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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/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/slab.h>
23
24/* Private data structure for of_gpiochip_is_match */
25struct gg_data {
26 enum of_gpio_flags *flags;
27 struct of_phandle_args gpiospec;
28
29 int out_gpio;
30};
31
32/* Private function for resolving node pointer to gpio_chip */
33static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
34{
35 struct gg_data *gg_data = data;
36 int ret;
37
38 if ((gc->of_node != gg_data->gpiospec.np) ||
39 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
40 (!gc->of_xlate))
41 return false;
42
43 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
44 if (ret < 0)
45 return false;
46
47 gg_data->out_gpio = ret + gc->base;
48 return true;
49}
50
51/**
52 * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
53 * @np: device node to get GPIO from
54 * @propname: property name containing gpio specifier(s)
55 * @index: index of the GPIO
56 * @flags: a flags pointer to fill in
57 *
58 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
59 * value on the error condition. If @flags is not NULL the function also fills
60 * in flags for the GPIO.
61 */
62int of_get_named_gpio_flags(struct device_node *np, const char *propname,
63 int index, enum of_gpio_flags *flags)
64{
65 struct gg_data gg_data = { .flags = flags, .out_gpio = -ENODEV };
66 int ret;
67
68 /* .of_xlate might decide to not fill in the flags, so clear it. */
69 if (flags)
70 *flags = 0;
71
72 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
73 &gg_data.gpiospec);
74 if (ret) {
75 pr_debug("%s: can't parse gpios property\n", __func__);
76 return -EINVAL;
77 }
78
79 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
80
81 of_node_put(gg_data.gpiospec.np);
82 pr_debug("%s exited with status %d\n", __func__, ret);
83 return gg_data.out_gpio;
84}
85EXPORT_SYMBOL(of_get_named_gpio_flags);
86
87/**
88 * of_gpio_named_count - Count GPIOs for a device
89 * @np: device node to count GPIOs for
90 * @propname: property name containing gpio specifier(s)
91 *
92 * The function returns the count of GPIOs specified for a node.
93 *
94 * Note that the empty GPIO specifiers counts too. For example,
95 *
96 * gpios = <0
97 * &pio1 1 2
98 * 0
99 * &pio2 3 4>;
100 *
101 * defines four GPIOs (so this function will return 4), two of which
102 * are not specified.
103 */
104unsigned int of_gpio_named_count(struct device_node *np, const char* propname)
105{
106 unsigned int cnt = 0;
107
108 do {
109 int ret;
110
111 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells",
112 cnt, NULL);
113 /* A hole in the gpios = <> counts anyway. */
114 if (ret < 0 && ret != -EEXIST)
115 break;
116 } while (++cnt);
117
118 return cnt;
119}
120EXPORT_SYMBOL(of_gpio_named_count);
121
122/**
123 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
124 * @gc: pointer to the gpio_chip structure
125 * @np: device node of the GPIO chip
126 * @gpio_spec: gpio specifier as found in the device tree
127 * @flags: a flags pointer to fill in
128 *
129 * This is simple translation function, suitable for the most 1:1 mapped
130 * gpio chips. This function performs only one sanity check: whether gpio
131 * is less than ngpios (that is specified in the gpio_chip).
132 */
133int of_gpio_simple_xlate(struct gpio_chip *gc,
134 const struct of_phandle_args *gpiospec, u32 *flags)
135{
136 /*
137 * We're discouraging gpio_cells < 2, since that way you'll have to
138 * write your own xlate function (that will have to retrive the GPIO
139 * number and the flags from a single gpio cell -- this is possible,
140 * but not recommended).
141 */
142 if (gc->of_gpio_n_cells < 2) {
143 WARN_ON(1);
144 return -EINVAL;
145 }
146
147 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
148 return -EINVAL;
149
150 if (gpiospec->args[0] >= gc->ngpio)
151 return -EINVAL;
152
153 if (flags)
154 *flags = gpiospec->args[1];
155
156 return gpiospec->args[0];
157}
158EXPORT_SYMBOL(of_gpio_simple_xlate);
159
160/**
161 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
162 * @np: device node of the GPIO chip
163 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
164 *
165 * To use this function you should allocate and fill mm_gc with:
166 *
167 * 1) In the gpio_chip structure:
168 * - all the callbacks
169 * - of_gpio_n_cells
170 * - of_xlate callback (optional)
171 *
172 * 3) In the of_mm_gpio_chip structure:
173 * - save_regs callback (optional)
174 *
175 * If succeeded, this function will map bank's memory and will
176 * do all necessary work for you. Then you'll able to use .regs
177 * to manage GPIOs from the callbacks.
178 */
179int of_mm_gpiochip_add(struct device_node *np,
180 struct of_mm_gpio_chip *mm_gc)
181{
182 int ret = -ENOMEM;
183 struct gpio_chip *gc = &mm_gc->gc;
184
185 gc->label = kstrdup(np->full_name, GFP_KERNEL);
186 if (!gc->label)
187 goto err0;
188
189 mm_gc->regs = of_iomap(np, 0);
190 if (!mm_gc->regs)
191 goto err1;
192
193 gc->base = -1;
194
195 if (mm_gc->save_regs)
196 mm_gc->save_regs(mm_gc);
197
198 mm_gc->gc.of_node = np;
199
200 ret = gpiochip_add(gc);
201 if (ret)
202 goto err2;
203
204 return 0;
205err2:
206 iounmap(mm_gc->regs);
207err1:
208 kfree(gc->label);
209err0:
210 pr_err("%s: GPIO chip registration failed with status %d\n",
211 np->full_name, ret);
212 return ret;
213}
214EXPORT_SYMBOL(of_mm_gpiochip_add);
215
216void of_gpiochip_add(struct gpio_chip *chip)
217{
218 if ((!chip->of_node) && (chip->dev))
219 chip->of_node = chip->dev->of_node;
220
221 if (!chip->of_node)
222 return;
223
224 if (!chip->of_xlate) {
225 chip->of_gpio_n_cells = 2;
226 chip->of_xlate = of_gpio_simple_xlate;
227 }
228
229 of_node_get(chip->of_node);
230}
231
232void of_gpiochip_remove(struct gpio_chip *chip)
233{
234 if (chip->of_node)
235 of_node_put(chip->of_node);
236}
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#include <linux/gpio/machine.h>
26
27#include "gpiolib.h"
28
29/* Private data structure for of_gpiochip_find_and_xlate */
30struct gg_data {
31 enum of_gpio_flags *flags;
32 struct of_phandle_args gpiospec;
33
34 struct gpio_desc *out_gpio;
35};
36
37/* Private function for resolving node pointer to gpio_chip */
38static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
39{
40 struct gg_data *gg_data = data;
41 int ret;
42
43 if ((gc->of_node != gg_data->gpiospec.np) ||
44 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
45 (!gc->of_xlate))
46 return false;
47
48 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
49 if (ret < 0) {
50 /* We've found a gpio chip, but the translation failed.
51 * Store translation error in out_gpio.
52 * Return false to keep looking, as more than one gpio chip
53 * could be registered per of-node.
54 */
55 gg_data->out_gpio = ERR_PTR(ret);
56 return false;
57 }
58
59 gg_data->out_gpio = gpiochip_get_desc(gc, ret);
60 return true;
61}
62
63/**
64 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
65 * @np: device node to get GPIO from
66 * @propname: property name containing gpio specifier(s)
67 * @index: index of the GPIO
68 * @flags: a flags pointer to fill in
69 *
70 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
71 * value on the error condition. If @flags is not NULL the function also fills
72 * in flags for the GPIO.
73 */
74struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
75 const char *propname, int index, enum of_gpio_flags *flags)
76{
77 /* Return -EPROBE_DEFER to support probe() functions to be called
78 * later when the GPIO actually becomes available
79 */
80 struct gg_data gg_data = {
81 .flags = flags,
82 .out_gpio = ERR_PTR(-EPROBE_DEFER)
83 };
84 int ret;
85
86 /* .of_xlate might decide to not fill in the flags, so clear it. */
87 if (flags)
88 *flags = 0;
89
90 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
91 &gg_data.gpiospec);
92 if (ret) {
93 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
94 __func__, propname, np->full_name, index);
95 return ERR_PTR(ret);
96 }
97
98 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
99
100 of_node_put(gg_data.gpiospec.np);
101 pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
102 __func__, propname, np->full_name, index,
103 PTR_ERR_OR_ZERO(gg_data.out_gpio));
104 return gg_data.out_gpio;
105}
106
107int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
108 int index, enum of_gpio_flags *flags)
109{
110 struct gpio_desc *desc;
111
112 desc = of_get_named_gpiod_flags(np, list_name, index, flags);
113
114 if (IS_ERR(desc))
115 return PTR_ERR(desc);
116 else
117 return desc_to_gpio(desc);
118}
119EXPORT_SYMBOL(of_get_named_gpio_flags);
120
121/**
122 * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
123 * @np: device node to get GPIO from
124 * @name: GPIO line name
125 * @lflags: gpio_lookup_flags - returned from of_find_gpio() or
126 * of_parse_own_gpio()
127 * @dflags: gpiod_flags - optional GPIO initialization flags
128 *
129 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
130 * value on the error condition.
131 */
132static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
133 const char **name,
134 enum gpio_lookup_flags *lflags,
135 enum gpiod_flags *dflags)
136{
137 struct device_node *chip_np;
138 enum of_gpio_flags xlate_flags;
139 struct gg_data gg_data = {
140 .flags = &xlate_flags,
141 };
142 u32 tmp;
143 int i, ret;
144
145 chip_np = np->parent;
146 if (!chip_np)
147 return ERR_PTR(-EINVAL);
148
149 xlate_flags = 0;
150 *lflags = 0;
151 *dflags = 0;
152
153 ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
154 if (ret)
155 return ERR_PTR(ret);
156
157 if (tmp > MAX_PHANDLE_ARGS)
158 return ERR_PTR(-EINVAL);
159
160 gg_data.gpiospec.args_count = tmp;
161 gg_data.gpiospec.np = chip_np;
162 for (i = 0; i < tmp; i++) {
163 ret = of_property_read_u32_index(np, "gpios", i,
164 &gg_data.gpiospec.args[i]);
165 if (ret)
166 return ERR_PTR(ret);
167 }
168
169 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
170 if (!gg_data.out_gpio) {
171 if (np->parent == np)
172 return ERR_PTR(-ENXIO);
173 else
174 return ERR_PTR(-EINVAL);
175 }
176
177 if (xlate_flags & OF_GPIO_ACTIVE_LOW)
178 *lflags |= GPIO_ACTIVE_LOW;
179
180 if (of_property_read_bool(np, "input"))
181 *dflags |= GPIOD_IN;
182 else if (of_property_read_bool(np, "output-low"))
183 *dflags |= GPIOD_OUT_LOW;
184 else if (of_property_read_bool(np, "output-high"))
185 *dflags |= GPIOD_OUT_HIGH;
186 else {
187 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
188 desc_to_gpio(gg_data.out_gpio), np->name);
189 return ERR_PTR(-EINVAL);
190 }
191
192 if (name && of_property_read_string(np, "line-name", name))
193 *name = np->name;
194
195 return gg_data.out_gpio;
196}
197
198/**
199 * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
200 * @chip: gpio chip to act on
201 *
202 * This is only used by of_gpiochip_add to request/set GPIO initial
203 * configuration.
204 */
205static void of_gpiochip_scan_gpios(struct gpio_chip *chip)
206{
207 struct gpio_desc *desc = NULL;
208 struct device_node *np;
209 const char *name;
210 enum gpio_lookup_flags lflags;
211 enum gpiod_flags dflags;
212
213 for_each_child_of_node(chip->of_node, np) {
214 if (!of_property_read_bool(np, "gpio-hog"))
215 continue;
216
217 desc = of_parse_own_gpio(np, &name, &lflags, &dflags);
218 if (IS_ERR(desc))
219 continue;
220
221 if (gpiod_hog(desc, name, lflags, dflags))
222 continue;
223 }
224}
225
226/**
227 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
228 * @gc: pointer to the gpio_chip structure
229 * @np: device node of the GPIO chip
230 * @gpio_spec: gpio specifier as found in the device tree
231 * @flags: a flags pointer to fill in
232 *
233 * This is simple translation function, suitable for the most 1:1 mapped
234 * gpio chips. This function performs only one sanity check: whether gpio
235 * is less than ngpios (that is specified in the gpio_chip).
236 */
237int of_gpio_simple_xlate(struct gpio_chip *gc,
238 const struct of_phandle_args *gpiospec, u32 *flags)
239{
240 /*
241 * We're discouraging gpio_cells < 2, since that way you'll have to
242 * write your own xlate function (that will have to retrieve the GPIO
243 * number and the flags from a single gpio cell -- this is possible,
244 * but not recommended).
245 */
246 if (gc->of_gpio_n_cells < 2) {
247 WARN_ON(1);
248 return -EINVAL;
249 }
250
251 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
252 return -EINVAL;
253
254 if (gpiospec->args[0] >= gc->ngpio)
255 return -EINVAL;
256
257 if (flags)
258 *flags = gpiospec->args[1];
259
260 return gpiospec->args[0];
261}
262EXPORT_SYMBOL(of_gpio_simple_xlate);
263
264/**
265 * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank)
266 * @np: device node of the GPIO chip
267 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
268 * @data: driver data to store in the struct gpio_chip
269 *
270 * To use this function you should allocate and fill mm_gc with:
271 *
272 * 1) In the gpio_chip structure:
273 * - all the callbacks
274 * - of_gpio_n_cells
275 * - of_xlate callback (optional)
276 *
277 * 3) In the of_mm_gpio_chip structure:
278 * - save_regs callback (optional)
279 *
280 * If succeeded, this function will map bank's memory and will
281 * do all necessary work for you. Then you'll able to use .regs
282 * to manage GPIOs from the callbacks.
283 */
284int of_mm_gpiochip_add_data(struct device_node *np,
285 struct of_mm_gpio_chip *mm_gc,
286 void *data)
287{
288 int ret = -ENOMEM;
289 struct gpio_chip *gc = &mm_gc->gc;
290
291 gc->label = kstrdup(np->full_name, GFP_KERNEL);
292 if (!gc->label)
293 goto err0;
294
295 mm_gc->regs = of_iomap(np, 0);
296 if (!mm_gc->regs)
297 goto err1;
298
299 gc->base = -1;
300
301 if (mm_gc->save_regs)
302 mm_gc->save_regs(mm_gc);
303
304 mm_gc->gc.of_node = np;
305
306 ret = gpiochip_add_data(gc, data);
307 if (ret)
308 goto err2;
309
310 return 0;
311err2:
312 iounmap(mm_gc->regs);
313err1:
314 kfree(gc->label);
315err0:
316 pr_err("%s: GPIO chip registration failed with status %d\n",
317 np->full_name, ret);
318 return ret;
319}
320EXPORT_SYMBOL(of_mm_gpiochip_add_data);
321
322/**
323 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
324 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
325 */
326void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
327{
328 struct gpio_chip *gc = &mm_gc->gc;
329
330 if (!mm_gc)
331 return;
332
333 gpiochip_remove(gc);
334 iounmap(mm_gc->regs);
335 kfree(gc->label);
336}
337EXPORT_SYMBOL(of_mm_gpiochip_remove);
338
339#ifdef CONFIG_PINCTRL
340static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
341{
342 struct device_node *np = chip->of_node;
343 struct of_phandle_args pinspec;
344 struct pinctrl_dev *pctldev;
345 int index = 0, ret;
346 const char *name;
347 static const char group_names_propname[] = "gpio-ranges-group-names";
348 struct property *group_names;
349
350 if (!np)
351 return 0;
352
353 group_names = of_find_property(np, group_names_propname, NULL);
354
355 for (;; index++) {
356 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
357 index, &pinspec);
358 if (ret)
359 break;
360
361 pctldev = of_pinctrl_get(pinspec.np);
362 if (!pctldev)
363 return -EPROBE_DEFER;
364
365 if (pinspec.args[2]) {
366 if (group_names) {
367 of_property_read_string_index(np,
368 group_names_propname,
369 index, &name);
370 if (strlen(name)) {
371 pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
372 np->full_name);
373 break;
374 }
375 }
376 /* npins != 0: linear range */
377 ret = gpiochip_add_pin_range(chip,
378 pinctrl_dev_get_devname(pctldev),
379 pinspec.args[0],
380 pinspec.args[1],
381 pinspec.args[2]);
382 if (ret)
383 return ret;
384 } else {
385 /* npins == 0: special range */
386 if (pinspec.args[1]) {
387 pr_err("%s: Illegal gpio-range format.\n",
388 np->full_name);
389 break;
390 }
391
392 if (!group_names) {
393 pr_err("%s: GPIO group range requested but no %s property.\n",
394 np->full_name, group_names_propname);
395 break;
396 }
397
398 ret = of_property_read_string_index(np,
399 group_names_propname,
400 index, &name);
401 if (ret)
402 break;
403
404 if (!strlen(name)) {
405 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
406 np->full_name);
407 break;
408 }
409
410 ret = gpiochip_add_pingroup_range(chip, pctldev,
411 pinspec.args[0], name);
412 if (ret)
413 return ret;
414 }
415 }
416
417 return 0;
418}
419
420#else
421static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
422#endif
423
424int of_gpiochip_add(struct gpio_chip *chip)
425{
426 int status;
427
428 if ((!chip->of_node) && (chip->parent))
429 chip->of_node = chip->parent->of_node;
430
431 if (!chip->of_node)
432 return 0;
433
434 if (!chip->of_xlate) {
435 chip->of_gpio_n_cells = 2;
436 chip->of_xlate = of_gpio_simple_xlate;
437 }
438
439 status = of_gpiochip_add_pin_range(chip);
440 if (status)
441 return status;
442
443 of_node_get(chip->of_node);
444
445 of_gpiochip_scan_gpios(chip);
446
447 return 0;
448}
449
450void of_gpiochip_remove(struct gpio_chip *chip)
451{
452 gpiochip_remove_pin_ranges(chip);
453 of_node_put(chip->of_node);
454}