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/errno.h> 16 #include <linux/module.h> 17 #include <linux/io.h> 18 #include <linux/gpio/consumer.h> 19 #include <linux/of.h> 20 #include <linux/of_address.h> 21 #include <linux/of_gpio.h> 22 #include <linux/pinctrl/pinctrl.h> 23 #include <linux/slab.h> 24 25 struct gpio_desc; 26 27 /* Private data structure for of_gpiochip_find_and_xlate */ 28 struct gg_data { 29 enum of_gpio_flags *flags; 30 struct of_phandle_args gpiospec; 31 32 struct gpio_desc *out_gpio; 33 }; 34 35 /* Private function for resolving node pointer to gpio_chip */ 36 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data) 37 { 38 struct gg_data *gg_data = data; 39 int ret; 40 41 if ((gc->of_node != gg_data->gpiospec.np) || 42 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) || 43 (!gc->of_xlate)) 44 return false; 45 46 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags); 47 if (ret < 0) 48 return false; 49 50 gg_data->out_gpio = gpio_to_desc(ret + gc->base); 51 return true; 52 } 53 54 /** 55 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API 56 * @np: device node to get GPIO from 57 * @propname: property name containing gpio specifier(s) 58 * @index: index of the GPIO 59 * @flags: a flags pointer to fill in 60 * 61 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno 62 * value on the error condition. If @flags is not NULL the function also fills 63 * in flags for the GPIO. 64 */ 65 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, 66 const char *propname, int index, enum of_gpio_flags *flags) 67 { 68 /* Return -EPROBE_DEFER to support probe() functions to be called 69 * later when the GPIO actually becomes available 70 */ 71 struct gg_data gg_data = { 72 .flags = flags, 73 .out_gpio = ERR_PTR(-EPROBE_DEFER) 74 }; 75 int ret; 76 77 /* .of_xlate might decide to not fill in the flags, so clear it. */ 78 if (flags) 79 *flags = 0; 80 81 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index, 82 &gg_data.gpiospec); 83 if (ret) { 84 pr_debug("%s: can't parse gpios property of node '%s[%d]'\n", 85 __func__, np->full_name, index); 86 return ERR_PTR(ret); 87 } 88 89 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate); 90 91 of_node_put(gg_data.gpiospec.np); 92 pr_debug("%s exited with status %d\n", __func__, 93 PTR_RET(gg_data.out_gpio)); 94 return gg_data.out_gpio; 95 } 96 EXPORT_SYMBOL(of_get_named_gpiod_flags); 97 98 /** 99 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags 100 * @gc: pointer to the gpio_chip structure 101 * @np: device node of the GPIO chip 102 * @gpio_spec: gpio specifier as found in the device tree 103 * @flags: a flags pointer to fill in 104 * 105 * This is simple translation function, suitable for the most 1:1 mapped 106 * gpio chips. This function performs only one sanity check: whether gpio 107 * is less than ngpios (that is specified in the gpio_chip). 108 */ 109 int of_gpio_simple_xlate(struct gpio_chip *gc, 110 const struct of_phandle_args *gpiospec, u32 *flags) 111 { 112 /* 113 * We're discouraging gpio_cells < 2, since that way you'll have to 114 * write your own xlate function (that will have to retrive the GPIO 115 * number and the flags from a single gpio cell -- this is possible, 116 * but not recommended). 117 */ 118 if (gc->of_gpio_n_cells < 2) { 119 WARN_ON(1); 120 return -EINVAL; 121 } 122 123 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) 124 return -EINVAL; 125 126 if (gpiospec->args[0] >= gc->ngpio) 127 return -EINVAL; 128 129 if (flags) 130 *flags = gpiospec->args[1]; 131 132 return gpiospec->args[0]; 133 } 134 EXPORT_SYMBOL(of_gpio_simple_xlate); 135 136 /** 137 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) 138 * @np: device node of the GPIO chip 139 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 140 * 141 * To use this function you should allocate and fill mm_gc with: 142 * 143 * 1) In the gpio_chip structure: 144 * - all the callbacks 145 * - of_gpio_n_cells 146 * - of_xlate callback (optional) 147 * 148 * 3) In the of_mm_gpio_chip structure: 149 * - save_regs callback (optional) 150 * 151 * If succeeded, this function will map bank's memory and will 152 * do all necessary work for you. Then you'll able to use .regs 153 * to manage GPIOs from the callbacks. 154 */ 155 int of_mm_gpiochip_add(struct device_node *np, 156 struct of_mm_gpio_chip *mm_gc) 157 { 158 int ret = -ENOMEM; 159 struct gpio_chip *gc = &mm_gc->gc; 160 161 gc->label = kstrdup(np->full_name, GFP_KERNEL); 162 if (!gc->label) 163 goto err0; 164 165 mm_gc->regs = of_iomap(np, 0); 166 if (!mm_gc->regs) 167 goto err1; 168 169 gc->base = -1; 170 171 if (mm_gc->save_regs) 172 mm_gc->save_regs(mm_gc); 173 174 mm_gc->gc.of_node = np; 175 176 ret = gpiochip_add(gc); 177 if (ret) 178 goto err2; 179 180 return 0; 181 err2: 182 iounmap(mm_gc->regs); 183 err1: 184 kfree(gc->label); 185 err0: 186 pr_err("%s: GPIO chip registration failed with status %d\n", 187 np->full_name, ret); 188 return ret; 189 } 190 EXPORT_SYMBOL(of_mm_gpiochip_add); 191 192 #ifdef CONFIG_PINCTRL 193 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) 194 { 195 struct device_node *np = chip->of_node; 196 struct of_phandle_args pinspec; 197 struct pinctrl_dev *pctldev; 198 int index = 0, ret; 199 const char *name; 200 static const char group_names_propname[] = "gpio-ranges-group-names"; 201 struct property *group_names; 202 203 if (!np) 204 return; 205 206 group_names = of_find_property(np, group_names_propname, NULL); 207 208 for (;; index++) { 209 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 210 index, &pinspec); 211 if (ret) 212 break; 213 214 pctldev = of_pinctrl_get(pinspec.np); 215 if (!pctldev) 216 break; 217 218 if (pinspec.args[2]) { 219 if (group_names) { 220 ret = of_property_read_string_index(np, 221 group_names_propname, 222 index, &name); 223 if (strlen(name)) { 224 pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n", 225 np->full_name); 226 break; 227 } 228 } 229 /* npins != 0: linear range */ 230 ret = gpiochip_add_pin_range(chip, 231 pinctrl_dev_get_devname(pctldev), 232 pinspec.args[0], 233 pinspec.args[1], 234 pinspec.args[2]); 235 if (ret) 236 break; 237 } else { 238 /* npins == 0: special range */ 239 if (pinspec.args[1]) { 240 pr_err("%s: Illegal gpio-range format.\n", 241 np->full_name); 242 break; 243 } 244 245 if (!group_names) { 246 pr_err("%s: GPIO group range requested but no %s property.\n", 247 np->full_name, group_names_propname); 248 break; 249 } 250 251 ret = of_property_read_string_index(np, 252 group_names_propname, 253 index, &name); 254 if (ret) 255 break; 256 257 if (!strlen(name)) { 258 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n", 259 np->full_name); 260 break; 261 } 262 263 ret = gpiochip_add_pingroup_range(chip, pctldev, 264 pinspec.args[0], name); 265 if (ret) 266 break; 267 } 268 } 269 } 270 271 #else 272 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {} 273 #endif 274 275 void of_gpiochip_add(struct gpio_chip *chip) 276 { 277 if ((!chip->of_node) && (chip->dev)) 278 chip->of_node = chip->dev->of_node; 279 280 if (!chip->of_node) 281 return; 282 283 if (!chip->of_xlate) { 284 chip->of_gpio_n_cells = 2; 285 chip->of_xlate = of_gpio_simple_xlate; 286 } 287 288 of_gpiochip_add_pin_range(chip); 289 of_node_get(chip->of_node); 290 } 291 292 void of_gpiochip_remove(struct gpio_chip *chip) 293 { 294 gpiochip_remove_pin_ranges(chip); 295 296 if (chip->of_node) 297 of_node_put(chip->of_node); 298 } 299