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

   1 /* ir-sony-decoder.c - handle Sony 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 SONY_UNIT               600000 /* ns */
  19 #define SONY_HEADER_PULSE       (4 * SONY_UNIT)
  20 #define SONY_HEADER_SPACE       (1 * SONY_UNIT)
  21 #define SONY_BIT_0_PULSE        (1 * SONY_UNIT)
  22 #define SONY_BIT_1_PULSE        (2 * SONY_UNIT)
  23 #define SONY_BIT_SPACE          (1 * SONY_UNIT)
  24 #define SONY_TRAILER_SPACE      (10 * SONY_UNIT) /* minimum */
  25
  26 /* Used to register sony_decoder clients */
  27 static LIST_HEAD(decoder_list);
  28 static DEFINE_SPINLOCK(decoder_lock);
  29
  30 enum sony_state {
  31         STATE_INACTIVE,
  32         STATE_HEADER_SPACE,
  33         STATE_BIT_PULSE,
  34         STATE_BIT_SPACE,
  35         STATE_FINISHED,
  36 };
  37
  38 struct decoder_data {
  39         struct list_head        list;
  40         struct ir_input_dev     *ir_dev;
  41         int                     enabled:1;
  42
  43         /* State machine control */
  44         enum sony_state         state;
  45         u32                     sony_bits;
  46         unsigned                count;
  47 };
  48
  49
  50 /**
  51  * get_decoder_data()   - gets decoder data
  52  * @input_dev:  input device
  53  *
  54  * Returns the struct decoder_data that corresponds to a device
  55  */
  56 static struct decoder_data *get_decoder_data(struct  ir_input_dev *ir_dev)
  57 {
  58         struct decoder_data *data = NULL;
  59
  60         spin_lock(&decoder_lock);
  61         list_for_each_entry(data, &decoder_list, list) {
  62                 if (data->ir_dev == ir_dev)
  63                         break;
  64         }
  65         spin_unlock(&decoder_lock);
  66         return data;
  67 }
  68
  69 static ssize_t store_enabled(struct device *d,
  70                              struct device_attribute *mattr,
  71                              const char *buf,
  72                              size_t len)
  73 {
  74         unsigned long value;
  75         struct ir_input_dev *ir_dev = dev_get_drvdata(d);
  76         struct decoder_data *data = get_decoder_data(ir_dev);
  77
  78         if (!data)
  79                 return -EINVAL;
  80
  81         if (strict_strtoul(buf, 10, &value) || value > 1)
  82                 return -EINVAL;
  83
  84         data->enabled = value;
  85
  86         return len;
  87 }
  88
  89 static ssize_t show_enabled(struct device *d,
  90                              struct device_attribute *mattr, char *buf)
  91 {
  92         struct ir_input_dev *ir_dev = dev_get_drvdata(d);
  93         struct decoder_data *data = get_decoder_data(ir_dev);
  94
  95         if (!data)
  96                 return -EINVAL;
  97
  98         if (data->enabled)
  99                 return sprintf(buf, "1\n");
 100         else
 101         return sprintf(buf, "0\n");
 102 }
 103
 104 static DEVICE_ATTR(enabled, S_IRUGO | S_IWUSR, show_enabled, store_enabled);
 105
 106 static struct attribute *decoder_attributes[] = {
 107         &dev_attr_enabled.attr,
 108         NULL
 109 };
 110
 111 static struct attribute_group decoder_attribute_group = {
 112         .name   = "sony_decoder",
 113         .attrs  = decoder_attributes,
 114 };
 115
 116 /**
 117  * ir_sony_decode() - Decode one Sony pulse or space
 118  * @input_dev:  the struct input_dev descriptor of the device
 119  * @ev:         the struct ir_raw_event descriptor of the pulse/space
 120  *
 121  * This function returns -EINVAL if the pulse violates the state machine
 122  */
 123 static int ir_sony_decode(struct input_dev *input_dev, struct ir_raw_event ev)
 124 {
 125         struct decoder_data *data;
 126         struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
 127         u32 scancode;
 128         u8 device, subdevice, function;
 129
 130         data = get_decoder_data(ir_dev);
 131         if (!data)
 132                 return -EINVAL;
 133
 134         if (!data->enabled)
 135                 return 0;
 136
 137         if (IS_RESET(ev)) {
 138                 data->state = STATE_INACTIVE;
 139                 return 0;
 140         }
 141
 142         if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2))
 143                 goto out;
 144
 145         IR_dprintk(2, "Sony decode started at state %d (%uus %s)\n",
 146                    data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 147
 148         switch (data->state) {
 149
 150         case STATE_INACTIVE:
 151                 if (!ev.pulse)
 152                         break;
 153
 154                 if (!eq_margin(ev.duration, SONY_HEADER_PULSE, SONY_UNIT / 2))
 155                         break;
 156
 157                 data->count = 0;
 158                 data->state = STATE_HEADER_SPACE;
 159                 return 0;
 160
 161         case STATE_HEADER_SPACE:
 162                 if (ev.pulse)
 163                         break;
 164
 165                 if (!eq_margin(ev.duration, SONY_HEADER_SPACE, SONY_UNIT / 2))
 166                         break;
 167
 168                 data->state = STATE_BIT_PULSE;
 169                 return 0;
 170
 171         case STATE_BIT_PULSE:
 172                 if (!ev.pulse)
 173                         break;
 174
 175                 data->sony_bits <<= 1;
 176                 if (eq_margin(ev.duration, SONY_BIT_1_PULSE, SONY_UNIT / 2))
 177                         data->sony_bits |= 1;
 178                 else if (!eq_margin(ev.duration, SONY_BIT_0_PULSE, SONY_UNIT / 2))
 179                         break;
 180
 181                 data->count++;
 182                 data->state = STATE_BIT_SPACE;
 183                 return 0;
 184
 185         case STATE_BIT_SPACE:
 186                 if (ev.pulse)
 187                         break;
 188
 189                 if (!geq_margin(ev.duration, SONY_BIT_SPACE, SONY_UNIT / 2))
 190                         break;
 191
 192                 decrease_duration(&ev, SONY_BIT_SPACE);
 193
 194                 if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2)) {
 195                         data->state = STATE_BIT_PULSE;
 196                         return 0;
 197                 }
 198
 199                 data->state = STATE_FINISHED;
 200                 /* Fall through */
 201
 202         case STATE_FINISHED:
 203                 if (ev.pulse)
 204                         break;
 205
 206                 if (!geq_margin(ev.duration, SONY_TRAILER_SPACE, SONY_UNIT / 2))
 207                         break;
 208
 209                 switch (data->count) {
 210                 case 12:
 211                         device    = bitrev8((data->sony_bits <<  3) & 0xF8);
 212                         subdevice = 0;
 213                         function  = bitrev8((data->sony_bits >>  4) & 0xFE);
 214                         break;
 215                 case 15:
 216                         device    = bitrev8((data->sony_bits >>  0) & 0xFF);
 217                         subdevice = 0;
 218                         function  = bitrev8((data->sony_bits >>  7) & 0xFD);
 219                         break;
 220                 case 20:
 221                         device    = bitrev8((data->sony_bits >>  5) & 0xF8);
 222                         subdevice = bitrev8((data->sony_bits >>  0) & 0xFF);
 223                         function  = bitrev8((data->sony_bits >> 12) & 0xFE);
 224                         break;
 225                 default:
 226                         IR_dprintk(1, "Sony invalid bitcount %u\n", data->count);
 227                         goto out;
 228                 }
 229
 230                 scancode = device << 16 | subdevice << 8 | function;
 231                 IR_dprintk(1, "Sony(%u) scancode 0x%05x\n", data->count, scancode);
 232                 ir_keydown(input_dev, scancode, 0);
 233                 data->state = STATE_INACTIVE;
 234                 return 0;
 235         }
 236
 237 out:
 238         IR_dprintk(1, "Sony decode failed at state %d (%uus %s)\n",
 239                    data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 240         data->state = STATE_INACTIVE;
 241         return -EINVAL;
 242 }
 243
 244 static int ir_sony_register(struct input_dev *input_dev)
 245 {
 246         struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
 247         struct decoder_data *data;
 248         int rc;
 249
 250         rc = sysfs_create_group(&ir_dev->dev.kobj, &decoder_attribute_group);
 251         if (rc < 0)
 252                 return rc;
 253
 254         data = kzalloc(sizeof(*data), GFP_KERNEL);
 255         if (!data) {
 256                 sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group);
 257                 return -ENOMEM;
 258         }
 259
 260         data->ir_dev = ir_dev;
 261         data->enabled = 1;
 262
 263         spin_lock(&decoder_lock);
 264         list_add_tail(&data->list, &decoder_list);
 265         spin_unlock(&decoder_lock);
 266
 267         return 0;
 268 }
 269
 270 static int ir_sony_unregister(struct input_dev *input_dev)
 271 {
 272         struct ir_input_dev *ir_dev = input_get_drvdata(input_dev);
 273         static struct decoder_data *data;
 274
 275         data = get_decoder_data(ir_dev);
 276         if (!data)
 277                 return 0;
 278
 279         sysfs_remove_group(&ir_dev->dev.kobj, &decoder_attribute_group);
 280
 281         spin_lock(&decoder_lock);
 282         list_del(&data->list);
 283         spin_unlock(&decoder_lock);
 284
 285         return 0;
 286 }
 287
 288 static struct ir_raw_handler sony_handler = {
 289         .decode         = ir_sony_decode,
 290         .raw_register   = ir_sony_register,
 291         .raw_unregister = ir_sony_unregister,
 292 };
 293
 294 static int __init ir_sony_decode_init(void)
 295 {
 296         ir_raw_handler_register(&sony_handler);
 297
 298         printk(KERN_INFO "IR Sony protocol handler initialized\n");
 299         return 0;
 300 }
 301
 302 static void __exit ir_sony_decode_exit(void)
 303 {
 304         ir_raw_handler_unregister(&sony_handler);
 305 }
 306
 307 module_init(ir_sony_decode_init);
 308 module_exit(ir_sony_decode_exit);
 309
 310 MODULE_LICENSE("GPL");
 311 MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
 312 MODULE_DESCRIPTION("Sony IR protocol decoder");