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