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 /* Private data structure for of_gpiochip_find_and_xlate */ 30 struct gg_data { 31 enum of_gpio_flags *flags; 32 struct of_phandle_args gpiospec; 33 34 struct gpio_desc *out_gpio; 35 }; 36 37 /* Private function for resolving node pointer to gpio_chip */ 38 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data) 39 { 40 struct gg_data *gg_data = data; 41 int ret; 42 43 if ((gc->of_node != gg_data->gpiospec.np) || 44 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) || 45 (!gc->of_xlate)) 46 return false; 47 48 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags); 49 if (ret < 0) { 50 /* We've found a gpio chip, but the translation failed. 51 * Store translation error in out_gpio. 52 * Return false to keep looking, as more than one gpio chip 53 * could be registered per of-node. 54 */ 55 gg_data->out_gpio = ERR_PTR(ret); 56 return false; 57 } 58 59 gg_data->out_gpio = gpiochip_get_desc(gc, ret); 60 return true; 61 } 62 63 /** 64 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API 65 * @np: device node to get GPIO from 66 * @propname: property name containing gpio specifier(s) 67 * @index: index of the GPIO 68 * @flags: a flags pointer to fill in 69 * 70 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 71 * value on the error condition. If @flags is not NULL the function also fills 72 * in flags for the GPIO. 73 */ 74 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, 75 const char *propname, int index, enum of_gpio_flags *flags) 76 { 77 /* Return -EPROBE_DEFER to support probe() functions to be called 78 * later when the GPIO actually becomes available 79 */ 80 struct gg_data gg_data = { 81 .flags = flags, 82 .out_gpio = ERR_PTR(-EPROBE_DEFER) 83 }; 84 int ret; 85 86 /* .of_xlate might decide to not fill in the flags, so clear it. */ 87 if (flags) 88 *flags = 0; 89 90 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index, 91 &gg_data.gpiospec); 92 if (ret) { 93 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n", 94 __func__, propname, np->full_name, index); 95 return ERR_PTR(ret); 96 } 97 98 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate); 99 100 of_node_put(gg_data.gpiospec.np); 101 pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n", 102 __func__, propname, np->full_name, index, 103 PTR_ERR_OR_ZERO(gg_data.out_gpio)); 104 return gg_data.out_gpio; 105 } 106 107 int of_get_named_gpio_flags(struct device_node *np, const char *list_name, 108 int index, enum of_gpio_flags *flags) 109 { 110 struct gpio_desc *desc; 111 112 desc = of_get_named_gpiod_flags(np, list_name, index, flags); 113 114 if (IS_ERR(desc)) 115 return PTR_ERR(desc); 116 else 117 return desc_to_gpio(desc); 118 } 119 EXPORT_SYMBOL(of_get_named_gpio_flags); 120 121 /** 122 * of_get_gpio_hog() - Get a GPIO hog descriptor, names and flags for GPIO API 123 * @np: device node to get GPIO from 124 * @name: GPIO line name 125 * @lflags: gpio_lookup_flags - returned from of_find_gpio() or 126 * of_get_gpio_hog() 127 * @dflags: gpiod_flags - optional GPIO initialization flags 128 * 129 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 130 * value on the error condition. 131 */ 132 static struct gpio_desc *of_get_gpio_hog(struct device_node *np, 133 const char **name, 134 enum gpio_lookup_flags *lflags, 135 enum gpiod_flags *dflags) 136 { 137 struct device_node *chip_np; 138 enum of_gpio_flags xlate_flags; 139 struct gg_data gg_data = { 140 .flags = &xlate_flags, 141 }; 142 u32 tmp; 143 int i, ret; 144 145 chip_np = np->parent; 146 if (!chip_np) 147 return ERR_PTR(-EINVAL); 148 149 xlate_flags = 0; 150 *lflags = 0; 151 *dflags = 0; 152 153 ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp); 154 if (ret) 155 return ERR_PTR(ret); 156 157 if (tmp > MAX_PHANDLE_ARGS) 158 return ERR_PTR(-EINVAL); 159 160 gg_data.gpiospec.args_count = tmp; 161 gg_data.gpiospec.np = chip_np; 162 for (i = 0; i < tmp; i++) { 163 ret = of_property_read_u32_index(np, "gpios", i, 164 &gg_data.gpiospec.args[i]); 165 if (ret) 166 return ERR_PTR(ret); 167 } 168 169 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate); 170 if (!gg_data.out_gpio) { 171 if (np->parent == np) 172 return ERR_PTR(-ENXIO); 173 else 174 return ERR_PTR(-EINVAL); 175 } 176 177 if (xlate_flags & OF_GPIO_ACTIVE_LOW) 178 *lflags |= GPIO_ACTIVE_LOW; 179 180 if (of_property_read_bool(np, "input")) 181 *dflags |= GPIOD_IN; 182 else if (of_property_read_bool(np, "output-low")) 183 *dflags |= GPIOD_OUT_LOW; 184 else if (of_property_read_bool(np, "output-high")) 185 *dflags |= GPIOD_OUT_HIGH; 186 else { 187 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n", 188 desc_to_gpio(gg_data.out_gpio), np->name); 189 return ERR_PTR(-EINVAL); 190 } 191 192 if (name && of_property_read_string(np, "line-name", name)) 193 *name = np->name; 194 195 return gg_data.out_gpio; 196 } 197 198 /** 199 * of_gpiochip_scan_hogs - Scan gpio-controller and apply GPIO hog as requested 200 * @chip: gpio chip to act on 201 * 202 * This is only used by of_gpiochip_add to request/set GPIO initial 203 * configuration. 204 */ 205 static void of_gpiochip_scan_hogs(struct gpio_chip *chip) 206 { 207 struct gpio_desc *desc = NULL; 208 struct device_node *np; 209 const char *name; 210 enum gpio_lookup_flags lflags; 211 enum gpiod_flags dflags; 212 213 for_each_child_of_node(chip->of_node, np) { 214 if (!of_property_read_bool(np, "gpio-hog")) 215 continue; 216 217 desc = of_get_gpio_hog(np, &name, &lflags, &dflags); 218 if (IS_ERR(desc)) 219 continue; 220 221 if (gpiod_hog(desc, name, lflags, dflags)) 222 continue; 223 } 224 } 225 226 /** 227 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags 228 * @gc: pointer to the gpio_chip structure 229 * @np: device node of the GPIO chip 230 * @gpio_spec: gpio specifier as found in the device tree 231 * @flags: a flags pointer to fill in 232 * 233 * This is simple translation function, suitable for the most 1:1 mapped 234 * gpio chips. This function performs only one sanity check: whether gpio 235 * is less than ngpios (that is specified in the gpio_chip). 236 */ 237 int of_gpio_simple_xlate(struct gpio_chip *gc, 238 const struct of_phandle_args *gpiospec, u32 *flags) 239 { 240 /* 241 * We're discouraging gpio_cells < 2, since that way you'll have to 242 * write your own xlate function (that will have to retrieve the GPIO 243 * number and the flags from a single gpio cell -- this is possible, 244 * but not recommended). 245 */ 246 if (gc->of_gpio_n_cells < 2) { 247 WARN_ON(1); 248 return -EINVAL; 249 } 250 251 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) 252 return -EINVAL; 253 254 if (gpiospec->args[0] >= gc->ngpio) 255 return -EINVAL; 256 257 if (flags) 258 *flags = gpiospec->args[1]; 259 260 return gpiospec->args[0]; 261 } 262 EXPORT_SYMBOL(of_gpio_simple_xlate); 263 264 /** 265 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) 266 * @np: device node of the GPIO chip 267 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 268 * 269 * To use this function you should allocate and fill mm_gc with: 270 * 271 * 1) In the gpio_chip structure: 272 * - all the callbacks 273 * - of_gpio_n_cells 274 * - of_xlate callback (optional) 275 * 276 * 3) In the of_mm_gpio_chip structure: 277 * - save_regs callback (optional) 278 * 279 * If succeeded, this function will map bank's memory and will 280 * do all necessary work for you. Then you'll able to use .regs 281 * to manage GPIOs from the callbacks. 282 */ 283 int of_mm_gpiochip_add(struct device_node *np, 284 struct of_mm_gpio_chip *mm_gc) 285 { 286 int ret = -ENOMEM; 287 struct gpio_chip *gc = &mm_gc->gc; 288 289 gc->label = kstrdup(np->full_name, GFP_KERNEL); 290 if (!gc->label) 291 goto err0; 292 293 mm_gc->regs = of_iomap(np, 0); 294 if (!mm_gc->regs) 295 goto err1; 296 297 gc->base = -1; 298 299 if (mm_gc->save_regs) 300 mm_gc->save_regs(mm_gc); 301 302 mm_gc->gc.of_node = np; 303 304 ret = gpiochip_add(gc); 305 if (ret) 306 goto err2; 307 308 return 0; 309 err2: 310 iounmap(mm_gc->regs); 311 err1: 312 kfree(gc->label); 313 err0: 314 pr_err("%s: GPIO chip registration failed with status %d\n", 315 np->full_name, ret); 316 return ret; 317 } 318 EXPORT_SYMBOL(of_mm_gpiochip_add); 319 320 /** 321 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank) 322 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 323 */ 324 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc) 325 { 326 struct gpio_chip *gc = &mm_gc->gc; 327 328 if (!mm_gc) 329 return; 330 331 gpiochip_remove(gc); 332 iounmap(mm_gc->regs); 333 kfree(gc->label); 334 } 335 EXPORT_SYMBOL(of_mm_gpiochip_remove); 336 337 #ifdef CONFIG_PINCTRL 338 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) 339 { 340 struct device_node *np = chip->of_node; 341 struct of_phandle_args pinspec; 342 struct pinctrl_dev *pctldev; 343 int index = 0, ret; 344 const char *name; 345 static const char group_names_propname[] = "gpio-ranges-group-names"; 346 struct property *group_names; 347 348 if (!np) 349 return 0; 350 351 group_names = of_find_property(np, group_names_propname, NULL); 352 353 for (;; index++) { 354 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 355 index, &pinspec); 356 if (ret) 357 break; 358 359 pctldev = of_pinctrl_get(pinspec.np); 360 if (!pctldev) 361 return -EPROBE_DEFER; 362 363 if (pinspec.args[2]) { 364 if (group_names) { 365 of_property_read_string_index(np, 366 group_names_propname, 367 index, &name); 368 if (strlen(name)) { 369 pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n", 370 np->full_name); 371 break; 372 } 373 } 374 /* npins != 0: linear range */ 375 ret = gpiochip_add_pin_range(chip, 376 pinctrl_dev_get_devname(pctldev), 377 pinspec.args[0], 378 pinspec.args[1], 379 pinspec.args[2]); 380 if (ret) 381 return ret; 382 } else { 383 /* npins == 0: special range */ 384 if (pinspec.args[1]) { 385 pr_err("%s: Illegal gpio-range format.\n", 386 np->full_name); 387 break; 388 } 389 390 if (!group_names) { 391 pr_err("%s: GPIO group range requested but no %s property.\n", 392 np->full_name, group_names_propname); 393 break; 394 } 395 396 ret = of_property_read_string_index(np, 397 group_names_propname, 398 index, &name); 399 if (ret) 400 break; 401 402 if (!strlen(name)) { 403 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n", 404 np->full_name); 405 break; 406 } 407 408 ret = gpiochip_add_pingroup_range(chip, pctldev, 409 pinspec.args[0], name); 410 if (ret) 411 return ret; 412 } 413 } 414 415 return 0; 416 } 417 418 #else 419 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; } 420 #endif 421 422 int of_gpiochip_add(struct gpio_chip *chip) 423 { 424 int status; 425 426 if ((!chip->of_node) && (chip->dev)) 427 chip->of_node = chip->dev->of_node; 428 429 if (!chip->of_node) 430 return 0; 431 432 if (!chip->of_xlate) { 433 chip->of_gpio_n_cells = 2; 434 chip->of_xlate = of_gpio_simple_xlate; 435 } 436 437 status = of_gpiochip_add_pin_range(chip); 438 if (status) 439 return status; 440 441 of_node_get(chip->of_node); 442 443 of_gpiochip_scan_hogs(chip); 444 445 return 0; 446 } 447 448 void of_gpiochip_remove(struct gpio_chip *chip) 449 { 450 gpiochip_remove_pin_ranges(chip); 451 of_node_put(chip->of_node); 452 } 453