drivers/gpio/basic_mmio_gpio.c

   1 /*
   2  * Driver for basic 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 unsigned long bgpio_pin2mask(struct bgpio_chip *bgc, unsigned int pin)
 108 {
 109         return 1 << pin;
 110 }
 111
 112 static unsigned long bgpio_pin2mask_be(struct bgpio_chip *bgc,
 113                                        unsigned int pin)
 114 {
 115         return 1 << (bgc->bits - 1 - pin);
 116 }
 117
 118 static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
 119 {
 120         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 121
 122         return bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio);
 123 }
 124
 125 static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
 126 {
 127         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 128         unsigned long mask = bgc->pin2mask(bgc, gpio);
 129         unsigned long flags;
 130
 131         spin_lock_irqsave(&bgc->lock, flags);
 132
 133         if (val)
 134                 bgc->data |= mask;
 135         else
 136                 bgc->data &= ~mask;
 137
 138         bgc->write_reg(bgc->reg_dat, bgc->data);
 139
 140         spin_unlock_irqrestore(&bgc->lock, flags);
 141 }
 142
 143 static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio,
 144                                  int val)
 145 {
 146         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 147         unsigned long mask = bgc->pin2mask(bgc, gpio);
 148
 149         if (val)
 150                 bgc->write_reg(bgc->reg_set, mask);
 151         else
 152                 bgc->write_reg(bgc->reg_clr, mask);
 153 }
 154
 155 static void bgpio_set_set(struct gpio_chip *gc, unsigned int gpio, int val)
 156 {
 157         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 158         unsigned long mask = bgc->pin2mask(bgc, gpio);
 159         unsigned long flags;
 160
 161         spin_lock_irqsave(&bgc->lock, flags);
 162
 163         if (val)
 164                 bgc->data |= mask;
 165         else
 166                 bgc->data &= ~mask;
 167
 168         bgc->write_reg(bgc->reg_set, bgc->data);
 169
 170         spin_unlock_irqrestore(&bgc->lock, flags);
 171 }
 172
 173 static int bgpio_simple_dir_in(struct gpio_chip *gc, unsigned int gpio)
 174 {
 175         return 0;
 176 }
 177
 178 static int bgpio_simple_dir_out(struct gpio_chip *gc, unsigned int gpio,
 179                                 int val)
 180 {
 181         gc->set(gc, gpio, val);
 182
 183         return 0;
 184 }
 185
 186 static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
 187 {
 188         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 189         unsigned long flags;
 190
 191         spin_lock_irqsave(&bgc->lock, flags);
 192
 193         bgc->dir &= ~bgc->pin2mask(bgc, gpio);
 194         bgc->write_reg(bgc->reg_dir, bgc->dir);
 195
 196         spin_unlock_irqrestore(&bgc->lock, flags);
 197
 198         return 0;
 199 }
 200
 201 static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
 202 {
 203         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 204         unsigned long flags;
 205
 206         gc->set(gc, gpio, val);
 207
 208         spin_lock_irqsave(&bgc->lock, flags);
 209
 210         bgc->dir |= bgc->pin2mask(bgc, gpio);
 211         bgc->write_reg(bgc->reg_dir, bgc->dir);
 212
 213         spin_unlock_irqrestore(&bgc->lock, flags);
 214
 215         return 0;
 216 }
 217
 218 static int bgpio_dir_in_inv(struct gpio_chip *gc, unsigned int gpio)
 219 {
 220         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 221         unsigned long flags;
 222
 223         spin_lock_irqsave(&bgc->lock, flags);
 224
 225         bgc->dir |= bgc->pin2mask(bgc, gpio);
 226         bgc->write_reg(bgc->reg_dir, bgc->dir);
 227
 228         spin_unlock_irqrestore(&bgc->lock, flags);
 229
 230         return 0;
 231 }
 232
 233 static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned int gpio, int val)
 234 {
 235         struct bgpio_chip *bgc = to_bgpio_chip(gc);
 236         unsigned long flags;
 237
 238         gc->set(gc, gpio, val);
 239
 240         spin_lock_irqsave(&bgc->lock, flags);
 241
 242         bgc->dir &= ~bgc->pin2mask(bgc, gpio);
 243         bgc->write_reg(bgc->reg_dir, bgc->dir);
 244
 245         spin_unlock_irqrestore(&bgc->lock, flags);
 246
 247         return 0;
 248 }
 249
 250 static int bgpio_setup_accessors(struct device *dev,
 251                                  struct bgpio_chip *bgc,
 252                                  bool be)
 253 {
 254
 255         switch (bgc->bits) {
 256         case 8:
 257                 bgc->read_reg   = bgpio_read8;
 258                 bgc->write_reg  = bgpio_write8;
 259                 break;
 260         case 16:
 261                 bgc->read_reg   = bgpio_read16;
 262                 bgc->write_reg  = bgpio_write16;
 263                 break;
 264         case 32:
 265                 bgc->read_reg   = bgpio_read32;
 266                 bgc->write_reg  = bgpio_write32;
 267                 break;
 268 #if BITS_PER_LONG >= 64
 269         case 64:
 270                 bgc->read_reg   = bgpio_read64;
 271                 bgc->write_reg  = bgpio_write64;
 272                 break;
 273 #endif /* BITS_PER_LONG >= 64 */
 274         default:
 275                 dev_err(dev, "unsupported data width %u bits\n", bgc->bits);
 276                 return -EINVAL;
 277         }
 278
 279         bgc->pin2mask = be ? bgpio_pin2mask_be : bgpio_pin2mask;
 280
 281         return 0;
 282 }
 283
 284 /*
 285  * Create the device and allocate the resources.  For setting GPIO's there are
 286  * three supported configurations:
 287  *
 288  *      - single input/output register resource (named "dat").
 289  *      - set/clear pair (named "set" and "clr").
 290  *      - single output register resource and single input resource ("set" and
 291  *      dat").
 292  *
 293  * For the single output register, this drives a 1 by setting a bit and a zero
 294  * by clearing a bit.  For the set clr pair, this drives a 1 by setting a bit
 295  * in the set register and clears it by setting a bit in the clear register.
 296  * The configuration is detected by which resources are present.
 297  *
 298  * For setting the GPIO direction, there are three supported configurations:
 299  *
 300  *      - simple bidirection GPIO that requires no configuration.
 301  *      - an output direction register (named "dirout") where a 1 bit
 302  *      indicates the GPIO is an output.
 303  *      - an input direction register (named "dirin") where a 1 bit indicates
 304  *      the GPIO is an input.
 305  */
 306 static int bgpio_setup_io(struct bgpio_chip *bgc,
 307                           void __iomem *dat,
 308                           void __iomem *set,
 309                           void __iomem *clr)
 310 {
 311
 312         bgc->reg_dat = dat;
 313         if (!bgc->reg_dat)
 314                 return -EINVAL;
 315
 316         if (set && clr) {
 317                 bgc->reg_set = set;
 318                 bgc->reg_clr = clr;
 319                 bgc->gc.set = bgpio_set_with_clear;
 320         } else if (set && !clr) {
 321                 bgc->reg_set = set;
 322                 bgc->gc.set = bgpio_set_set;
 323         } else {
 324                 bgc->gc.set = bgpio_set;
 325         }
 326
 327         bgc->gc.get = bgpio_get;
 328
 329         return 0;
 330 }
 331
 332 static int bgpio_setup_direction(struct bgpio_chip *bgc,
 333                                  void __iomem *dirout,
 334                                  void __iomem *dirin)
 335 {
 336         if (dirout && dirin) {
 337                 return -EINVAL;
 338         } else if (dirout) {
 339                 bgc->reg_dir = dirout;
 340                 bgc->gc.direction_output = bgpio_dir_out;
 341                 bgc->gc.direction_input = bgpio_dir_in;
 342         } else if (dirin) {
 343                 bgc->reg_dir = dirin;
 344                 bgc->gc.direction_output = bgpio_dir_out_inv;
 345                 bgc->gc.direction_input = bgpio_dir_in_inv;
 346         } else {
 347                 bgc->gc.direction_output = bgpio_simple_dir_out;
 348                 bgc->gc.direction_input = bgpio_simple_dir_in;
 349         }
 350
 351         return 0;
 352 }
 353
 354 int __devexit bgpio_remove(struct bgpio_chip *bgc)
 355 {
 356         int err = gpiochip_remove(&bgc->gc);
 357
 358         kfree(bgc);
 359
 360         return err;
 361 }
 362 EXPORT_SYMBOL_GPL(bgpio_remove);
 363
 364 int __devinit bgpio_init(struct bgpio_chip *bgc,
 365                          struct device *dev,
 366                          unsigned long sz,
 367                          void __iomem *dat,
 368                          void __iomem *set,
 369                          void __iomem *clr,
 370                          void __iomem *dirout,
 371                          void __iomem *dirin,
 372                          bool big_endian)
 373 {
 374         int ret;
 375
 376         if (!is_power_of_2(sz))
 377                 return -EINVAL;
 378
 379         bgc->bits = sz * 8;
 380         if (bgc->bits > BITS_PER_LONG)
 381                 return -EINVAL;
 382
 383         spin_lock_init(&bgc->lock);
 384         bgc->gc.dev = dev;
 385         bgc->gc.label = dev_name(dev);
 386         bgc->gc.base = -1;
 387         bgc->gc.ngpio = bgc->bits;
 388
 389         ret = bgpio_setup_io(bgc, dat, set, clr);
 390         if (ret)
 391                 return ret;
 392
 393         ret = bgpio_setup_accessors(dev, bgc, big_endian);
 394         if (ret)
 395                 return ret;
 396
 397         ret = bgpio_setup_direction(bgc, dirout, dirin);
 398         if (ret)
 399                 return ret;
 400
 401         bgc->data = bgc->read_reg(bgc->reg_dat);
 402
 403         return ret;
 404 }
 405 EXPORT_SYMBOL_GPL(bgpio_init);
 406
 407 #ifdef CONFIG_GPIO_BASIC_MMIO
 408
 409 static void __iomem *bgpio_map(struct platform_device *pdev,
 410                                const char *name,
 411                                resource_size_t sane_sz,
 412                                int *err)
 413 {
 414         struct device *dev = &pdev->dev;
 415         struct resource *r;
 416         resource_size_t start;
 417         resource_size_t sz;
 418         void __iomem *ret;
 419
 420         *err = 0;
 421
 422         r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
 423         if (!r)
 424                 return NULL;
 425
 426         sz = resource_size(r);
 427         if (sz != sane_sz) {
 428                 *err = -EINVAL;
 429                 return NULL;
 430         }
 431
 432         start = r->start;
 433         if (!devm_request_mem_region(dev, start, sz, r->name)) {
 434                 *err = -EBUSY;
 435                 return NULL;
 436         }
 437
 438         ret = devm_ioremap(dev, start, sz);
 439         if (!ret) {
 440                 *err = -ENOMEM;
 441                 return NULL;
 442         }
 443
 444         return ret;
 445 }
 446
 447 static int __devinit bgpio_pdev_probe(struct platform_device *pdev)
 448 {
 449         struct device *dev = &pdev->dev;
 450         struct resource *r;
 451         void __iomem *dat;
 452         void __iomem *set;
 453         void __iomem *clr;
 454         void __iomem *dirout;
 455         void __iomem *dirin;
 456         unsigned long sz;
 457         bool be;
 458         int err;
 459         struct bgpio_chip *bgc;
 460         struct bgpio_pdata *pdata = dev_get_platdata(dev);
 461
 462         r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
 463         if (!r)
 464                 return -EINVAL;
 465
 466         sz = resource_size(r);
 467
 468         dat = bgpio_map(pdev, "dat", sz, &err);
 469         if (!dat)
 470                 return err ? err : -EINVAL;
 471
 472         set = bgpio_map(pdev, "set", sz, &err);
 473         if (err)
 474                 return err;
 475
 476         clr = bgpio_map(pdev, "clr", sz, &err);
 477         if (err)
 478                 return err;
 479
 480         dirout = bgpio_map(pdev, "dirout", sz, &err);
 481         if (err)
 482                 return err;
 483
 484         dirin = bgpio_map(pdev, "dirin", sz, &err);
 485         if (err)
 486                 return err;
 487
 488         be = !strcmp(platform_get_device_id(pdev)->name, "basic-mmio-gpio-be");
 489
 490         bgc = devm_kzalloc(&pdev->dev, sizeof(*bgc), GFP_KERNEL);
 491         if (!bgc)
 492                 return -ENOMEM;
 493
 494         err = bgpio_init(bgc, dev, sz, dat, set, clr, dirout, dirin, be);
 495         if (err)
 496                 return err;
 497
 498         if (pdata) {
 499                 bgc->gc.base = pdata->base;
 500                 if (pdata->ngpio > 0)
 501                         bgc->gc.ngpio = pdata->ngpio;
 502         }
 503
 504         platform_set_drvdata(pdev, bgc);
 505
 506         return gpiochip_add(&bgc->gc);
 507 }
 508
 509 static int __devexit bgpio_pdev_remove(struct platform_device *pdev)
 510 {
 511         struct bgpio_chip *bgc = platform_get_drvdata(pdev);
 512
 513         return bgpio_remove(bgc);
 514 }
 515
 516 static const struct platform_device_id bgpio_id_table[] = {
 517         { "basic-mmio-gpio", },
 518         { "basic-mmio-gpio-be", },
 519         {},
 520 };
 521 MODULE_DEVICE_TABLE(platform, bgpio_id_table);
 522
 523 static struct platform_driver bgpio_driver = {
 524         .driver = {
 525                 .name = "basic-mmio-gpio",
 526         },
 527         .id_table = bgpio_id_table,
 528         .probe = bgpio_pdev_probe,
 529         .remove = __devexit_p(bgpio_pdev_remove),
 530 };
 531
 532 static int __init bgpio_platform_init(void)
 533 {
 534         return platform_driver_register(&bgpio_driver);
 535 }
 536 module_init(bgpio_platform_init);
 537
 538 static void __exit bgpio_platform_exit(void)
 539 {
 540         platform_driver_unregister(&bgpio_driver);
 541 }
 542 module_exit(bgpio_platform_exit);
 543
 544 #endif /* CONFIG_GPIO_BASIC_MMIO */
 545
 546 MODULE_DESCRIPTION("Driver for basic memory-mapped GPIO controllers");
 547 MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@gmail.com>");
 548 MODULE_LICENSE("GPL");