1/*
2 * drivers/clk/clkdev.c
3 *
4 *  Copyright (C) 2008 Russell King.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Helper for the clk API to assist looking up a struct clk.
11 */
12#include <linux/module.h>
13#include <linux/kernel.h>
14#include <linux/device.h>
15#include <linux/list.h>
16#include <linux/errno.h>
17#include <linux/err.h>
18#include <linux/string.h>
19#include <linux/mutex.h>
20#include <linux/clk.h>
21#include <linux/clkdev.h>
22#include <linux/clk-provider.h>
23#include <linux/of.h>
24
25#include "clk.h"
26
27static LIST_HEAD(clocks);
28static DEFINE_MUTEX(clocks_mutex);
29
30#if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
31static struct clk *__of_clk_get(struct device_node *np, int index,
32			       const char *dev_id, const char *con_id)
33{
34	struct of_phandle_args clkspec;
35	struct clk *clk;
36	int rc;
37
38	if (index < 0)
39		return ERR_PTR(-EINVAL);
40
41	rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
42					&clkspec);
43	if (rc)
44		return ERR_PTR(rc);
45
46	clk = __of_clk_get_from_provider(&clkspec, dev_id, con_id);
47	of_node_put(clkspec.np);
48
49	return clk;
50}
51
52struct clk *of_clk_get(struct device_node *np, int index)
53{
54	return __of_clk_get(np, index, np->full_name, NULL);
55}
56EXPORT_SYMBOL(of_clk_get);
57
58static struct clk *__of_clk_get_by_name(struct device_node *np,
59					const char *dev_id,
60					const char *name)
61{
62	struct clk *clk = ERR_PTR(-ENOENT);
63
64	/* Walk up the tree of devices looking for a clock that matches */
65	while (np) {
66		int index = 0;
67
68		/*
69		 * For named clocks, first look up the name in the
70		 * "clock-names" property.  If it cannot be found, then
71		 * index will be an error code, and of_clk_get() will fail.
72		 */
73		if (name)
74			index = of_property_match_string(np, "clock-names", name);
75		clk = __of_clk_get(np, index, dev_id, name);
76		if (!IS_ERR(clk)) {
77			break;
78		} else if (name && index >= 0) {
79			if (PTR_ERR(clk) != -EPROBE_DEFER)
80				pr_err("ERROR: could not get clock %s:%s(%i)\n",
81					np->full_name, name ? name : "", index);
82			return clk;
83		}
84
85		/*
86		 * No matching clock found on this node.  If the parent node
87		 * has a "clock-ranges" property, then we can try one of its
88		 * clocks.
89		 */
90		np = np->parent;
91		if (np && !of_get_property(np, "clock-ranges", NULL))
92			break;
93	}
94
95	return clk;
96}
97
98/**
99 * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node
100 * @np: pointer to clock consumer node
101 * @name: name of consumer's clock input, or NULL for the first clock reference
102 *
103 * This function parses the clocks and clock-names properties,
104 * and uses them to look up the struct clk from the registered list of clock
105 * providers.
106 */
107struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
108{
109	if (!np)
110		return ERR_PTR(-ENOENT);
111
112	return __of_clk_get_by_name(np, np->full_name, name);
113}
114EXPORT_SYMBOL(of_clk_get_by_name);
115
116#else /* defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) */
117
118static struct clk *__of_clk_get_by_name(struct device_node *np,
119					const char *dev_id,
120					const char *name)
121{
122	return ERR_PTR(-ENOENT);
123}
124#endif
125
126/*
127 * Find the correct struct clk for the device and connection ID.
128 * We do slightly fuzzy matching here:
129 *  An entry with a NULL ID is assumed to be a wildcard.
130 *  If an entry has a device ID, it must match
131 *  If an entry has a connection ID, it must match
132 * Then we take the most specific entry - with the following
133 * order of precedence: dev+con > dev only > con only.
134 */
135static struct clk_lookup *clk_find(const char *dev_id, const char *con_id)
136{
137	struct clk_lookup *p, *cl = NULL;
138	int match, best_found = 0, best_possible = 0;
139
140	if (dev_id)
141		best_possible += 2;
142	if (con_id)
143		best_possible += 1;
144
145	list_for_each_entry(p, &clocks, node) {
146		match = 0;
147		if (p->dev_id) {
148			if (!dev_id || strcmp(p->dev_id, dev_id))
149				continue;
150			match += 2;
151		}
152		if (p->con_id) {
153			if (!con_id || strcmp(p->con_id, con_id))
154				continue;
155			match += 1;
156		}
157
158		if (match > best_found) {
159			cl = p;
160			if (match != best_possible)
161				best_found = match;
162			else
163				break;
164		}
165	}
166	return cl;
167}
168
169struct clk *clk_get_sys(const char *dev_id, const char *con_id)
170{
171	struct clk_lookup *cl;
172	struct clk *clk = NULL;
173
174	mutex_lock(&clocks_mutex);
175
176	cl = clk_find(dev_id, con_id);
177	if (!cl)
178		goto out;
179
180	clk = __clk_create_clk(cl->clk_hw, dev_id, con_id);
181	if (IS_ERR(clk))
182		goto out;
183
184	if (!__clk_get(clk)) {
185		__clk_free_clk(clk);
186		cl = NULL;
187		goto out;
188	}
189
190out:
191	mutex_unlock(&clocks_mutex);
192
193	return cl ? clk : ERR_PTR(-ENOENT);
194}
195EXPORT_SYMBOL(clk_get_sys);
196
197struct clk *clk_get(struct device *dev, const char *con_id)
198{
199	const char *dev_id = dev ? dev_name(dev) : NULL;
200	struct clk *clk;
201
202	if (dev) {
203		clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id);
204		if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER)
205			return clk;
206	}
207
208	return clk_get_sys(dev_id, con_id);
209}
210EXPORT_SYMBOL(clk_get);
211
212void clk_put(struct clk *clk)
213{
214	__clk_put(clk);
215}
216EXPORT_SYMBOL(clk_put);
217
218static void __clkdev_add(struct clk_lookup *cl)
219{
220	mutex_lock(&clocks_mutex);
221	list_add_tail(&cl->node, &clocks);
222	mutex_unlock(&clocks_mutex);
223}
224
225void clkdev_add(struct clk_lookup *cl)
226{
227	if (!cl->clk_hw)
228		cl->clk_hw = __clk_get_hw(cl->clk);
229	__clkdev_add(cl);
230}
231EXPORT_SYMBOL(clkdev_add);
232
233void clkdev_add_table(struct clk_lookup *cl, size_t num)
234{
235	mutex_lock(&clocks_mutex);
236	while (num--) {
237		cl->clk_hw = __clk_get_hw(cl->clk);
238		list_add_tail(&cl->node, &clocks);
239		cl++;
240	}
241	mutex_unlock(&clocks_mutex);
242}
243
244#define MAX_DEV_ID	20
245#define MAX_CON_ID	16
246
247struct clk_lookup_alloc {
248	struct clk_lookup cl;
249	char	dev_id[MAX_DEV_ID];
250	char	con_id[MAX_CON_ID];
251};
252
253static struct clk_lookup * __init_refok
254vclkdev_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt,
255	va_list ap)
256{
257	struct clk_lookup_alloc *cla;
258
259	cla = __clkdev_alloc(sizeof(*cla));
260	if (!cla)
261		return NULL;
262
263	cla->cl.clk_hw = hw;
264	if (con_id) {
265		strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
266		cla->cl.con_id = cla->con_id;
267	}
268
269	if (dev_fmt) {
270		vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
271		cla->cl.dev_id = cla->dev_id;
272	}
273
274	return &cla->cl;
275}
276
277static struct clk_lookup *
278vclkdev_create(struct clk_hw *hw, const char *con_id, const char *dev_fmt,
279	va_list ap)
280{
281	struct clk_lookup *cl;
282
283	cl = vclkdev_alloc(hw, con_id, dev_fmt, ap);
284	if (cl)
285		__clkdev_add(cl);
286
287	return cl;
288}
289
290struct clk_lookup * __init_refok
291clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...)
292{
293	struct clk_lookup *cl;
294	va_list ap;
295
296	va_start(ap, dev_fmt);
297	cl = vclkdev_alloc(__clk_get_hw(clk), con_id, dev_fmt, ap);
298	va_end(ap);
299
300	return cl;
301}
302EXPORT_SYMBOL(clkdev_alloc);
303
304/**
305 * clkdev_create - allocate and add a clkdev lookup structure
306 * @clk: struct clk to associate with all clk_lookups
307 * @con_id: connection ID string on device
308 * @dev_fmt: format string describing device name
309 *
310 * Returns a clk_lookup structure, which can be later unregistered and
311 * freed.
312 */
313struct clk_lookup *clkdev_create(struct clk *clk, const char *con_id,
314	const char *dev_fmt, ...)
315{
316	struct clk_lookup *cl;
317	va_list ap;
318
319	va_start(ap, dev_fmt);
320	cl = vclkdev_create(__clk_get_hw(clk), con_id, dev_fmt, ap);
321	va_end(ap);
322
323	return cl;
324}
325EXPORT_SYMBOL_GPL(clkdev_create);
326
327int clk_add_alias(const char *alias, const char *alias_dev_name,
328	const char *con_id, struct device *dev)
329{
330	struct clk *r = clk_get(dev, con_id);
331	struct clk_lookup *l;
332
333	if (IS_ERR(r))
334		return PTR_ERR(r);
335
336	l = clkdev_create(r, alias, alias_dev_name ? "%s" : NULL,
337			  alias_dev_name);
338	clk_put(r);
339
340	return l ? 0 : -ENODEV;
341}
342EXPORT_SYMBOL(clk_add_alias);
343
344/*
345 * clkdev_drop - remove a clock dynamically allocated
346 */
347void clkdev_drop(struct clk_lookup *cl)
348{
349	mutex_lock(&clocks_mutex);
350	list_del(&cl->node);
351	mutex_unlock(&clocks_mutex);
352	kfree(cl);
353}
354EXPORT_SYMBOL(clkdev_drop);
355
356/**
357 * clk_register_clkdev - register one clock lookup for a struct clk
358 * @clk: struct clk to associate with all clk_lookups
359 * @con_id: connection ID string on device
360 * @dev_id: format string describing device name
361 *
362 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
363 * clkdev.
364 *
365 * To make things easier for mass registration, we detect error clks
366 * from a previous clk_register() call, and return the error code for
367 * those.  This is to permit this function to be called immediately
368 * after clk_register().
369 */
370int clk_register_clkdev(struct clk *clk, const char *con_id,
371	const char *dev_fmt, ...)
372{
373	struct clk_lookup *cl;
374	va_list ap;
375
376	if (IS_ERR(clk))
377		return PTR_ERR(clk);
378
379	va_start(ap, dev_fmt);
380	cl = vclkdev_create(__clk_get_hw(clk), con_id, dev_fmt, ap);
381	va_end(ap);
382
383	return cl ? 0 : -ENOMEM;
384}
385EXPORT_SYMBOL(clk_register_clkdev);
386
387/**
388 * clk_register_clkdevs - register a set of clk_lookup for a struct clk
389 * @clk: struct clk to associate with all clk_lookups
390 * @cl: array of clk_lookup structures with con_id and dev_id pre-initialized
391 * @num: number of clk_lookup structures to register
392 *
393 * To make things easier for mass registration, we detect error clks
394 * from a previous clk_register() call, and return the error code for
395 * those.  This is to permit this function to be called immediately
396 * after clk_register().
397 */
398int clk_register_clkdevs(struct clk *clk, struct clk_lookup *cl, size_t num)
399{
400	unsigned i;
401
402	if (IS_ERR(clk))
403		return PTR_ERR(clk);
404
405	for (i = 0; i < num; i++, cl++) {
406		cl->clk_hw = __clk_get_hw(clk);
407		__clkdev_add(cl);
408	}
409
410	return 0;
411}
412EXPORT_SYMBOL(clk_register_clkdevs);
413