         return sprintf(buf, "0\n");
 108 }
 109
 110 static DEVICE_ATTR(enabled, S_IRUGO | S_IWUSR, show_enabled, store_enabled);
 111
 112 static struct attribute *decoder_attributes[] = {
 113         &dev_attr_enabled.attr,
 114         NULL
 115 };
 116
 117 static struct attribute_group decoder_attribute_group = {
 118         .name   = "jvc_decoder",
 119         .attrs  = decoder_attributes,
 120 };
 121
 122 /**
 123  * ir_jvc_decode() - Decode one JVC pulse or space
 124  * @input_dev:  the struct input_dev descriptor of the device
 125  * @duration:   the struct ir_raw_event descriptor of the pulse/space
 126  *
 127  * This function returns -EINVAL if the pulse violates the state machine
 128  */
 129 static int ir_jvc_decode(struct input_dev *input_dev, struct ir_raw_event ev)
 130 {
 131         struct decoder_data *data;
 132         struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
 133
 134         data = get_decoder_data(ir_dev);
 135         if (!data)
 136                 return -EINVAL;
 137
 138         if (!data->enabled)
 139                 return 0;
 140
 141         if (IS_RESET(ev)) {
 142                 data->state = STATE_INACTIVE;
 143                 return 0;
 144         }
 145
 146         if (!geq_margin(ev.duration, JVC_UNIT, JVC_UNIT / 2))
 147                 goto out;
 148
 149         IR_dprintk(2, "JVC decode started at state %d (%uus %s)\n",
 150                    data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 151
 152         switch (data->state) {
 153
 154         case STATE_INACTIVE:
 155                 if (!ev.pulse)
 156                         break;
 157
 158                 if (!eq_margin(ev.duration, JVC_HEADER_PULSE, JVC_UNIT / 2))
 159                         break;
 160
 161                 data->count = 0;
 162                 data->first = true;
 163                 data->toggle = !data->toggle;
 164                 data->state = STATE_HEADER_SPACE;
 165                 return 0;
 166
 167         case STATE_HEADER_SPACE:
 168                 if (ev.pulse)
 169                         break;
 170
 171                 if (!eq_margin(ev.duration, JVC_HEADER_SPACE, JVC_UNIT / 2))
 172                         break;
 173
 174                 data->state = STATE_BIT_PULSE;
 175                 return 0;
 176
 177         case STATE_BIT_PULSE:
 178                 if (!ev.pulse)
 179                         break;
 180
 181                 if (!eq_margin(ev.duration, JVC_BIT_PULSE, JVC_UNIT / 2))
 182                         break;
 183
 184                 data->state = STATE_BIT_SPACE;
 185                 return 0;
 186
 187         case STATE_BIT_SPACE:
 188                 if (ev.pulse)
 189                         break;
 190
 191                 data->jvc_bits <<= 1;
 192                 if (eq_margin(ev.duration, JVC_BIT_1_SPACE, JVC_UNIT / 2)) {
 193                         data->jvc_bits |= 1;
 194                         decrease_duration(&ev, JVC_BIT_1_SPACE);
 195                 } else if (eq_margin(ev.duration, JVC_BIT_0_SPACE, JVC_UNIT / 2))
 196                         decrease_duration(&ev, JVC_BIT_0_SPACE);
 197                 else
 198                         break;
 199                 data->count++;
 200
 201                 if (data->count == JVC_NBITS)
 202                         data->state = STATE_TRAILER_PULSE;
 203                 else
 204                         data->state = STATE_BIT_PULSE;
 205                 return 0;
 206
 207         case STATE_TRAILER_PULSE:
 208                 if (!ev.pulse)
 209                         break;
 210
 211                 if (!eq_margin(ev.duration, JVC_TRAILER_PULSE, JVC_UNIT / 2))
 212                         break;
 213
 214                 data->state = STATE_TRAILER_SPACE;
 215                 return 0;
 216
 217         case STATE_TRAILER_SPACE:
 218                 if (ev.pulse)
 219                         break;
 220
 221                 if (!geq_margin(ev.duration, JVC_TRAILER_SPACE, JVC_UNIT / 2))
 222                         break;
 223
 224                 if (data->first) {
 225                         u32 scancode;
 226                         scancode = (bitrev8((data->jvc_bits >> 8) & 0xff) << 8) |
 227                                    (bitrev8((data->jvc_bits >> 0) & 0xff) << 0);
 228                         IR_dprintk(1, "JVC scancode 0x%04x\n", scancode);
 229                         ir_keydown(input_dev, scancode, data->toggle);
 230                         data->first = false;
 231                         data->jvc_old_bits = data->jvc_bits;
 232                 } else if (data->jvc_bits == data->jvc_old_bits) {
 233                         IR_dprintk(1, "JVC repeat\n");
 234                         ir_repeat(input_dev);
 235                 } else {
 236                         IR_dprintk(1, "JVC invalid repeat msg\n");
 237                         break;
 238                 }
 239
 240                 data->count = 0;
 241                 data->state = STATE_BIT_PULSE;
 242                 return 0;
 243         }
 244
 245 out:
 246         IR_dprintk(1, "JVC decode failed at state %d (%uus %s)\n",
 247                    data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 248         data->state = STATE_INACTIVE;
 249         return -EINVAL;
 250 }
 251
 252 static int ir_jvc_register(struct input_dev *input_dev)
 253 {
 254         struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
 255         struct decoder_data *data;
 256         int rc;
 257
 258         rc = sysfs_create_group(&ir_dev->dev.kobj, &decoder_attribute_group);
 259         if (rc < 0)
 260                 return rc;
 261
 262         data = kzalloc(sizeof(*data), GFP_KERNEL);
 263         if (!data) {
 264                 sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group);
 265                 return -ENOMEM;
 266         }
 267
 268         data->ir_dev = ir_dev;
 269         data->enabled = 1;
 270
 271         spin_lock(&decoder_lock);
 272         list_add_tail(&data->list, &decoder_list);
 273         spin_unlock(&decoder_lock);
 274
 275         return 0;
 276 }
 277
 278 static int ir_jvc_unregister(struct input_dev *input_dev)
 279 {
 280         struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
 281         static struct decoder_data *data;
 282
 283         data = get_decoder_data(ir_dev);
 284         if (!data)
 285                 return 0;
 286
 287         sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group);
 288
 289         spin_lock(&decoder_lock);
 290         list_del(&data->list);
 291         spin_unlock(&decoder_lock);
 292
 293         return 0;
 294 }
 295
 296 static struct ir_raw_handler jvc_handler = {
 297         .decode         = ir_jvc_decode,
 298         .raw_register   = ir_jvc_register,
 299         .raw_unregister = ir_jvc_unregister,
 300 };
 301
 302 static int __init ir_jvc_decode_init(void)
 303 {
 304         ir_raw_handler_register(&jvc_handler);
 305
 306         printk(KERN_INFO "IR JVC protocol handler initialized\n");
 307         return 0;
 308 }
 309
 310 static void __exit ir_jvc_decode_exit(void)
 311 {
 312         ir_raw_handler_unregister(&jvc_handler);
 313 }
 314
 315 module_init(ir_jvc_decode_init);
 316 module_exit(ir_jvc_decode_exit);
 317
 318 MODULE_LICENSE("GPL");
 319 MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
 320 MODULE_DESCRIPTION("JVC IR protocol decoder");