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_simple_xlate - translate gpio_spec to the GPIO number and flags 93 * @gc: pointer to the gpio_chip structure 94 * @np: device node of the GPIO chip 95 * @gpio_spec: gpio specifier as found in the device tree 96 * @flags: a flags pointer to fill in 97 * 98 * This is simple translation function, suitable for the most 1:1 mapped 99 * gpio chips. This function performs only one sanity check: whether gpio 100 * is less than ngpios (that is specified in the gpio_chip). 101 */ 102 int of_gpio_simple_xlate(struct gpio_chip *gc, 103 const struct of_phandle_args *gpiospec, u32 *flags) 104 { 105 /* 106 * We're discouraging gpio_cells < 2, since that way you'll have to 107 * write your own xlate function (that will have to retrive the GPIO 108 * number and the flags from a single gpio cell -- this is possible, 109 * but not recommended). 110 */ 111 if (gc->of_gpio_n_cells < 2) { 112 WARN_ON(1); 113 return -EINVAL; 114 } 115 116 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) 117 return -EINVAL; 118 119 if (gpiospec->args[0] >= gc->ngpio) 120 return -EINVAL; 121 122 if (flags) 123 *flags = gpiospec->args[1]; 124 125 return gpiospec->args[0]; 126 } 127 EXPORT_SYMBOL(of_gpio_simple_xlate); 128 129 /** 130 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) 131 * @np: device node of the GPIO chip 132 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 133 * 134 * To use this function you should allocate and fill mm_gc with: 135 * 136 * 1) In the gpio_chip structure: 137 * - all the callbacks 138 * - of_gpio_n_cells 139 * - of_xlate callback (optional) 140 * 141 * 3) In the of_mm_gpio_chip structure: 142 * - save_regs callback (optional) 143 * 144 * If succeeded, this function will map bank's memory and will 145 * do all necessary work for you. Then you'll able to use .regs 146 * to manage GPIOs from the callbacks. 147 */ 148 int of_mm_gpiochip_add(struct device_node *np, 149 struct of_mm_gpio_chip *mm_gc) 150 { 151 int ret = -ENOMEM; 152 struct gpio_chip *gc = &mm_gc->gc; 153 154 gc->label = kstrdup(np->full_name, GFP_KERNEL); 155 if (!gc->label) 156 goto err0; 157 158 mm_gc->regs = of_iomap(np, 0); 159 if (!mm_gc->regs) 160 goto err1; 161 162 gc->base = -1; 163 164 if (mm_gc->save_regs) 165 mm_gc->save_regs(mm_gc); 166 167 mm_gc->gc.of_node = np; 168 169 ret = gpiochip_add(gc); 170 if (ret) 171 goto err2; 172 173 return 0; 174 err2: 175 iounmap(mm_gc->regs); 176 err1: 177 kfree(gc->label); 178 err0: 179 pr_err("%s: GPIO chip registration failed with status %d\n", 180 np->full_name, ret); 181 return ret; 182 } 183 EXPORT_SYMBOL(of_mm_gpiochip_add); 184 185 #ifdef CONFIG_PINCTRL 186 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) 187 { 188 struct device_node *np = chip->of_node; 189 struct of_phandle_args pinspec; 190 struct pinctrl_dev *pctldev; 191 int index = 0, ret; 192 193 if (!np) 194 return; 195 196 for (;; index++) { 197 ret = of_parse_phandle_with_args(np, "gpio-ranges", 198 "#gpio-range-cells", index, &pinspec); 199 if (ret) 200 break; 201 202 pctldev = of_pinctrl_get(pinspec.np); 203 if (!pctldev) 204 break; 205 206 ret = gpiochip_add_pin_range(chip, 207 pinctrl_dev_get_devname(pctldev), 208 pinspec.args[0], 209 pinspec.args[1], 210 pinspec.args[2]); 211 212 if (ret) 213 break; 214 } 215 } 216 217 #else 218 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {} 219 #endif 220 221 void of_gpiochip_add(struct gpio_chip *chip) 222 { 223 if ((!chip->of_node) && (chip->dev)) 224 chip->of_node = chip->dev->of_node; 225 226 if (!chip->of_node) 227 return; 228 229 if (!chip->of_xlate) { 230 chip->of_gpio_n_cells = 2; 231 chip->of_xlate = of_gpio_simple_xlate; 232 } 233 234 of_gpiochip_add_pin_range(chip); 235 of_node_get(chip->of_node); 236 } 237 238 void of_gpiochip_remove(struct gpio_chip *chip) 239 { 240 gpiochip_remove_pin_ranges(chip); 241 242 if (chip->of_node) 243 of_node_put(chip->of_node); 244 } 245