drivers/gpio/gpio-generic.c

   1 /*
   2  * Generic driver for memory-mapped GPIO controllers.
   3  *
   4  * Copyright 2008 MontaVista Software, Inc.
   5  * Copyright 2008,2010 Anton Vorontsov <cbouatmailru@gmail.com>
   6  *
   7  * This program is free software; you can redistribute  it and/or modify it
   8  * under  the terms of  the GNU General  Public License as published by the
   9  * Free Software Foundation;  either version 2 of the  License, or (at your
  10  * option) any later version.
  11  *
  12  * ....``.```~~~~````.`.`.`.`.```````'',,,.........`````......`.......
  13  * ...``                                                         ```````..
  14  * ..The simplest form of a GPIO controller that the driver supports is``
  15  *  `.just a single "data" register, where GPIO state can be read and/or `
  16  *    `,..written. ,,..``~~~~ .....``.`.`.~~.```.`.........``````.```````
  17  *        `````````
  18                                     ___
  19 _/~~|___/~|   . ```~~~~~~       ___/___\___     ,~.`.`.`.`````.~~...,,,,...
  20 __________|~$@~~~        %~    /o*o*o*o*o*o\   .. Implementing such a GPIO .
  21 o        `                     ~~~~\___/~~~~    ` controller in FPGA is ,.`
  22                                                  `....trivial..'~`.```.```
  23  *                                                    ```````
  24  *  .```````~~~~`..`.``.``.
  25  * .  The driver supports  `...       ,..```.`~~~```````````````....````.``,,
  26  * .   big-endian notation, just`.  .. A bit more sophisticated controllers ,
  27  *  . register the device with -be`. .with a pair of set/clear-bit registers ,
  28  *   `.. suffix.  ```~~`````....`.`   . affecting the data register and the .`
  29  *     ``.`.``...```                  ```.. output pins are also supported.`
  30  *                        ^^             `````.`````````.,``~``~``~~``````
  31  *                                                   .                  ^^
  32  *   ,..`.`.`...````````````......`.`.`.`.`.`..`.`.`..
  33  * .. The expectation is that in at least some cases .    ,-~~~-,
  34  *  .this will be used with roll-your-own ASIC/FPGA .`     \   /
  35  *  .logic in Verilog or VHDL. ~~~`````````..`````~~`       \ /
  36  *  ..````````......```````````                             \o_
  37  *                                                           |
  38  *                              ^^                          / \
  39  *
  40  *           ...`````~~`.....``.`..........``````.`.``.```........``.
  41  *            `  8, 16, 32 and 64 bits registers are supported, and``.
  42  *            . the number of GPIOs is determined by the width of   ~
  43  *             .. the registers. ,............```.`.`..`.`.~~~.`.`.`~
  44  *               `.......````.```
  45  */
  46
  47 #include <linux/init.h>
  48 #include <linux/err.h>
  49 #include <linux/bug.h>
  50 #include <linux/kernel.h>
  51 #include <linux/module.h>
  52 #include <linux/spinlock.h>
  53 #include <linux/compiler.h>
  54 #include <linux/types.h>
  55 #include <linux/errno.h>
  56 #include <linux/log2.h>
  57 #include <linux/ioport.h>
  58 #include <linux/io.h>
  59 #include <linux/gpio.h>
  60 #include <linux/slab.h>
  61 #include <linux/platform_device.h>
  62 #include <linux/mod_devicetable.h>
  63 #include <linux/basic_mmio_gpio.h>
  64
  65 static void bgpio_write8(void __iomem *reg, unsigned long data)
  66 {
  67         writeb(data, reg);
  68 }
  69
  70 static unsigned long bgpio_read8(void __iomem *reg)
  71 {
  72         return readb(reg);
  73 }
  74
  75 static void bgpio_write16(void __iomem *reg, unsigned long data)
  76 {
  77         writew(data, reg);
  78 }
  79
  80 static unsigned long bgpio_read16(void __iomem *reg)
  81 {
  82         return readw(reg);
  83 }
  84
  85 static void bgpio_write32(void __iomem *reg, unsigned long data)
  86 {
  87         writel(data, reg);
  88 }
  89
  90 static unsigned long bgpio_read32(void __iomem *reg)
  91 {
  92         return readl(reg);
  93 }
  94
  95 #if BITS_PER_LONG >= 64
  96 static void bgpio_write64(void __iomem *reg, unsigned long data)
  97 {
  98         writeq(data, reg);
  99 }
 100
 101 static unsigned long bgpio_read64(void __iomem *reg)
 102 {
 103         return readq(reg);
 104 }
 105 #endif /* BITS_PER_LONG >= 64 */
 106
 107 static void bgpio_write16be(void __iomem *reg, unsigned long data)
 108 {
 109         iowrite16be(data, reg);
 110 }
 111
 112 static unsigned long bgpio_read16be(void __iomem *reg)
 113 {
 114         return ioread16be(reg);
 115 }
 116
 117 static void bgpio_write32be(void __iomem *reg, unsigned long data)
 118 {
 119         iowrite32be(data, reg);
 120 }
 121
 122 static unsigned long bgpio_read32be(void __iomem *reg)
 123 {
 124         return ioread32be(reg);
 125 }
 126
 127 static unsigned long bgpio_pin2mask(struct bgpio_chip *bgc, unsigned int pin)
 128 {
 129         return 1 << pin;
 130 }
 131
 132 static unsigned long bgpio_pin2mask_be(struct bgpio_chip *bgc,
 133                                        unsigned int pin)
 134 {
 135         return 1 << (bgc->bits - 1 - pin);
 136 }
 137
 138 static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
 139 {
 140         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 141
 142         return !!(bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio));
 143 }
 144
 145 static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 146 {
 147         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 148         unsigned long mask = bgc->pin2mask(bgc, gpio);
 149         unsigned long flags;
 150
 151         spin_lock_irqsave(&bgc->lock, flags);
 152
 153         if (val)
 154                 bgc->data |= mask;
 155         else
 156                 bgc->data &= ~mask;
 157
 158         bgc->write_reg(bgc->reg_dat, bgc->data);
 159
 160         spin_unlock_irqrestore(&bgc->lock, flags);
 161 }
 162
 163 static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio,
 164                                  int val)
 165 {
 166         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 167         unsigned long mask = bgc->pin2mask(bgc, gpio);
 168
 169         if (val)
 170                 bgc->write_reg(bgc->reg_set, mask);
 171         else
 172                 bgc->write_reg(bgc->reg_clr, mask);
 173 }
 174
 175 static void bgpio_set_set(struct gpio_chip *gc, unsigned int gpio, int val)
 176 {
 177         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 178         unsigned long mask = bgc->pin2mask(bgc, gpio);
 179         unsigned long flags;
 180
 181         spin_lock_irqsave(&bgc->lock, flags);
 182
 183         if (val)
 184                 bgc->data |= mask;
 185         else
 186                 bgc->data &= ~mask;
 187
 188         bgc->write_reg(bgc->reg_set, bgc->data);
 189
 190         spin_unlock_irqrestore(&bgc->lock, flags);
 191 }
 192
 193 static int bgpio_simple_dir_in(struct gpio_chip *gc, unsigned int gpio)
 194 {
 195         return 0;
 196 }
 197
 198 static int bgpio_simple_dir_out(struct gpio_chip *gc, unsigned int gpio,
 199                                 int val)
 200 {
 201         gc->set(gc, gpio, val);
 202
 203         return 0;
 204 }
 205
 206 static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
 207 {
 208         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 209         unsigned long flags;
 210
 211         spin_lock_irqsave(&bgc->lock, flags);
 212
 213         bgc->dir &= ~bgc->pin2mask(bgc, gpio);
 214         bgc->write_reg(bgc->reg_dir, bgc->dir);
 215
 216         spin_unlock_irqrestore(&bgc->lock, flags);
 217
 218         return 0;
 219 }
 220
 221 static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 222 {
 223         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 224         unsigned long flags;
 225
 226         gc->set(gc, gpio, val);
 227
 228         spin_lock_irqsave(&bgc->lock, flags);
 229
 230         bgc->dir |= bgc->pin2mask(bgc, gpio);
 231         bgc->write_reg(bgc->reg_dir, bgc->dir);
 232
 233         spin_unlock_irqrestore(&bgc->lock, flags);
 234
 235         return 0;
 236 }
 237
 238 static int bgpio_dir_in_inv(struct gpio_chip *gc, unsigned int gpio)
 239 {
 240         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 241         unsigned long flags;
 242
 243         spin_lock_irqsave(&bgc->lock, flags);
 244
 245         bgc->dir |= bgc->pin2mask(bgc, gpio);
 246         bgc->write_reg(bgc->reg_dir, bgc->dir);
 247
 248         spin_unlock_irqrestore(&bgc->lock, flags);
 249
 250         return 0;
 251 }
 252
 253 static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned int gpio, int val)
 254 {
 255         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 256         unsigned long flags;
 257
 258         gc->set(gc, gpio, val);
 259
 260         spin_lock_irqsave(&bgc->lock, flags);
 261
 262         bgc->dir &= ~bgc->pin2mask(bgc, gpio);
 263         bgc->write_reg(bgc->reg_dir, bgc->dir);
 264
 265         spin_unlock_irqrestore(&bgc->lock, flags);
 266
 267         return 0;
 268 }
 269
 270 static int bgpio_setup_accessors(struct device *dev,
 271                                  struct bgpio_chip *bgc,
 272                                  bool bit_be,
 273                                  bool byte_be)
 274 {
 275
 276         switch (bgc->bits) {
 277         case 8:
 278                 bgc->read_reg   = bgpio_read8;
 279                 bgc->write_reg  = bgpio_write8;
 280                 break;
 281         case 16:
 282                 if (byte_be) {
 283                         bgc->read_reg   = bgpio_read16be;
 284                         bgc->write_reg  = bgpio_write16be;
 285                 } else {
 286                         bgc->read_reg   = bgpio_read16;
 287                         bgc->write_reg  = bgpio_write16;
 288                 }
 289                 break;
 290         case 32:
 291                 if (byte_be) {
 292                         bgc->read_reg   = bgpio_read32be;
 293                         bgc->write_reg  = bgpio_write32be;
 294                 } else {
 295                         bgc->read_reg   = bgpio_read32;
 296                         bgc->write_reg  = bgpio_write32;
 297                 }
 298                 break;
 299 #if BITS_PER_LONG >= 64
 300         case 64:
 301                 if (byte_be) {
 302                         dev_err(dev,
 303                                 "64 bit big endian byte order unsupported\n");
 304                         return -EINVAL;
 305                 } else {
 306                         bgc->read_reg   = bgpio_read64;
 307                         bgc->write_reg  = bgpio_write64;
 308                 }
 309                 break;
 310 #endif /* BITS_PER_LONG >= 64 */
 311         default:
 312                 dev_err(dev, "unsupported data width %u bits\n", bgc->bits);
 313                 return -EINVAL;
 314         }
 315
 316         bgc->pin2mask = bit_be ? bgpio_pin2mask_be : bgpio_pin2mask;
 317
 318         return 0;
 319 }
 320
 321 /*
 322  * Create the device and allocate the resources.  For setting GPIO's there are
 323  * three supported configurations:
 324  *
 325  *      - single input/output register resource (named "dat").
 326  *      - set/clear pair (named "set" and "clr").
 327  *      - single output register resource and single input resource ("set" and
 328  *      dat").
 329  *
 330  * For the single output register, this drives a 1 by setting a bit and a zero
 331  * by clearing a bit.  For the set clr pair, this drives a 1 by setting a bit
 332  * in the set register and clears it by setting a bit in the clear register.
 333  * The configuration is detected by which resources are present.
 334  *
 335  * For setting the GPIO direction, there are three supported configurations:
 336  *
 337  *      - simple bidirection GPIO that requires no configuration.
 338  *      - an output direction register (named "dirout") where a 1 bit
 339  *      indicates the GPIO is an output.
 340  *      - an input direction register (named "dirin") where a 1 bit indicates
 341  *      the GPIO is an input.
 342  */
 343 static int bgpio_setup_io(struct bgpio_chip *bgc,
 344                           void __iomem *dat,
 345                           void __iomem *set,
 346                           void __iomem *clr)
 347 {
 348
 349         bgc->reg_dat = dat;
 350         if (!bgc->reg_dat)
 351                 return -EINVAL;
 352
 353         if (set && clr) {
 354                 bgc->reg_set = set;
 355                 bgc->reg_clr = clr;
 356                 bgc->gc.set = bgpio_set_with_clear;
 357         } else if (set && !clr) {
 358                 bgc->reg_set = set;
 359                 bgc->gc.set = bgpio_set_set;
 360         } else {
 361                 bgc->gc.set = bgpio_set;
 362         }
 363
 364         bgc->gc.get = bgpio_get;
 365
 366         return 0;
 367 }
 368
 369 static int bgpio_setup_direction(struct bgpio_chip *bgc,
 370                                  void __iomem *dirout,
 371                                  void __iomem *dirin)
 372 {
 373         if (dirout && dirin) {
 374                 return -EINVAL;
 375         } else if (dirout) {
 376                 bgc->reg_dir = dirout;
 377                 bgc->gc.direction_output = bgpio_dir_out;
 378                 bgc->gc.direction_input = bgpio_dir_in;
 379         } else if (dirin) {
 380                 bgc->reg_dir = dirin;
 381                 bgc->gc.direction_output = bgpio_dir_out_inv;
 382                 bgc->gc.direction_input = bgpio_dir_in_inv;
 383         } else {
 384                 bgc->gc.direction_output = bgpio_simple_dir_out;
 385                 bgc->gc.direction_input = bgpio_simple_dir_in;
 386         }
 387
 388         return 0;
 389 }
 390
 391 static int bgpio_request(struct gpio_chip *chip, unsigned gpio_pin)
 392 {
 393         if (gpio_pin < chip->ngpio)
 394                 return 0;
 395
 396         return -EINVAL;
 397 }
 398
 399 int bgpio_remove(struct bgpio_chip *bgc)
 400 {
 401         gpiochip_remove(&bgc->gc);
 402         return 0;
 403 }
 404 EXPORT_SYMBOL_GPL(bgpio_remove);
 405
 406 int bgpio_init(struct bgpio_chip *bgc, struct device *dev,
 407                unsigned long sz, void __iomem *dat, void __iomem *set,
 408                void __iomem *clr, void __iomem *dirout, void __iomem *dirin,
 409                unsigned long flags)
 410 {
 411         int ret;
 412
 413         if (!is_power_of_2(sz))
 414                 return -EINVAL;
 415
 416         bgc->bits = sz * 8;
 417         if (bgc->bits > BITS_PER_LONG)
 418                 return -EINVAL;
 419
 420         spin_lock_init(&bgc->lock);
 421         bgc->gc.dev = dev;
 422         bgc->gc.label = dev_name(dev);
 423         bgc->gc.base = -1;
 424         bgc->gc.ngpio = bgc->bits;
 425         bgc->gc.request = bgpio_request;
 426
 427         ret = bgpio_setup_io(bgc, dat, set, clr);
 428         if (ret)
 429                 return ret;
 430
 431         ret = bgpio_setup_accessors(dev, bgc, flags & BGPIOF_BIG_ENDIAN,
 432                                     flags & BGPIOF_BIG_ENDIAN_BYTE_ORDER);
 433         if (ret)
 434                 return ret;
 435
 436         ret = bgpio_setup_direction(bgc, dirout, dirin);
 437         if (ret)
 438                 return ret;
 439
 440         bgc->data = bgc->read_reg(bgc->reg_dat);
 441         if (bgc->gc.set == bgpio_set_set &&
 442                         !(flags & BGPIOF_UNREADABLE_REG_SET))
 443                 bgc->data = bgc->read_reg(bgc->reg_set);
 444         if (bgc->reg_dir && !(flags & BGPIOF_UNREADABLE_REG_DIR))
 445                 bgc->dir = bgc->read_reg(bgc->reg_dir);
 446
 447         return ret;
 448 }
 449 EXPORT_SYMBOL_GPL(bgpio_init);
 450
 451 #ifdef CONFIG_GPIO_GENERIC_PLATFORM
 452
 453 static void __iomem *bgpio_map(struct platform_device *pdev,
 454                                const char *name,
 455                                resource_size_t sane_sz,
 456                                int *err)
 457 {
 458         struct device *dev = &pdev->dev;
 459         struct resource *r;
 460         resource_size_t start;
 461         resource_size_t sz;
 462         void __iomem *ret;
 463
 464         *err = 0;
 465
 466         r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
 467         if (!r)
 468                 return NULL;
 469
 470         sz = resource_size(r);
 471         if (sz != sane_sz) {
 472                 *err = -EINVAL;
 473                 return NULL;
 474         }
 475
 476         start = r->start;
 477         if (!devm_request_mem_region(dev, start, sz, r->name)) {
 478                 *err = -EBUSY;
 479                 return NULL;
 480         }
 481
 482         ret = devm_ioremap(dev, start, sz);
 483         if (!ret) {
 484                 *err = -ENOMEM;
 485                 return NULL;
 486         }
 487
 488         return ret;
 489 }
 490
 491 static int bgpio_pdev_probe(struct platform_device *pdev)
 492 {
 493         struct device *dev = &pdev->dev;
 494         struct resource *r;
 495         void __iomem *dat;
 496         void __iomem *set;
 497         void __iomem *clr;
 498         void __iomem *dirout;
 499         void __iomem *dirin;
 500         unsigned long sz;
 501         unsigned long flags = pdev->id_entry->driver_data;
 502         int err;
 503         struct bgpio_chip *bgc;
 504         struct bgpio_pdata *pdata = dev_get_platdata(dev);
 505
 506         r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
 507         if (!r)
 508                 return -EINVAL;
 509
 510         sz = resource_size(r);
 511
 512         dat = bgpio_map(pdev, "dat", sz, &err);
 513         if (!dat)
 514                 return err ? err : -EINVAL;
 515
 516         set = bgpio_map(pdev, "set", sz, &err);
 517         if (err)
 518                 return err;
 519
 520         clr = bgpio_map(pdev, "clr", sz, &err);
 521         if (err)
 522                 return err;
 523
 524         dirout = bgpio_map(pdev, "dirout", sz, &err);
 525         if (err)
 526                 return err;
 527
 528         dirin = bgpio_map(pdev, "dirin", sz, &err);
 529         if (err)
 530                 return err;
 531
 532         bgc = devm_kzalloc(&pdev->dev, sizeof(*bgc), GFP_KERNEL);
 533         if (!bgc)
 534                 return -ENOMEM;
 535
 536         err = bgpio_init(bgc, dev, sz, dat, set, clr, dirout, dirin, flags);
 537         if (err)
 538                 return err;
 539
 540         if (pdata) {
 541                 if (pdata->label)
 542                         bgc->gc.label = pdata->label;
 543                 bgc->gc.base = pdata->base;
 544                 if (pdata->ngpio > 0)
 545                         bgc->gc.ngpio = pdata->ngpio;
 546         }
 547
 548         platform_set_drvdata(pdev, bgc);
 549
 550         return gpiochip_add(&bgc->gc);
 551 }
 552
 553 static int bgpio_pdev_remove(struct platform_device *pdev)
 554 {
 555         struct bgpio_chip *bgc = platform_get_drvdata(pdev);
 556
 557         return bgpio_remove(bgc);
 558 }
 559
 560 static const struct platform_device_id bgpio_id_table[] = {
 561         {
 562                 .name           = "basic-mmio-gpio",
 563                 .driver_data    = 0,
 564         }, {
 565                 .name           = "basic-mmio-gpio-be",
 566                 .driver_data    = BGPIOF_BIG_ENDIAN,
 567         },
 568         { }
 569 };
 570 MODULE_DEVICE_TABLE(platform, bgpio_id_table);
 571
 572 static struct platform_driver bgpio_driver = {
 573         .driver = {
 574                 .name = "basic-mmio-gpio",
 575         },
 576         .id_table = bgpio_id_table,
 577         .probe = bgpio_pdev_probe,
 578         .remove = bgpio_pdev_remove,
 579 };
 580
 581 module_platform_driver(bgpio_driver);
 582
 583 #endif /* CONFIG_GPIO_GENERIC_PLATFORM */
 584
 585 MODULE_DESCRIPTION("Driver for basic memory-mapped GPIO controllers");
 586 MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@gmail.com>");
 587 MODULE_LICENSE("GPL");