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