drivers/media/rc/sir_ir.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * IR SIR driver, (C) 2000 Milan Pikula <www@fornax.sk>
   4  *
   5  * sir_ir - Device driver for use with SIR (serial infra red)
   6  * mode of IrDA on many notebooks.
   7  */
   8
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/module.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/kernel.h>
  14 #include <linux/serial_reg.h>
  15 #include <linux/ktime.h>
  16 #include <linux/delay.h>
  17 #include <linux/platform_device.h>
  18
  19 #include <media/rc-core.h>
  20
  21 /* SECTION: Definitions */
  22 #define PULSE '['
  23
  24 /* 9bit * 1s/115200bit in milli seconds = 78.125ms*/
  25 #define TIME_CONST (9000000ul / 115200ul)
  26
  27 /* timeout for sequences in jiffies (=5/100s), must be longer than TIME_CONST */
  28 #define SIR_TIMEOUT     (HZ * 5 / 100)
  29
  30 /* onboard sir ports are typically com3 */
  31 static int io = 0x3e8;
  32 static int irq = 4;
  33 static int threshold = 3;
  34
  35 static DEFINE_SPINLOCK(timer_lock);
  36 static struct timer_list timerlist;
  37 /* time of last signal change detected */
  38 static ktime_t last;
  39 /* time of last UART data ready interrupt */
  40 static ktime_t last_intr_time;
  41 static int last_value;
  42 static struct rc_dev *rcdev;
  43
  44 static struct platform_device *sir_ir_dev;
  45
  46 static DEFINE_SPINLOCK(hardware_lock);
  47
  48 /* SECTION: Prototypes */
  49
  50 /* Communication with user-space */
  51 static void add_read_queue(int flag, unsigned long val);
  52 /* Hardware */
  53 static irqreturn_t sir_interrupt(int irq, void *dev_id);
  54 static void send_space(unsigned long len);
  55 static void send_pulse(unsigned long len);
  56 static int init_hardware(void);
  57 static void drop_hardware(void);
  58 /* Initialisation */
  59
  60 static inline unsigned int sinp(int offset)
  61 {
  62         return inb(io + offset);
  63 }
  64
  65 static inline void soutp(int offset, int value)
  66 {
  67         outb(value, io + offset);
  68 }
  69
  70 /* SECTION: Communication with user-space */
  71 static int sir_tx_ir(struct rc_dev *dev, unsigned int *tx_buf,
  72                      unsigned int count)
  73 {
  74         unsigned long flags;
  75         int i;
  76
  77         local_irq_save(flags);
  78         for (i = 0; i < count;) {
  79                 if (tx_buf[i])
  80                         send_pulse(tx_buf[i]);
  81                 i++;
  82                 if (i >= count)
  83                         break;
  84                 if (tx_buf[i])
  85                         send_space(tx_buf[i]);
  86                 i++;
  87         }
  88         local_irq_restore(flags);
  89
  90         return count;
  91 }
  92
  93 static void add_read_queue(int flag, unsigned long val)
  94 {
  95         struct ir_raw_event ev = {};
  96
  97         pr_debug("add flag %d with val %lu\n", flag, val);
  98
  99         /*
 100          * statistically, pulses are ~TIME_CONST/2 too long. we could
 101          * maybe make this more exact, but this is good enough
 102          */
 103         if (flag) {
 104                 /* pulse */
 105                 if (val > TIME_CONST / 2)
 106                         val -= TIME_CONST / 2;
 107                 else /* should not ever happen */
 108                         val = 1;
 109                 ev.pulse = true;
 110         } else {
 111                 val += TIME_CONST / 2;
 112         }
 113         ev.duration = US_TO_NS(val);
 114
 115         ir_raw_event_store_with_filter(rcdev, &ev);
 116 }
 117
 118 /* SECTION: Hardware */
 119 static void sir_timeout(struct timer_list *unused)
 120 {
 121         /*
 122          * if last received signal was a pulse, but receiving stopped
 123          * within the 9 bit frame, we need to finish this pulse and
 124          * simulate a signal change to from pulse to space. Otherwise
 125          * upper layers will receive two sequences next time.
 126          */
 127
 128         unsigned long flags;
 129         unsigned long pulse_end;
 130
 131         /* avoid interference with interrupt */
 132         spin_lock_irqsave(&timer_lock, flags);
 133         if (last_value) {
 134                 /* clear unread bits in UART and restart */
 135                 outb(UART_FCR_CLEAR_RCVR, io + UART_FCR);
 136                 /* determine 'virtual' pulse end: */
 137                 pulse_end = min_t(unsigned long,
 138                                   ktime_us_delta(last, last_intr_time),
 139                                   IR_MAX_DURATION);
 140                 dev_dbg(&sir_ir_dev->dev, "timeout add %d for %lu usec\n",
 141                         last_value, pulse_end);
 142                 add_read_queue(last_value, pulse_end);
 143                 last_value = 0;
 144                 last = last_intr_time;
 145         }
 146         spin_unlock_irqrestore(&timer_lock, flags);
 147         ir_raw_event_handle(rcdev);
 148 }
 149
 150 static irqreturn_t sir_interrupt(int irq, void *dev_id)
 151 {
 152         unsigned char data;
 153         ktime_t curr_time;
 154         unsigned long delt;
 155         unsigned long deltintr;
 156         unsigned long flags;
 157         int counter = 0;
 158         int iir, lsr;
 159
 160         while ((iir = inb(io + UART_IIR) & UART_IIR_ID)) {
 161                 if (++counter > 256) {
 162                         dev_err(&sir_ir_dev->dev, "Trapped in interrupt");
 163                         break;
 164                 }
 165
 166                 switch (iir & UART_IIR_ID) { /* FIXME toto treba preriedit */
 167                 case UART_IIR_MSI:
 168                         (void)inb(io + UART_MSR);
 169                         break;
 170                 case UART_IIR_RLSI:
 171                 case UART_IIR_THRI:
 172                         (void)inb(io + UART_LSR);
 173                         break;
 174                 case UART_IIR_RDI:
 175                         /* avoid interference with timer */
 176                         spin_lock_irqsave(&timer_lock, flags);
 177                         do {
 178                                 del_timer(&timerlist);
 179                                 data = inb(io + UART_RX);
 180                                 curr_time = ktime_get();
 181                                 delt = min_t(unsigned long,
 182                                              ktime_us_delta(last, curr_time),
 183                                              IR_MAX_DURATION);
 184                                 deltintr = min_t(unsigned long,
 185                                                  ktime_us_delta(last_intr_time,
 186                                                                 curr_time),
 187                                                  IR_MAX_DURATION);
 188                                 dev_dbg(&sir_ir_dev->dev, "t %lu, d %d\n",
 189                                         deltintr, (int)data);
 190                                 /*
 191                                  * if nothing came in last X cycles,
 192                                  * it was gap
 193                                  */
 194                                 if (deltintr > TIME_CONST * threshold) {
 195                                         if (last_value) {
 196                                                 dev_dbg(&sir_ir_dev->dev, "GAP\n");
 197                                                 /* simulate signal change */
 198                                                 add_read_queue(last_value,
 199                                                                delt -
 200                                                                deltintr);
 201                                                 last_value = 0;
 202                                                 last = last_intr_time;
 203                                                 delt = deltintr;
 204                                         }
 205                                 }
 206                                 data = 1;
 207                                 if (data ^ last_value) {
 208                                         /*
 209                                          * deltintr > 2*TIME_CONST, remember?
 210                                          * the other case is timeout
 211                                          */
 212                                         add_read_queue(last_value,
 213                                                        delt - TIME_CONST);
 214                                         last_value = data;
 215                                         last = curr_time;
 216                                         last = ktime_sub_us(last,
 217                                                             TIME_CONST);
 218                                 }
 219                                 last_intr_time = curr_time;
 220                                 if (data) {
 221                                         /*
 222                                          * start timer for end of
 223                                          * sequence detection
 224                                          */
 225                                         timerlist.expires = jiffies +
 226                                                                 SIR_TIMEOUT;
 227                                         add_timer(&timerlist);
 228                                 }
 229
 230                                 lsr = inb(io + UART_LSR);
 231                         } while (lsr & UART_LSR_DR); /* data ready */
 232                         spin_unlock_irqrestore(&timer_lock, flags);
 233                         break;
 234                 default:
 235                         break;
 236                 }
 237         }
 238         ir_raw_event_handle(rcdev);
 239         return IRQ_RETVAL(IRQ_HANDLED);
 240 }
 241
 242 static void send_space(unsigned long len)
 243 {
 244         usleep_range(len, len + 25);
 245 }
 246
 247 static void send_pulse(unsigned long len)
 248 {
 249         long bytes_out = len / TIME_CONST;
 250
 251         if (bytes_out == 0)
 252                 bytes_out++;
 253
 254         while (bytes_out--) {
 255                 outb(PULSE, io + UART_TX);
 256                 /* FIXME treba seriozne cakanie z char/serial.c */
 257                 while (!(inb(io + UART_LSR) & UART_LSR_THRE))
 258                         ;
 259         }
 260 }
 261
 262 static int init_hardware(void)
 263 {
 264         u8 scratch, scratch2, scratch3;
 265         unsigned long flags;
 266
 267         spin_lock_irqsave(&hardware_lock, flags);
 268
 269         /*
 270          * This is a simple port existence test, borrowed from the autoconfig
 271          * function in drivers/tty/serial/8250/8250_port.c
 272          */
 273         scratch = sinp(UART_IER);
 274         soutp(UART_IER, 0);
 275 #ifdef __i386__
 276         outb(0xff, 0x080);
 277 #endif
 278         scratch2 = sinp(UART_IER) & 0x0f;
 279         soutp(UART_IER, 0x0f);
 280 #ifdef __i386__
 281         outb(0x00, 0x080);
 282 #endif
 283         scratch3 = sinp(UART_IER) & 0x0f;
 284         soutp(UART_IER, scratch);
 285         if (scratch2 != 0 || scratch3 != 0x0f) {
 286                 /* we fail, there's nothing here */
 287                 spin_unlock_irqrestore(&hardware_lock, flags);
 288                 pr_err("port existence test failed, cannot continue\n");
 289                 return -ENODEV;
 290         }
 291
 292         /* reset UART */
 293         outb(0, io + UART_MCR);
 294         outb(0, io + UART_IER);
 295         /* init UART */
 296         /* set DLAB, speed = 115200 */
 297         outb(UART_LCR_DLAB | UART_LCR_WLEN7, io + UART_LCR);
 298         outb(1, io + UART_DLL); outb(0, io + UART_DLM);
 299         /* 7N1+start = 9 bits at 115200 ~ 3 bits at 44000 */
 300         outb(UART_LCR_WLEN7, io + UART_LCR);
 301         /* FIFO operation */
 302         outb(UART_FCR_ENABLE_FIFO, io + UART_FCR);
 303         /* interrupts */
 304         /* outb(UART_IER_RLSI|UART_IER_RDI|UART_IER_THRI, io + UART_IER); */
 305         outb(UART_IER_RDI, io + UART_IER);
 306         /* turn on UART */
 307         outb(UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2, io + UART_MCR);
 308         spin_unlock_irqrestore(&hardware_lock, flags);
 309
 310         return 0;
 311 }
 312
 313 static void drop_hardware(void)
 314 {
 315         unsigned long flags;
 316
 317         spin_lock_irqsave(&hardware_lock, flags);
 318
 319         /* turn off interrupts */
 320         outb(0, io + UART_IER);
 321
 322         spin_unlock_irqrestore(&hardware_lock, flags);
 323 }
 324
 325 /* SECTION: Initialisation */
 326 static int sir_ir_probe(struct platform_device *dev)
 327 {
 328         int retval;
 329
 330         rcdev = devm_rc_allocate_device(&sir_ir_dev->dev, RC_DRIVER_IR_RAW);
 331         if (!rcdev)
 332                 return -ENOMEM;
 333
 334         rcdev->device_name = "SIR IrDA port";
 335         rcdev->input_phys = KBUILD_MODNAME "/input0";
 336         rcdev->input_id.bustype = BUS_HOST;
 337         rcdev->input_id.vendor = 0x0001;
 338         rcdev->input_id.product = 0x0001;
 339         rcdev->input_id.version = 0x0100;
 340         rcdev->tx_ir = sir_tx_ir;
 341         rcdev->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER;
 342         rcdev->driver_name = KBUILD_MODNAME;
 343         rcdev->map_name = RC_MAP_RC6_MCE;
 344         rcdev->timeout = IR_DEFAULT_TIMEOUT;
 345         rcdev->dev.parent = &sir_ir_dev->dev;
 346
 347         timer_setup(&timerlist, sir_timeout, 0);
 348
 349         /* get I/O port access and IRQ line */
 350         if (!devm_request_region(&sir_ir_dev->dev, io, 8, KBUILD_MODNAME)) {
 351                 pr_err("i/o port 0x%.4x already in use.\n", io);
 352                 return -EBUSY;
 353         }
 354         retval = devm_request_irq(&sir_ir_dev->dev, irq, sir_interrupt, 0,
 355                                   KBUILD_MODNAME, NULL);
 356         if (retval < 0) {
 357                 pr_err("IRQ %d already in use.\n", irq);
 358                 return retval;
 359         }
 360
 361         retval = init_hardware();
 362         if (retval) {
 363                 del_timer_sync(&timerlist);
 364                 return retval;
 365         }
 366
 367         pr_info("I/O port 0x%.4x, IRQ %d.\n", io, irq);
 368
 369         retval = devm_rc_register_device(&sir_ir_dev->dev, rcdev);
 370         if (retval < 0)
 371                 return retval;
 372
 373         return 0;
 374 }
 375
 376 static int sir_ir_remove(struct platform_device *dev)
 377 {
 378         drop_hardware();
 379         del_timer_sync(&timerlist);
 380         return 0;
 381 }
 382
 383 static struct platform_driver sir_ir_driver = {
 384         .probe          = sir_ir_probe,
 385         .remove         = sir_ir_remove,
 386         .driver         = {
 387                 .name   = "sir_ir",
 388         },
 389 };
 390
 391 static int __init sir_ir_init(void)
 392 {
 393         int retval;
 394
 395         retval = platform_driver_register(&sir_ir_driver);
 396         if (retval)
 397                 return retval;
 398
 399         sir_ir_dev = platform_device_alloc("sir_ir", 0);
 400         if (!sir_ir_dev) {
 401                 retval = -ENOMEM;
 402                 goto pdev_alloc_fail;
 403         }
 404
 405         retval = platform_device_add(sir_ir_dev);
 406         if (retval)
 407                 goto pdev_add_fail;
 408
 409         return 0;
 410
 411 pdev_add_fail:
 412         platform_device_put(sir_ir_dev);
 413 pdev_alloc_fail:
 414         platform_driver_unregister(&sir_ir_driver);
 415         return retval;
 416 }
 417
 418 static void __exit sir_ir_exit(void)
 419 {
 420         platform_device_unregister(sir_ir_dev);
 421         platform_driver_unregister(&sir_ir_driver);
 422 }
 423
 424 module_init(sir_ir_init);
 425 module_exit(sir_ir_exit);
 426
 427 MODULE_DESCRIPTION("Infrared receiver driver for SIR type serial ports");
 428 MODULE_AUTHOR("Milan Pikula");
 429 MODULE_LICENSE("GPL");
 430
 431 module_param_hw(io, int, ioport, 0444);
 432 MODULE_PARM_DESC(io, "I/O address base (0x3f8 or 0x2f8)");
 433
 434 module_param_hw(irq, int, irq, 0444);
 435 MODULE_PARM_DESC(irq, "Interrupt (4 or 3)");
 436
 437 module_param(threshold, int, 0444);
 438 MODULE_PARM_DESC(threshold, "space detection threshold (3)");