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 26 #include "gpiolib.h" 27 28 /* Private data structure for of_gpiochip_find_and_xlate */ 29 struct gg_data { 30 enum of_gpio_flags *flags; 31 struct of_phandle_args gpiospec; 32 33 struct gpio_desc *out_gpio; 34 }; 35 36 /* Private function for resolving node pointer to gpio_chip */ 37 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data) 38 { 39 struct gg_data *gg_data = data; 40 int ret; 41 42 if ((gc->of_node != gg_data->gpiospec.np) || 43 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) || 44 (!gc->of_xlate)) 45 return false; 46 47 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags); 48 if (ret < 0) { 49 /* We've found the gpio chip, but the translation failed. 50 * Return true to stop looking and return the translation 51 * error via out_gpio 52 */ 53 gg_data->out_gpio = ERR_PTR(ret); 54 return true; 55 } 56 57 gg_data->out_gpio = gpiochip_get_desc(gc, ret); 58 return true; 59 } 60 61 /** 62 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API 63 * @np: device node to get GPIO from 64 * @propname: property name containing gpio specifier(s) 65 * @index: index of the GPIO 66 * @flags: a flags pointer to fill in 67 * 68 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 69 * value on the error condition. If @flags is not NULL the function also fills 70 * in flags for the GPIO. 71 */ 72 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, 73 const char *propname, int index, enum of_gpio_flags *flags) 74 { 75 /* Return -EPROBE_DEFER to support probe() functions to be called 76 * later when the GPIO actually becomes available 77 */ 78 struct gg_data gg_data = { 79 .flags = flags, 80 .out_gpio = ERR_PTR(-EPROBE_DEFER) 81 }; 82 int ret; 83 84 /* .of_xlate might decide to not fill in the flags, so clear it. */ 85 if (flags) 86 *flags = 0; 87 88 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index, 89 &gg_data.gpiospec); 90 if (ret) { 91 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n", 92 __func__, propname, np->full_name, index); 93 return ERR_PTR(ret); 94 } 95 96 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate); 97 98 of_node_put(gg_data.gpiospec.np); 99 pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n", 100 __func__, propname, np->full_name, index, 101 PTR_ERR_OR_ZERO(gg_data.out_gpio)); 102 return gg_data.out_gpio; 103 } 104 105 int of_get_named_gpio_flags(struct device_node *np, const char *list_name, 106 int index, enum of_gpio_flags *flags) 107 { 108 struct gpio_desc *desc; 109 110 desc = of_get_named_gpiod_flags(np, list_name, index, flags); 111 112 if (IS_ERR(desc)) 113 return PTR_ERR(desc); 114 else 115 return desc_to_gpio(desc); 116 } 117 EXPORT_SYMBOL(of_get_named_gpio_flags); 118 119 /** 120 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags 121 * @gc: pointer to the gpio_chip structure 122 * @np: device node of the GPIO chip 123 * @gpio_spec: gpio specifier as found in the device tree 124 * @flags: a flags pointer to fill in 125 * 126 * This is simple translation function, suitable for the most 1:1 mapped 127 * gpio chips. This function performs only one sanity check: whether gpio 128 * is less than ngpios (that is specified in the gpio_chip). 129 */ 130 int of_gpio_simple_xlate(struct gpio_chip *gc, 131 const struct of_phandle_args *gpiospec, u32 *flags) 132 { 133 /* 134 * We're discouraging gpio_cells < 2, since that way you'll have to 135 * write your own xlate function (that will have to retrive the GPIO 136 * number and the flags from a single gpio cell -- this is possible, 137 * but not recommended). 138 */ 139 if (gc->of_gpio_n_cells < 2) { 140 WARN_ON(1); 141 return -EINVAL; 142 } 143 144 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) 145 return -EINVAL; 146 147 if (gpiospec->args[0] >= gc->ngpio) 148 return -EINVAL; 149 150 if (flags) 151 *flags = gpiospec->args[1]; 152 153 return gpiospec->args[0]; 154 } 155 EXPORT_SYMBOL(of_gpio_simple_xlate); 156 157 /** 158 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) 159 * @np: device node of the GPIO chip 160 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 161 * 162 * To use this function you should allocate and fill mm_gc with: 163 * 164 * 1) In the gpio_chip structure: 165 * - all the callbacks 166 * - of_gpio_n_cells 167 * - of_xlate callback (optional) 168 * 169 * 3) In the of_mm_gpio_chip structure: 170 * - save_regs callback (optional) 171 * 172 * If succeeded, this function will map bank's memory and will 173 * do all necessary work for you. Then you'll able to use .regs 174 * to manage GPIOs from the callbacks. 175 */ 176 int of_mm_gpiochip_add(struct device_node *np, 177 struct of_mm_gpio_chip *mm_gc) 178 { 179 int ret = -ENOMEM; 180 struct gpio_chip *gc = &mm_gc->gc; 181 182 gc->label = kstrdup(np->full_name, GFP_KERNEL); 183 if (!gc->label) 184 goto err0; 185 186 mm_gc->regs = of_iomap(np, 0); 187 if (!mm_gc->regs) 188 goto err1; 189 190 gc->base = -1; 191 192 if (mm_gc->save_regs) 193 mm_gc->save_regs(mm_gc); 194 195 mm_gc->gc.of_node = np; 196 197 ret = gpiochip_add(gc); 198 if (ret) 199 goto err2; 200 201 return 0; 202 err2: 203 iounmap(mm_gc->regs); 204 err1: 205 kfree(gc->label); 206 err0: 207 pr_err("%s: GPIO chip registration failed with status %d\n", 208 np->full_name, ret); 209 return ret; 210 } 211 EXPORT_SYMBOL(of_mm_gpiochip_add); 212 213 #ifdef CONFIG_PINCTRL 214 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) 215 { 216 struct device_node *np = chip->of_node; 217 struct of_phandle_args pinspec; 218 struct pinctrl_dev *pctldev; 219 int index = 0, ret; 220 const char *name; 221 static const char group_names_propname[] = "gpio-ranges-group-names"; 222 struct property *group_names; 223 224 if (!np) 225 return; 226 227 group_names = of_find_property(np, group_names_propname, NULL); 228 229 for (;; index++) { 230 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 231 index, &pinspec); 232 if (ret) 233 break; 234 235 pctldev = of_pinctrl_get(pinspec.np); 236 if (!pctldev) 237 break; 238 239 if (pinspec.args[2]) { 240 if (group_names) { 241 ret = of_property_read_string_index(np, 242 group_names_propname, 243 index, &name); 244 if (strlen(name)) { 245 pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n", 246 np->full_name); 247 break; 248 } 249 } 250 /* npins != 0: linear range */ 251 ret = gpiochip_add_pin_range(chip, 252 pinctrl_dev_get_devname(pctldev), 253 pinspec.args[0], 254 pinspec.args[1], 255 pinspec.args[2]); 256 if (ret) 257 break; 258 } else { 259 /* npins == 0: special range */ 260 if (pinspec.args[1]) { 261 pr_err("%s: Illegal gpio-range format.\n", 262 np->full_name); 263 break; 264 } 265 266 if (!group_names) { 267 pr_err("%s: GPIO group range requested but no %s property.\n", 268 np->full_name, group_names_propname); 269 break; 270 } 271 272 ret = of_property_read_string_index(np, 273 group_names_propname, 274 index, &name); 275 if (ret) 276 break; 277 278 if (!strlen(name)) { 279 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n", 280 np->full_name); 281 break; 282 } 283 284 ret = gpiochip_add_pingroup_range(chip, pctldev, 285 pinspec.args[0], name); 286 if (ret) 287 break; 288 } 289 } 290 } 291 292 #else 293 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {} 294 #endif 295 296 void of_gpiochip_add(struct gpio_chip *chip) 297 { 298 if ((!chip->of_node) && (chip->dev)) 299 chip->of_node = chip->dev->of_node; 300 301 if (!chip->of_node) 302 return; 303 304 if (!chip->of_xlate) { 305 chip->of_gpio_n_cells = 2; 306 chip->of_xlate = of_gpio_simple_xlate; 307 } 308 309 of_gpiochip_add_pin_range(chip); 310 of_node_get(chip->of_node); 311 } 312 313 void of_gpiochip_remove(struct gpio_chip *chip) 314 { 315 gpiochip_remove_pin_ranges(chip); 316 of_node_put(chip->of_node); 317 } 318