LXR linux/drivers/media/rc/sir

   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 */
  31static int io = 0x3e8;
  32static int irq = 4;
  33static int threshold = 3;
  34
  35static DEFINE_SPINLOCK(timer_lock);
  36static struct timer_list timerlist;
  37/* time of last signal change detected */
  38static ktime_t last;
  39/* time of last UART data ready interrupt */
  40static ktime_t last_intr_time;
  41static int last_value;
  42static struct rc_dev *rcdev;
  43
  44static struct platform_device *sir_ir_dev;
  45
  46static DEFINE_SPINLOCK(hardware_lock);
  47
  48/* SECTION: Prototypes */
  49
  50/* Communication with user-space */
  51static void add_read_queue(int flag, unsigned long val);
  52/* Hardware */
  53static irqreturn_t sir_interrupt(int irq, void *dev_id);
  54static void send_space(unsigned long len);
  55static void send_pulse(unsigned long len);
  56static int init_hardware(void);
  57static void drop_hardware(void);
  58/* Initialisation */
  59
  60static inline unsigned int sinp(int offset)
  61{
  62        return inb(io + offset);
  63}
  64
  65static inline void soutp(int offset, int value)
  66{
  67        outb(value, io + offset);
  68}
  69
  70/* SECTION: Communication with user-space */
  71static 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
  93static 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 */
 119static 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
 150static 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
 242static void send_space(unsigned long len)
 243{
 244        usleep_range(len, len + 25);
 245}
 246
 247static 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
 262static 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
 313static 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 */
 326static 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
 376static int sir_ir_remove(struct platform_device *dev)
 377{
 378        drop_hardware();
 379        del_timer_sync(&timerlist);
 380        return 0;
 381}
 382
 383static 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
 391static 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
 411pdev_add_fail:
 412        platform_device_put(sir_ir_dev);
 413pdev_alloc_fail:
 414        platform_driver_unregister(&sir_ir_driver);
 415        return retval;
 416}
 417
 418static void __exit sir_ir_exit(void)
 419{
 420        platform_device_unregister(sir_ir_dev);
 421        platform_driver_unregister(&sir_ir_driver);
 422}
 423
 424module_init(sir_ir_init);
 425module_exit(sir_ir_exit);
 426
 427MODULE_DESCRIPTION("Infrared receiver driver for SIR type serial ports");
 428MODULE_AUTHOR("Milan Pikula");
 429MODULE_LICENSE("GPL");
 430
 431module_param_hw(io, int, ioport, 0444);
 432MODULE_PARM_DESC(io, "I/O address base (0x3f8 or 0x2f8)");
 433
 434module_param_hw(irq, int, irq, 0444);
 435MODULE_PARM_DESC(irq, "Interrupt (4 or 3)");
 436
 437module_param(threshold, int, 0444);
 438MODULE_PARM_DESC(threshold, "space detection threshold (3)");
 439