drivers/gpio/gpio-adnp.c

   1 /*
   2  * Copyright (C) 2011-2012 Avionic Design GmbH
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/gpio.h>
  10 #include <linux/i2c.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/irqdomain.h>
  13 #include <linux/module.h>
  14 #include <linux/of_irq.h>
  15 #include <linux/seq_file.h>
  16 #include <linux/slab.h>
  17
  18 #define GPIO_DDR(gpio) (0x00 << (gpio)->reg_shift)
  19 #define GPIO_PLR(gpio) (0x01 << (gpio)->reg_shift)
  20 #define GPIO_IER(gpio) (0x02 << (gpio)->reg_shift)
  21 #define GPIO_ISR(gpio) (0x03 << (gpio)->reg_shift)
  22 #define GPIO_PTR(gpio) (0x04 << (gpio)->reg_shift)
  23
  24 struct adnp {
  25         struct i2c_client *client;
  26         struct gpio_chip gpio;
  27         unsigned int reg_shift;
  28
  29         struct mutex i2c_lock;
  30
  31         struct irq_domain *domain;
  32         struct mutex irq_lock;
  33
  34         u8 *irq_enable;
  35         u8 *irq_level;
  36         u8 *irq_rise;
  37         u8 *irq_fall;
  38         u8 *irq_high;
  39         u8 *irq_low;
  40 };
  41
  42 static inline struct adnp *to_adnp(struct gpio_chip *chip)
  43 {
  44         return container_of(chip, struct adnp, gpio);
  45 }
  46
  47 static int adnp_read(struct adnp *adnp, unsigned offset, uint8_t *value)
  48 {
  49         int err;
  50
  51         err = i2c_smbus_read_byte_data(adnp->client, offset);
  52         if (err < 0) {
  53                 dev_err(adnp->gpio.dev, "%s failed: %d\n",
  54                         "i2c_smbus_read_byte_data()", err);
  55                 return err;
  56         }
  57
  58         *value = err;
  59         return 0;
  60 }
  61
  62 static int adnp_write(struct adnp *adnp, unsigned offset, uint8_t value)
  63 {
  64         int err;
  65
  66         err = i2c_smbus_write_byte_data(adnp->client, offset, value);
  67         if (err < 0) {
  68                 dev_err(adnp->gpio.dev, "%s failed: %d\n",
  69                         "i2c_smbus_write_byte_data()", err);
  70                 return err;
  71         }
  72
  73         return 0;
  74 }
  75
  76 static int adnp_gpio_get(struct gpio_chip *chip, unsigned offset)
  77 {
  78         struct adnp *adnp = to_adnp(chip);
  79         unsigned int reg = offset >> adnp->reg_shift;
  80         unsigned int pos = offset & 7;
  81         u8 value;
  82         int err;
  83
  84         err = adnp_read(adnp, GPIO_PLR(adnp) + reg, &value);
  85         if (err < 0)
  86                 return err;
  87
  88         return (value & BIT(pos)) ? 1 : 0;
  89 }
  90
  91 static void __adnp_gpio_set(struct adnp *adnp, unsigned offset, int value)
  92 {
  93         unsigned int reg = offset >> adnp->reg_shift;
  94         unsigned int pos = offset & 7;
  95         int err;
  96         u8 val;
  97
  98         err = adnp_read(adnp, GPIO_PLR(adnp) + reg, &val);
  99         if (err < 0)
 100                 return;
 101
 102         if (value)
 103                 val |= BIT(pos);
 104         else
 105                 val &= ~BIT(pos);
 106
 107         adnp_write(adnp, GPIO_PLR(adnp) + reg, val);
 108 }
 109
 110 static void adnp_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 111 {
 112         struct adnp *adnp = to_adnp(chip);
 113
 114         mutex_lock(&adnp->i2c_lock);
 115         __adnp_gpio_set(adnp, offset, value);
 116         mutex_unlock(&adnp->i2c_lock);
 117 }
 118
 119 static int adnp_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 120 {
 121         struct adnp *adnp = to_adnp(chip);
 122         unsigned int reg = offset >> adnp->reg_shift;
 123         unsigned int pos = offset & 7;
 124         u8 value;
 125         int err;
 126
 127         mutex_lock(&adnp->i2c_lock);
 128
 129         err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &value);
 130         if (err < 0)
 131                 goto out;
 132
 133         value &= ~BIT(pos);
 134
 135         err = adnp_write(adnp, GPIO_DDR(adnp) + reg, value);
 136         if (err < 0)
 137                 goto out;
 138
 139         err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &value);
 140         if (err < 0)
 141                 goto out;
 142
 143         if (err & BIT(pos))
 144                 err = -EACCES;
 145
 146         err = 0;
 147
 148 out:
 149         mutex_unlock(&adnp->i2c_lock);
 150         return err;
 151 }
 152
 153 static int adnp_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
 154                                       int value)
 155 {
 156         struct adnp *adnp = to_adnp(chip);
 157         unsigned int reg = offset >> adnp->reg_shift;
 158         unsigned int pos = offset & 7;
 159         int err;
 160         u8 val;
 161
 162         mutex_lock(&adnp->i2c_lock);
 163
 164         err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &val);
 165         if (err < 0)
 166                 goto out;
 167
 168         val |= BIT(pos);
 169
 170         err = adnp_write(adnp, GPIO_DDR(adnp) + reg, val);
 171         if (err < 0)
 172                 goto out;
 173
 174         err = adnp_read(adnp, GPIO_DDR(adnp) + reg, &val);
 175         if (err < 0)
 176                 goto out;
 177
 178         if (!(val & BIT(pos))) {
 179                 err = -EPERM;
 180                 goto out;
 181         }
 182
 183         __adnp_gpio_set(adnp, offset, value);
 184         err = 0;
 185
 186 out:
 187         mutex_unlock(&adnp->i2c_lock);
 188         return err;
 189 }
 190
 191 static void adnp_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 192 {
 193         struct adnp *adnp = to_adnp(chip);
 194         unsigned int num_regs = 1 << adnp->reg_shift, i, j;
 195         int err;
 196
 197         for (i = 0; i < num_regs; i++) {
 198                 u8 ddr, plr, ier, isr;
 199
 200                 mutex_lock(&adnp->i2c_lock);
 201
 202                 err = adnp_read(adnp, GPIO_DDR(adnp) + i, &ddr);
 203                 if (err < 0) {
 204                         mutex_unlock(&adnp->i2c_lock);
 205                         return;
 206                 }
 207
 208                 err = adnp_read(adnp, GPIO_PLR(adnp) + i, &plr);
 209                 if (err < 0) {
 210                         mutex_unlock(&adnp->i2c_lock);
 211                         return;
 212                 }
 213
 214                 err = adnp_read(adnp, GPIO_IER(adnp) + i, &ier);
 215                 if (err < 0) {
 216                         mutex_unlock(&adnp->i2c_lock);
 217                         return;
 218                 }
 219
 220                 err = adnp_read(adnp, GPIO_ISR(adnp) + i, &isr);
 221                 if (err < 0) {
 222                         mutex_unlock(&adnp->i2c_lock);
 223                         return;
 224                 }
 225
 226                 mutex_unlock(&adnp->i2c_lock);
 227
 228                 for (j = 0; j < 8; j++) {
 229                         unsigned int bit = (i << adnp->reg_shift) + j;
 230                         const char *direction = "input ";
 231                         const char *level = "low ";
 232                         const char *interrupt = "disabled";
 233                         const char *pending = "";
 234
 235                         if (ddr & BIT(j))
 236                                 direction = "output";
 237
 238                         if (plr & BIT(j))
 239                                 level = "high";
 240
 241                         if (ier & BIT(j))
 242                                 interrupt = "enabled ";
 243
 244                         if (isr & BIT(j))
 245                                 pending = "pending";
 246
 247                         seq_printf(s, "%2u: %s %s IRQ %s %s\n", bit,
 248                                    direction, level, interrupt, pending);
 249                 }
 250         }
 251 }
 252
 253 static int adnp_gpio_setup(struct adnp *adnp, unsigned int num_gpios)
 254 {
 255         struct gpio_chip *chip = &adnp->gpio;
 256
 257         adnp->reg_shift = get_count_order(num_gpios) - 3;
 258
 259         chip->direction_input = adnp_gpio_direction_input;
 260         chip->direction_output = adnp_gpio_direction_output;
 261         chip->get = adnp_gpio_get;
 262         chip->set = adnp_gpio_set;
 263         chip->can_sleep = 1;
 264
 265         if (IS_ENABLED(CONFIG_DEBUG_FS))
 266                 chip->dbg_show = adnp_gpio_dbg_show;
 267
 268         chip->base = -1;
 269         chip->ngpio = num_gpios;
 270         chip->label = adnp->client->name;
 271         chip->dev = &adnp->client->dev;
 272         chip->of_node = chip->dev->of_node;
 273         chip->owner = THIS_MODULE;
 274
 275         return 0;
 276 }
 277
 278 static irqreturn_t adnp_irq(int irq, void *data)
 279 {
 280         struct adnp *adnp = data;
 281         unsigned int num_regs, i;
 282
 283         num_regs = 1 << adnp->reg_shift;
 284
 285         for (i = 0; i < num_regs; i++) {
 286                 unsigned int base = i << adnp->reg_shift, bit;
 287                 u8 changed, level, isr, ier;
 288                 unsigned long pending;
 289                 int err;
 290
 291                 mutex_lock(&adnp->i2c_lock);
 292
 293                 err = adnp_read(adnp, GPIO_PLR(adnp) + i, &level);
 294                 if (err < 0) {
 295                         mutex_unlock(&adnp->i2c_lock);
 296                         continue;
 297                 }
 298
 299                 err = adnp_read(adnp, GPIO_ISR(adnp) + i, &isr);
 300                 if (err < 0) {
 301                         mutex_unlock(&adnp->i2c_lock);
 302                         continue;
 303                 }
 304
 305                 err = adnp_read(adnp, GPIO_IER(adnp) + i, &ier);
 306                 if (err < 0) {
 307                         mutex_unlock(&adnp->i2c_lock);
 308                         continue;
 309                 }
 310
 311                 mutex_unlock(&adnp->i2c_lock);
 312
 313                 /* determine pins that changed levels */
 314                 changed = level ^ adnp->irq_level[i];
 315
 316                 /* compute edge-triggered interrupts */
 317                 pending = changed & ((adnp->irq_fall[i] & ~level) |
 318                                      (adnp->irq_rise[i] & level));
 319
 320                 /* add in level-triggered interrupts */
 321                 pending |= (adnp->irq_high[i] & level) |
 322                            (adnp->irq_low[i] & ~level);
 323
 324                 /* mask out non-pending and disabled interrupts */
 325                 pending &= isr & ier;
 326
 327                 for_each_set_bit(bit, &pending, 8) {
 328                         unsigned int virq;
 329                         virq = irq_find_mapping(adnp->domain, base + bit);
 330                         handle_nested_irq(virq);
 331                 }
 332         }
 333
 334         return IRQ_HANDLED;
 335 }
 336
 337 static int adnp_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
 338 {
 339         struct adnp *adnp = to_adnp(chip);
 340         return irq_create_mapping(adnp->domain, offset);
 341 }
 342
 343 static void adnp_irq_mask(struct irq_data *data)
 344 {
 345         struct adnp *adnp = irq_data_get_irq_chip_data(data);
 346         unsigned int reg = data->hwirq >> adnp->reg_shift;
 347         unsigned int pos = data->hwirq & 7;
 348
 349         adnp->irq_enable[reg] &= ~BIT(pos);
 350 }
 351
 352 static void adnp_irq_unmask(struct irq_data *data)
 353 {
 354         struct adnp *adnp = irq_data_get_irq_chip_data(data);
 355         unsigned int reg = data->hwirq >> adnp->reg_shift;
 356         unsigned int pos = data->hwirq & 7;
 357
 358         adnp->irq_enable[reg] |= BIT(pos);
 359 }
 360
 361 static int adnp_irq_set_type(struct irq_data *data, unsigned int type)
 362 {
 363         struct adnp *adnp = irq_data_get_irq_chip_data(data);
 364         unsigned int reg = data->hwirq >> adnp->reg_shift;
 365         unsigned int pos = data->hwirq & 7;
 366
 367         if (type & IRQ_TYPE_EDGE_RISING)
 368                 adnp->irq_rise[reg] |= BIT(pos);
 369         else
 370                 adnp->irq_rise[reg] &= ~BIT(pos);
 371
 372         if (type & IRQ_TYPE_EDGE_FALLING)
 373                 adnp->irq_fall[reg] |= BIT(pos);
 374         else
 375                 adnp->irq_fall[reg] &= ~BIT(pos);
 376
 377         if (type & IRQ_TYPE_LEVEL_HIGH)
 378                 adnp->irq_high[reg] |= BIT(pos);
 379         else
 380                 adnp->irq_high[reg] &= ~BIT(pos);
 381
 382         if (type & IRQ_TYPE_LEVEL_LOW)
 383                 adnp->irq_low[reg] |= BIT(pos);
 384         else
 385                 adnp->irq_low[reg] &= ~BIT(pos);
 386
 387         return 0;
 388 }
 389
 390 static void adnp_irq_bus_lock(struct irq_data *data)
 391 {
 392         struct adnp *adnp = irq_data_get_irq_chip_data(data);
 393
 394         mutex_lock(&adnp->irq_lock);
 395 }
 396
 397 static void adnp_irq_bus_unlock(struct irq_data *data)
 398 {
 399         struct adnp *adnp = irq_data_get_irq_chip_data(data);
 400         unsigned int num_regs = 1 << adnp->reg_shift, i;
 401
 402         mutex_lock(&adnp->i2c_lock);
 403
 404         for (i = 0; i < num_regs; i++)
 405                 adnp_write(adnp, GPIO_IER(adnp) + i, adnp->irq_enable[i]);
 406
 407         mutex_unlock(&adnp->i2c_lock);
 408         mutex_unlock(&adnp->irq_lock);
 409 }
 410
 411 static struct irq_chip adnp_irq_chip = {
 412         .name = "gpio-adnp",
 413         .irq_mask = adnp_irq_mask,
 414         .irq_unmask = adnp_irq_unmask,
 415         .irq_set_type = adnp_irq_set_type,
 416         .irq_bus_lock = adnp_irq_bus_lock,
 417         .irq_bus_sync_unlock = adnp_irq_bus_unlock,
 418 };
 419
 420 static int adnp_irq_map(struct irq_domain *domain, unsigned int irq,
 421                         irq_hw_number_t hwirq)
 422 {
 423         irq_set_chip_data(irq, domain->host_data);
 424         irq_set_chip(irq, &adnp_irq_chip);
 425         irq_set_nested_thread(irq, true);
 426
 427 #ifdef CONFIG_ARM
 428         set_irq_flags(irq, IRQF_VALID);
 429 #else
 430         irq_set_noprobe(irq);
 431 #endif
 432
 433         return 0;
 434 }
 435
 436 static const struct irq_domain_ops adnp_irq_domain_ops = {
 437         .map = adnp_irq_map,
 438         .xlate = irq_domain_xlate_twocell,
 439 };
 440
 441 static int adnp_irq_setup(struct adnp *adnp)
 442 {
 443         unsigned int num_regs = 1 << adnp->reg_shift, i;
 444         struct gpio_chip *chip = &adnp->gpio;
 445         int err;
 446
 447         mutex_init(&adnp->irq_lock);
 448
 449         /*
 450          * Allocate memory to keep track of the current level and trigger
 451          * modes of the interrupts. To avoid multiple allocations, a single
 452          * large buffer is allocated and pointers are setup to point at the
 453          * corresponding offsets. For consistency, the layout of the buffer
 454          * is chosen to match the register layout of the hardware in that
 455          * each segment contains the corresponding bits for all interrupts.
 456          */
 457         adnp->irq_enable = devm_kzalloc(chip->dev, num_regs * 6, GFP_KERNEL);
 458         if (!adnp->irq_enable)
 459                 return -ENOMEM;
 460
 461         adnp->irq_level = adnp->irq_enable + (num_regs * 1);
 462         adnp->irq_rise = adnp->irq_enable + (num_regs * 2);
 463         adnp->irq_fall = adnp->irq_enable + (num_regs * 3);
 464         adnp->irq_high = adnp->irq_enable + (num_regs * 4);
 465         adnp->irq_low = adnp->irq_enable + (num_regs * 5);
 466
 467         for (i = 0; i < num_regs; i++) {
 468                 /*
 469                  * Read the initial level of all pins to allow the emulation
 470                  * of edge triggered interrupts.
 471                  */
 472                 err = adnp_read(adnp, GPIO_PLR(adnp) + i, &adnp->irq_level[i]);
 473                 if (err < 0)
 474                         return err;
 475
 476                 /* disable all interrupts */
 477                 err = adnp_write(adnp, GPIO_IER(adnp) + i, 0);
 478                 if (err < 0)
 479                         return err;
 480
 481                 adnp->irq_enable[i] = 0x00;
 482         }
 483
 484         adnp->domain = irq_domain_add_linear(chip->of_node, chip->ngpio,
 485                                              &adnp_irq_domain_ops, adnp);
 486
 487         err = request_threaded_irq(adnp->client->irq, NULL, adnp_irq,
 488                                    IRQF_TRIGGER_RISING | IRQF_ONESHOT,
 489                                    dev_name(chip->dev), adnp);
 490         if (err != 0) {
 491                 dev_err(chip->dev, "can't request IRQ#%d: %d\n",
 492                         adnp->client->irq, err);
 493                 goto error;
 494         }
 495
 496         chip->to_irq = adnp_gpio_to_irq;
 497         return 0;
 498
 499 error:
 500         irq_domain_remove(adnp->domain);
 501         return err;
 502 }
 503
 504 static void adnp_irq_teardown(struct adnp *adnp)
 505 {
 506         unsigned int irq, i;
 507
 508         free_irq(adnp->client->irq, adnp);
 509
 510         for (i = 0; i < adnp->gpio.ngpio; i++) {
 511                 irq = irq_find_mapping(adnp->domain, i);
 512                 if (irq > 0)
 513                         irq_dispose_mapping(irq);
 514         }
 515
 516         irq_domain_remove(adnp->domain);
 517 }
 518
 519 static int adnp_i2c_probe(struct i2c_client *client,
 520                                     const struct i2c_device_id *id)
 521 {
 522         struct device_node *np = client->dev.of_node;
 523         struct adnp *adnp;
 524         u32 num_gpios;
 525         int err;
 526
 527         err = of_property_read_u32(np, "nr-gpios", &num_gpios);
 528         if (err < 0)
 529                 return err;
 530
 531         client->irq = irq_of_parse_and_map(np, 0);
 532         if (!client->irq)
 533                 return -EPROBE_DEFER;
 534
 535         adnp = devm_kzalloc(&client->dev, sizeof(*adnp), GFP_KERNEL);
 536         if (!adnp)
 537                 return -ENOMEM;
 538
 539         mutex_init(&adnp->i2c_lock);
 540         adnp->client = client;
 541
 542         err = adnp_gpio_setup(adnp, num_gpios);
 543         if (err < 0)
 544                 return err;
 545
 546         if (of_find_property(np, "interrupt-controller", NULL)) {
 547                 err = adnp_irq_setup(adnp);
 548                 if (err < 0)
 549                         goto teardown;
 550         }
 551
 552         err = gpiochip_add(&adnp->gpio);
 553         if (err < 0)
 554                 goto teardown;
 555
 556         i2c_set_clientdata(client, adnp);
 557         return 0;
 558
 559 teardown:
 560         if (of_find_property(np, "interrupt-controller", NULL))
 561                 adnp_irq_teardown(adnp);
 562
 563         return err;
 564 }
 565
 566 static int adnp_i2c_remove(struct i2c_client *client)
 567 {
 568         struct adnp *adnp = i2c_get_clientdata(client);
 569         struct device_node *np = client->dev.of_node;
 570         int err;
 571
 572         err = gpiochip_remove(&adnp->gpio);
 573         if (err < 0) {
 574                 dev_err(&client->dev, "%s failed: %d\n", "gpiochip_remove()",
 575                         err);
 576                 return err;
 577         }
 578
 579         if (of_find_property(np, "interrupt-controller", NULL))
 580                 adnp_irq_teardown(adnp);
 581
 582         return 0;
 583 }
 584
 585 static const struct i2c_device_id adnp_i2c_id[] = {
 586         { "gpio-adnp" },
 587         { },
 588 };
 589 MODULE_DEVICE_TABLE(i2c, adnp_i2c_id);
 590
 591 static const struct of_device_id adnp_of_match[] = {
 592         { .compatible = "ad,gpio-adnp", },
 593         { },
 594 };
 595 MODULE_DEVICE_TABLE(of, adnp_of_match);
 596
 597 static struct i2c_driver adnp_i2c_driver = {
 598         .driver = {
 599                 .name = "gpio-adnp",
 600                 .owner = THIS_MODULE,
 601                 .of_match_table = of_match_ptr(adnp_of_match),
 602         },
 603         .probe = adnp_i2c_probe,
 604         .remove = adnp_i2c_remove,
 605         .id_table = adnp_i2c_id,
 606 };
 607 module_i2c_driver(adnp_i2c_driver);
 608
 609 MODULE_DESCRIPTION("Avionic Design N-bit GPIO expander");
 610 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
 611 MODULE_LICENSE("GPL");