1 /* 2 * OF helpers for the GPIO API 3 * 4 * Copyright (c) 2007-2008 MontaVista Software, Inc. 5 * 6 * Author: Anton Vorontsov <avorontsov@ru.mvista.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 */ 13 14 #include <linux/device.h> 15 #include <linux/err.h> 16 #include <linux/errno.h> 17 #include <linux/module.h> 18 #include <linux/io.h> 19 #include <linux/gpio/consumer.h> 20 #include <linux/of.h> 21 #include <linux/of_address.h> 22 #include <linux/of_gpio.h> 23 #include <linux/pinctrl/pinctrl.h> 24 #include <linux/slab.h> 25 #include <linux/gpio/machine.h> 26 27 #include "gpiolib.h" 28 29 static int of_gpiochip_match_node(struct gpio_chip *chip, void *data) 30 { 31 return chip->gpiodev->dev.of_node == data; 32 } 33 34 static struct gpio_chip *of_find_gpiochip_by_node(struct device_node *np) 35 { 36 return gpiochip_find(np, of_gpiochip_match_node); 37 } 38 39 static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip, 40 struct of_phandle_args *gpiospec, 41 enum of_gpio_flags *flags) 42 { 43 int ret; 44 45 if (chip->of_gpio_n_cells != gpiospec->args_count) 46 return ERR_PTR(-EINVAL); 47 48 ret = chip->of_xlate(chip, gpiospec, flags); 49 if (ret < 0) 50 return ERR_PTR(ret); 51 52 return gpiochip_get_desc(chip, ret); 53 } 54 55 /** 56 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API 57 * @np: device node to get GPIO from 58 * @propname: property name containing gpio specifier(s) 59 * @index: index of the GPIO 60 * @flags: a flags pointer to fill in 61 * 62 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 63 * value on the error condition. If @flags is not NULL the function also fills 64 * in flags for the GPIO. 65 */ 66 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, 67 const char *propname, int index, enum of_gpio_flags *flags) 68 { 69 struct of_phandle_args gpiospec; 70 struct gpio_chip *chip; 71 struct gpio_desc *desc; 72 int ret; 73 74 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index, 75 &gpiospec); 76 if (ret) { 77 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n", 78 __func__, propname, np->full_name, index); 79 return ERR_PTR(ret); 80 } 81 82 chip = of_find_gpiochip_by_node(gpiospec.np); 83 if (!chip) { 84 desc = ERR_PTR(-EPROBE_DEFER); 85 goto out; 86 } 87 88 desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags); 89 if (IS_ERR(desc)) 90 goto out; 91 92 pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n", 93 __func__, propname, np->full_name, index, 94 PTR_ERR_OR_ZERO(desc)); 95 96 out: 97 of_node_put(gpiospec.np); 98 99 return desc; 100 } 101 102 int of_get_named_gpio_flags(struct device_node *np, const char *list_name, 103 int index, enum of_gpio_flags *flags) 104 { 105 struct gpio_desc *desc; 106 107 desc = of_get_named_gpiod_flags(np, list_name, index, flags); 108 109 if (IS_ERR(desc)) 110 return PTR_ERR(desc); 111 else 112 return desc_to_gpio(desc); 113 } 114 EXPORT_SYMBOL(of_get_named_gpio_flags); 115 116 /** 117 * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API 118 * @np: device node to get GPIO from 119 * @chip: GPIO chip whose hog is parsed 120 * @name: GPIO line name 121 * @lflags: gpio_lookup_flags - returned from of_find_gpio() or 122 * of_parse_own_gpio() 123 * @dflags: gpiod_flags - optional GPIO initialization flags 124 * 125 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 126 * value on the error condition. 127 */ 128 static struct gpio_desc *of_parse_own_gpio(struct device_node *np, 129 struct gpio_chip *chip, 130 const char **name, 131 enum gpio_lookup_flags *lflags, 132 enum gpiod_flags *dflags) 133 { 134 struct device_node *chip_np; 135 enum of_gpio_flags xlate_flags; 136 struct of_phandle_args gpiospec; 137 struct gpio_desc *desc; 138 u32 tmp; 139 int ret; 140 141 chip_np = chip->of_node; 142 if (!chip_np) 143 return ERR_PTR(-EINVAL); 144 145 xlate_flags = 0; 146 *lflags = 0; 147 *dflags = 0; 148 149 ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp); 150 if (ret) 151 return ERR_PTR(ret); 152 153 gpiospec.np = chip_np; 154 gpiospec.args_count = tmp; 155 156 ret = of_property_read_u32_array(np, "gpios", gpiospec.args, tmp); 157 if (ret) 158 return ERR_PTR(ret); 159 160 desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags); 161 if (IS_ERR(desc)) 162 return desc; 163 164 if (xlate_flags & OF_GPIO_ACTIVE_LOW) 165 *lflags |= GPIO_ACTIVE_LOW; 166 167 if (of_property_read_bool(np, "input")) 168 *dflags |= GPIOD_IN; 169 else if (of_property_read_bool(np, "output-low")) 170 *dflags |= GPIOD_OUT_LOW; 171 else if (of_property_read_bool(np, "output-high")) 172 *dflags |= GPIOD_OUT_HIGH; 173 else { 174 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n", 175 desc_to_gpio(desc), np->name); 176 return ERR_PTR(-EINVAL); 177 } 178 179 if (name && of_property_read_string(np, "line-name", name)) 180 *name = np->name; 181 182 return desc; 183 } 184 185 /** 186 * of_gpiochip_set_names() - set up the names of the lines 187 * @chip: GPIO chip whose lines should be named, if possible 188 */ 189 static void of_gpiochip_set_names(struct gpio_chip *gc) 190 { 191 struct gpio_device *gdev = gc->gpiodev; 192 struct device_node *np = gc->of_node; 193 int i; 194 int nstrings; 195 196 nstrings = of_property_count_strings(np, "gpio-line-names"); 197 if (nstrings <= 0) 198 /* Lines names not present */ 199 return; 200 201 /* This is normally not what you want */ 202 if (gdev->ngpio != nstrings) 203 dev_info(&gdev->dev, "gpio-line-names specifies %d line " 204 "names but there are %d lines on the chip\n", 205 nstrings, gdev->ngpio); 206 207 /* 208 * Make sure to not index beyond the end of the number of descriptors 209 * of the GPIO device. 210 */ 211 for (i = 0; i < gdev->ngpio; i++) { 212 const char *name; 213 int ret; 214 215 ret = of_property_read_string_index(np, 216 "gpio-line-names", 217 i, 218 &name); 219 if (ret) { 220 if (ret != -ENODATA) 221 dev_err(&gdev->dev, 222 "unable to name line %d: %d\n", 223 i, ret); 224 break; 225 } 226 gdev->descs[i].name = name; 227 } 228 } 229 230 /** 231 * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions 232 * @chip: gpio chip to act on 233 * 234 * This is only used by of_gpiochip_add to request/set GPIO initial 235 * configuration. 236 * It retures error if it fails otherwise 0 on success. 237 */ 238 static int of_gpiochip_scan_gpios(struct gpio_chip *chip) 239 { 240 struct gpio_desc *desc = NULL; 241 struct device_node *np; 242 const char *name; 243 enum gpio_lookup_flags lflags; 244 enum gpiod_flags dflags; 245 int ret; 246 247 for_each_available_child_of_node(chip->of_node, np) { 248 if (!of_property_read_bool(np, "gpio-hog")) 249 continue; 250 251 desc = of_parse_own_gpio(np, chip, &name, &lflags, &dflags); 252 if (IS_ERR(desc)) 253 continue; 254 255 ret = gpiod_hog(desc, name, lflags, dflags); 256 if (ret < 0) 257 return ret; 258 } 259 260 return 0; 261 } 262 263 /** 264 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags 265 * @gc: pointer to the gpio_chip structure 266 * @np: device node of the GPIO chip 267 * @gpio_spec: gpio specifier as found in the device tree 268 * @flags: a flags pointer to fill in 269 * 270 * This is simple translation function, suitable for the most 1:1 mapped 271 * gpio chips. This function performs only one sanity check: whether gpio 272 * is less than ngpios (that is specified in the gpio_chip). 273 */ 274 int of_gpio_simple_xlate(struct gpio_chip *gc, 275 const struct of_phandle_args *gpiospec, u32 *flags) 276 { 277 /* 278 * We're discouraging gpio_cells < 2, since that way you'll have to 279 * write your own xlate function (that will have to retrieve the GPIO 280 * number and the flags from a single gpio cell -- this is possible, 281 * but not recommended). 282 */ 283 if (gc->of_gpio_n_cells < 2) { 284 WARN_ON(1); 285 return -EINVAL; 286 } 287 288 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) 289 return -EINVAL; 290 291 if (gpiospec->args[0] >= gc->ngpio) 292 return -EINVAL; 293 294 if (flags) 295 *flags = gpiospec->args[1]; 296 297 return gpiospec->args[0]; 298 } 299 EXPORT_SYMBOL(of_gpio_simple_xlate); 300 301 /** 302 * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank) 303 * @np: device node of the GPIO chip 304 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 305 * @data: driver data to store in the struct gpio_chip 306 * 307 * To use this function you should allocate and fill mm_gc with: 308 * 309 * 1) In the gpio_chip structure: 310 * - all the callbacks 311 * - of_gpio_n_cells 312 * - of_xlate callback (optional) 313 * 314 * 3) In the of_mm_gpio_chip structure: 315 * - save_regs callback (optional) 316 * 317 * If succeeded, this function will map bank's memory and will 318 * do all necessary work for you. Then you'll able to use .regs 319 * to manage GPIOs from the callbacks. 320 */ 321 int of_mm_gpiochip_add_data(struct device_node *np, 322 struct of_mm_gpio_chip *mm_gc, 323 void *data) 324 { 325 int ret = -ENOMEM; 326 struct gpio_chip *gc = &mm_gc->gc; 327 328 gc->label = kstrdup(np->full_name, GFP_KERNEL); 329 if (!gc->label) 330 goto err0; 331 332 mm_gc->regs = of_iomap(np, 0); 333 if (!mm_gc->regs) 334 goto err1; 335 336 gc->base = -1; 337 338 if (mm_gc->save_regs) 339 mm_gc->save_regs(mm_gc); 340 341 mm_gc->gc.of_node = np; 342 343 ret = gpiochip_add_data(gc, data); 344 if (ret) 345 goto err2; 346 347 return 0; 348 err2: 349 iounmap(mm_gc->regs); 350 err1: 351 kfree(gc->label); 352 err0: 353 pr_err("%s: GPIO chip registration failed with status %d\n", 354 np->full_name, ret); 355 return ret; 356 } 357 EXPORT_SYMBOL(of_mm_gpiochip_add_data); 358 359 /** 360 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank) 361 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 362 */ 363 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc) 364 { 365 struct gpio_chip *gc = &mm_gc->gc; 366 367 if (!mm_gc) 368 return; 369 370 gpiochip_remove(gc); 371 iounmap(mm_gc->regs); 372 kfree(gc->label); 373 } 374 EXPORT_SYMBOL(of_mm_gpiochip_remove); 375 376 #ifdef CONFIG_PINCTRL 377 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) 378 { 379 struct device_node *np = chip->of_node; 380 struct of_phandle_args pinspec; 381 struct pinctrl_dev *pctldev; 382 int index = 0, ret; 383 const char *name; 384 static const char group_names_propname[] = "gpio-ranges-group-names"; 385 struct property *group_names; 386 387 if (!np) 388 return 0; 389 390 group_names = of_find_property(np, group_names_propname, NULL); 391 392 for (;; index++) { 393 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 394 index, &pinspec); 395 if (ret) 396 break; 397 398 pctldev = of_pinctrl_get(pinspec.np); 399 of_node_put(pinspec.np); 400 if (!pctldev) 401 return -EPROBE_DEFER; 402 403 if (pinspec.args[2]) { 404 if (group_names) { 405 of_property_read_string_index(np, 406 group_names_propname, 407 index, &name); 408 if (strlen(name)) { 409 pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n", 410 np->full_name); 411 break; 412 } 413 } 414 /* npins != 0: linear range */ 415 ret = gpiochip_add_pin_range(chip, 416 pinctrl_dev_get_devname(pctldev), 417 pinspec.args[0], 418 pinspec.args[1], 419 pinspec.args[2]); 420 if (ret) 421 return ret; 422 } else { 423 /* npins == 0: special range */ 424 if (pinspec.args[1]) { 425 pr_err("%s: Illegal gpio-range format.\n", 426 np->full_name); 427 break; 428 } 429 430 if (!group_names) { 431 pr_err("%s: GPIO group range requested but no %s property.\n", 432 np->full_name, group_names_propname); 433 break; 434 } 435 436 ret = of_property_read_string_index(np, 437 group_names_propname, 438 index, &name); 439 if (ret) 440 break; 441 442 if (!strlen(name)) { 443 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n", 444 np->full_name); 445 break; 446 } 447 448 ret = gpiochip_add_pingroup_range(chip, pctldev, 449 pinspec.args[0], name); 450 if (ret) 451 return ret; 452 } 453 } 454 455 return 0; 456 } 457 458 #else 459 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; } 460 #endif 461 462 int of_gpiochip_add(struct gpio_chip *chip) 463 { 464 int status; 465 466 if ((!chip->of_node) && (chip->parent)) 467 chip->of_node = chip->parent->of_node; 468 469 if (!chip->of_node) 470 return 0; 471 472 if (!chip->of_xlate) { 473 chip->of_gpio_n_cells = 2; 474 chip->of_xlate = of_gpio_simple_xlate; 475 } 476 477 if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS) 478 return -EINVAL; 479 480 status = of_gpiochip_add_pin_range(chip); 481 if (status) 482 return status; 483 484 /* If the chip defines names itself, these take precedence */ 485 if (!chip->names) 486 of_gpiochip_set_names(chip); 487 488 of_node_get(chip->of_node); 489 490 return of_gpiochip_scan_gpios(chip); 491 } 492 493 void of_gpiochip_remove(struct gpio_chip *chip) 494 { 495 gpiochip_remove_pin_ranges(chip); 496 of_node_put(chip->of_node); 497 } 498