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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/err.h> | |
16 | #include <linux/errno.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/io.h> | |
19 | #include <linux/gpio/consumer.h> | |
20 | #include <linux/of.h> | |
21 | #include <linux/of_address.h> | |
22 | #include <linux/of_gpio.h> | |
23 | #include <linux/pinctrl/pinctrl.h> | |
24 | #include <linux/slab.h> | |
25 | ||
26 | #include "gpiolib.h" | |
27 | ||
28 | /* Private data structure for of_gpiochip_find_and_xlate */ | |
29 | struct gg_data { | |
30 | enum of_gpio_flags *flags; | |
31 | struct of_phandle_args gpiospec; | |
32 | ||
33 | struct gpio_desc *out_gpio; | |
34 | }; | |
35 | ||
36 | /* Private function for resolving node pointer to gpio_chip */ | |
37 | static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data) | |
38 | { | |
39 | struct gg_data *gg_data = data; | |
40 | int ret; | |
41 | ||
42 | if ((gc->of_node != gg_data->gpiospec.np) || | |
43 | (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) || | |
44 | (!gc->of_xlate)) | |
45 | return false; | |
46 | ||
47 | ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags); | |
48 | if (ret < 0) { | |
49 | /* We've found the gpio chip, but the translation failed. | |
50 | * Return true to stop looking and return the translation | |
51 | * error via out_gpio | |
52 | */ | |
53 | gg_data->out_gpio = ERR_PTR(ret); | |
54 | return true; | |
55 | } | |
56 | ||
57 | gg_data->out_gpio = gpiochip_get_desc(gc, ret); | |
58 | return true; | |
59 | } | |
60 | ||
61 | /** | |
62 | * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API | |
63 | * @np: device node to get GPIO from | |
64 | * @propname: property name containing gpio specifier(s) | |
65 | * @index: index of the GPIO | |
66 | * @flags: a flags pointer to fill in | |
67 | * | |
68 | * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno | |
69 | * value on the error condition. If @flags is not NULL the function also fills | |
70 | * in flags for the GPIO. | |
71 | */ | |
72 | struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, | |
73 | const char *propname, int index, enum of_gpio_flags *flags) | |
74 | { | |
75 | /* Return -EPROBE_DEFER to support probe() functions to be called | |
76 | * later when the GPIO actually becomes available | |
77 | */ | |
78 | struct gg_data gg_data = { | |
79 | .flags = flags, | |
80 | .out_gpio = ERR_PTR(-EPROBE_DEFER) | |
81 | }; | |
82 | int ret; | |
83 | ||
84 | /* .of_xlate might decide to not fill in the flags, so clear it. */ | |
85 | if (flags) | |
86 | *flags = 0; | |
87 | ||
88 | ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index, | |
89 | &gg_data.gpiospec); | |
90 | if (ret) { | |
91 | pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n", | |
92 | __func__, propname, np->full_name, index); | |
93 | return ERR_PTR(ret); | |
94 | } | |
95 | ||
96 | gpiochip_find(&gg_data, of_gpiochip_find_and_xlate); | |
97 | ||
98 | of_node_put(gg_data.gpiospec.np); | |
99 | pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n", | |
100 | __func__, propname, np->full_name, index, | |
101 | PTR_ERR_OR_ZERO(gg_data.out_gpio)); | |
102 | return gg_data.out_gpio; | |
103 | } | |
104 | ||
105 | int of_get_named_gpio_flags(struct device_node *np, const char *list_name, | |
106 | int index, enum of_gpio_flags *flags) | |
107 | { | |
108 | struct gpio_desc *desc; | |
109 | ||
110 | desc = of_get_named_gpiod_flags(np, list_name, index, flags); | |
111 | ||
112 | if (IS_ERR(desc)) | |
113 | return PTR_ERR(desc); | |
114 | else | |
115 | return desc_to_gpio(desc); | |
116 | } | |
117 | EXPORT_SYMBOL(of_get_named_gpio_flags); | |
118 | ||
119 | /** | |
120 | * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags | |
121 | * @gc: pointer to the gpio_chip structure | |
122 | * @np: device node of the GPIO chip | |
123 | * @gpio_spec: gpio specifier as found in the device tree | |
124 | * @flags: a flags pointer to fill in | |
125 | * | |
126 | * This is simple translation function, suitable for the most 1:1 mapped | |
127 | * gpio chips. This function performs only one sanity check: whether gpio | |
128 | * is less than ngpios (that is specified in the gpio_chip). | |
129 | */ | |
130 | int of_gpio_simple_xlate(struct gpio_chip *gc, | |
131 | const struct of_phandle_args *gpiospec, u32 *flags) | |
132 | { | |
133 | /* | |
134 | * We're discouraging gpio_cells < 2, since that way you'll have to | |
135 | * write your own xlate function (that will have to retrive the GPIO | |
136 | * number and the flags from a single gpio cell -- this is possible, | |
137 | * but not recommended). | |
138 | */ | |
139 | if (gc->of_gpio_n_cells < 2) { | |
140 | WARN_ON(1); | |
141 | return -EINVAL; | |
142 | } | |
143 | ||
144 | if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) | |
145 | return -EINVAL; | |
146 | ||
147 | if (gpiospec->args[0] >= gc->ngpio) | |
148 | return -EINVAL; | |
149 | ||
150 | if (flags) | |
151 | *flags = gpiospec->args[1]; | |
152 | ||
153 | return gpiospec->args[0]; | |
154 | } | |
155 | EXPORT_SYMBOL(of_gpio_simple_xlate); | |
156 | ||
157 | /** | |
158 | * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) | |
159 | * @np: device node of the GPIO chip | |
160 | * @mm_gc: pointer to the of_mm_gpio_chip allocated structure | |
161 | * | |
162 | * To use this function you should allocate and fill mm_gc with: | |
163 | * | |
164 | * 1) In the gpio_chip structure: | |
165 | * - all the callbacks | |
166 | * - of_gpio_n_cells | |
167 | * - of_xlate callback (optional) | |
168 | * | |
169 | * 3) In the of_mm_gpio_chip structure: | |
170 | * - save_regs callback (optional) | |
171 | * | |
172 | * If succeeded, this function will map bank's memory and will | |
173 | * do all necessary work for you. Then you'll able to use .regs | |
174 | * to manage GPIOs from the callbacks. | |
175 | */ | |
176 | int of_mm_gpiochip_add(struct device_node *np, | |
177 | struct of_mm_gpio_chip *mm_gc) | |
178 | { | |
179 | int ret = -ENOMEM; | |
180 | struct gpio_chip *gc = &mm_gc->gc; | |
181 | ||
182 | gc->label = kstrdup(np->full_name, GFP_KERNEL); | |
183 | if (!gc->label) | |
184 | goto err0; | |
185 | ||
186 | mm_gc->regs = of_iomap(np, 0); | |
187 | if (!mm_gc->regs) | |
188 | goto err1; | |
189 | ||
190 | gc->base = -1; | |
191 | ||
192 | if (mm_gc->save_regs) | |
193 | mm_gc->save_regs(mm_gc); | |
194 | ||
195 | mm_gc->gc.of_node = np; | |
196 | ||
197 | ret = gpiochip_add(gc); | |
198 | if (ret) | |
199 | goto err2; | |
200 | ||
201 | return 0; | |
202 | err2: | |
203 | iounmap(mm_gc->regs); | |
204 | err1: | |
205 | kfree(gc->label); | |
206 | err0: | |
207 | pr_err("%s: GPIO chip registration failed with status %d\n", | |
208 | np->full_name, ret); | |
209 | return ret; | |
210 | } | |
211 | EXPORT_SYMBOL(of_mm_gpiochip_add); | |
212 | ||
213 | #ifdef CONFIG_PINCTRL | |
214 | static void of_gpiochip_add_pin_range(struct gpio_chip *chip) | |
215 | { | |
216 | struct device_node *np = chip->of_node; | |
217 | struct of_phandle_args pinspec; | |
218 | struct pinctrl_dev *pctldev; | |
219 | int index = 0, ret; | |
220 | const char *name; | |
221 | static const char group_names_propname[] = "gpio-ranges-group-names"; | |
222 | struct property *group_names; | |
223 | ||
224 | if (!np) | |
225 | return; | |
226 | ||
227 | group_names = of_find_property(np, group_names_propname, NULL); | |
228 | ||
229 | for (;; index++) { | |
230 | ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, | |
231 | index, &pinspec); | |
232 | if (ret) | |
233 | break; | |
234 | ||
235 | pctldev = of_pinctrl_get(pinspec.np); | |
236 | if (!pctldev) | |
237 | break; | |
238 | ||
239 | if (pinspec.args[2]) { | |
240 | if (group_names) { | |
241 | ret = of_property_read_string_index(np, | |
242 | group_names_propname, | |
243 | index, &name); | |
244 | if (strlen(name)) { | |
245 | pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n", | |
246 | np->full_name); | |
247 | break; | |
248 | } | |
249 | } | |
250 | /* npins != 0: linear range */ | |
251 | ret = gpiochip_add_pin_range(chip, | |
252 | pinctrl_dev_get_devname(pctldev), | |
253 | pinspec.args[0], | |
254 | pinspec.args[1], | |
255 | pinspec.args[2]); | |
256 | if (ret) | |
257 | break; | |
258 | } else { | |
259 | /* npins == 0: special range */ | |
260 | if (pinspec.args[1]) { | |
261 | pr_err("%s: Illegal gpio-range format.\n", | |
262 | np->full_name); | |
263 | break; | |
264 | } | |
265 | ||
266 | if (!group_names) { | |
267 | pr_err("%s: GPIO group range requested but no %s property.\n", | |
268 | np->full_name, group_names_propname); | |
269 | break; | |
270 | } | |
271 | ||
272 | ret = of_property_read_string_index(np, | |
273 | group_names_propname, | |
274 | index, &name); | |
275 | if (ret) | |
276 | break; | |
277 | ||
278 | if (!strlen(name)) { | |
279 | pr_err("%s: Group name of GPIO group range cannot be the empty string.\n", | |
280 | np->full_name); | |
281 | break; | |
282 | } | |
283 | ||
284 | ret = gpiochip_add_pingroup_range(chip, pctldev, | |
285 | pinspec.args[0], name); | |
286 | if (ret) | |
287 | break; | |
288 | } | |
289 | } | |
290 | } | |
291 | ||
292 | #else | |
293 | static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {} | |
294 | #endif | |
295 | ||
296 | void of_gpiochip_add(struct gpio_chip *chip) | |
297 | { | |
298 | if ((!chip->of_node) && (chip->dev)) | |
299 | chip->of_node = chip->dev->of_node; | |
300 | ||
301 | if (!chip->of_node) | |
302 | return; | |
303 | ||
304 | if (!chip->of_xlate) { | |
305 | chip->of_gpio_n_cells = 2; | |
306 | chip->of_xlate = of_gpio_simple_xlate; | |
307 | } | |
308 | ||
309 | of_gpiochip_add_pin_range(chip); | |
310 | of_node_get(chip->of_node); | |
311 | } | |
312 | ||
313 | void of_gpiochip_remove(struct gpio_chip *chip) | |
314 | { | |
315 | gpiochip_remove_pin_ranges(chip); | |
316 | of_node_put(chip->of_node); | |
317 | } |