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 - 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 *
269 * To use this function you should allocate and fill mm_gc with:
270 *
271 * 1) In the gpio_chip structure:
272 *    - all the callbacks
273 *    - of_gpio_n_cells
274 *    - of_xlate callback (optional)
275 *
276 * 3) In the of_mm_gpio_chip structure:
277 *    - save_regs callback (optional)
278 *
279 * If succeeded, this function will map bank's memory and will
280 * do all necessary work for you. Then you'll able to use .regs
281 * to manage GPIOs from the callbacks.
282 */
283int of_mm_gpiochip_add(struct device_node *np,
284		       struct of_mm_gpio_chip *mm_gc)
285{
286	int ret = -ENOMEM;
287	struct gpio_chip *gc = &mm_gc->gc;
288
289	gc->label = kstrdup(np->full_name, GFP_KERNEL);
290	if (!gc->label)
291		goto err0;
292
293	mm_gc->regs = of_iomap(np, 0);
294	if (!mm_gc->regs)
295		goto err1;
296
297	gc->base = -1;
298
299	if (mm_gc->save_regs)
300		mm_gc->save_regs(mm_gc);
301
302	mm_gc->gc.of_node = np;
303
304	ret = gpiochip_add(gc);
305	if (ret)
306		goto err2;
307
308	return 0;
309err2:
310	iounmap(mm_gc->regs);
311err1:
312	kfree(gc->label);
313err0:
314	pr_err("%s: GPIO chip registration failed with status %d\n",
315	       np->full_name, ret);
316	return ret;
317}
318EXPORT_SYMBOL(of_mm_gpiochip_add);
319
320/**
321 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
322 * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
323 */
324void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
325{
326	struct gpio_chip *gc = &mm_gc->gc;
327
328	if (!mm_gc)
329		return;
330
331	gpiochip_remove(gc);
332	iounmap(mm_gc->regs);
333	kfree(gc->label);
334}
335EXPORT_SYMBOL(of_mm_gpiochip_remove);
336
337#ifdef CONFIG_PINCTRL
338static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
339{
340	struct device_node *np = chip->of_node;
341	struct of_phandle_args pinspec;
342	struct pinctrl_dev *pctldev;
343	int index = 0, ret;
344	const char *name;
345	static const char group_names_propname[] = "gpio-ranges-group-names";
346	struct property *group_names;
347
348	if (!np)
349		return 0;
350
351	group_names = of_find_property(np, group_names_propname, NULL);
352
353	for (;; index++) {
354		ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
355				index, &pinspec);
356		if (ret)
357			break;
358
359		pctldev = of_pinctrl_get(pinspec.np);
360		if (!pctldev)
361			return -EPROBE_DEFER;
362
363		if (pinspec.args[2]) {
364			if (group_names) {
365				of_property_read_string_index(np,
366						group_names_propname,
367						index, &name);
368				if (strlen(name)) {
369					pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
370						np->full_name);
371					break;
372				}
373			}
374			/* npins != 0: linear range */
375			ret = gpiochip_add_pin_range(chip,
376					pinctrl_dev_get_devname(pctldev),
377					pinspec.args[0],
378					pinspec.args[1],
379					pinspec.args[2]);
380			if (ret)
381				return ret;
382		} else {
383			/* npins == 0: special range */
384			if (pinspec.args[1]) {
385				pr_err("%s: Illegal gpio-range format.\n",
386					np->full_name);
387				break;
388			}
389
390			if (!group_names) {
391				pr_err("%s: GPIO group range requested but no %s property.\n",
392					np->full_name, group_names_propname);
393				break;
394			}
395
396			ret = of_property_read_string_index(np,
397						group_names_propname,
398						index, &name);
399			if (ret)
400				break;
401
402			if (!strlen(name)) {
403				pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
404				np->full_name);
405				break;
406			}
407
408			ret = gpiochip_add_pingroup_range(chip, pctldev,
409						pinspec.args[0], name);
410			if (ret)
411				return ret;
412		}
413	}
414
415	return 0;
416}
417
418#else
419static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
420#endif
421
422int of_gpiochip_add(struct gpio_chip *chip)
423{
424	int status;
425
426	if ((!chip->of_node) && (chip->dev))
427		chip->of_node = chip->dev->of_node;
428
429	if (!chip->of_node)
430		return 0;
431
432	if (!chip->of_xlate) {
433		chip->of_gpio_n_cells = 2;
434		chip->of_xlate = of_gpio_simple_xlate;
435	}
436
437	status = of_gpiochip_add_pin_range(chip);
438	if (status)
439		return status;
440
441	of_node_get(chip->of_node);
442
443	of_gpiochip_scan_gpios(chip);
444
445	return 0;
446}
447
448void of_gpiochip_remove(struct gpio_chip *chip)
449{
450	gpiochip_remove_pin_ranges(chip);
451	of_node_put(chip->of_node);
452}
453