target/linux/s3c24xx/files-2.6.31/drivers/power/hdq.c

   1 /*
   2  * HDQ generic GPIO bitbang driver using FIQ
   3  *
   4  * (C) 2006-2007 by Openmoko, Inc.
   5  * Author: Andy Green <andy@openmoko.com>
   6  * All rights reserved.
   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 version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/delay.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/hdq.h>
  19
  20 #define HDQ_READ 0
  21 #define HDQ_WRITE 0x80
  22
  23 enum hdq_bitbang_states {
  24         HDQB_IDLE = 0,
  25         HDQB_TX_BREAK,
  26         HDQB_TX_BREAK_RECOVERY,
  27         HDQB_ADS_CALC,
  28         HDQB_ADS_LOW,
  29         HDQB_ADS_HIGH,
  30         HDQB_WAIT_RX,
  31         HDQB_DATA_RX_LOW,
  32         HDQB_DATA_RX_HIGH,
  33         HDQB_WAIT_TX,
  34 };
  35
  36 static struct hdq_priv {
  37         u8 hdq_probed; /* nonzero after HDQ driver probed */
  38         struct mutex hdq_lock; /* if you want to use hdq, you have to take lock */
  39         unsigned long hdq_gpio_pin; /* GTA02 = GPD14 which pin to meddle with */
  40         u8 hdq_ads; /* b7..b6 = register address, b0 = r/w */
  41         u8 hdq_tx_data; /* data to tx for write action */
  42         u8 hdq_rx_data; /* data received in read action */
  43         u8 hdq_request_ctr; /* incremented by "user" to request a transfer */
  44         u8 hdq_transaction_ctr; /* incremented after each transfer */
  45         u8 hdq_error; /* 0 = no error */
  46         u8 hdq_ctr;
  47         u8 hdq_ctr2;
  48         u8 hdq_bit;
  49         u8 hdq_shifter;
  50         u8 hdq_tx_data_done;
  51         enum hdq_bitbang_states hdq_state;
  52         int reported_error;
  53
  54         struct hdq_platform_data *pdata;
  55 } hdq_priv;
  56
  57
  58 static void hdq_bad(void)
  59 {
  60         if (!hdq_priv.reported_error)
  61                 printk(KERN_ERR "HDQ error: %d\n", hdq_priv.hdq_error);
  62         hdq_priv.reported_error = 1;
  63 }
  64
  65 static void hdq_good(void)
  66 {
  67         if (hdq_priv.reported_error)
  68                 printk(KERN_INFO "HDQ responds again\n");
  69         hdq_priv.reported_error = 0;
  70 }
  71
  72 int hdq_fiq_handler(void)
  73 {
  74         if (!hdq_priv.hdq_probed)
  75                 return 0;
  76
  77         switch (hdq_priv.hdq_state) {
  78         case HDQB_IDLE:
  79                 if (hdq_priv.hdq_request_ctr == hdq_priv.hdq_transaction_ctr)
  80                         break;
  81                 hdq_priv.hdq_ctr = 250 / HDQ_SAMPLE_PERIOD_US;
  82                 hdq_priv.pdata->gpio_set(0);
  83                 hdq_priv.pdata->gpio_dir_out();
  84                 hdq_priv.hdq_tx_data_done = 0;
  85                 hdq_priv.hdq_state = HDQB_TX_BREAK;
  86                 break;
  87
  88         case HDQB_TX_BREAK: /* issue low for > 190us */
  89                 if (--hdq_priv.hdq_ctr == 0) {
  90                         hdq_priv.hdq_ctr = 60 / HDQ_SAMPLE_PERIOD_US;
  91                         hdq_priv.hdq_state = HDQB_TX_BREAK_RECOVERY;
  92                         hdq_priv.pdata->gpio_set(1);
  93                 }
  94                 break;
  95
  96         case HDQB_TX_BREAK_RECOVERY: /* issue low for > 40us */
  97                 if (--hdq_priv.hdq_ctr)
  98                         break;
  99                 hdq_priv.hdq_shifter = hdq_priv.hdq_ads;
 100                 hdq_priv.hdq_bit = 8; /* 8 bits of ads / rw */
 101                 hdq_priv.hdq_tx_data_done = 0; /* doing ads */
 102                 /* fallthru on last one */
 103         case HDQB_ADS_CALC:
 104                 if (hdq_priv.hdq_shifter & 1)
 105                         hdq_priv.hdq_ctr = 50 / HDQ_SAMPLE_PERIOD_US;
 106                 else
 107                         hdq_priv.hdq_ctr = 120 / HDQ_SAMPLE_PERIOD_US;
 108                 /* carefully precompute the other phase length */
 109                 hdq_priv.hdq_ctr2 = (210 - (hdq_priv.hdq_ctr * HDQ_SAMPLE_PERIOD_US)) /
 110                                 HDQ_SAMPLE_PERIOD_US;
 111                 hdq_priv.hdq_state = HDQB_ADS_LOW;
 112                 hdq_priv.hdq_shifter >>= 1;
 113                 hdq_priv.hdq_bit--;
 114                 hdq_priv.pdata->gpio_set(0);
 115                 break;
 116
 117         case HDQB_ADS_LOW:
 118                 if (--hdq_priv.hdq_ctr)
 119                         break;
 120                 hdq_priv.pdata->gpio_set(1);
 121                 hdq_priv.hdq_state = HDQB_ADS_HIGH;
 122                 break;
 123
 124         case HDQB_ADS_HIGH:
 125                 if (--hdq_priv.hdq_ctr2 > 1) /* account for HDQB_ADS_CALC */
 126                         break;
 127                 if (hdq_priv.hdq_bit) { /* more bits to do */
 128                         hdq_priv.hdq_state = HDQB_ADS_CALC;
 129                         break;
 130                 }
 131                 /* no more bits, wait it out until hdq_priv.hdq_ctr2 exhausted */
 132                 if (hdq_priv.hdq_ctr2)
 133                         break;
 134                 /* ok no more bits and very last state */
 135                 hdq_priv.hdq_ctr = 60 / HDQ_SAMPLE_PERIOD_US;
 136                 /* FIXME 0 = read */
 137                 if (hdq_priv.hdq_ads & 0x80) { /* write the byte out */
 138                          /* set delay before payload */
 139                         hdq_priv.hdq_ctr = 300 / HDQ_SAMPLE_PERIOD_US;
 140                         /* already high, no need to write */
 141                         hdq_priv.hdq_state = HDQB_WAIT_TX;
 142                         break;
 143                 }
 144                 /* read the next byte */
 145                 hdq_priv.hdq_bit = 8; /* 8 bits of data */
 146                 hdq_priv.hdq_ctr = 2500 / HDQ_SAMPLE_PERIOD_US;
 147                 hdq_priv.hdq_state = HDQB_WAIT_RX;
 148                 hdq_priv.pdata->gpio_dir_in();
 149                 break;
 150
 151         case HDQB_WAIT_TX: /* issue low for > 40us */
 152                 if (--hdq_priv.hdq_ctr)
 153                         break;
 154                 if (!hdq_priv.hdq_tx_data_done) { /* was that the data sent? */
 155                         hdq_priv.hdq_tx_data_done++;
 156                         hdq_priv.hdq_shifter = hdq_priv.hdq_tx_data;
 157                         hdq_priv.hdq_bit = 8; /* 8 bits of data */
 158                         hdq_priv.hdq_state = HDQB_ADS_CALC; /* start sending */
 159                         break;
 160                 }
 161                 hdq_priv.hdq_error = 0;
 162                 hdq_priv.hdq_transaction_ctr = hdq_priv.hdq_request_ctr;
 163                 hdq_priv.hdq_state = HDQB_IDLE; /* all tx is done */
 164                 /* idle in input mode, it's pulled up by 10K */
 165                 hdq_priv.pdata->gpio_dir_in();
 166                 break;
 167
 168         case HDQB_WAIT_RX: /* wait for battery to talk to us */
 169                 if (hdq_priv.pdata->gpio_get() == 0) {
 170                         /* it talks to us! */
 171                         hdq_priv.hdq_ctr2 = 1;
 172                         hdq_priv.hdq_bit = 8; /* 8 bits of data */
 173                         /* timeout */
 174                         hdq_priv.hdq_ctr = 500 / HDQ_SAMPLE_PERIOD_US;
 175                         hdq_priv.hdq_state = HDQB_DATA_RX_LOW;
 176                         break;
 177                 }
 178                 if (--hdq_priv.hdq_ctr == 0) { /* timed out, error */
 179                         hdq_priv.hdq_error = 1;
 180                         hdq_priv.hdq_transaction_ctr = hdq_priv.hdq_request_ctr;
 181                         hdq_priv.hdq_state = HDQB_IDLE; /* abort */
 182                 }
 183                 break;
 184
 185         /*
 186          * HDQ basically works by measuring the low time of the bit cell
 187          * 32-50us --> '1', 80 - 145us --> '0'
 188          */
 189
 190         case HDQB_DATA_RX_LOW:
 191                 if (hdq_priv.pdata->gpio_get()) {
 192                         hdq_priv.hdq_rx_data >>= 1;
 193                         if (hdq_priv.hdq_ctr2 <= (65 / HDQ_SAMPLE_PERIOD_US))
 194                                 hdq_priv.hdq_rx_data |= 0x80;
 195
 196                         if (--hdq_priv.hdq_bit == 0) {
 197                                 hdq_priv.hdq_error = 0;
 198                                 hdq_priv.hdq_transaction_ctr =
 199                                                         hdq_priv.hdq_request_ctr;
 200
 201                                 hdq_priv.hdq_state = HDQB_IDLE;
 202                         } else
 203                                 hdq_priv.hdq_state = HDQB_DATA_RX_HIGH;
 204                         /* timeout */
 205                         hdq_priv.hdq_ctr = 1000 / HDQ_SAMPLE_PERIOD_US;
 206                         hdq_priv.hdq_ctr2 = 1;
 207                         break;
 208                 }
 209                 hdq_priv.hdq_ctr2++;
 210                 if (--hdq_priv.hdq_ctr)
 211                         break;
 212                  /* timed out, error */
 213                 hdq_priv.hdq_error = 2;
 214                 hdq_priv.hdq_transaction_ctr = hdq_priv.hdq_request_ctr;
 215                 hdq_priv.hdq_state = HDQB_IDLE; /* abort */
 216                 break;
 217
 218         case HDQB_DATA_RX_HIGH:
 219                 if (!hdq_priv.pdata->gpio_get()) {
 220                         /* it talks to us! */
 221                         hdq_priv.hdq_ctr2 = 1;
 222                         /* timeout */
 223                         hdq_priv.hdq_ctr = 400 / HDQ_SAMPLE_PERIOD_US;
 224                         hdq_priv.hdq_state = HDQB_DATA_RX_LOW;
 225                         break;
 226                 }
 227                 if (--hdq_priv.hdq_ctr)
 228                         break;
 229                 /* timed out, error */
 230                 hdq_priv.hdq_error = 3;
 231                 hdq_priv.hdq_transaction_ctr = hdq_priv.hdq_request_ctr;
 232
 233                 /* we're in input mode already */
 234                 hdq_priv.hdq_state = HDQB_IDLE; /* abort */
 235                 break;
 236         }
 237
 238         /* Are we interested in keeping the FIQ source alive ? */
 239         if (hdq_priv.hdq_state != HDQB_IDLE)
 240                 return 1;
 241         else
 242                 return 0;
 243 }
 244 static int fiq_busy(void)
 245 {
 246         int request = (volatile u8)hdq_priv.hdq_request_ctr;
 247         int transact = (volatile u8)hdq_priv.hdq_transaction_ctr;
 248
 249
 250         return (request != transact);
 251 }
 252
 253 int hdq_initialized(void)
 254 {
 255         return hdq_priv.hdq_probed;
 256 }
 257 EXPORT_SYMBOL_GPL(hdq_initialized);
 258
 259 int hdq_read(int address)
 260 {
 261         int count_sleeps = 5;
 262         int ret = -ETIME;
 263
 264         if (!hdq_priv.hdq_probed)
 265                 return -EINVAL;
 266
 267         mutex_lock(&hdq_priv.hdq_lock);
 268
 269         hdq_priv.hdq_error = 0;
 270         hdq_priv.hdq_ads = address | HDQ_READ;
 271         hdq_priv.hdq_request_ctr++;
 272         hdq_priv.pdata->kick_fiq();
 273         /*
 274          * FIQ takes care of it while we block our calling process
 275          * But we're not spinning -- other processes run normally while
 276          * we wait for the result
 277          */
 278         while (count_sleeps--) {
 279                 msleep(10); /* valid transaction always completes in < 10ms */
 280
 281                 if (fiq_busy())
 282                         continue;
 283
 284                 if (hdq_priv.hdq_error) {
 285                         hdq_bad();
 286                         goto done; /* didn't see a response in good time */
 287                 }
 288                 hdq_good();
 289
 290                 ret = hdq_priv.hdq_rx_data;
 291                 goto done;
 292         }
 293
 294 done:
 295         mutex_unlock(&hdq_priv.hdq_lock);
 296         return ret;
 297 }
 298 EXPORT_SYMBOL_GPL(hdq_read);
 299
 300 int hdq_write(int address, u8 data)
 301 {
 302         int count_sleeps = 5;
 303         int ret = -ETIME;
 304
 305         if (!hdq_priv.hdq_probed)
 306                 return -EINVAL;
 307
 308         mutex_lock(&hdq_priv.hdq_lock);
 309
 310         hdq_priv.hdq_error = 0;
 311         hdq_priv.hdq_ads = address | HDQ_WRITE;
 312         hdq_priv.hdq_tx_data = data;
 313         hdq_priv.hdq_request_ctr++;
 314         hdq_priv.pdata->kick_fiq();
 315         /*
 316          * FIQ takes care of it while we block our calling process
 317          * But we're not spinning -- other processes run normally while
 318          * we wait for the result
 319          */
 320         while (count_sleeps--) {
 321                 msleep(10); /* valid transaction always completes in < 10ms */
 322
 323                 if (fiq_busy())
 324                         continue; /* something bad with FIQ */
 325
 326                 if (hdq_priv.hdq_error) {
 327                         hdq_bad();
 328                         goto done; /* didn't see a response in good time */
 329                 }
 330                 hdq_good();
 331
 332                 ret = 0;
 333                 goto done;
 334         }
 335
 336 done:
 337         mutex_unlock(&hdq_priv.hdq_lock);
 338         return ret;
 339 }
 340 EXPORT_SYMBOL_GPL(hdq_write);
 341
 342 /* sysfs */
 343
 344 static ssize_t hdq_sysfs_dump(struct device *dev, struct device_attribute *attr,
 345                          char *buf)
 346 {
 347         int n;
 348         int v;
 349         u8 u8a[128]; /* whole address space for HDQ */
 350         char *end = buf;
 351
 352         if (!hdq_priv.hdq_probed)
 353                 return -EINVAL;
 354
 355         /* the dump does not take care about 16 bit regs, because at this
 356          * bus level we don't know about the chip details
 357          */
 358         for (n = 0; n < sizeof(u8a); n++) {
 359                 v = hdq_read(n);
 360                 if (v < 0)
 361                         goto bail;
 362                 u8a[n] = v;
 363         }
 364
 365         for (n = 0; n < sizeof(u8a); n += 16) {
 366                 hex_dump_to_buffer(u8a + n, sizeof(u8a), 16, 1, end, 4096, 0);
 367                 end += strlen(end);
 368                 *end++ = '\n';
 369                 *end = '\0';
 370         }
 371         return (end - buf);
 372
 373 bail:
 374         return sprintf(buf, "ERROR %d\n", v);
 375 }
 376
 377 /* you write by <address> <data>, eg, "34 128" */
 378
 379 #define atoi(str) simple_strtoul(((str != NULL) ? str : ""), NULL, 0)
 380
 381 static ssize_t hdq_sysfs_write(struct device *dev,
 382                                struct device_attribute *attr,
 383                                const char *buf, size_t count)
 384 {
 385         const char *end = buf + count;
 386         int address = atoi(buf);
 387
 388         if (!hdq_priv.hdq_probed)
 389                 return -EINVAL;
 390
 391         while ((buf != end) && (*buf != ' '))
 392                 buf++;
 393         if (buf >= end)
 394                 return 0;
 395         while ((buf < end) && (*buf == ' '))
 396                 buf++;
 397         if (buf >= end)
 398                 return 0;
 399
 400         hdq_write(address, atoi(buf));
 401
 402         return count;
 403 }
 404
 405 static DEVICE_ATTR(dump, 0400, hdq_sysfs_dump, NULL);
 406 static DEVICE_ATTR(write, 0600, NULL, hdq_sysfs_write);
 407
 408 static struct attribute *hdq_sysfs_entries[] = {
 409         &dev_attr_dump.attr,
 410         &dev_attr_write.attr,
 411         NULL
 412 };
 413
 414 static struct attribute_group hdq_attr_group = {
 415         .name   = "hdq",
 416         .attrs  = hdq_sysfs_entries,
 417 };
 418
 419
 420 #ifdef CONFIG_PM
 421 static int hdq_suspend(struct platform_device *pdev, pm_message_t state)
 422 {
 423         /* after 18s of this, the battery monitor will also go to sleep */
 424         hdq_priv.pdata->gpio_dir_in();
 425         hdq_priv.pdata->disable_fiq();
 426         return 0;
 427 }
 428
 429 static int hdq_resume(struct platform_device *pdev)
 430 {
 431         hdq_priv.pdata->gpio_set(1);
 432         hdq_priv.pdata->gpio_dir_out();
 433         hdq_priv.pdata->enable_fiq();
 434         return 0;
 435 }
 436 #endif
 437
 438 static int __init hdq_probe(struct platform_device *pdev)
 439 {
 440         struct resource *r = platform_get_resource(pdev, 0, 0);
 441         int ret;
 442         struct hdq_platform_data *pdata = pdev->dev.platform_data;
 443
 444         if (!r || !pdata)
 445                 return -EINVAL;
 446
 447         platform_set_drvdata(pdev, NULL);
 448
 449         mutex_init(&hdq_priv.hdq_lock);
 450
 451         /* set our HDQ comms pin from the platform data */
 452         hdq_priv.hdq_gpio_pin = r->start;
 453         hdq_priv.pdata = pdata;
 454
 455         hdq_priv.pdata->gpio_set(1);
 456         hdq_priv.pdata->gpio_dir_out();
 457
 458         /* Initialize FIQ */
 459         if (hdq_priv.pdata->enable_fiq() < 0) {
 460                 dev_err(&pdev->dev, "Could not enable FIQ source\n");
 461                 return -EINVAL;
 462         }
 463
 464         ret = sysfs_create_group(&pdev->dev.kobj, &hdq_attr_group);
 465         if (ret)
 466                 return ret;
 467
 468         hdq_priv.hdq_probed = 1; /* we are ready to do stuff now */
 469
 470         /*
 471          * if wanted, users can defer registration of devices
 472          * that depend on HDQ until after we register, and can use our
 473          * device as parent so suspend-resume ordering is correct
 474          */
 475         if (pdata->attach_child_devices)
 476                 (pdata->attach_child_devices)(&pdev->dev);
 477
 478         hdq_priv.pdata = pdata;
 479
 480         return 0;
 481 }
 482
 483 static int hdq_remove(struct platform_device *pdev)
 484 {
 485         sysfs_remove_group(&pdev->dev.kobj, &hdq_attr_group);
 486         return 0;
 487 }
 488
 489 static struct platform_driver hdq_driver = {
 490         .probe          = hdq_probe,
 491         .remove         = hdq_remove,
 492 #ifdef CONFIG_PM
 493         .suspend        = hdq_suspend,
 494         .resume         = hdq_resume,
 495 #endif
 496         .driver         = {
 497                 .name           = "hdq",
 498         },
 499 };
 500
 501 static int __init hdq_init(void)
 502 {
 503         return platform_driver_register(&hdq_driver);
 504 }
 505
 506 static void __exit hdq_exit(void)
 507 {
 508         platform_driver_unregister(&hdq_driver);
 509 }
 510
 511 module_init(hdq_init);
 512 module_exit(hdq_exit);
 513
 514 MODULE_AUTHOR("Andy Green <andy@openmoko.com>");
 515 MODULE_DESCRIPTION("HDQ driver");