drivers/mfd/htc-i2cpld.c

   1 /*
   2  *  htc-i2cpld.c
   3  *  Chip driver for an unknown CPLD chip found on omap850 HTC devices like
   4  *  the HTC Wizard and HTC Herald.
   5  *  The cpld is located on the i2c bus and acts as an input/output GPIO
   6  *  extender.
   7  *
   8  *  Copyright (C) 2009 Cory Maccarrone <darkstar6262@gmail.com>
   9  *
  10  *  Based on work done in the linwizard project
  11  *  Copyright (C) 2008-2009 Angelo Arrifano <miknix@gmail.com>
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  26  */
  27
  28 #include <linux/kernel.h>
  29 #include <linux/init.h>
  30 #include <linux/interrupt.h>
  31 #include <linux/platform_device.h>
  32 #include <linux/i2c.h>
  33 #include <linux/irq.h>
  34 #include <linux/spinlock.h>
  35 #include <linux/htcpld.h>
  36 #include <linux/gpio.h>
  37 #include <linux/slab.h>
  38
  39 struct htcpld_chip {
  40         spinlock_t              lock;
  41
  42         /* chip info */
  43         u8                      reset;
  44         u8                      addr;
  45         struct device           *dev;
  46         struct i2c_client       *client;
  47
  48         /* Output details */
  49         u8                      cache_out;
  50         struct gpio_chip        chip_out;
  51
  52         /* Input details */
  53         u8                      cache_in;
  54         struct gpio_chip        chip_in;
  55
  56         u16                     irqs_enabled;
  57         uint                    irq_start;
  58         int                     nirqs;
  59
  60         unsigned int            flow_type;
  61         /*
  62          * Work structure to allow for setting values outside of any
  63          * possible interrupt context
  64          */
  65         struct work_struct set_val_work;
  66 };
  67
  68 struct htcpld_data {
  69         /* irq info */
  70         u16                irqs_enabled;
  71         uint               irq_start;
  72         int                nirqs;
  73         uint               chained_irq;
  74         unsigned int       int_reset_gpio_hi;
  75         unsigned int       int_reset_gpio_lo;
  76
  77         /* htcpld info */
  78         struct htcpld_chip *chip;
  79         unsigned int       nchips;
  80 };
  81
  82 /* There does not appear to be a way to proactively mask interrupts
  83  * on the htcpld chip itself.  So, we simply ignore interrupts that
  84  * aren't desired. */
  85 static void htcpld_mask(struct irq_data *data)
  86 {
  87         struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
  88         chip->irqs_enabled &= ~(1 << (data->irq - chip->irq_start));
  89         pr_debug("HTCPLD mask %d %04x\n", data->irq, chip->irqs_enabled);
  90 }
  91 static void htcpld_unmask(struct irq_data *data)
  92 {
  93         struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
  94         chip->irqs_enabled |= 1 << (data->irq - chip->irq_start);
  95         pr_debug("HTCPLD unmask %d %04x\n", data->irq, chip->irqs_enabled);
  96 }
  97
  98 static int htcpld_set_type(struct irq_data *data, unsigned int flags)
  99 {
 100         struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
 101
 102         if (flags & ~IRQ_TYPE_SENSE_MASK)
 103                 return -EINVAL;
 104
 105         /* We only allow edge triggering */
 106         if (flags & (IRQ_TYPE_LEVEL_LOW|IRQ_TYPE_LEVEL_HIGH))
 107                 return -EINVAL;
 108
 109         chip->flow_type = flags;
 110         return 0;
 111 }
 112
 113 static struct irq_chip htcpld_muxed_chip = {
 114         .name         = "htcpld",
 115         .irq_mask     = htcpld_mask,
 116         .irq_unmask   = htcpld_unmask,
 117         .irq_set_type = htcpld_set_type,
 118 };
 119
 120 /* To properly dispatch IRQ events, we need to read from the
 121  * chip.  This is an I2C action that could possibly sleep
 122  * (which is bad in interrupt context) -- so we use a threaded
 123  * interrupt handler to get around that.
 124  */
 125 static irqreturn_t htcpld_handler(int irq, void *dev)
 126 {
 127         struct htcpld_data *htcpld = dev;
 128         unsigned int i;
 129         unsigned long flags;
 130         int irqpin;
 131
 132         if (!htcpld) {
 133                 pr_debug("htcpld is null in ISR\n");
 134                 return IRQ_HANDLED;
 135         }
 136
 137         /*
 138          * For each chip, do a read of the chip and trigger any interrupts
 139          * desired.  The interrupts will be triggered from LSB to MSB (i.e.
 140          * bit 0 first, then bit 1, etc.)
 141          *
 142          * For chips that have no interrupt range specified, just skip 'em.
 143          */
 144         for (i = 0; i < htcpld->nchips; i++) {
 145                 struct htcpld_chip *chip = &htcpld->chip[i];
 146                 struct i2c_client *client;
 147                 int val;
 148                 unsigned long uval, old_val;
 149
 150                 if (!chip) {
 151                         pr_debug("chip %d is null in ISR\n", i);
 152                         continue;
 153                 }
 154
 155                 if (chip->nirqs == 0)
 156                         continue;
 157
 158                 client = chip->client;
 159                 if (!client) {
 160                         pr_debug("client %d is null in ISR\n", i);
 161                         continue;
 162                 }
 163
 164                 /* Scan the chip */
 165                 val = i2c_smbus_read_byte_data(client, chip->cache_out);
 166                 if (val < 0) {
 167                         /* Throw a warning and skip this chip */
 168                         dev_warn(chip->dev, "Unable to read from chip: %d\n",
 169                                  val);
 170                         continue;
 171                 }
 172
 173                 uval = (unsigned long)val;
 174
 175                 spin_lock_irqsave(&chip->lock, flags);
 176
 177                 /* Save away the old value so we can compare it */
 178                 old_val = chip->cache_in;
 179
 180                 /* Write the new value */
 181                 chip->cache_in = uval;
 182
 183                 spin_unlock_irqrestore(&chip->lock, flags);
 184
 185                 /*
 186                  * For each bit in the data (starting at bit 0), trigger
 187                  * associated interrupts.
 188                  */
 189                 for (irqpin = 0; irqpin < chip->nirqs; irqpin++) {
 190                         unsigned oldb, newb, type = chip->flow_type;
 191
 192                         irq = chip->irq_start + irqpin;
 193
 194                         /* Run the IRQ handler, but only if the bit value
 195                          * changed, and the proper flags are set */
 196                         oldb = (old_val >> irqpin) & 1;
 197                         newb = (uval >> irqpin) & 1;
 198
 199                         if ((!oldb && newb && (type & IRQ_TYPE_EDGE_RISING)) ||
 200                             (oldb && !newb && (type & IRQ_TYPE_EDGE_FALLING))) {
 201                                 pr_debug("fire IRQ %d\n", irqpin);
 202                                 generic_handle_irq(irq);
 203                         }
 204                 }
 205         }
 206
 207         /*
 208          * In order to continue receiving interrupts, the int_reset_gpio must
 209          * be asserted.
 210          */
 211         if (htcpld->int_reset_gpio_hi)
 212                 gpio_set_value(htcpld->int_reset_gpio_hi, 1);
 213         if (htcpld->int_reset_gpio_lo)
 214                 gpio_set_value(htcpld->int_reset_gpio_lo, 0);
 215
 216         return IRQ_HANDLED;
 217 }
 218
 219 /*
 220  * The GPIO set routines can be called from interrupt context, especially if,
 221  * for example they're attached to the led-gpio framework and a trigger is
 222  * enabled.  As such, we declared work above in the htcpld_chip structure,
 223  * and that work is scheduled in the set routine.  The kernel can then run
 224  * the I2C functions, which will sleep, in process context.
 225  */
 226 static void htcpld_chip_set(struct gpio_chip *chip, unsigned offset, int val)
 227 {
 228         struct i2c_client *client;
 229         struct htcpld_chip *chip_data = gpiochip_get_data(chip);
 230         unsigned long flags;
 231
 232         client = chip_data->client;
 233         if (!client)
 234                 return;
 235
 236         spin_lock_irqsave(&chip_data->lock, flags);
 237         if (val)
 238                 chip_data->cache_out |= (1 << offset);
 239         else
 240                 chip_data->cache_out &= ~(1 << offset);
 241         spin_unlock_irqrestore(&chip_data->lock, flags);
 242
 243         schedule_work(&(chip_data->set_val_work));
 244 }
 245
 246 static void htcpld_chip_set_ni(struct work_struct *work)
 247 {
 248         struct htcpld_chip *chip_data;
 249         struct i2c_client *client;
 250
 251         chip_data = container_of(work, struct htcpld_chip, set_val_work);
 252         client = chip_data->client;
 253         i2c_smbus_read_byte_data(client, chip_data->cache_out);
 254 }
 255
 256 static int htcpld_chip_get(struct gpio_chip *chip, unsigned offset)
 257 {
 258         struct htcpld_chip *chip_data = gpiochip_get_data(chip);
 259         u8 cache;
 260
 261         if (!strncmp(chip->label, "htcpld-out", 10)) {
 262                 cache = chip_data->cache_out;
 263         } else if (!strncmp(chip->label, "htcpld-in", 9)) {
 264                 cache = chip_data->cache_in;
 265         } else
 266                 return -EINVAL;
 267
 268         return (cache >> offset) & 1;
 269 }
 270
 271 static int htcpld_direction_output(struct gpio_chip *chip,
 272                                         unsigned offset, int value)
 273 {
 274         htcpld_chip_set(chip, offset, value);
 275         return 0;
 276 }
 277
 278 static int htcpld_direction_input(struct gpio_chip *chip,
 279                                         unsigned offset)
 280 {
 281         /*
 282          * No-op: this function can only be called on the input chip.
 283          * We do however make sure the offset is within range.
 284          */
 285         return (offset < chip->ngpio) ? 0 : -EINVAL;
 286 }
 287
 288 static int htcpld_chip_to_irq(struct gpio_chip *chip, unsigned offset)
 289 {
 290         struct htcpld_chip *chip_data = gpiochip_get_data(chip);
 291
 292         if (offset < chip_data->nirqs)
 293                 return chip_data->irq_start + offset;
 294         else
 295                 return -EINVAL;
 296 }
 297
 298 static void htcpld_chip_reset(struct i2c_client *client)
 299 {
 300         struct htcpld_chip *chip_data = i2c_get_clientdata(client);
 301         if (!chip_data)
 302                 return;
 303
 304         i2c_smbus_read_byte_data(
 305                 client, (chip_data->cache_out = chip_data->reset));
 306 }
 307
 308 static int htcpld_setup_chip_irq(
 309                 struct platform_device *pdev,
 310                 int chip_index)
 311 {
 312         struct htcpld_data *htcpld;
 313         struct htcpld_chip *chip;
 314         unsigned int irq, irq_end;
 315
 316         /* Get the platform and driver data */
 317         htcpld = platform_get_drvdata(pdev);
 318         chip = &htcpld->chip[chip_index];
 319
 320         /* Setup irq handlers */
 321         irq_end = chip->irq_start + chip->nirqs;
 322         for (irq = chip->irq_start; irq < irq_end; irq++) {
 323                 irq_set_chip_and_handler(irq, &htcpld_muxed_chip,
 324                                          handle_simple_irq);
 325                 irq_set_chip_data(irq, chip);
 326                 irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
 327         }
 328
 329         return 0;
 330 }
 331
 332 static int htcpld_register_chip_i2c(
 333                 struct platform_device *pdev,
 334                 int chip_index)
 335 {
 336         struct htcpld_data *htcpld;
 337         struct device *dev = &pdev->dev;
 338         struct htcpld_core_platform_data *pdata;
 339         struct htcpld_chip *chip;
 340         struct htcpld_chip_platform_data *plat_chip_data;
 341         struct i2c_adapter *adapter;
 342         struct i2c_client *client;
 343         struct i2c_board_info info;
 344
 345         /* Get the platform and driver data */
 346         pdata = dev_get_platdata(dev);
 347         htcpld = platform_get_drvdata(pdev);
 348         chip = &htcpld->chip[chip_index];
 349         plat_chip_data = &pdata->chip[chip_index];
 350
 351         adapter = i2c_get_adapter(pdata->i2c_adapter_id);
 352         if (!adapter) {
 353                 /* Eek, no such I2C adapter!  Bail out. */
 354                 dev_warn(dev, "Chip at i2c address 0x%x: Invalid i2c adapter %d\n",
 355                          plat_chip_data->addr, pdata->i2c_adapter_id);
 356                 return -ENODEV;
 357         }
 358
 359         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
 360                 dev_warn(dev, "i2c adapter %d non-functional\n",
 361                          pdata->i2c_adapter_id);
 362                 return -EINVAL;
 363         }
 364
 365         memset(&info, 0, sizeof(struct i2c_board_info));
 366         info.addr = plat_chip_data->addr;
 367         strlcpy(info.type, "htcpld-chip", I2C_NAME_SIZE);
 368         info.platform_data = chip;
 369
 370         /* Add the I2C device.  This calls the probe() function. */
 371         client = i2c_new_device(adapter, &info);
 372         if (!client) {
 373                 /* I2C device registration failed, contineu with the next */
 374                 dev_warn(dev, "Unable to add I2C device for 0x%x\n",
 375                          plat_chip_data->addr);
 376                 return -ENODEV;
 377         }
 378
 379         i2c_set_clientdata(client, chip);
 380         snprintf(client->name, I2C_NAME_SIZE, "Chip_0x%x", client->addr);
 381         chip->client = client;
 382
 383         /* Reset the chip */
 384         htcpld_chip_reset(client);
 385         chip->cache_in = i2c_smbus_read_byte_data(client, chip->cache_out);
 386
 387         return 0;
 388 }
 389
 390 static void htcpld_unregister_chip_i2c(
 391                 struct platform_device *pdev,
 392                 int chip_index)
 393 {
 394         struct htcpld_data *htcpld;
 395         struct htcpld_chip *chip;
 396
 397         /* Get the platform and driver data */
 398         htcpld = platform_get_drvdata(pdev);
 399         chip = &htcpld->chip[chip_index];
 400
 401         if (chip->client)
 402                 i2c_unregister_device(chip->client);
 403 }
 404
 405 static int htcpld_register_chip_gpio(
 406                 struct platform_device *pdev,
 407                 int chip_index)
 408 {
 409         struct htcpld_data *htcpld;
 410         struct device *dev = &pdev->dev;
 411         struct htcpld_core_platform_data *pdata;
 412         struct htcpld_chip *chip;
 413         struct htcpld_chip_platform_data *plat_chip_data;
 414         struct gpio_chip *gpio_chip;
 415         int ret = 0;
 416
 417         /* Get the platform and driver data */
 418         pdata = dev_get_platdata(dev);
 419         htcpld = platform_get_drvdata(pdev);
 420         chip = &htcpld->chip[chip_index];
 421         plat_chip_data = &pdata->chip[chip_index];
 422
 423         /* Setup the GPIO chips */
 424         gpio_chip = &(chip->chip_out);
 425         gpio_chip->label           = "htcpld-out";
 426         gpio_chip->parent             = dev;
 427         gpio_chip->owner           = THIS_MODULE;
 428         gpio_chip->get             = htcpld_chip_get;
 429         gpio_chip->set             = htcpld_chip_set;
 430         gpio_chip->direction_input = NULL;
 431         gpio_chip->direction_output = htcpld_direction_output;
 432         gpio_chip->base            = plat_chip_data->gpio_out_base;
 433         gpio_chip->ngpio           = plat_chip_data->num_gpios;
 434
 435         gpio_chip = &(chip->chip_in);
 436         gpio_chip->label           = "htcpld-in";
 437         gpio_chip->parent             = dev;
 438         gpio_chip->owner           = THIS_MODULE;
 439         gpio_chip->get             = htcpld_chip_get;
 440         gpio_chip->set             = NULL;
 441         gpio_chip->direction_input = htcpld_direction_input;
 442         gpio_chip->direction_output = NULL;
 443         gpio_chip->to_irq          = htcpld_chip_to_irq;
 444         gpio_chip->base            = plat_chip_data->gpio_in_base;
 445         gpio_chip->ngpio           = plat_chip_data->num_gpios;
 446
 447         /* Add the GPIO chips */
 448         ret = gpiochip_add_data(&(chip->chip_out), chip);
 449         if (ret) {
 450                 dev_warn(dev, "Unable to register output GPIOs for 0x%x: %d\n",
 451                          plat_chip_data->addr, ret);
 452                 return ret;
 453         }
 454
 455         ret = gpiochip_add_data(&(chip->chip_in), chip);
 456         if (ret) {
 457                 dev_warn(dev, "Unable to register input GPIOs for 0x%x: %d\n",
 458                          plat_chip_data->addr, ret);
 459                 gpiochip_remove(&(chip->chip_out));
 460                 return ret;
 461         }
 462
 463         return 0;
 464 }
 465
 466 static int htcpld_setup_chips(struct platform_device *pdev)
 467 {
 468         struct htcpld_data *htcpld;
 469         struct device *dev = &pdev->dev;
 470         struct htcpld_core_platform_data *pdata;
 471         int i;
 472
 473         /* Get the platform and driver data */
 474         pdata = dev_get_platdata(dev);
 475         htcpld = platform_get_drvdata(pdev);
 476
 477         /* Setup each chip's output GPIOs */
 478         htcpld->nchips = pdata->num_chip;
 479         htcpld->chip = devm_kcalloc(dev,
 480                                     htcpld->nchips,
 481                                     sizeof(struct htcpld_chip),
 482                                     GFP_KERNEL);
 483         if (!htcpld->chip)
 484                 return -ENOMEM;
 485
 486         /* Add the chips as best we can */
 487         for (i = 0; i < htcpld->nchips; i++) {
 488                 int ret;
 489
 490                 /* Setup the HTCPLD chips */
 491                 htcpld->chip[i].reset = pdata->chip[i].reset;
 492                 htcpld->chip[i].cache_out = pdata->chip[i].reset;
 493                 htcpld->chip[i].cache_in = 0;
 494                 htcpld->chip[i].dev = dev;
 495                 htcpld->chip[i].irq_start = pdata->chip[i].irq_base;
 496                 htcpld->chip[i].nirqs = pdata->chip[i].num_irqs;
 497
 498                 INIT_WORK(&(htcpld->chip[i].set_val_work), &htcpld_chip_set_ni);
 499                 spin_lock_init(&(htcpld->chip[i].lock));
 500
 501                 /* Setup the interrupts for the chip */
 502                 if (htcpld->chained_irq) {
 503                         ret = htcpld_setup_chip_irq(pdev, i);
 504                         if (ret)
 505                                 continue;
 506                 }
 507
 508                 /* Register the chip with I2C */
 509                 ret = htcpld_register_chip_i2c(pdev, i);
 510                 if (ret)
 511                         continue;
 512
 513
 514                 /* Register the chips with the GPIO subsystem */
 515                 ret = htcpld_register_chip_gpio(pdev, i);
 516                 if (ret) {
 517                         /* Unregister the chip from i2c and continue */
 518                         htcpld_unregister_chip_i2c(pdev, i);
 519                         continue;
 520                 }
 521
 522                 dev_info(dev, "Registered chip at 0x%x\n", pdata->chip[i].addr);
 523         }
 524
 525         return 0;
 526 }
 527
 528 static int htcpld_core_probe(struct platform_device *pdev)
 529 {
 530         struct htcpld_data *htcpld;
 531         struct device *dev = &pdev->dev;
 532         struct htcpld_core_platform_data *pdata;
 533         struct resource *res;
 534         int ret = 0;
 535
 536         if (!dev)
 537                 return -ENODEV;
 538
 539         pdata = dev_get_platdata(dev);
 540         if (!pdata) {
 541                 dev_warn(dev, "Platform data not found for htcpld core!\n");
 542                 return -ENXIO;
 543         }
 544
 545         htcpld = devm_kzalloc(dev, sizeof(struct htcpld_data), GFP_KERNEL);
 546         if (!htcpld)
 547                 return -ENOMEM;
 548
 549         /* Find chained irq */
 550         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 551         if (res) {
 552                 int flags;
 553                 htcpld->chained_irq = res->start;
 554
 555                 /* Setup the chained interrupt handler */
 556                 flags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING |
 557                         IRQF_ONESHOT;
 558                 ret = request_threaded_irq(htcpld->chained_irq,
 559                                            NULL, htcpld_handler,
 560                                            flags, pdev->name, htcpld);
 561                 if (ret) {
 562                         dev_warn(dev, "Unable to setup chained irq handler: %d\n", ret);
 563                         return ret;
 564                 } else
 565                         device_init_wakeup(dev, 0);
 566         }
 567
 568         /* Set the driver data */
 569         platform_set_drvdata(pdev, htcpld);
 570
 571         /* Setup the htcpld chips */
 572         ret = htcpld_setup_chips(pdev);
 573         if (ret)
 574                 return ret;
 575
 576         /* Request the GPIO(s) for the int reset and set them up */
 577         if (pdata->int_reset_gpio_hi) {
 578                 ret = gpio_request(pdata->int_reset_gpio_hi, "htcpld-core");
 579                 if (ret) {
 580                         /*
 581                          * If it failed, that sucks, but we can probably
 582                          * continue on without it.
 583                          */
 584                         dev_warn(dev, "Unable to request int_reset_gpio_hi -- interrupts may not work\n");
 585                         htcpld->int_reset_gpio_hi = 0;
 586                 } else {
 587                         htcpld->int_reset_gpio_hi = pdata->int_reset_gpio_hi;
 588                         gpio_set_value(htcpld->int_reset_gpio_hi, 1);
 589                 }
 590         }
 591
 592         if (pdata->int_reset_gpio_lo) {
 593                 ret = gpio_request(pdata->int_reset_gpio_lo, "htcpld-core");
 594                 if (ret) {
 595                         /*
 596                          * If it failed, that sucks, but we can probably
 597                          * continue on without it.
 598                          */
 599                         dev_warn(dev, "Unable to request int_reset_gpio_lo -- interrupts may not work\n");
 600                         htcpld->int_reset_gpio_lo = 0;
 601                 } else {
 602                         htcpld->int_reset_gpio_lo = pdata->int_reset_gpio_lo;
 603                         gpio_set_value(htcpld->int_reset_gpio_lo, 0);
 604                 }
 605         }
 606
 607         dev_info(dev, "Initialized successfully\n");
 608         return 0;
 609 }
 610
 611 /* The I2C Driver -- used internally */
 612 static const struct i2c_device_id htcpld_chip_id[] = {
 613         { "htcpld-chip", 0 },
 614         { }
 615 };
 616
 617 static struct i2c_driver htcpld_chip_driver = {
 618         .driver = {
 619                 .name   = "htcpld-chip",
 620         },
 621         .id_table = htcpld_chip_id,
 622 };
 623
 624 /* The Core Driver */
 625 static struct platform_driver htcpld_core_driver = {
 626         .driver = {
 627                 .name = "i2c-htcpld",
 628         },
 629 };
 630
 631 static int __init htcpld_core_init(void)
 632 {
 633         int ret;
 634
 635         /* Register the I2C Chip driver */
 636         ret = i2c_add_driver(&htcpld_chip_driver);
 637         if (ret)
 638                 return ret;
 639
 640         /* Probe for our chips */
 641         return platform_driver_probe(&htcpld_core_driver, htcpld_core_probe);
 642 }
 643 device_initcall(htcpld_core_init);