drivers/mfd/htc-i2cpld.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  htc-i2cpld.c
   4  *  Chip driver for an unknown CPLD chip found on omap850 HTC devices like
   5  *  the HTC Wizard and HTC Herald.
   6  *  The cpld is located on the i2c bus and acts as an input/output GPIO
   7  *  extender.
   8  *
   9  *  Copyright (C) 2009 Cory Maccarrone <darkstar6262@gmail.com>
  10  *
  11  *  Based on work done in the linwizard project
  12  *  Copyright (C) 2008-2009 Angelo Arrifano <miknix@gmail.com>
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/init.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/i2c.h>
  20 #include <linux/irq.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/htcpld.h>
  23 #include <linux/gpio.h>
  24 #include <linux/slab.h>
  25
  26 struct htcpld_chip {
  27         spinlock_t              lock;
  28
  29         /* chip info */
  30         u8                      reset;
  31         u8                      addr;
  32         struct device           *dev;
  33         struct i2c_client       *client;
  34
  35         /* Output details */
  36         u8                      cache_out;
  37         struct gpio_chip        chip_out;
  38
  39         /* Input details */
  40         u8                      cache_in;
  41         struct gpio_chip        chip_in;
  42
  43         u16                     irqs_enabled;
  44         uint                    irq_start;
  45         int                     nirqs;
  46
  47         unsigned int            flow_type;
  48         /*
  49          * Work structure to allow for setting values outside of any
  50          * possible interrupt context
  51          */
  52         struct work_struct set_val_work;
  53 };
  54
  55 struct htcpld_data {
  56         /* irq info */
  57         u16                irqs_enabled;
  58         uint               irq_start;
  59         int                nirqs;
  60         uint               chained_irq;
  61         unsigned int       int_reset_gpio_hi;
  62         unsigned int       int_reset_gpio_lo;
  63
  64         /* htcpld info */
  65         struct htcpld_chip *chip;
  66         unsigned int       nchips;
  67 };
  68
  69 /* There does not appear to be a way to proactively mask interrupts
  70  * on the htcpld chip itself.  So, we simply ignore interrupts that
  71  * aren't desired. */
  72 static void htcpld_mask(struct irq_data *data)
  73 {
  74         struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
  75         chip->irqs_enabled &= ~(1 << (data->irq - chip->irq_start));
  76         pr_debug("HTCPLD mask %d %04x\n", data->irq, chip->irqs_enabled);
  77 }
  78 static void htcpld_unmask(struct irq_data *data)
  79 {
  80         struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
  81         chip->irqs_enabled |= 1 << (data->irq - chip->irq_start);
  82         pr_debug("HTCPLD unmask %d %04x\n", data->irq, chip->irqs_enabled);
  83 }
  84
  85 static int htcpld_set_type(struct irq_data *data, unsigned int flags)
  86 {
  87         struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
  88
  89         if (flags & ~IRQ_TYPE_SENSE_MASK)
  90                 return -EINVAL;
  91
  92         /* We only allow edge triggering */
  93         if (flags & (IRQ_TYPE_LEVEL_LOW|IRQ_TYPE_LEVEL_HIGH))
  94                 return -EINVAL;
  95
  96         chip->flow_type = flags;
  97         return 0;
  98 }
  99
 100 static struct irq_chip htcpld_muxed_chip = {
 101         .name         = "htcpld",
 102         .irq_mask     = htcpld_mask,
 103         .irq_unmask   = htcpld_unmask,
 104         .irq_set_type = htcpld_set_type,
 105 };
 106
 107 /* To properly dispatch IRQ events, we need to read from the
 108  * chip.  This is an I2C action that could possibly sleep
 109  * (which is bad in interrupt context) -- so we use a threaded
 110  * interrupt handler to get around that.
 111  */
 112 static irqreturn_t htcpld_handler(int irq, void *dev)
 113 {
 114         struct htcpld_data *htcpld = dev;
 115         unsigned int i;
 116         unsigned long flags;
 117         int irqpin;
 118
 119         if (!htcpld) {
 120                 pr_debug("htcpld is null in ISR\n");
 121                 return IRQ_HANDLED;
 122         }
 123
 124         /*
 125          * For each chip, do a read of the chip and trigger any interrupts
 126          * desired.  The interrupts will be triggered from LSB to MSB (i.e.
 127          * bit 0 first, then bit 1, etc.)
 128          *
 129          * For chips that have no interrupt range specified, just skip 'em.
 130          */
 131         for (i = 0; i < htcpld->nchips; i++) {
 132                 struct htcpld_chip *chip = &htcpld->chip[i];
 133                 struct i2c_client *client;
 134                 int val;
 135                 unsigned long uval, old_val;
 136
 137                 if (!chip) {
 138                         pr_debug("chip %d is null in ISR\n", i);
 139                         continue;
 140                 }
 141
 142                 if (chip->nirqs == 0)
 143                         continue;
 144
 145                 client = chip->client;
 146                 if (!client) {
 147                         pr_debug("client %d is null in ISR\n", i);
 148                         continue;
 149                 }
 150
 151                 /* Scan the chip */
 152                 val = i2c_smbus_read_byte_data(client, chip->cache_out);
 153                 if (val < 0) {
 154                         /* Throw a warning and skip this chip */
 155                         dev_warn(chip->dev, "Unable to read from chip: %d\n",
 156                                  val);
 157                         continue;
 158                 }
 159
 160                 uval = (unsigned long)val;
 161
 162                 spin_lock_irqsave(&chip->lock, flags);
 163
 164                 /* Save away the old value so we can compare it */
 165                 old_val = chip->cache_in;
 166
 167                 /* Write the new value */
 168                 chip->cache_in = uval;
 169
 170                 spin_unlock_irqrestore(&chip->lock, flags);
 171
 172                 /*
 173                  * For each bit in the data (starting at bit 0), trigger
 174                  * associated interrupts.
 175                  */
 176                 for (irqpin = 0; irqpin < chip->nirqs; irqpin++) {
 177                         unsigned oldb, newb, type = chip->flow_type;
 178
 179                         irq = chip->irq_start + irqpin;
 180
 181                         /* Run the IRQ handler, but only if the bit value
 182                          * changed, and the proper flags are set */
 183                         oldb = (old_val >> irqpin) & 1;
 184                         newb = (uval >> irqpin) & 1;
 185
 186                         if ((!oldb && newb && (type & IRQ_TYPE_EDGE_RISING)) ||
 187                             (oldb && !newb && (type & IRQ_TYPE_EDGE_FALLING))) {
 188                                 pr_debug("fire IRQ %d\n", irqpin);
 189                                 generic_handle_irq(irq);
 190                         }
 191                 }
 192         }
 193
 194         /*
 195          * In order to continue receiving interrupts, the int_reset_gpio must
 196          * be asserted.
 197          */
 198         if (htcpld->int_reset_gpio_hi)
 199                 gpio_set_value(htcpld->int_reset_gpio_hi, 1);
 200         if (htcpld->int_reset_gpio_lo)
 201                 gpio_set_value(htcpld->int_reset_gpio_lo, 0);
 202
 203         return IRQ_HANDLED;
 204 }
 205
 206 /*
 207  * The GPIO set routines can be called from interrupt context, especially if,
 208  * for example they're attached to the led-gpio framework and a trigger is
 209  * enabled.  As such, we declared work above in the htcpld_chip structure,
 210  * and that work is scheduled in the set routine.  The kernel can then run
 211  * the I2C functions, which will sleep, in process context.
 212  */
 213 static void htcpld_chip_set(struct gpio_chip *chip, unsigned offset, int val)
 214 {
 215         struct i2c_client *client;
 216         struct htcpld_chip *chip_data = gpiochip_get_data(chip);
 217         unsigned long flags;
 218
 219         client = chip_data->client;
 220         if (!client)
 221                 return;
 222
 223         spin_lock_irqsave(&chip_data->lock, flags);
 224         if (val)
 225                 chip_data->cache_out |= (1 << offset);
 226         else
 227                 chip_data->cache_out &= ~(1 << offset);
 228         spin_unlock_irqrestore(&chip_data->lock, flags);
 229
 230         schedule_work(&(chip_data->set_val_work));
 231 }
 232
 233 static void htcpld_chip_set_ni(struct work_struct *work)
 234 {
 235         struct htcpld_chip *chip_data;
 236         struct i2c_client *client;
 237
 238         chip_data = container_of(work, struct htcpld_chip, set_val_work);
 239         client = chip_data->client;
 240         i2c_smbus_read_byte_data(client, chip_data->cache_out);
 241 }
 242
 243 static int htcpld_chip_get(struct gpio_chip *chip, unsigned offset)
 244 {
 245         struct htcpld_chip *chip_data = gpiochip_get_data(chip);
 246         u8 cache;
 247
 248         if (!strncmp(chip->label, "htcpld-out", 10)) {
 249                 cache = chip_data->cache_out;
 250         } else if (!strncmp(chip->label, "htcpld-in", 9)) {
 251                 cache = chip_data->cache_in;
 252         } else
 253                 return -EINVAL;
 254
 255         return (cache >> offset) & 1;
 256 }
 257
 258 static int htcpld_direction_output(struct gpio_chip *chip,
 259                                         unsigned offset, int value)
 260 {
 261         htcpld_chip_set(chip, offset, value);
 262         return 0;
 263 }
 264
 265 static int htcpld_direction_input(struct gpio_chip *chip,
 266                                         unsigned offset)
 267 {
 268         /*
 269          * No-op: this function can only be called on the input chip.
 270          * We do however make sure the offset is within range.
 271          */
 272         return (offset < chip->ngpio) ? 0 : -EINVAL;
 273 }
 274
 275 static int htcpld_chip_to_irq(struct gpio_chip *chip, unsigned offset)
 276 {
 277         struct htcpld_chip *chip_data = gpiochip_get_data(chip);
 278
 279         if (offset < chip_data->nirqs)
 280                 return chip_data->irq_start + offset;
 281         else
 282                 return -EINVAL;
 283 }
 284
 285 static void htcpld_chip_reset(struct i2c_client *client)
 286 {
 287         struct htcpld_chip *chip_data = i2c_get_clientdata(client);
 288         if (!chip_data)
 289                 return;
 290
 291         i2c_smbus_read_byte_data(
 292                 client, (chip_data->cache_out = chip_data->reset));
 293 }
 294
 295 static int htcpld_setup_chip_irq(
 296                 struct platform_device *pdev,
 297                 int chip_index)
 298 {
 299         struct htcpld_data *htcpld;
 300         struct htcpld_chip *chip;
 301         unsigned int irq, irq_end;
 302
 303         /* Get the platform and driver data */
 304         htcpld = platform_get_drvdata(pdev);
 305         chip = &htcpld->chip[chip_index];
 306
 307         /* Setup irq handlers */
 308         irq_end = chip->irq_start + chip->nirqs;
 309         for (irq = chip->irq_start; irq < irq_end; irq++) {
 310                 irq_set_chip_and_handler(irq, &htcpld_muxed_chip,
 311                                          handle_simple_irq);
 312                 irq_set_chip_data(irq, chip);
 313                 irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
 314         }
 315
 316         return 0;
 317 }
 318
 319 static int htcpld_register_chip_i2c(
 320                 struct platform_device *pdev,
 321                 int chip_index)
 322 {
 323         struct htcpld_data *htcpld;
 324         struct device *dev = &pdev->dev;
 325         struct htcpld_core_platform_data *pdata;
 326         struct htcpld_chip *chip;
 327         struct htcpld_chip_platform_data *plat_chip_data;
 328         struct i2c_adapter *adapter;
 329         struct i2c_client *client;
 330         struct i2c_board_info info;
 331
 332         /* Get the platform and driver data */
 333         pdata = dev_get_platdata(dev);
 334         htcpld = platform_get_drvdata(pdev);
 335         chip = &htcpld->chip[chip_index];
 336         plat_chip_data = &pdata->chip[chip_index];
 337
 338         adapter = i2c_get_adapter(pdata->i2c_adapter_id);
 339         if (!adapter) {
 340                 /* Eek, no such I2C adapter!  Bail out. */
 341                 dev_warn(dev, "Chip at i2c address 0x%x: Invalid i2c adapter %d\n",
 342                          plat_chip_data->addr, pdata->i2c_adapter_id);
 343                 return -ENODEV;
 344         }
 345
 346         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
 347                 dev_warn(dev, "i2c adapter %d non-functional\n",
 348                          pdata->i2c_adapter_id);
 349                 return -EINVAL;
 350         }
 351
 352         memset(&info, 0, sizeof(struct i2c_board_info));
 353         info.addr = plat_chip_data->addr;
 354         strlcpy(info.type, "htcpld-chip", I2C_NAME_SIZE);
 355         info.platform_data = chip;
 356
 357         /* Add the I2C device.  This calls the probe() function. */
 358         client = i2c_new_device(adapter, &info);
 359         if (!client) {
 360                 /* I2C device registration failed, contineu with the next */
 361                 dev_warn(dev, "Unable to add I2C device for 0x%x\n",
 362                          plat_chip_data->addr);
 363                 return -ENODEV;
 364         }
 365
 366         i2c_set_clientdata(client, chip);
 367         snprintf(client->name, I2C_NAME_SIZE, "Chip_0x%x", client->addr);
 368         chip->client = client;
 369
 370         /* Reset the chip */
 371         htcpld_chip_reset(client);
 372         chip->cache_in = i2c_smbus_read_byte_data(client, chip->cache_out);
 373
 374         return 0;
 375 }
 376
 377 static void htcpld_unregister_chip_i2c(
 378                 struct platform_device *pdev,
 379                 int chip_index)
 380 {
 381         struct htcpld_data *htcpld;
 382         struct htcpld_chip *chip;
 383
 384         /* Get the platform and driver data */
 385         htcpld = platform_get_drvdata(pdev);
 386         chip = &htcpld->chip[chip_index];
 387
 388         i2c_unregister_device(chip->client);
 389 }
 390
 391 static int htcpld_register_chip_gpio(
 392                 struct platform_device *pdev,
 393                 int chip_index)
 394 {
 395         struct htcpld_data *htcpld;
 396         struct device *dev = &pdev->dev;
 397         struct htcpld_core_platform_data *pdata;
 398         struct htcpld_chip *chip;
 399         struct htcpld_chip_platform_data *plat_chip_data;
 400         struct gpio_chip *gpio_chip;
 401         int ret = 0;
 402
 403         /* Get the platform and driver data */
 404         pdata = dev_get_platdata(dev);
 405         htcpld = platform_get_drvdata(pdev);
 406         chip = &htcpld->chip[chip_index];
 407         plat_chip_data = &pdata->chip[chip_index];
 408
 409         /* Setup the GPIO chips */
 410         gpio_chip = &(chip->chip_out);
 411         gpio_chip->label           = "htcpld-out";
 412         gpio_chip->parent             = dev;
 413         gpio_chip->owner           = THIS_MODULE;
 414         gpio_chip->get             = htcpld_chip_get;
 415         gpio_chip->set             = htcpld_chip_set;
 416         gpio_chip->direction_input = NULL;
 417         gpio_chip->direction_output = htcpld_direction_output;
 418         gpio_chip->base            = plat_chip_data->gpio_out_base;
 419         gpio_chip->ngpio           = plat_chip_data->num_gpios;
 420
 421         gpio_chip = &(chip->chip_in);
 422         gpio_chip->label           = "htcpld-in";
 423         gpio_chip->parent             = dev;
 424         gpio_chip->owner           = THIS_MODULE;
 425         gpio_chip->get             = htcpld_chip_get;
 426         gpio_chip->set             = NULL;
 427         gpio_chip->direction_input = htcpld_direction_input;
 428         gpio_chip->direction_output = NULL;
 429         gpio_chip->to_irq          = htcpld_chip_to_irq;
 430         gpio_chip->base            = plat_chip_data->gpio_in_base;
 431         gpio_chip->ngpio           = plat_chip_data->num_gpios;
 432
 433         /* Add the GPIO chips */
 434         ret = gpiochip_add_data(&(chip->chip_out), chip);
 435         if (ret) {
 436                 dev_warn(dev, "Unable to register output GPIOs for 0x%x: %d\n",
 437                          plat_chip_data->addr, ret);
 438                 return ret;
 439         }
 440
 441         ret = gpiochip_add_data(&(chip->chip_in), chip);
 442         if (ret) {
 443                 dev_warn(dev, "Unable to register input GPIOs for 0x%x: %d\n",
 444                          plat_chip_data->addr, ret);
 445                 gpiochip_remove(&(chip->chip_out));
 446                 return ret;
 447         }
 448
 449         return 0;
 450 }
 451
 452 static int htcpld_setup_chips(struct platform_device *pdev)
 453 {
 454         struct htcpld_data *htcpld;
 455         struct device *dev = &pdev->dev;
 456         struct htcpld_core_platform_data *pdata;
 457         int i;
 458
 459         /* Get the platform and driver data */
 460         pdata = dev_get_platdata(dev);
 461         htcpld = platform_get_drvdata(pdev);
 462
 463         /* Setup each chip's output GPIOs */
 464         htcpld->nchips = pdata->num_chip;
 465         htcpld->chip = devm_kcalloc(dev,
 466                                     htcpld->nchips,
 467                                     sizeof(struct htcpld_chip),
 468                                     GFP_KERNEL);
 469         if (!htcpld->chip)
 470                 return -ENOMEM;
 471
 472         /* Add the chips as best we can */
 473         for (i = 0; i < htcpld->nchips; i++) {
 474                 int ret;
 475
 476                 /* Setup the HTCPLD chips */
 477                 htcpld->chip[i].reset = pdata->chip[i].reset;
 478                 htcpld->chip[i].cache_out = pdata->chip[i].reset;
 479                 htcpld->chip[i].cache_in = 0;
 480                 htcpld->chip[i].dev = dev;
 481                 htcpld->chip[i].irq_start = pdata->chip[i].irq_base;
 482                 htcpld->chip[i].nirqs = pdata->chip[i].num_irqs;
 483
 484                 INIT_WORK(&(htcpld->chip[i].set_val_work), &htcpld_chip_set_ni);
 485                 spin_lock_init(&(htcpld->chip[i].lock));
 486
 487                 /* Setup the interrupts for the chip */
 488                 if (htcpld->chained_irq) {
 489                         ret = htcpld_setup_chip_irq(pdev, i);
 490                         if (ret)
 491                                 continue;
 492                 }
 493
 494                 /* Register the chip with I2C */
 495                 ret = htcpld_register_chip_i2c(pdev, i);
 496                 if (ret)
 497                         continue;
 498
 499
 500                 /* Register the chips with the GPIO subsystem */
 501                 ret = htcpld_register_chip_gpio(pdev, i);
 502                 if (ret) {
 503                         /* Unregister the chip from i2c and continue */
 504                         htcpld_unregister_chip_i2c(pdev, i);
 505                         continue;
 506                 }
 507
 508                 dev_info(dev, "Registered chip at 0x%x\n", pdata->chip[i].addr);
 509         }
 510
 511         return 0;
 512 }
 513
 514 static int htcpld_core_probe(struct platform_device *pdev)
 515 {
 516         struct htcpld_data *htcpld;
 517         struct device *dev = &pdev->dev;
 518         struct htcpld_core_platform_data *pdata;
 519         struct resource *res;
 520         int ret = 0;
 521
 522         if (!dev)
 523                 return -ENODEV;
 524
 525         pdata = dev_get_platdata(dev);
 526         if (!pdata) {
 527                 dev_warn(dev, "Platform data not found for htcpld core!\n");
 528                 return -ENXIO;
 529         }
 530
 531         htcpld = devm_kzalloc(dev, sizeof(struct htcpld_data), GFP_KERNEL);
 532         if (!htcpld)
 533                 return -ENOMEM;
 534
 535         /* Find chained irq */
 536         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 537         if (res) {
 538                 int flags;
 539                 htcpld->chained_irq = res->start;
 540
 541                 /* Setup the chained interrupt handler */
 542                 flags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING |
 543                         IRQF_ONESHOT;
 544                 ret = request_threaded_irq(htcpld->chained_irq,
 545                                            NULL, htcpld_handler,
 546                                            flags, pdev->name, htcpld);
 547                 if (ret) {
 548                         dev_warn(dev, "Unable to setup chained irq handler: %d\n", ret);
 549                         return ret;
 550                 } else
 551                         device_init_wakeup(dev, 0);
 552         }
 553
 554         /* Set the driver data */
 555         platform_set_drvdata(pdev, htcpld);
 556
 557         /* Setup the htcpld chips */
 558         ret = htcpld_setup_chips(pdev);
 559         if (ret)
 560                 return ret;
 561
 562         /* Request the GPIO(s) for the int reset and set them up */
 563         if (pdata->int_reset_gpio_hi) {
 564                 ret = gpio_request(pdata->int_reset_gpio_hi, "htcpld-core");
 565                 if (ret) {
 566                         /*
 567                          * If it failed, that sucks, but we can probably
 568                          * continue on without it.
 569                          */
 570                         dev_warn(dev, "Unable to request int_reset_gpio_hi -- interrupts may not work\n");
 571                         htcpld->int_reset_gpio_hi = 0;
 572                 } else {
 573                         htcpld->int_reset_gpio_hi = pdata->int_reset_gpio_hi;
 574                         gpio_set_value(htcpld->int_reset_gpio_hi, 1);
 575                 }
 576         }
 577
 578         if (pdata->int_reset_gpio_lo) {
 579                 ret = gpio_request(pdata->int_reset_gpio_lo, "htcpld-core");
 580                 if (ret) {
 581                         /*
 582                          * If it failed, that sucks, but we can probably
 583                          * continue on without it.
 584                          */
 585                         dev_warn(dev, "Unable to request int_reset_gpio_lo -- interrupts may not work\n");
 586                         htcpld->int_reset_gpio_lo = 0;
 587                 } else {
 588                         htcpld->int_reset_gpio_lo = pdata->int_reset_gpio_lo;
 589                         gpio_set_value(htcpld->int_reset_gpio_lo, 0);
 590                 }
 591         }
 592
 593         dev_info(dev, "Initialized successfully\n");
 594         return 0;
 595 }
 596
 597 /* The I2C Driver -- used internally */
 598 static const struct i2c_device_id htcpld_chip_id[] = {
 599         { "htcpld-chip", 0 },
 600         { }
 601 };
 602
 603 static struct i2c_driver htcpld_chip_driver = {
 604         .driver = {
 605                 .name   = "htcpld-chip",
 606         },
 607         .id_table = htcpld_chip_id,
 608 };
 609
 610 /* The Core Driver */
 611 static struct platform_driver htcpld_core_driver = {
 612         .driver = {
 613                 .name = "i2c-htcpld",
 614         },
 615 };
 616
 617 static int __init htcpld_core_init(void)
 618 {
 619         int ret;
 620
 621         /* Register the I2C Chip driver */
 622         ret = i2c_add_driver(&htcpld_chip_driver);
 623         if (ret)
 624                 return ret;
 625
 626         /* Probe for our chips */
 627         return platform_driver_probe(&htcpld_core_driver, htcpld_core_probe);
 628 }
 629 device_initcall(htcpld_core_init);