| 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/of.h> |
| 19 | #include <linux/of_address.h> |
| 20 | #include <linux/of_gpio.h> |
| 21 | #include <linux/slab.h> |
| 22 | |
| 23 | /** |
| 24 | * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API |
| 25 | * @np: device node to get GPIO from |
| 26 | * @propname: property name containing gpio specifier(s) |
| 27 | * @index: index of the GPIO |
| 28 | * @flags: a flags pointer to fill in |
| 29 | * |
| 30 | * Returns GPIO number to use with Linux generic GPIO API, or one of the errno |
| 31 | * value on the error condition. If @flags is not NULL the function also fills |
| 32 | * in flags for the GPIO. |
| 33 | */ |
| 34 | int of_get_named_gpio_flags(struct device_node *np, const char *propname, |
| 35 | int index, enum of_gpio_flags *flags) |
| 36 | { |
| 37 | int ret; |
| 38 | struct gpio_chip *gc; |
| 39 | struct of_phandle_args gpiospec; |
| 40 | |
| 41 | ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index, |
| 42 | &gpiospec); |
| 43 | if (ret) { |
| 44 | pr_debug("%s: can't parse gpios property\n", __func__); |
| 45 | goto err0; |
| 46 | } |
| 47 | |
| 48 | gc = of_node_to_gpiochip(gpiospec.np); |
| 49 | if (!gc) { |
| 50 | pr_debug("%s: gpio controller %s isn't registered\n", |
| 51 | np->full_name, gpiospec.np->full_name); |
| 52 | ret = -ENODEV; |
| 53 | goto err1; |
| 54 | } |
| 55 | |
| 56 | if (gpiospec.args_count != gc->of_gpio_n_cells) { |
| 57 | pr_debug("%s: wrong #gpio-cells for %s\n", |
| 58 | np->full_name, gpiospec.np->full_name); |
| 59 | ret = -EINVAL; |
| 60 | goto err1; |
| 61 | } |
| 62 | |
| 63 | /* .xlate might decide to not fill in the flags, so clear it. */ |
| 64 | if (flags) |
| 65 | *flags = 0; |
| 66 | |
| 67 | ret = gc->of_xlate(gc, &gpiospec, flags); |
| 68 | if (ret < 0) |
| 69 | goto err1; |
| 70 | |
| 71 | ret += gc->base; |
| 72 | err1: |
| 73 | of_node_put(gpiospec.np); |
| 74 | err0: |
| 75 | pr_debug("%s exited with status %d\n", __func__, ret); |
| 76 | return ret; |
| 77 | } |
| 78 | EXPORT_SYMBOL(of_get_named_gpio_flags); |
| 79 | |
| 80 | /** |
| 81 | * of_gpio_named_count - Count GPIOs for a device |
| 82 | * @np: device node to count GPIOs for |
| 83 | * @propname: property name containing gpio specifier(s) |
| 84 | * |
| 85 | * The function returns the count of GPIOs specified for a node. |
| 86 | * |
| 87 | * Note that the empty GPIO specifiers counts too. For example, |
| 88 | * |
| 89 | * gpios = <0 |
| 90 | * &pio1 1 2 |
| 91 | * 0 |
| 92 | * &pio2 3 4>; |
| 93 | * |
| 94 | * defines four GPIOs (so this function will return 4), two of which |
| 95 | * are not specified. |
| 96 | */ |
| 97 | unsigned int of_gpio_named_count(struct device_node *np, const char* propname) |
| 98 | { |
| 99 | unsigned int cnt = 0; |
| 100 | |
| 101 | do { |
| 102 | int ret; |
| 103 | |
| 104 | ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", |
| 105 | cnt, NULL); |
| 106 | /* A hole in the gpios = <> counts anyway. */ |
| 107 | if (ret < 0 && ret != -EEXIST) |
| 108 | break; |
| 109 | } while (++cnt); |
| 110 | |
| 111 | return cnt; |
| 112 | } |
| 113 | EXPORT_SYMBOL(of_gpio_named_count); |
| 114 | |
| 115 | /** |
| 116 | * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags |
| 117 | * @gc: pointer to the gpio_chip structure |
| 118 | * @np: device node of the GPIO chip |
| 119 | * @gpio_spec: gpio specifier as found in the device tree |
| 120 | * @flags: a flags pointer to fill in |
| 121 | * |
| 122 | * This is simple translation function, suitable for the most 1:1 mapped |
| 123 | * gpio chips. This function performs only one sanity check: whether gpio |
| 124 | * is less than ngpios (that is specified in the gpio_chip). |
| 125 | */ |
| 126 | int of_gpio_simple_xlate(struct gpio_chip *gc, |
| 127 | const struct of_phandle_args *gpiospec, u32 *flags) |
| 128 | { |
| 129 | /* |
| 130 | * We're discouraging gpio_cells < 2, since that way you'll have to |
| 131 | * write your own xlate function (that will have to retrive the GPIO |
| 132 | * number and the flags from a single gpio cell -- this is possible, |
| 133 | * but not recommended). |
| 134 | */ |
| 135 | if (gc->of_gpio_n_cells < 2) { |
| 136 | WARN_ON(1); |
| 137 | return -EINVAL; |
| 138 | } |
| 139 | |
| 140 | if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) |
| 141 | return -EINVAL; |
| 142 | |
| 143 | if (gpiospec->args[0] > gc->ngpio) |
| 144 | return -EINVAL; |
| 145 | |
| 146 | if (flags) |
| 147 | *flags = gpiospec->args[1]; |
| 148 | |
| 149 | return gpiospec->args[0]; |
| 150 | } |
| 151 | EXPORT_SYMBOL(of_gpio_simple_xlate); |
| 152 | |
| 153 | /** |
| 154 | * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) |
| 155 | * @np: device node of the GPIO chip |
| 156 | * @mm_gc: pointer to the of_mm_gpio_chip allocated structure |
| 157 | * |
| 158 | * To use this function you should allocate and fill mm_gc with: |
| 159 | * |
| 160 | * 1) In the gpio_chip structure: |
| 161 | * - all the callbacks |
| 162 | * - of_gpio_n_cells |
| 163 | * - of_xlate callback (optional) |
| 164 | * |
| 165 | * 3) In the of_mm_gpio_chip structure: |
| 166 | * - save_regs callback (optional) |
| 167 | * |
| 168 | * If succeeded, this function will map bank's memory and will |
| 169 | * do all necessary work for you. Then you'll able to use .regs |
| 170 | * to manage GPIOs from the callbacks. |
| 171 | */ |
| 172 | int of_mm_gpiochip_add(struct device_node *np, |
| 173 | struct of_mm_gpio_chip *mm_gc) |
| 174 | { |
| 175 | int ret = -ENOMEM; |
| 176 | struct gpio_chip *gc = &mm_gc->gc; |
| 177 | |
| 178 | gc->label = kstrdup(np->full_name, GFP_KERNEL); |
| 179 | if (!gc->label) |
| 180 | goto err0; |
| 181 | |
| 182 | mm_gc->regs = of_iomap(np, 0); |
| 183 | if (!mm_gc->regs) |
| 184 | goto err1; |
| 185 | |
| 186 | gc->base = -1; |
| 187 | |
| 188 | if (mm_gc->save_regs) |
| 189 | mm_gc->save_regs(mm_gc); |
| 190 | |
| 191 | mm_gc->gc.of_node = np; |
| 192 | |
| 193 | ret = gpiochip_add(gc); |
| 194 | if (ret) |
| 195 | goto err2; |
| 196 | |
| 197 | return 0; |
| 198 | err2: |
| 199 | iounmap(mm_gc->regs); |
| 200 | err1: |
| 201 | kfree(gc->label); |
| 202 | err0: |
| 203 | pr_err("%s: GPIO chip registration failed with status %d\n", |
| 204 | np->full_name, ret); |
| 205 | return ret; |
| 206 | } |
| 207 | EXPORT_SYMBOL(of_mm_gpiochip_add); |
| 208 | |
| 209 | void of_gpiochip_add(struct gpio_chip *chip) |
| 210 | { |
| 211 | if ((!chip->of_node) && (chip->dev)) |
| 212 | chip->of_node = chip->dev->of_node; |
| 213 | |
| 214 | if (!chip->of_node) |
| 215 | return; |
| 216 | |
| 217 | if (!chip->of_xlate) { |
| 218 | chip->of_gpio_n_cells = 2; |
| 219 | chip->of_xlate = of_gpio_simple_xlate; |
| 220 | } |
| 221 | |
| 222 | of_node_get(chip->of_node); |
| 223 | } |
| 224 | |
| 225 | void of_gpiochip_remove(struct gpio_chip *chip) |
| 226 | { |
| 227 | if (chip->of_node) |
| 228 | of_node_put(chip->of_node); |
| 229 | } |
| 230 | |
| 231 | /* Private function for resolving node pointer to gpio_chip */ |
| 232 | static int of_gpiochip_is_match(struct gpio_chip *chip, const void *data) |
| 233 | { |
| 234 | return chip->of_node == data; |
| 235 | } |
| 236 | |
| 237 | struct gpio_chip *of_node_to_gpiochip(struct device_node *np) |
| 238 | { |
| 239 | return gpiochip_find(np, of_gpiochip_is_match); |
| 240 | } |