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.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 /* Private data structure for of_gpiochip_find_and_xlate */ 26 struct gg_data { 27 enum of_gpio_flags *flags; 28 struct of_phandle_args gpiospec; 29 30 int out_gpio; 31 }; 32 33 /* Private function for resolving node pointer to gpio_chip */ 34 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data) 35 { 36 struct gg_data *gg_data = data; 37 int ret; 38 39 if ((gc->of_node != gg_data->gpiospec.np) || 40 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) || 41 (!gc->of_xlate)) 42 return false; 43 44 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags); 45 if (ret < 0) 46 return false; 47 48 gg_data->out_gpio = ret + gc->base; 49 return true; 50 } 51 52 /** 53 * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API 54 * @np: device node to get GPIO from 55 * @propname: property name containing gpio specifier(s) 56 * @index: index of the GPIO 57 * @flags: a flags pointer to fill in 58 * 59 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 60 * value on the error condition. If @flags is not NULL the function also fills 61 * in flags for the GPIO. 62 */ 63 int of_get_named_gpio_flags(struct device_node *np, const char *propname, 64 int index, enum of_gpio_flags *flags) 65 { 66 /* Return -EPROBE_DEFER to support probe() functions to be called 67 * later when the GPIO actually becomes available 68 */ 69 struct gg_data gg_data = { .flags = flags, .out_gpio = -EPROBE_DEFER }; 70 int ret; 71 72 /* .of_xlate might decide to not fill in the flags, so clear it. */ 73 if (flags) 74 *flags = 0; 75 76 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index, 77 &gg_data.gpiospec); 78 if (ret) { 79 pr_debug("%s: can't parse gpios property\n", __func__); 80 return ret; 81 } 82 83 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate); 84 85 of_node_put(gg_data.gpiospec.np); 86 pr_debug("%s exited with status %d\n", __func__, gg_data.out_gpio); 87 return gg_data.out_gpio; 88 } 89 EXPORT_SYMBOL(of_get_named_gpio_flags); 90 91 /** 92 * of_gpio_named_count - Count GPIOs for a device 93 * @np: device node to count GPIOs for 94 * @propname: property name containing gpio specifier(s) 95 * 96 * The function returns the count of GPIOs specified for a node. 97 * 98 * Note that the empty GPIO specifiers counts too. For example, 99 * 100 * gpios = <0 101 * &pio1 1 2 102 * 0 103 * &pio2 3 4>; 104 * 105 * defines four GPIOs (so this function will return 4), two of which 106 * are not specified. 107 */ 108 unsigned int of_gpio_named_count(struct device_node *np, const char* propname) 109 { 110 unsigned int cnt = 0; 111 112 do { 113 int ret; 114 115 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", 116 cnt, NULL); 117 /* A hole in the gpios = <> counts anyway. */ 118 if (ret < 0 && ret != -EEXIST) 119 break; 120 } while (++cnt); 121 122 return cnt; 123 } 124 EXPORT_SYMBOL(of_gpio_named_count); 125 126 /** 127 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags 128 * @gc: pointer to the gpio_chip structure 129 * @np: device node of the GPIO chip 130 * @gpio_spec: gpio specifier as found in the device tree 131 * @flags: a flags pointer to fill in 132 * 133 * This is simple translation function, suitable for the most 1:1 mapped 134 * gpio chips. This function performs only one sanity check: whether gpio 135 * is less than ngpios (that is specified in the gpio_chip). 136 */ 137 int of_gpio_simple_xlate(struct gpio_chip *gc, 138 const struct of_phandle_args *gpiospec, u32 *flags) 139 { 140 /* 141 * We're discouraging gpio_cells < 2, since that way you'll have to 142 * write your own xlate function (that will have to retrive the GPIO 143 * number and the flags from a single gpio cell -- this is possible, 144 * but not recommended). 145 */ 146 if (gc->of_gpio_n_cells < 2) { 147 WARN_ON(1); 148 return -EINVAL; 149 } 150 151 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) 152 return -EINVAL; 153 154 if (gpiospec->args[0] >= gc->ngpio) 155 return -EINVAL; 156 157 if (flags) 158 *flags = gpiospec->args[1]; 159 160 return gpiospec->args[0]; 161 } 162 EXPORT_SYMBOL(of_gpio_simple_xlate); 163 164 /** 165 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) 166 * @np: device node of the GPIO chip 167 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 168 * 169 * To use this function you should allocate and fill mm_gc with: 170 * 171 * 1) In the gpio_chip structure: 172 * - all the callbacks 173 * - of_gpio_n_cells 174 * - of_xlate callback (optional) 175 * 176 * 3) In the of_mm_gpio_chip structure: 177 * - save_regs callback (optional) 178 * 179 * If succeeded, this function will map bank's memory and will 180 * do all necessary work for you. Then you'll able to use .regs 181 * to manage GPIOs from the callbacks. 182 */ 183 int of_mm_gpiochip_add(struct device_node *np, 184 struct of_mm_gpio_chip *mm_gc) 185 { 186 int ret = -ENOMEM; 187 struct gpio_chip *gc = &mm_gc->gc; 188 189 gc->label = kstrdup(np->full_name, GFP_KERNEL); 190 if (!gc->label) 191 goto err0; 192 193 mm_gc->regs = of_iomap(np, 0); 194 if (!mm_gc->regs) 195 goto err1; 196 197 gc->base = -1; 198 199 if (mm_gc->save_regs) 200 mm_gc->save_regs(mm_gc); 201 202 mm_gc->gc.of_node = np; 203 204 ret = gpiochip_add(gc); 205 if (ret) 206 goto err2; 207 208 return 0; 209 err2: 210 iounmap(mm_gc->regs); 211 err1: 212 kfree(gc->label); 213 err0: 214 pr_err("%s: GPIO chip registration failed with status %d\n", 215 np->full_name, ret); 216 return ret; 217 } 218 EXPORT_SYMBOL(of_mm_gpiochip_add); 219 220 #ifdef CONFIG_PINCTRL 221 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) 222 { 223 struct device_node *np = chip->of_node; 224 struct of_phandle_args pinspec; 225 struct pinctrl_dev *pctldev; 226 int index = 0, ret; 227 228 if (!np) 229 return; 230 231 do { 232 ret = of_parse_phandle_with_args(np, "gpio-ranges", 233 "#gpio-range-cells", index, &pinspec); 234 if (ret) 235 break; 236 237 pctldev = of_pinctrl_get(pinspec.np); 238 if (!pctldev) 239 break; 240 241 /* 242 * This assumes that the n GPIO pins are consecutive in the 243 * GPIO number space, and that the pins are also consecutive 244 * in their local number space. Currently it is not possible 245 * to add different ranges for one and the same GPIO chip, 246 * as the code assumes that we have one consecutive range 247 * on both, mapping 1-to-1. 248 * 249 * TODO: make the OF bindings handle multiple sparse ranges 250 * on the same GPIO chip. 251 */ 252 ret = gpiochip_add_pin_range(chip, 253 pinctrl_dev_get_name(pctldev), 254 0, /* offset in gpiochip */ 255 pinspec.args[0], 256 pinspec.args[1]); 257 258 if (ret) 259 break; 260 261 } while (index++); 262 } 263 264 #else 265 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {} 266 #endif 267 268 void of_gpiochip_add(struct gpio_chip *chip) 269 { 270 if ((!chip->of_node) && (chip->dev)) 271 chip->of_node = chip->dev->of_node; 272 273 if (!chip->of_node) 274 return; 275 276 if (!chip->of_xlate) { 277 chip->of_gpio_n_cells = 2; 278 chip->of_xlate = of_gpio_simple_xlate; 279 } 280 281 of_gpiochip_add_pin_range(chip); 282 of_node_get(chip->of_node); 283 } 284 285 void of_gpiochip_remove(struct gpio_chip *chip) 286 { 287 gpiochip_remove_pin_ranges(chip); 288 289 if (chip->of_node) 290 of_node_put(chip->of_node); 291 } 292