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 of node '%s[%d]'\n", 80 __func__, np->full_name, index); 81 return ret; 82 } 83 84 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate); 85 86 of_node_put(gg_data.gpiospec.np); 87 pr_debug("%s exited with status %d\n", __func__, gg_data.out_gpio); 88 return gg_data.out_gpio; 89 } 90 EXPORT_SYMBOL(of_get_named_gpio_flags); 91 92 /** 93 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags 94 * @gc: pointer to the gpio_chip structure 95 * @np: device node of the GPIO chip 96 * @gpio_spec: gpio specifier as found in the device tree 97 * @flags: a flags pointer to fill in 98 * 99 * This is simple translation function, suitable for the most 1:1 mapped 100 * gpio chips. This function performs only one sanity check: whether gpio 101 * is less than ngpios (that is specified in the gpio_chip). 102 */ 103 int of_gpio_simple_xlate(struct gpio_chip *gc, 104 const struct of_phandle_args *gpiospec, u32 *flags) 105 { 106 /* 107 * We're discouraging gpio_cells < 2, since that way you'll have to 108 * write your own xlate function (that will have to retrive the GPIO 109 * number and the flags from a single gpio cell -- this is possible, 110 * but not recommended). 111 */ 112 if (gc->of_gpio_n_cells < 2) { 113 WARN_ON(1); 114 return -EINVAL; 115 } 116 117 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) 118 return -EINVAL; 119 120 if (gpiospec->args[0] >= gc->ngpio) 121 return -EINVAL; 122 123 if (flags) 124 *flags = gpiospec->args[1]; 125 126 return gpiospec->args[0]; 127 } 128 EXPORT_SYMBOL(of_gpio_simple_xlate); 129 130 /** 131 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) 132 * @np: device node of the GPIO chip 133 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure 134 * 135 * To use this function you should allocate and fill mm_gc with: 136 * 137 * 1) In the gpio_chip structure: 138 * - all the callbacks 139 * - of_gpio_n_cells 140 * - of_xlate callback (optional) 141 * 142 * 3) In the of_mm_gpio_chip structure: 143 * - save_regs callback (optional) 144 * 145 * If succeeded, this function will map bank's memory and will 146 * do all necessary work for you. Then you'll able to use .regs 147 * to manage GPIOs from the callbacks. 148 */ 149 int of_mm_gpiochip_add(struct device_node *np, 150 struct of_mm_gpio_chip *mm_gc) 151 { 152 int ret = -ENOMEM; 153 struct gpio_chip *gc = &mm_gc->gc; 154 155 gc->label = kstrdup(np->full_name, GFP_KERNEL); 156 if (!gc->label) 157 goto err0; 158 159 mm_gc->regs = of_iomap(np, 0); 160 if (!mm_gc->regs) 161 goto err1; 162 163 gc->base = -1; 164 165 if (mm_gc->save_regs) 166 mm_gc->save_regs(mm_gc); 167 168 mm_gc->gc.of_node = np; 169 170 ret = gpiochip_add(gc); 171 if (ret) 172 goto err2; 173 174 return 0; 175 err2: 176 iounmap(mm_gc->regs); 177 err1: 178 kfree(gc->label); 179 err0: 180 pr_err("%s: GPIO chip registration failed with status %d\n", 181 np->full_name, ret); 182 return ret; 183 } 184 EXPORT_SYMBOL(of_mm_gpiochip_add); 185 186 #ifdef CONFIG_PINCTRL 187 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) 188 { 189 struct device_node *np = chip->of_node; 190 struct of_phandle_args pinspec; 191 struct pinctrl_dev *pctldev; 192 int index = 0, ret; 193 194 if (!np) 195 return; 196 197 for (;; index++) { 198 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, 199 index, &pinspec); 200 if (ret) 201 break; 202 203 pctldev = of_pinctrl_get(pinspec.np); 204 if (!pctldev) 205 break; 206 207 ret = gpiochip_add_pin_range(chip, 208 pinctrl_dev_get_devname(pctldev), 209 pinspec.args[0], 210 pinspec.args[1], 211 pinspec.args[2]); 212 213 if (ret) 214 break; 215 } 216 } 217 218 #else 219 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {} 220 #endif 221 222 void of_gpiochip_add(struct gpio_chip *chip) 223 { 224 if ((!chip->of_node) && (chip->dev)) 225 chip->of_node = chip->dev->of_node; 226 227 if (!chip->of_node) 228 return; 229 230 if (!chip->of_xlate) { 231 chip->of_gpio_n_cells = 2; 232 chip->of_xlate = of_gpio_simple_xlate; 233 } 234 235 of_gpiochip_add_pin_range(chip); 236 of_node_get(chip->of_node); 237 } 238 239 void of_gpiochip_remove(struct gpio_chip *chip) 240 { 241 gpiochip_remove_pin_ranges(chip); 242 243 if (chip->of_node) 244 of_node_put(chip->of_node); 245 } 246