devicetree.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Device tree integration for the pin control subsystem
  4 *
  5 * Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved.
  6 */
  7
  8#include <linux/device.h>
  9#include <linux/of.h>
 10#include <linux/pinctrl/pinctrl.h>
 11#include <linux/slab.h>
 12
 13#include "core.h"
 14#include "devicetree.h"
 15
 16/**
 17 * struct pinctrl_dt_map - mapping table chunk parsed from device tree
 18 * @node: list node for struct pinctrl's @dt_maps field
 19 * @pctldev: the pin controller that allocated this struct, and will free it
 20 * @map: the mapping table entries
 21 * @num_maps: number of mapping table entries
 22 */
 23struct pinctrl_dt_map {
 24	struct list_head node;
 25	struct pinctrl_dev *pctldev;
 26	struct pinctrl_map *map;
 27	unsigned int num_maps;
 28};
 29
 30static void dt_free_map(struct pinctrl_dev *pctldev,
 31			struct pinctrl_map *map, unsigned int num_maps)
 32{
 33	int i;
 34
 35	for (i = 0; i < num_maps; ++i) {
 36		kfree_const(map[i].dev_name);
 37		map[i].dev_name = NULL;
 38	}
 39
 40	if (pctldev) {
 41		const struct pinctrl_ops *ops = pctldev->desc->pctlops;
 42		if (ops->dt_free_map)
 43			ops->dt_free_map(pctldev, map, num_maps);
 44	} else {
 45		/* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */
 46		kfree(map);
 47	}
 48}
 49
 50void pinctrl_dt_free_maps(struct pinctrl *p)
 51{
 52	struct pinctrl_dt_map *dt_map, *n1;
 53
 54	list_for_each_entry_safe(dt_map, n1, &p->dt_maps, node) {
 55		pinctrl_unregister_mappings(dt_map->map);
 56		list_del(&dt_map->node);
 57		dt_free_map(dt_map->pctldev, dt_map->map,
 58			    dt_map->num_maps);
 59		kfree(dt_map);
 60	}
 61
 62	of_node_put(p->dev->of_node);
 63}
 64
 65static int dt_remember_or_free_map(struct pinctrl *p, const char *statename,
 66				   struct pinctrl_dev *pctldev,
 67				   struct pinctrl_map *map, unsigned int num_maps)
 68{
 69	int i;
 70	struct pinctrl_dt_map *dt_map;
 71
 72	/* Initialize common mapping table entry fields */
 73	for (i = 0; i < num_maps; i++) {
 74		const char *devname;
 75
 76		devname = kstrdup_const(dev_name(p->dev), GFP_KERNEL);
 77		if (!devname)
 78			goto err_free_map;
 79
 80		map[i].dev_name = devname;
 81		map[i].name = statename;
 82		if (pctldev)
 83			map[i].ctrl_dev_name = dev_name(pctldev->dev);
 84	}
 85
 86	/* Remember the converted mapping table entries */
 87	dt_map = kzalloc(sizeof(*dt_map), GFP_KERNEL);
 88	if (!dt_map)
 89		goto err_free_map;
 90
 91	dt_map->pctldev = pctldev;
 92	dt_map->map = map;
 93	dt_map->num_maps = num_maps;
 94	list_add_tail(&dt_map->node, &p->dt_maps);
 95
 96	return pinctrl_register_mappings(map, num_maps);
 97
 98err_free_map:
 99	dt_free_map(pctldev, map, num_maps);
100	return -ENOMEM;
101}
102
103struct pinctrl_dev *of_pinctrl_get(struct device_node *np)
104{
105	return get_pinctrl_dev_from_of_node(np);
106}
107EXPORT_SYMBOL_GPL(of_pinctrl_get);
108
109static int dt_to_map_one_config(struct pinctrl *p,
110				struct pinctrl_dev *hog_pctldev,
111				const char *statename,
112				struct device_node *np_config)
113{
114	struct pinctrl_dev *pctldev = NULL;
115	struct device_node *np_pctldev;
116	const struct pinctrl_ops *ops;
117	int ret;
118	struct pinctrl_map *map;
119	unsigned int num_maps;
120	bool allow_default = false;
121
122	/* Find the pin controller containing np_config */
123	np_pctldev = of_node_get(np_config);
124	for (;;) {
125		if (!allow_default)
126			allow_default = of_property_read_bool(np_pctldev,
127							      "pinctrl-use-default");
128
129		np_pctldev = of_get_next_parent(np_pctldev);
130		if (!np_pctldev || of_node_is_root(np_pctldev)) {
131			of_node_put(np_pctldev);
132			ret = -ENODEV;
133			/* keep deferring if modules are enabled */
134			if (IS_ENABLED(CONFIG_MODULES) && !allow_default && ret < 0)
135				ret = -EPROBE_DEFER;
136			return ret;
137		}
138		/* If we're creating a hog we can use the passed pctldev */
139		if (hog_pctldev && (np_pctldev == p->dev->of_node)) {
140			pctldev = hog_pctldev;
141			break;
142		}
143		pctldev = get_pinctrl_dev_from_of_node(np_pctldev);
144		if (pctldev)
145			break;
146		/*
147		 * Do not defer probing of hogs (circular loop)
148		 *
149		 * Return 1 to let the caller catch the case.
150		 */
151		if (np_pctldev == p->dev->of_node) {
152			of_node_put(np_pctldev);
153			return 1;
154		}
155	}
156	of_node_put(np_pctldev);
157
158	/*
159	 * Call pinctrl driver to parse device tree node, and
160	 * generate mapping table entries
161	 */
162	ops = pctldev->desc->pctlops;
163	if (!ops->dt_node_to_map) {
164		dev_err(p->dev, "pctldev %s doesn't support DT\n",
165			dev_name(pctldev->dev));
166		return -ENODEV;
167	}
168	ret = ops->dt_node_to_map(pctldev, np_config, &map, &num_maps);
169	if (ret < 0)
170		return ret;
171	else if (num_maps == 0) {
172		/*
173		 * If we have no valid maps (maybe caused by empty pinctrl node
174		 * or typing error) ther is no need remember this, so just
175		 * return.
176		 */
177		dev_info(p->dev,
178			 "there is not valid maps for state %s\n", statename);
179		return 0;
180	}
181
182	/* Stash the mapping table chunk away for later use */
183	return dt_remember_or_free_map(p, statename, pctldev, map, num_maps);
184}
185
186static int dt_remember_dummy_state(struct pinctrl *p, const char *statename)
187{
188	struct pinctrl_map *map;
189
190	map = kzalloc(sizeof(*map), GFP_KERNEL);
191	if (!map)
192		return -ENOMEM;
193
194	/* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */
195	map->type = PIN_MAP_TYPE_DUMMY_STATE;
196
197	return dt_remember_or_free_map(p, statename, NULL, map, 1);
198}
199
200int pinctrl_dt_to_map(struct pinctrl *p, struct pinctrl_dev *pctldev)
201{
202	struct device_node *np = p->dev->of_node;
203	int state, ret;
204	char *propname;
205	struct property *prop;
206	const char *statename;
207	const __be32 *list;
208	int size, config;
209	phandle phandle;
210	struct device_node *np_config;
211
212	/* CONFIG_OF enabled, p->dev not instantiated from DT */
213	if (!np) {
214		if (of_have_populated_dt())
215			dev_dbg(p->dev,
216				"no of_node; not parsing pinctrl DT\n");
217		return 0;
218	}
219
220	/* We may store pointers to property names within the node */
221	of_node_get(np);
222
223	/* For each defined state ID */
224	for (state = 0; ; state++) {
225		/* Retrieve the pinctrl-* property */
226		propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
227		if (!propname) {
228			ret = -ENOMEM;
229			goto err;
230		}
231		prop = of_find_property(np, propname, &size);
232		kfree(propname);
233		if (!prop) {
234			if (state == 0) {
235				ret = -ENODEV;
236				goto err;
237			}
238			break;
239		}
240		list = prop->value;
241		size /= sizeof(*list);
242
243		/* Determine whether pinctrl-names property names the state */
244		ret = of_property_read_string_index(np, "pinctrl-names",
245						    state, &statename);
246		/*
247		 * If not, statename is just the integer state ID. But rather
248		 * than dynamically allocate it and have to free it later,
249		 * just point part way into the property name for the string.
250		 */
251		if (ret < 0)
252			statename = prop->name + strlen("pinctrl-");
253
254		/* For every referenced pin configuration node in it */
255		for (config = 0; config < size; config++) {
256			phandle = be32_to_cpup(list++);
257
258			/* Look up the pin configuration node */
259			np_config = of_find_node_by_phandle(phandle);
260			if (!np_config) {
261				dev_err(p->dev,
262					"prop %s index %i invalid phandle\n",
263					prop->name, config);
264				ret = -EINVAL;
265				goto err;
266			}
267
268			/* Parse the node */
269			ret = dt_to_map_one_config(p, pctldev, statename,
270						   np_config);
271			of_node_put(np_config);
272			if (ret == 1)
273				continue;
274			if (ret < 0)
275				goto err;
276		}
277
278		/* No entries in DT? Generate a dummy state table entry */
279		if (!size) {
280			ret = dt_remember_dummy_state(p, statename);
281			if (ret < 0)
282				goto err;
283		}
284	}
285
286	return 0;
287
288err:
289	pinctrl_dt_free_maps(p);
290	return ret;
291}
292
293/*
294 * For pinctrl binding, typically #pinctrl-cells is for the pin controller
295 * device, so either parent or grandparent. See pinctrl-bindings.txt.
296 */
297static int pinctrl_find_cells_size(const struct device_node *np)
298{
299	const char *cells_name = "#pinctrl-cells";
300	int cells_size, error;
301
302	error = of_property_read_u32(np->parent, cells_name, &cells_size);
303	if (error) {
304		error = of_property_read_u32(np->parent->parent,
305					     cells_name, &cells_size);
306		if (error)
307			return -ENOENT;
308	}
309
310	return cells_size;
311}
312
313/**
314 * pinctrl_get_list_and_count - Gets the list and it's cell size and number
315 * @np: pointer to device node with the property
316 * @list_name: property that contains the list
317 * @list: pointer for the list found
318 * @cells_size: pointer for the cell size found
319 * @nr_elements: pointer for the number of elements found
320 *
321 * Typically np is a single pinctrl entry containing the list.
322 */
323static int pinctrl_get_list_and_count(const struct device_node *np,
324				      const char *list_name,
325				      const __be32 **list,
326				      int *cells_size,
327				      int *nr_elements)
328{
329	int size;
330
331	*cells_size = 0;
332	*nr_elements = 0;
333
334	*list = of_get_property(np, list_name, &size);
335	if (!*list)
336		return -ENOENT;
337
338	*cells_size = pinctrl_find_cells_size(np);
339	if (*cells_size < 0)
340		return -ENOENT;
341
342	/* First element is always the index within the pinctrl device */
343	*nr_elements = (size / sizeof(**list)) / (*cells_size + 1);
344
345	return 0;
346}
347
348/**
349 * pinctrl_count_index_with_args - Count number of elements in a pinctrl entry
350 * @np: pointer to device node with the property
351 * @list_name: property that contains the list
352 *
353 * Counts the number of elements in a pinctrl array consisting of an index
354 * within the controller and a number of u32 entries specified for each
355 * entry. Note that device_node is always for the parent pin controller device.
356 */
357int pinctrl_count_index_with_args(const struct device_node *np,
358				  const char *list_name)
359{
360	const __be32 *list;
361	int size, nr_cells, error;
362
363	error = pinctrl_get_list_and_count(np, list_name, &list,
364					   &nr_cells, &size);
365	if (error)
366		return error;
367
368	return size;
369}
370EXPORT_SYMBOL_GPL(pinctrl_count_index_with_args);
371
372/**
373 * pinctrl_copy_args - Populates of_phandle_args based on index
374 * @np: pointer to device node with the property
375 * @list: pointer to a list with the elements
376 * @index: entry within the list of elements
377 * @nr_cells: number of cells in the list
378 * @nr_elem: number of elements for each entry in the list
379 * @out_args: returned values
380 *
381 * Populates the of_phandle_args based on the index in the list.
382 */
383static int pinctrl_copy_args(const struct device_node *np,
384			     const __be32 *list,
385			     int index, int nr_cells, int nr_elem,
386			     struct of_phandle_args *out_args)
387{
388	int i;
389
390	memset(out_args, 0, sizeof(*out_args));
391	out_args->np = (struct device_node *)np;
392	out_args->args_count = nr_cells + 1;
393
394	if (index >= nr_elem)
395		return -EINVAL;
396
397	list += index * (nr_cells + 1);
398
399	for (i = 0; i < nr_cells + 1; i++)
400		out_args->args[i] = be32_to_cpup(list++);
401
402	return 0;
403}
404
405/**
406 * pinctrl_parse_index_with_args - Find a node pointed by index in a list
407 * @np: pointer to device node with the property
408 * @list_name: property that contains the list
409 * @index: index within the list
410 * @out_args: entries in the list pointed by index
411 *
412 * Finds the selected element in a pinctrl array consisting of an index
413 * within the controller and a number of u32 entries specified for each
414 * entry. Note that device_node is always for the parent pin controller device.
415 */
416int pinctrl_parse_index_with_args(const struct device_node *np,
417				  const char *list_name, int index,
418				  struct of_phandle_args *out_args)
419{
420	const __be32 *list;
421	int nr_elem, nr_cells, error;
422
423	error = pinctrl_get_list_and_count(np, list_name, &list,
424					   &nr_cells, &nr_elem);
425	if (error || !nr_cells)
426		return error;
427
428	error = pinctrl_copy_args(np, list, index, nr_cells, nr_elem,
429				  out_args);
430	if (error)
431		return error;
432
433	return 0;
434}
435EXPORT_SYMBOL_GPL(pinctrl_parse_index_with_args);