drivers/staging/greybus/gpio.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * GPIO Greybus driver.
   4  *
   5  * Copyright 2014 Google Inc.
   6  * Copyright 2014 Linaro Ltd.
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/slab.h>
  12 #include <linux/irq.h>
  13 #include <linux/irqdomain.h>
  14 #include <linux/gpio/driver.h>
  15 #include <linux/mutex.h>
  16 #include <linux/greybus.h>
  17
  18 #include "gbphy.h"
  19
  20 struct gb_gpio_line {
  21         /* The following has to be an array of line_max entries */
  22         /* --> make them just a flags field */
  23         u8                      active:    1,
  24                                 direction: 1,   /* 0 = output, 1 = input */
  25                                 value:     1;   /* 0 = low, 1 = high */
  26         u16                     debounce_usec;
  27
  28         u8                      irq_type;
  29         bool                    irq_type_pending;
  30         bool                    masked;
  31         bool                    masked_pending;
  32 };
  33
  34 struct gb_gpio_controller {
  35         struct gbphy_device     *gbphy_dev;
  36         struct gb_connection    *connection;
  37         u8                      line_max;       /* max line number */
  38         struct gb_gpio_line     *lines;
  39
  40         struct gpio_chip        chip;
  41         struct irq_chip         irqc;
  42         struct mutex            irq_lock;
  43 };
  44 #define gpio_chip_to_gb_gpio_controller(chip) \
  45         container_of(chip, struct gb_gpio_controller, chip)
  46 #define irq_data_to_gpio_chip(d) (d->domain->host_data)
  47
  48 static int gb_gpio_line_count_operation(struct gb_gpio_controller *ggc)
  49 {
  50         struct gb_gpio_line_count_response response;
  51         int ret;
  52
  53         ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_LINE_COUNT,
  54                                 NULL, 0, &response, sizeof(response));
  55         if (!ret)
  56                 ggc->line_max = response.count;
  57         return ret;
  58 }
  59
  60 static int gb_gpio_activate_operation(struct gb_gpio_controller *ggc, u8 which)
  61 {
  62         struct gb_gpio_activate_request request;
  63         struct gbphy_device *gbphy_dev = ggc->gbphy_dev;
  64         int ret;
  65
  66         ret = gbphy_runtime_get_sync(gbphy_dev);
  67         if (ret)
  68                 return ret;
  69
  70         request.which = which;
  71         ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_ACTIVATE,
  72                                 &request, sizeof(request), NULL, 0);
  73         if (ret) {
  74                 gbphy_runtime_put_autosuspend(gbphy_dev);
  75                 return ret;
  76         }
  77
  78         ggc->lines[which].active = true;
  79
  80         return 0;
  81 }
  82
  83 static void gb_gpio_deactivate_operation(struct gb_gpio_controller *ggc,
  84                                          u8 which)
  85 {
  86         struct gbphy_device *gbphy_dev = ggc->gbphy_dev;
  87         struct device *dev = &gbphy_dev->dev;
  88         struct gb_gpio_deactivate_request request;
  89         int ret;
  90
  91         request.which = which;
  92         ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DEACTIVATE,
  93                                 &request, sizeof(request), NULL, 0);
  94         if (ret) {
  95                 dev_err(dev, "failed to deactivate gpio %u\n", which);
  96                 goto out_pm_put;
  97         }
  98
  99         ggc->lines[which].active = false;
 100
 101 out_pm_put:
 102         gbphy_runtime_put_autosuspend(gbphy_dev);
 103 }
 104
 105 static int gb_gpio_get_direction_operation(struct gb_gpio_controller *ggc,
 106                                            u8 which)
 107 {
 108         struct device *dev = &ggc->gbphy_dev->dev;
 109         struct gb_gpio_get_direction_request request;
 110         struct gb_gpio_get_direction_response response;
 111         int ret;
 112         u8 direction;
 113
 114         request.which = which;
 115         ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_GET_DIRECTION,
 116                                 &request, sizeof(request),
 117                                 &response, sizeof(response));
 118         if (ret)
 119                 return ret;
 120
 121         direction = response.direction;
 122         if (direction && direction != 1) {
 123                 dev_warn(dev, "gpio %u direction was %u (should be 0 or 1)\n",
 124                          which, direction);
 125         }
 126         ggc->lines[which].direction = direction ? 1 : 0;
 127         return 0;
 128 }
 129
 130 static int gb_gpio_direction_in_operation(struct gb_gpio_controller *ggc,
 131                                           u8 which)
 132 {
 133         struct gb_gpio_direction_in_request request;
 134         int ret;
 135
 136         request.which = which;
 137         ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DIRECTION_IN,
 138                                 &request, sizeof(request), NULL, 0);
 139         if (!ret)
 140                 ggc->lines[which].direction = 1;
 141         return ret;
 142 }
 143
 144 static int gb_gpio_direction_out_operation(struct gb_gpio_controller *ggc,
 145                                            u8 which, bool value_high)
 146 {
 147         struct gb_gpio_direction_out_request request;
 148         int ret;
 149
 150         request.which = which;
 151         request.value = value_high ? 1 : 0;
 152         ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DIRECTION_OUT,
 153                                 &request, sizeof(request), NULL, 0);
 154         if (!ret)
 155                 ggc->lines[which].direction = 0;
 156         return ret;
 157 }
 158
 159 static int gb_gpio_get_value_operation(struct gb_gpio_controller *ggc,
 160                                        u8 which)
 161 {
 162         struct device *dev = &ggc->gbphy_dev->dev;
 163         struct gb_gpio_get_value_request request;
 164         struct gb_gpio_get_value_response response;
 165         int ret;
 166         u8 value;
 167
 168         request.which = which;
 169         ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_GET_VALUE,
 170                                 &request, sizeof(request),
 171                                 &response, sizeof(response));
 172         if (ret) {
 173                 dev_err(dev, "failed to get value of gpio %u\n", which);
 174                 return ret;
 175         }
 176
 177         value = response.value;
 178         if (value && value != 1) {
 179                 dev_warn(dev, "gpio %u value was %u (should be 0 or 1)\n",
 180                          which, value);
 181         }
 182         ggc->lines[which].value = value ? 1 : 0;
 183         return 0;
 184 }
 185
 186 static void gb_gpio_set_value_operation(struct gb_gpio_controller *ggc,
 187                                         u8 which, bool value_high)
 188 {
 189         struct device *dev = &ggc->gbphy_dev->dev;
 190         struct gb_gpio_set_value_request request;
 191         int ret;
 192
 193         if (ggc->lines[which].direction == 1) {
 194                 dev_warn(dev, "refusing to set value of input gpio %u\n",
 195                          which);
 196                 return;
 197         }
 198
 199         request.which = which;
 200         request.value = value_high ? 1 : 0;
 201         ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_SET_VALUE,
 202                                 &request, sizeof(request), NULL, 0);
 203         if (ret) {
 204                 dev_err(dev, "failed to set value of gpio %u\n", which);
 205                 return;
 206         }
 207
 208         ggc->lines[which].value = request.value;
 209 }
 210
 211 static int gb_gpio_set_debounce_operation(struct gb_gpio_controller *ggc,
 212                                           u8 which, u16 debounce_usec)
 213 {
 214         struct gb_gpio_set_debounce_request request;
 215         int ret;
 216
 217         request.which = which;
 218         request.usec = cpu_to_le16(debounce_usec);
 219         ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_SET_DEBOUNCE,
 220                                 &request, sizeof(request), NULL, 0);
 221         if (!ret)
 222                 ggc->lines[which].debounce_usec = debounce_usec;
 223         return ret;
 224 }
 225
 226 static void _gb_gpio_irq_mask(struct gb_gpio_controller *ggc, u8 hwirq)
 227 {
 228         struct device *dev = &ggc->gbphy_dev->dev;
 229         struct gb_gpio_irq_mask_request request;
 230         int ret;
 231
 232         request.which = hwirq;
 233         ret = gb_operation_sync(ggc->connection,
 234                                 GB_GPIO_TYPE_IRQ_MASK,
 235                                 &request, sizeof(request), NULL, 0);
 236         if (ret)
 237                 dev_err(dev, "failed to mask irq: %d\n", ret);
 238 }
 239
 240 static void _gb_gpio_irq_unmask(struct gb_gpio_controller *ggc, u8 hwirq)
 241 {
 242         struct device *dev = &ggc->gbphy_dev->dev;
 243         struct gb_gpio_irq_unmask_request request;
 244         int ret;
 245
 246         request.which = hwirq;
 247         ret = gb_operation_sync(ggc->connection,
 248                                 GB_GPIO_TYPE_IRQ_UNMASK,
 249                                 &request, sizeof(request), NULL, 0);
 250         if (ret)
 251                 dev_err(dev, "failed to unmask irq: %d\n", ret);
 252 }
 253
 254 static void _gb_gpio_irq_set_type(struct gb_gpio_controller *ggc,
 255                                   u8 hwirq, u8 type)
 256 {
 257         struct device *dev = &ggc->gbphy_dev->dev;
 258         struct gb_gpio_irq_type_request request;
 259         int ret;
 260
 261         request.which = hwirq;
 262         request.type = type;
 263
 264         ret = gb_operation_sync(ggc->connection,
 265                                 GB_GPIO_TYPE_IRQ_TYPE,
 266                                 &request, sizeof(request), NULL, 0);
 267         if (ret)
 268                 dev_err(dev, "failed to set irq type: %d\n", ret);
 269 }
 270
 271 static void gb_gpio_irq_mask(struct irq_data *d)
 272 {
 273         struct gpio_chip *chip = irq_data_to_gpio_chip(d);
 274         struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
 275         struct gb_gpio_line *line = &ggc->lines[d->hwirq];
 276
 277         line->masked = true;
 278         line->masked_pending = true;
 279 }
 280
 281 static void gb_gpio_irq_unmask(struct irq_data *d)
 282 {
 283         struct gpio_chip *chip = irq_data_to_gpio_chip(d);
 284         struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
 285         struct gb_gpio_line *line = &ggc->lines[d->hwirq];
 286
 287         line->masked = false;
 288         line->masked_pending = true;
 289 }
 290
 291 static int gb_gpio_irq_set_type(struct irq_data *d, unsigned int type)
 292 {
 293         struct gpio_chip *chip = irq_data_to_gpio_chip(d);
 294         struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
 295         struct gb_gpio_line *line = &ggc->lines[d->hwirq];
 296         struct device *dev = &ggc->gbphy_dev->dev;
 297         u8 irq_type;
 298
 299         switch (type) {
 300         case IRQ_TYPE_NONE:
 301                 irq_type = GB_GPIO_IRQ_TYPE_NONE;
 302                 break;
 303         case IRQ_TYPE_EDGE_RISING:
 304                 irq_type = GB_GPIO_IRQ_TYPE_EDGE_RISING;
 305                 break;
 306         case IRQ_TYPE_EDGE_FALLING:
 307                 irq_type = GB_GPIO_IRQ_TYPE_EDGE_FALLING;
 308                 break;
 309         case IRQ_TYPE_EDGE_BOTH:
 310                 irq_type = GB_GPIO_IRQ_TYPE_EDGE_BOTH;
 311                 break;
 312         case IRQ_TYPE_LEVEL_LOW:
 313                 irq_type = GB_GPIO_IRQ_TYPE_LEVEL_LOW;
 314                 break;
 315         case IRQ_TYPE_LEVEL_HIGH:
 316                 irq_type = GB_GPIO_IRQ_TYPE_LEVEL_HIGH;
 317                 break;
 318         default:
 319                 dev_err(dev, "unsupported irq type: %u\n", type);
 320                 return -EINVAL;
 321         }
 322
 323         line->irq_type = irq_type;
 324         line->irq_type_pending = true;
 325
 326         return 0;
 327 }
 328
 329 static void gb_gpio_irq_bus_lock(struct irq_data *d)
 330 {
 331         struct gpio_chip *chip = irq_data_to_gpio_chip(d);
 332         struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
 333
 334         mutex_lock(&ggc->irq_lock);
 335 }
 336
 337 static void gb_gpio_irq_bus_sync_unlock(struct irq_data *d)
 338 {
 339         struct gpio_chip *chip = irq_data_to_gpio_chip(d);
 340         struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
 341         struct gb_gpio_line *line = &ggc->lines[d->hwirq];
 342
 343         if (line->irq_type_pending) {
 344                 _gb_gpio_irq_set_type(ggc, d->hwirq, line->irq_type);
 345                 line->irq_type_pending = false;
 346         }
 347
 348         if (line->masked_pending) {
 349                 if (line->masked)
 350                         _gb_gpio_irq_mask(ggc, d->hwirq);
 351                 else
 352                         _gb_gpio_irq_unmask(ggc, d->hwirq);
 353                 line->masked_pending = false;
 354         }
 355
 356         mutex_unlock(&ggc->irq_lock);
 357 }
 358
 359 static int gb_gpio_request_handler(struct gb_operation *op)
 360 {
 361         struct gb_connection *connection = op->connection;
 362         struct gb_gpio_controller *ggc = gb_connection_get_data(connection);
 363         struct device *dev = &ggc->gbphy_dev->dev;
 364         struct gb_message *request;
 365         struct gb_gpio_irq_event_request *event;
 366         u8 type = op->type;
 367         int irq;
 368         struct irq_desc *desc;
 369
 370         if (type != GB_GPIO_TYPE_IRQ_EVENT) {
 371                 dev_err(dev, "unsupported unsolicited request: %u\n", type);
 372                 return -EINVAL;
 373         }
 374
 375         request = op->request;
 376
 377         if (request->payload_size < sizeof(*event)) {
 378                 dev_err(dev, "short event received (%zu < %zu)\n",
 379                         request->payload_size, sizeof(*event));
 380                 return -EINVAL;
 381         }
 382
 383         event = request->payload;
 384         if (event->which > ggc->line_max) {
 385                 dev_err(dev, "invalid hw irq: %d\n", event->which);
 386                 return -EINVAL;
 387         }
 388
 389         irq = irq_find_mapping(ggc->chip.irq.domain, event->which);
 390         if (!irq) {
 391                 dev_err(dev, "failed to find IRQ\n");
 392                 return -EINVAL;
 393         }
 394         desc = irq_to_desc(irq);
 395         if (!desc) {
 396                 dev_err(dev, "failed to look up irq\n");
 397                 return -EINVAL;
 398         }
 399
 400         local_irq_disable();
 401         generic_handle_irq_desc(desc);
 402         local_irq_enable();
 403
 404         return 0;
 405 }
 406
 407 static int gb_gpio_request(struct gpio_chip *chip, unsigned int offset)
 408 {
 409         struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
 410
 411         return gb_gpio_activate_operation(ggc, (u8)offset);
 412 }
 413
 414 static void gb_gpio_free(struct gpio_chip *chip, unsigned int offset)
 415 {
 416         struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
 417
 418         gb_gpio_deactivate_operation(ggc, (u8)offset);
 419 }
 420
 421 static int gb_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
 422 {
 423         struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
 424         u8 which;
 425         int ret;
 426
 427         which = (u8)offset;
 428         ret = gb_gpio_get_direction_operation(ggc, which);
 429         if (ret)
 430                 return ret;
 431
 432         return ggc->lines[which].direction ? 1 : 0;
 433 }
 434
 435 static int gb_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
 436 {
 437         struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
 438
 439         return gb_gpio_direction_in_operation(ggc, (u8)offset);
 440 }
 441
 442 static int gb_gpio_direction_output(struct gpio_chip *chip, unsigned int offset,
 443                                     int value)
 444 {
 445         struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
 446
 447         return gb_gpio_direction_out_operation(ggc, (u8)offset, !!value);
 448 }
 449
 450 static int gb_gpio_get(struct gpio_chip *chip, unsigned int offset)
 451 {
 452         struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
 453         u8 which;
 454         int ret;
 455
 456         which = (u8)offset;
 457         ret = gb_gpio_get_value_operation(ggc, which);
 458         if (ret)
 459                 return ret;
 460
 461         return ggc->lines[which].value;
 462 }
 463
 464 static void gb_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
 465 {
 466         struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
 467
 468         gb_gpio_set_value_operation(ggc, (u8)offset, !!value);
 469 }
 470
 471 static int gb_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
 472                               unsigned long config)
 473 {
 474         struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
 475         u32 debounce;
 476
 477         if (pinconf_to_config_param(config) != PIN_CONFIG_INPUT_DEBOUNCE)
 478                 return -ENOTSUPP;
 479
 480         debounce = pinconf_to_config_argument(config);
 481         if (debounce > U16_MAX)
 482                 return -EINVAL;
 483
 484         return gb_gpio_set_debounce_operation(ggc, (u8)offset, (u16)debounce);
 485 }
 486
 487 static int gb_gpio_controller_setup(struct gb_gpio_controller *ggc)
 488 {
 489         int ret;
 490
 491         /* Now find out how many lines there are */
 492         ret = gb_gpio_line_count_operation(ggc);
 493         if (ret)
 494                 return ret;
 495
 496         ggc->lines = kcalloc(ggc->line_max + 1, sizeof(*ggc->lines),
 497                              GFP_KERNEL);
 498         if (!ggc->lines)
 499                 return -ENOMEM;
 500
 501         return ret;
 502 }
 503
 504 static int gb_gpio_probe(struct gbphy_device *gbphy_dev,
 505                          const struct gbphy_device_id *id)
 506 {
 507         struct gb_connection *connection;
 508         struct gb_gpio_controller *ggc;
 509         struct gpio_chip *gpio;
 510         struct irq_chip *irqc;
 511         int ret;
 512
 513         ggc = kzalloc(sizeof(*ggc), GFP_KERNEL);
 514         if (!ggc)
 515                 return -ENOMEM;
 516
 517         connection =
 518                 gb_connection_create(gbphy_dev->bundle,
 519                                      le16_to_cpu(gbphy_dev->cport_desc->id),
 520                                      gb_gpio_request_handler);
 521         if (IS_ERR(connection)) {
 522                 ret = PTR_ERR(connection);
 523                 goto exit_ggc_free;
 524         }
 525
 526         ggc->connection = connection;
 527         gb_connection_set_data(connection, ggc);
 528         ggc->gbphy_dev = gbphy_dev;
 529         gb_gbphy_set_data(gbphy_dev, ggc);
 530
 531         ret = gb_connection_enable_tx(connection);
 532         if (ret)
 533                 goto exit_connection_destroy;
 534
 535         ret = gb_gpio_controller_setup(ggc);
 536         if (ret)
 537                 goto exit_connection_disable;
 538
 539         irqc = &ggc->irqc;
 540         irqc->irq_mask = gb_gpio_irq_mask;
 541         irqc->irq_unmask = gb_gpio_irq_unmask;
 542         irqc->irq_set_type = gb_gpio_irq_set_type;
 543         irqc->irq_bus_lock = gb_gpio_irq_bus_lock;
 544         irqc->irq_bus_sync_unlock = gb_gpio_irq_bus_sync_unlock;
 545         irqc->name = "greybus_gpio";
 546
 547         mutex_init(&ggc->irq_lock);
 548
 549         gpio = &ggc->chip;
 550
 551         gpio->label = "greybus_gpio";
 552         gpio->parent = &gbphy_dev->dev;
 553         gpio->owner = THIS_MODULE;
 554
 555         gpio->request = gb_gpio_request;
 556         gpio->free = gb_gpio_free;
 557         gpio->get_direction = gb_gpio_get_direction;
 558         gpio->direction_input = gb_gpio_direction_input;
 559         gpio->direction_output = gb_gpio_direction_output;
 560         gpio->get = gb_gpio_get;
 561         gpio->set = gb_gpio_set;
 562         gpio->set_config = gb_gpio_set_config;
 563         gpio->base = -1;                /* Allocate base dynamically */
 564         gpio->ngpio = ggc->line_max + 1;
 565         gpio->can_sleep = true;
 566
 567         ret = gb_connection_enable(connection);
 568         if (ret)
 569                 goto exit_line_free;
 570
 571         ret = gpiochip_add(gpio);
 572         if (ret) {
 573                 dev_err(&gbphy_dev->dev, "failed to add gpio chip: %d\n", ret);
 574                 goto exit_line_free;
 575         }
 576
 577         ret = gpiochip_irqchip_add(gpio, irqc, 0, handle_level_irq,
 578                                    IRQ_TYPE_NONE);
 579         if (ret) {
 580                 dev_err(&gbphy_dev->dev, "failed to add irq chip: %d\n", ret);
 581                 goto exit_gpiochip_remove;
 582         }
 583
 584         gbphy_runtime_put_autosuspend(gbphy_dev);
 585         return 0;
 586
 587 exit_gpiochip_remove:
 588         gpiochip_remove(gpio);
 589 exit_line_free:
 590         kfree(ggc->lines);
 591 exit_connection_disable:
 592         gb_connection_disable(connection);
 593 exit_connection_destroy:
 594         gb_connection_destroy(connection);
 595 exit_ggc_free:
 596         kfree(ggc);
 597         return ret;
 598 }
 599
 600 static void gb_gpio_remove(struct gbphy_device *gbphy_dev)
 601 {
 602         struct gb_gpio_controller *ggc = gb_gbphy_get_data(gbphy_dev);
 603         struct gb_connection *connection = ggc->connection;
 604         int ret;
 605
 606         ret = gbphy_runtime_get_sync(gbphy_dev);
 607         if (ret)
 608                 gbphy_runtime_get_noresume(gbphy_dev);
 609
 610         gb_connection_disable_rx(connection);
 611         gpiochip_remove(&ggc->chip);
 612         gb_connection_disable(connection);
 613         gb_connection_destroy(connection);
 614         kfree(ggc->lines);
 615         kfree(ggc);
 616 }
 617
 618 static const struct gbphy_device_id gb_gpio_id_table[] = {
 619         { GBPHY_PROTOCOL(GREYBUS_PROTOCOL_GPIO) },
 620         { },
 621 };
 622 MODULE_DEVICE_TABLE(gbphy, gb_gpio_id_table);
 623
 624 static struct gbphy_driver gpio_driver = {
 625         .name           = "gpio",
 626         .probe          = gb_gpio_probe,
 627         .remove         = gb_gpio_remove,
 628         .id_table       = gb_gpio_id_table,
 629 };
 630
 631 module_gbphy_driver(gpio_driver);
 632 MODULE_LICENSE("GPL v2");