drivers/gpio/gpio-grgpio.c

   1 /*
   2  * Driver for Aeroflex Gaisler GRGPIO General Purpose I/O cores.
   3  *
   4  * 2013 (c) Aeroflex Gaisler AB
   5  *
   6  * This driver supports the GRGPIO GPIO core available in the GRLIB VHDL
   7  * IP core library.
   8  *
   9  * Full documentation of the GRGPIO core can be found here:
  10  * http://www.gaisler.com/products/grlib/grip.pdf
  11  *
  12  * See "Documentation/devicetree/bindings/gpio/gpio-grgpio.txt" for
  13  * information on open firmware properties.
  14  *
  15  * This program is free software; you can redistribute it and/or modify it
  16  * under the terms of the GNU General Public License as published by the
  17  * Free Software Foundation; either version 2 of the License, or (at your
  18  * option) any later version.
  19  *
  20  * Contributors: Andreas Larsson <andreas@gaisler.com>
  21  */
  22
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/init.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/io.h>
  28 #include <linux/of.h>
  29 #include <linux/of_gpio.h>
  30 #include <linux/of_platform.h>
  31 #include <linux/gpio.h>
  32 #include <linux/slab.h>
  33 #include <linux/err.h>
  34 #include <linux/basic_mmio_gpio.h>
  35 #include <linux/interrupt.h>
  36 #include <linux/irq.h>
  37 #include <linux/irqdomain.h>
  38
  39 #define GRGPIO_MAX_NGPIO 32
  40
  41 #define GRGPIO_DATA             0x00
  42 #define GRGPIO_OUTPUT           0x04
  43 #define GRGPIO_DIR              0x08
  44 #define GRGPIO_IMASK            0x0c
  45 #define GRGPIO_IPOL             0x10
  46 #define GRGPIO_IEDGE            0x14
  47 #define GRGPIO_BYPASS           0x18
  48 #define GRGPIO_IMAP_BASE        0x20
  49
  50 /* Structure for an irq of the core - called an underlying irq */
  51 struct grgpio_uirq {
  52         u8 refcnt; /* Reference counter to manage requesting/freeing of uirq */
  53         u8 uirq; /* Underlying irq of the gpio driver */
  54 };
  55
  56 /*
  57  * Structure for an irq of a gpio line handed out by this driver. The index is
  58  * used to map to the corresponding underlying irq.
  59  */
  60 struct grgpio_lirq {
  61         s8 index; /* Index into struct grgpio_priv's uirqs, or -1 */
  62         u8 irq; /* irq for the gpio line */
  63 };
  64
  65 struct grgpio_priv {
  66         struct bgpio_chip bgc;
  67         void __iomem *regs;
  68         struct device *dev;
  69
  70         u32 imask; /* irq mask shadow register */
  71
  72         /*
  73          * The grgpio core can have multiple "underlying" irqs. The gpio lines
  74          * can be mapped to any one or none of these underlying irqs
  75          * independently of each other. This driver sets up an irq domain and
  76          * hands out separate irqs to each gpio line
  77          */
  78         struct irq_domain *domain;
  79
  80         /*
  81          * This array contains information on each underlying irq, each
  82          * irq of the grgpio core itself.
  83          */
  84         struct grgpio_uirq uirqs[GRGPIO_MAX_NGPIO];
  85
  86         /*
  87          * This array contains information for each gpio line on the irqs
  88          * obtains from this driver. An index value of -1 for a certain gpio
  89          * line indicates that the line has no irq. Otherwise the index connects
  90          * the irq to the underlying irq by pointing into the uirqs array.
  91          */
  92         struct grgpio_lirq lirqs[GRGPIO_MAX_NGPIO];
  93 };
  94
  95 static inline struct grgpio_priv *grgpio_gc_to_priv(struct gpio_chip *gc)
  96 {
  97         struct bgpio_chip *bgc = to_bgpio_chip(gc);
  98
  99         return container_of(bgc, struct grgpio_priv, bgc);
 100 }
 101
 102 static void grgpio_set_imask(struct grgpio_priv *priv, unsigned int offset,
 103                              int val)
 104 {
 105         struct bgpio_chip *bgc = &priv->bgc;
 106         unsigned long mask = bgc->pin2mask(bgc, offset);
 107         unsigned long flags;
 108
 109         spin_lock_irqsave(&bgc->lock, flags);
 110
 111         if (val)
 112                 priv->imask |= mask;
 113         else
 114                 priv->imask &= ~mask;
 115         bgc->write_reg(priv->regs + GRGPIO_IMASK, priv->imask);
 116
 117         spin_unlock_irqrestore(&bgc->lock, flags);
 118 }
 119
 120 static int grgpio_to_irq(struct gpio_chip *gc, unsigned offset)
 121 {
 122         struct grgpio_priv *priv = grgpio_gc_to_priv(gc);
 123
 124         if (offset >= gc->ngpio)
 125                 return -ENXIO;
 126
 127         if (priv->lirqs[offset].index < 0)
 128                 return -ENXIO;
 129
 130         return irq_create_mapping(priv->domain, offset);
 131 }
 132
 133 /* -------------------- IRQ chip functions -------------------- */
 134
 135 static int grgpio_irq_set_type(struct irq_data *d, unsigned int type)
 136 {
 137         struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
 138         unsigned long flags;
 139         u32 mask = BIT(d->hwirq);
 140         u32 ipol;
 141         u32 iedge;
 142         u32 pol;
 143         u32 edge;
 144
 145         switch (type) {
 146         case IRQ_TYPE_LEVEL_LOW:
 147                 pol = 0;
 148                 edge = 0;
 149                 break;
 150         case IRQ_TYPE_LEVEL_HIGH:
 151                 pol = mask;
 152                 edge = 0;
 153                 break;
 154         case IRQ_TYPE_EDGE_FALLING:
 155                 pol = 0;
 156                 edge = mask;
 157                 break;
 158         case IRQ_TYPE_EDGE_RISING:
 159                 pol = mask;
 160                 edge = mask;
 161                 break;
 162         default:
 163                 return -EINVAL;
 164         }
 165
 166         spin_lock_irqsave(&priv->bgc.lock, flags);
 167
 168         ipol = priv->bgc.read_reg(priv->regs + GRGPIO_IPOL) & ~mask;
 169         iedge = priv->bgc.read_reg(priv->regs + GRGPIO_IEDGE) & ~mask;
 170
 171         priv->bgc.write_reg(priv->regs + GRGPIO_IPOL, ipol | pol);
 172         priv->bgc.write_reg(priv->regs + GRGPIO_IEDGE, iedge | edge);
 173
 174         spin_unlock_irqrestore(&priv->bgc.lock, flags);
 175
 176         return 0;
 177 }
 178
 179 static void grgpio_irq_mask(struct irq_data *d)
 180 {
 181         struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
 182         int offset = d->hwirq;
 183
 184         grgpio_set_imask(priv, offset, 0);
 185 }
 186
 187 static void grgpio_irq_unmask(struct irq_data *d)
 188 {
 189         struct grgpio_priv *priv = irq_data_get_irq_chip_data(d);
 190         int offset = d->hwirq;
 191
 192         grgpio_set_imask(priv, offset, 1);
 193 }
 194
 195 static struct irq_chip grgpio_irq_chip = {
 196         .name                   = "grgpio",
 197         .irq_mask               = grgpio_irq_mask,
 198         .irq_unmask             = grgpio_irq_unmask,
 199         .irq_set_type           = grgpio_irq_set_type,
 200 };
 201
 202 static irqreturn_t grgpio_irq_handler(int irq, void *dev)
 203 {
 204         struct grgpio_priv *priv = dev;
 205         int ngpio = priv->bgc.gc.ngpio;
 206         unsigned long flags;
 207         int i;
 208         int match = 0;
 209
 210         spin_lock_irqsave(&priv->bgc.lock, flags);
 211
 212         /*
 213          * For each gpio line, call its interrupt handler if it its underlying
 214          * irq matches the current irq that is handled.
 215          */
 216         for (i = 0; i < ngpio; i++) {
 217                 struct grgpio_lirq *lirq = &priv->lirqs[i];
 218
 219                 if (priv->imask & BIT(i) && lirq->index >= 0 &&
 220                     priv->uirqs[lirq->index].uirq == irq) {
 221                         generic_handle_irq(lirq->irq);
 222                         match = 1;
 223                 }
 224         }
 225
 226         spin_unlock_irqrestore(&priv->bgc.lock, flags);
 227
 228         if (!match)
 229                 dev_warn(priv->dev, "No gpio line matched irq %d\n", irq);
 230
 231         return IRQ_HANDLED;
 232 }
 233
 234 /*
 235  * This function will be called as a consequence of the call to
 236  * irq_create_mapping in grgpio_to_irq
 237  */
 238 static int grgpio_irq_map(struct irq_domain *d, unsigned int irq,
 239                           irq_hw_number_t hwirq)
 240 {
 241         struct grgpio_priv *priv = d->host_data;
 242         struct grgpio_lirq *lirq;
 243         struct grgpio_uirq *uirq;
 244         unsigned long flags;
 245         int offset = hwirq;
 246         int ret = 0;
 247
 248         if (!priv)
 249                 return -EINVAL;
 250
 251         lirq = &priv->lirqs[offset];
 252         if (lirq->index < 0)
 253                 return -EINVAL;
 254
 255         dev_dbg(priv->dev, "Mapping irq %d for gpio line %d\n",
 256                 irq, offset);
 257
 258         spin_lock_irqsave(&priv->bgc.lock, flags);
 259
 260         /* Request underlying irq if not already requested */
 261         lirq->irq = irq;
 262         uirq = &priv->uirqs[lirq->index];
 263         if (uirq->refcnt == 0) {
 264                 ret = request_irq(uirq->uirq, grgpio_irq_handler, 0,
 265                                   dev_name(priv->dev), priv);
 266                 if (ret) {
 267                         dev_err(priv->dev,
 268                                 "Could not request underlying irq %d\n",
 269                                 uirq->uirq);
 270
 271                         spin_unlock_irqrestore(&priv->bgc.lock, flags);
 272
 273                         return ret;
 274                 }
 275         }
 276         uirq->refcnt++;
 277
 278         spin_unlock_irqrestore(&priv->bgc.lock, flags);
 279
 280         /* Setup irq  */
 281         irq_set_chip_data(irq, priv);
 282         irq_set_chip_and_handler(irq, &grgpio_irq_chip,
 283                                  handle_simple_irq);
 284         irq_clear_status_flags(irq, IRQ_NOREQUEST);
 285 #ifdef CONFIG_ARM
 286         set_irq_flags(irq, IRQF_VALID);
 287 #else
 288         irq_set_noprobe(irq);
 289 #endif
 290
 291         return ret;
 292 }
 293
 294 static void grgpio_irq_unmap(struct irq_domain *d, unsigned int irq)
 295 {
 296         struct grgpio_priv *priv = d->host_data;
 297         int index;
 298         struct grgpio_lirq *lirq;
 299         struct grgpio_uirq *uirq;
 300         unsigned long flags;
 301         int ngpio = priv->bgc.gc.ngpio;
 302         int i;
 303
 304 #ifdef CONFIG_ARM
 305         set_irq_flags(irq, 0);
 306 #endif
 307         irq_set_chip_and_handler(irq, NULL, NULL);
 308         irq_set_chip_data(irq, NULL);
 309
 310         spin_lock_irqsave(&priv->bgc.lock, flags);
 311
 312         /* Free underlying irq if last user unmapped */
 313         index = -1;
 314         for (i = 0; i < ngpio; i++) {
 315                 lirq = &priv->lirqs[i];
 316                 if (lirq->irq == irq) {
 317                         grgpio_set_imask(priv, i, 0);
 318                         lirq->irq = 0;
 319                         index = lirq->index;
 320                         break;
 321                 }
 322         }
 323         WARN_ON(index < 0);
 324
 325         if (index >= 0) {
 326                 uirq = &priv->uirqs[lirq->index];
 327                 uirq->refcnt--;
 328                 if (uirq->refcnt == 0)
 329                         free_irq(uirq->uirq, priv);
 330         }
 331
 332         spin_unlock_irqrestore(&priv->bgc.lock, flags);
 333 }
 334
 335 static const struct irq_domain_ops grgpio_irq_domain_ops = {
 336         .map    = grgpio_irq_map,
 337         .unmap  = grgpio_irq_unmap,
 338 };
 339
 340 /* ------------------------------------------------------------ */
 341
 342 static int grgpio_probe(struct platform_device *ofdev)
 343 {
 344         struct device_node *np = ofdev->dev.of_node;
 345         void  __iomem *regs;
 346         struct gpio_chip *gc;
 347         struct bgpio_chip *bgc;
 348         struct grgpio_priv *priv;
 349         struct resource *res;
 350         int err;
 351         u32 prop;
 352         s32 *irqmap;
 353         int size;
 354         int i;
 355
 356         priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL);
 357         if (!priv)
 358                 return -ENOMEM;
 359
 360         res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
 361         regs = devm_ioremap_resource(&ofdev->dev, res);
 362         if (IS_ERR(regs))
 363                 return PTR_ERR(regs);
 364
 365         bgc = &priv->bgc;
 366         err = bgpio_init(bgc, &ofdev->dev, 4, regs + GRGPIO_DATA,
 367                          regs + GRGPIO_OUTPUT, NULL, regs + GRGPIO_DIR, NULL,
 368                          BGPIOF_BIG_ENDIAN_BYTE_ORDER);
 369         if (err) {
 370                 dev_err(&ofdev->dev, "bgpio_init() failed\n");
 371                 return err;
 372         }
 373
 374         priv->regs = regs;
 375         priv->imask = bgc->read_reg(regs + GRGPIO_IMASK);
 376         priv->dev = &ofdev->dev;
 377
 378         gc = &bgc->gc;
 379         gc->of_node = np;
 380         gc->owner = THIS_MODULE;
 381         gc->to_irq = grgpio_to_irq;
 382         gc->label = np->full_name;
 383         gc->base = -1;
 384
 385         err = of_property_read_u32(np, "nbits", &prop);
 386         if (err || prop <= 0 || prop > GRGPIO_MAX_NGPIO) {
 387                 gc->ngpio = GRGPIO_MAX_NGPIO;
 388                 dev_dbg(&ofdev->dev,
 389                         "No or invalid nbits property: assume %d\n", gc->ngpio);
 390         } else {
 391                 gc->ngpio = prop;
 392         }
 393
 394         /*
 395          * The irqmap contains the index values indicating which underlying irq,
 396          * if anyone, is connected to that line
 397          */
 398         irqmap = (s32 *)of_get_property(np, "irqmap", &size);
 399         if (irqmap) {
 400                 if (size < gc->ngpio) {
 401                         dev_err(&ofdev->dev,
 402                                 "irqmap shorter than ngpio (%d < %d)\n",
 403                                 size, gc->ngpio);
 404                         return -EINVAL;
 405                 }
 406
 407                 priv->domain = irq_domain_add_linear(np, gc->ngpio,
 408                                                      &grgpio_irq_domain_ops,
 409                                                      priv);
 410                 if (!priv->domain) {
 411                         dev_err(&ofdev->dev, "Could not add irq domain\n");
 412                         return -EINVAL;
 413                 }
 414
 415                 for (i = 0; i < gc->ngpio; i++) {
 416                         struct grgpio_lirq *lirq;
 417                         int ret;
 418
 419                         lirq = &priv->lirqs[i];
 420                         lirq->index = irqmap[i];
 421
 422                         if (lirq->index < 0)
 423                                 continue;
 424
 425                         ret = platform_get_irq(ofdev, lirq->index);
 426                         if (ret <= 0) {
 427                                 /*
 428                                  * Continue without irq functionality for that
 429                                  * gpio line
 430                                  */
 431                                 dev_err(priv->dev,
 432                                         "Failed to get irq for offset %d\n", i);
 433                                 continue;
 434                         }
 435                         priv->uirqs[lirq->index].uirq = ret;
 436                 }
 437         }
 438
 439         platform_set_drvdata(ofdev, priv);
 440
 441         err = gpiochip_add(gc);
 442         if (err) {
 443                 dev_err(&ofdev->dev, "Could not add gpiochip\n");
 444                 if (priv->domain)
 445                         irq_domain_remove(priv->domain);
 446                 return err;
 447         }
 448
 449         dev_info(&ofdev->dev, "regs=0x%p, base=%d, ngpio=%d, irqs=%s\n",
 450                  priv->regs, gc->base, gc->ngpio, priv->domain ? "on" : "off");
 451
 452         return 0;
 453 }
 454
 455 static int grgpio_remove(struct platform_device *ofdev)
 456 {
 457         struct grgpio_priv *priv = platform_get_drvdata(ofdev);
 458         unsigned long flags;
 459         int i;
 460         int ret = 0;
 461
 462         spin_lock_irqsave(&priv->bgc.lock, flags);
 463
 464         if (priv->domain) {
 465                 for (i = 0; i < GRGPIO_MAX_NGPIO; i++) {
 466                         if (priv->uirqs[i].refcnt != 0) {
 467                                 ret = -EBUSY;
 468                                 goto out;
 469                         }
 470                 }
 471         }
 472
 473         gpiochip_remove(&priv->bgc.gc);
 474
 475         if (priv->domain)
 476                 irq_domain_remove(priv->domain);
 477
 478 out:
 479         spin_unlock_irqrestore(&priv->bgc.lock, flags);
 480
 481         return ret;
 482 }
 483
 484 static const struct of_device_id grgpio_match[] = {
 485         {.name = "GAISLER_GPIO"},
 486         {.name = "01_01a"},
 487         {},
 488 };
 489
 490 MODULE_DEVICE_TABLE(of, grgpio_match);
 491
 492 static struct platform_driver grgpio_driver = {
 493         .driver = {
 494                 .name = "grgpio",
 495                 .of_match_table = grgpio_match,
 496         },
 497         .probe = grgpio_probe,
 498         .remove = grgpio_remove,
 499 };
 500 module_platform_driver(grgpio_driver);
 501
 502 MODULE_AUTHOR("Aeroflex Gaisler AB.");
 503 MODULE_DESCRIPTION("Driver for Aeroflex Gaisler GRGPIO");
 504 MODULE_LICENSE("GPL");