1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Driver for Aeroflex Gaisler GRGPIO General Purpose I/O cores. 4 * 5 * 2013 (c) Aeroflex Gaisler AB 6 * 7 * This driver supports the GRGPIO GPIO core available in the GRLIB VHDL 8 * IP core library. 9 * 10 * Full documentation of the GRGPIO core can be found here: 11 * http://www.gaisler.com/products/grlib/grip.pdf 12 * 13 * See "Documentation/devicetree/bindings/gpio/gpio-grgpio.txt" for 14 * information on open firmware properties. 15 * 16 * Contributors: Andreas Larsson <andreas@gaisler.com> 17 */ 18 19 #include <linux/kernel.h> 20 #include <linux/module.h> 21 #include <linux/init.h> 22 #include <linux/platform_device.h> 23 #include <linux/spinlock.h> 24 #include <linux/io.h> 25 #include <linux/of.h> 26 #include <linux/gpio/driver.h> 27 #include <linux/slab.h> 28 #include <linux/err.h> 29 #include <linux/interrupt.h> 30 #include <linux/irq.h> 31 #include <linux/irqdomain.h> 32 #include <linux/bitops.h> 33 34 #define GRGPIO_MAX_NGPIO 32 35 36 #define GRGPIO_DATA 0x00 37 #define GRGPIO_OUTPUT 0x04 38 #define GRGPIO_DIR 0x08 39 #define GRGPIO_IMASK 0x0c 40 #define GRGPIO_IPOL 0x10 41 #define GRGPIO_IEDGE 0x14 42 #define GRGPIO_BYPASS 0x18 43 #define GRGPIO_IMAP_BASE 0x20 44 45 /* Structure for an irq of the core - called an underlying irq */ 46 struct grgpio_uirq { 47 u8 refcnt; /* Reference counter to manage requesting/freeing of uirq */ 48 u8 uirq; /* Underlying irq of the gpio driver */ 49 }; 50 51 /* 52 * Structure for an irq of a gpio line handed out by this driver. The index is 53 * used to map to the corresponding underlying irq. 54 */ 55 struct grgpio_lirq { 56 s8 index; /* Index into struct grgpio_priv's uirqs, or -1 */ 57 u8 irq; /* irq for the gpio line */ 58 }; 59 60 struct grgpio_priv { 61 struct gpio_chip gc; 62 void __iomem *regs; 63 struct device *dev; 64 65 u32 imask; /* irq mask shadow register */ 66 67 /* 68 * The grgpio core can have multiple "underlying" irqs. The gpio lines 69 * can be mapped to any one or none of these underlying irqs 70 * independently of each other. This driver sets up an irq domain and 71 * hands out separate irqs to each gpio line 72 */ 73 struct irq_domain *domain; 74 75 /* 76 * This array contains information on each underlying irq, each 77 * irq of the grgpio core itself. 78 */ 79 struct grgpio_uirq uirqs[GRGPIO_MAX_NGPIO]; 80 81 /* 82 * This array contains information for each gpio line on the irqs 83 * obtains from this driver. An index value of -1 for a certain gpio 84 * line indicates that the line has no irq. Otherwise the index connects 85 * the irq to the underlying irq by pointing into the uirqs array. 86 */ 87 struct grgpio_lirq lirqs[GRGPIO_MAX_NGPIO]; 88 }; 89 90 static void grgpio_set_imask(struct grgpio_priv *priv, unsigned int offset, 91 int val) 92 { 93 struct gpio_chip *gc = &priv->gc; 94 95 if (val) 96 priv->imask |= BIT(offset); 97 else 98 priv->imask &= ~BIT(offset); 99 gc->write_reg(priv->regs + GRGPIO_IMASK, priv->imask); 100 } 101 102 static int grgpio_to_irq(struct gpio_chip *gc, unsigned offset) 103 { 104 struct grgpio_priv *priv = gpiochip_get_data(gc); 105 106 if (offset >= gc->ngpio) 107 return -ENXIO; 108 109 if (priv->lirqs[offset].index < 0) 110 return -ENXIO; 111 112 return irq_create_mapping(priv->domain, offset); 113 } 114 115 /* -------------------- IRQ chip functions -------------------- */ 116 117 static int grgpio_irq_set_type(struct irq_data *d, unsigned int type) 118 { 119 struct grgpio_priv *priv = irq_data_get_irq_chip_data(d); 120 unsigned long flags; 121 u32 mask = BIT(d->hwirq); 122 u32 ipol; 123 u32 iedge; 124 u32 pol; 125 u32 edge; 126 127 switch (type) { 128 case IRQ_TYPE_LEVEL_LOW: 129 pol = 0; 130 edge = 0; 131 break; 132 case IRQ_TYPE_LEVEL_HIGH: 133 pol = mask; 134 edge = 0; 135 break; 136 case IRQ_TYPE_EDGE_FALLING: 137 pol = 0; 138 edge = mask; 139 break; 140 case IRQ_TYPE_EDGE_RISING: 141 pol = mask; 142 edge = mask; 143 break; 144 default: 145 return -EINVAL; 146 } 147 148 raw_spin_lock_irqsave(&priv->gc.bgpio_lock, flags); 149 150 ipol = priv->gc.read_reg(priv->regs + GRGPIO_IPOL) & ~mask; 151 iedge = priv->gc.read_reg(priv->regs + GRGPIO_IEDGE) & ~mask; 152 153 priv->gc.write_reg(priv->regs + GRGPIO_IPOL, ipol | pol); 154 priv->gc.write_reg(priv->regs + GRGPIO_IEDGE, iedge | edge); 155 156 raw_spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags); 157 158 return 0; 159 } 160 161 static void grgpio_irq_mask(struct irq_data *d) 162 { 163 struct grgpio_priv *priv = irq_data_get_irq_chip_data(d); 164 int offset = d->hwirq; 165 unsigned long flags; 166 167 raw_spin_lock_irqsave(&priv->gc.bgpio_lock, flags); 168 169 grgpio_set_imask(priv, offset, 0); 170 171 raw_spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags); 172 } 173 174 static void grgpio_irq_unmask(struct irq_data *d) 175 { 176 struct grgpio_priv *priv = irq_data_get_irq_chip_data(d); 177 int offset = d->hwirq; 178 unsigned long flags; 179 180 raw_spin_lock_irqsave(&priv->gc.bgpio_lock, flags); 181 182 grgpio_set_imask(priv, offset, 1); 183 184 raw_spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags); 185 } 186 187 static struct irq_chip grgpio_irq_chip = { 188 .name = "grgpio", 189 .irq_mask = grgpio_irq_mask, 190 .irq_unmask = grgpio_irq_unmask, 191 .irq_set_type = grgpio_irq_set_type, 192 }; 193 194 static irqreturn_t grgpio_irq_handler(int irq, void *dev) 195 { 196 struct grgpio_priv *priv = dev; 197 int ngpio = priv->gc.ngpio; 198 unsigned long flags; 199 int i; 200 int match = 0; 201 202 raw_spin_lock_irqsave(&priv->gc.bgpio_lock, flags); 203 204 /* 205 * For each gpio line, call its interrupt handler if it its underlying 206 * irq matches the current irq that is handled. 207 */ 208 for (i = 0; i < ngpio; i++) { 209 struct grgpio_lirq *lirq = &priv->lirqs[i]; 210 211 if (priv->imask & BIT(i) && lirq->index >= 0 && 212 priv->uirqs[lirq->index].uirq == irq) { 213 generic_handle_irq(lirq->irq); 214 match = 1; 215 } 216 } 217 218 raw_spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags); 219 220 if (!match) 221 dev_warn(priv->dev, "No gpio line matched irq %d\n", irq); 222 223 return IRQ_HANDLED; 224 } 225 226 /* 227 * This function will be called as a consequence of the call to 228 * irq_create_mapping in grgpio_to_irq 229 */ 230 static int grgpio_irq_map(struct irq_domain *d, unsigned int irq, 231 irq_hw_number_t hwirq) 232 { 233 struct grgpio_priv *priv = d->host_data; 234 struct grgpio_lirq *lirq; 235 struct grgpio_uirq *uirq; 236 unsigned long flags; 237 int offset = hwirq; 238 int ret = 0; 239 240 if (!priv) 241 return -EINVAL; 242 243 lirq = &priv->lirqs[offset]; 244 if (lirq->index < 0) 245 return -EINVAL; 246 247 dev_dbg(priv->dev, "Mapping irq %d for gpio line %d\n", 248 irq, offset); 249 250 raw_spin_lock_irqsave(&priv->gc.bgpio_lock, flags); 251 252 /* Request underlying irq if not already requested */ 253 lirq->irq = irq; 254 uirq = &priv->uirqs[lirq->index]; 255 if (uirq->refcnt == 0) { 256 raw_spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags); 257 ret = request_irq(uirq->uirq, grgpio_irq_handler, 0, 258 dev_name(priv->dev), priv); 259 if (ret) { 260 dev_err(priv->dev, 261 "Could not request underlying irq %d\n", 262 uirq->uirq); 263 return ret; 264 } 265 raw_spin_lock_irqsave(&priv->gc.bgpio_lock, flags); 266 } 267 uirq->refcnt++; 268 269 raw_spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags); 270 271 /* Setup irq */ 272 irq_set_chip_data(irq, priv); 273 irq_set_chip_and_handler(irq, &grgpio_irq_chip, 274 handle_simple_irq); 275 irq_set_noprobe(irq); 276 277 return ret; 278 } 279 280 static void grgpio_irq_unmap(struct irq_domain *d, unsigned int irq) 281 { 282 struct grgpio_priv *priv = d->host_data; 283 int index; 284 struct grgpio_lirq *lirq; 285 struct grgpio_uirq *uirq; 286 unsigned long flags; 287 int ngpio = priv->gc.ngpio; 288 int i; 289 290 irq_set_chip_and_handler(irq, NULL, NULL); 291 irq_set_chip_data(irq, NULL); 292 293 raw_spin_lock_irqsave(&priv->gc.bgpio_lock, flags); 294 295 /* Free underlying irq if last user unmapped */ 296 index = -1; 297 for (i = 0; i < ngpio; i++) { 298 lirq = &priv->lirqs[i]; 299 if (lirq->irq == irq) { 300 grgpio_set_imask(priv, i, 0); 301 lirq->irq = 0; 302 index = lirq->index; 303 break; 304 } 305 } 306 WARN_ON(index < 0); 307 308 if (index >= 0) { 309 uirq = &priv->uirqs[lirq->index]; 310 uirq->refcnt--; 311 if (uirq->refcnt == 0) { 312 raw_spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags); 313 free_irq(uirq->uirq, priv); 314 return; 315 } 316 } 317 318 raw_spin_unlock_irqrestore(&priv->gc.bgpio_lock, flags); 319 } 320 321 static const struct irq_domain_ops grgpio_irq_domain_ops = { 322 .map = grgpio_irq_map, 323 .unmap = grgpio_irq_unmap, 324 }; 325 326 /* ------------------------------------------------------------ */ 327 328 static int grgpio_probe(struct platform_device *ofdev) 329 { 330 struct device_node *np = ofdev->dev.of_node; 331 void __iomem *regs; 332 struct gpio_chip *gc; 333 struct grgpio_priv *priv; 334 int err; 335 u32 prop; 336 s32 *irqmap; 337 int size; 338 int i; 339 340 priv = devm_kzalloc(&ofdev->dev, sizeof(*priv), GFP_KERNEL); 341 if (!priv) 342 return -ENOMEM; 343 344 regs = devm_platform_ioremap_resource(ofdev, 0); 345 if (IS_ERR(regs)) 346 return PTR_ERR(regs); 347 348 gc = &priv->gc; 349 err = bgpio_init(gc, &ofdev->dev, 4, regs + GRGPIO_DATA, 350 regs + GRGPIO_OUTPUT, NULL, regs + GRGPIO_DIR, NULL, 351 BGPIOF_BIG_ENDIAN_BYTE_ORDER); 352 if (err) { 353 dev_err(&ofdev->dev, "bgpio_init() failed\n"); 354 return err; 355 } 356 357 priv->regs = regs; 358 priv->imask = gc->read_reg(regs + GRGPIO_IMASK); 359 priv->dev = &ofdev->dev; 360 361 gc->owner = THIS_MODULE; 362 gc->to_irq = grgpio_to_irq; 363 gc->label = devm_kasprintf(&ofdev->dev, GFP_KERNEL, "%pOF", np); 364 gc->base = -1; 365 366 err = of_property_read_u32(np, "nbits", &prop); 367 if (err || prop <= 0 || prop > GRGPIO_MAX_NGPIO) { 368 gc->ngpio = GRGPIO_MAX_NGPIO; 369 dev_dbg(&ofdev->dev, 370 "No or invalid nbits property: assume %d\n", gc->ngpio); 371 } else { 372 gc->ngpio = prop; 373 } 374 375 /* 376 * The irqmap contains the index values indicating which underlying irq, 377 * if anyone, is connected to that line 378 */ 379 irqmap = (s32 *)of_get_property(np, "irqmap", &size); 380 if (irqmap) { 381 if (size < gc->ngpio) { 382 dev_err(&ofdev->dev, 383 "irqmap shorter than ngpio (%d < %d)\n", 384 size, gc->ngpio); 385 return -EINVAL; 386 } 387 388 priv->domain = irq_domain_add_linear(np, gc->ngpio, 389 &grgpio_irq_domain_ops, 390 priv); 391 if (!priv->domain) { 392 dev_err(&ofdev->dev, "Could not add irq domain\n"); 393 return -EINVAL; 394 } 395 396 for (i = 0; i < gc->ngpio; i++) { 397 struct grgpio_lirq *lirq; 398 int ret; 399 400 lirq = &priv->lirqs[i]; 401 lirq->index = irqmap[i]; 402 403 if (lirq->index < 0) 404 continue; 405 406 ret = platform_get_irq(ofdev, lirq->index); 407 if (ret <= 0) { 408 /* 409 * Continue without irq functionality for that 410 * gpio line 411 */ 412 continue; 413 } 414 priv->uirqs[lirq->index].uirq = ret; 415 } 416 } 417 418 platform_set_drvdata(ofdev, priv); 419 420 err = gpiochip_add_data(gc, priv); 421 if (err) { 422 dev_err(&ofdev->dev, "Could not add gpiochip\n"); 423 if (priv->domain) 424 irq_domain_remove(priv->domain); 425 return err; 426 } 427 428 dev_info(&ofdev->dev, "regs=0x%p, base=%d, ngpio=%d, irqs=%s\n", 429 priv->regs, gc->base, gc->ngpio, priv->domain ? "on" : "off"); 430 431 return 0; 432 } 433 434 static int grgpio_remove(struct platform_device *ofdev) 435 { 436 struct grgpio_priv *priv = platform_get_drvdata(ofdev); 437 438 gpiochip_remove(&priv->gc); 439 440 if (priv->domain) 441 irq_domain_remove(priv->domain); 442 443 return 0; 444 } 445 446 static const struct of_device_id grgpio_match[] = { 447 {.name = "GAISLER_GPIO"}, 448 {.name = "01_01a"}, 449 {}, 450 }; 451 452 MODULE_DEVICE_TABLE(of, grgpio_match); 453 454 static struct platform_driver grgpio_driver = { 455 .driver = { 456 .name = "grgpio", 457 .of_match_table = grgpio_match, 458 }, 459 .probe = grgpio_probe, 460 .remove = grgpio_remove, 461 }; 462 module_platform_driver(grgpio_driver); 463 464 MODULE_AUTHOR("Aeroflex Gaisler AB."); 465 MODULE_DESCRIPTION("Driver for Aeroflex Gaisler GRGPIO"); 466 MODULE_LICENSE("GPL"); 467