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Russell King0318e692008-11-09 16:32:46 +00001/*
Jean-Christop PLAGNIOL-VILLARD6d803ba2010-11-17 10:04:33 +01002 * drivers/clk/clkdev.c
Russell King0318e692008-11-09 16:32:46 +00003 *
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>
Hartley Sweetenc0c60c42009-08-04 23:38:06 +010020#include <linux/clk.h>
Jean-Christop PLAGNIOL-VILLARD6d803ba2010-11-17 10:04:33 +010021#include <linux/clkdev.h>
Grant Likely766e6a42012-04-09 14:50:06 -050022#include <linux/of.h>
Russell King0318e692008-11-09 16:32:46 +000023
24static LIST_HEAD(clocks);
25static DEFINE_MUTEX(clocks_mutex);
26
Rob Herring137f8a72012-07-18 11:52:23 +080027#if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
Grant Likely766e6a42012-04-09 14:50:06 -050028struct clk *of_clk_get(struct device_node *np, int index)
29{
30 struct of_phandle_args clkspec;
31 struct clk *clk;
32 int rc;
33
34 if (index < 0)
35 return ERR_PTR(-EINVAL);
36
37 rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
38 &clkspec);
39 if (rc)
40 return ERR_PTR(rc);
41
42 clk = of_clk_get_from_provider(&clkspec);
43 of_node_put(clkspec.np);
44 return clk;
45}
46EXPORT_SYMBOL(of_clk_get);
47
48/**
49 * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node
50 * @np: pointer to clock consumer node
51 * @name: name of consumer's clock input, or NULL for the first clock reference
52 *
53 * This function parses the clocks and clock-names properties,
54 * and uses them to look up the struct clk from the registered list of clock
55 * providers.
56 */
57struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
58{
59 struct clk *clk = ERR_PTR(-ENOENT);
60
61 /* Walk up the tree of devices looking for a clock that matches */
62 while (np) {
63 int index = 0;
64
65 /*
66 * For named clocks, first look up the name in the
67 * "clock-names" property. If it cannot be found, then
68 * index will be an error code, and of_clk_get() will fail.
69 */
70 if (name)
71 index = of_property_match_string(np, "clock-names", name);
72 clk = of_clk_get(np, index);
73 if (!IS_ERR(clk))
74 break;
75 else if (name && index >= 0) {
76 pr_err("ERROR: could not get clock %s:%s(%i)\n",
77 np->full_name, name ? name : "", index);
78 return clk;
79 }
80
81 /*
82 * No matching clock found on this node. If the parent node
83 * has a "clock-ranges" property, then we can try one of its
84 * clocks.
85 */
86 np = np->parent;
87 if (np && !of_get_property(np, "clock-ranges", NULL))
88 break;
89 }
90
91 return clk;
92}
93EXPORT_SYMBOL(of_clk_get_by_name);
94#endif
95
Russell King409dc362009-01-24 10:14:37 +000096/*
97 * Find the correct struct clk for the device and connection ID.
98 * We do slightly fuzzy matching here:
99 * An entry with a NULL ID is assumed to be a wildcard.
100 * If an entry has a device ID, it must match
101 * If an entry has a connection ID, it must match
102 * Then we take the most specific entry - with the following
Uwe Kleine-König659431f2010-01-18 16:02:48 +0100103 * order of precedence: dev+con > dev only > con only.
Russell King409dc362009-01-24 10:14:37 +0000104 */
Russell Kinge8bf8df2011-04-30 10:14:08 +0100105static struct clk_lookup *clk_find(const char *dev_id, const char *con_id)
Russell King0318e692008-11-09 16:32:46 +0000106{
Russell Kinge8bf8df2011-04-30 10:14:08 +0100107 struct clk_lookup *p, *cl = NULL;
viresh kumar67b50872012-04-19 04:23:25 +0100108 int match, best_found = 0, best_possible = 0;
109
110 if (dev_id)
111 best_possible += 2;
112 if (con_id)
113 best_possible += 1;
Russell King0318e692008-11-09 16:32:46 +0000114
115 list_for_each_entry(p, &clocks, node) {
Russell King0318e692008-11-09 16:32:46 +0000116 match = 0;
Russell King409dc362009-01-24 10:14:37 +0000117 if (p->dev_id) {
118 if (!dev_id || strcmp(p->dev_id, dev_id))
119 continue;
120 match += 2;
121 }
122 if (p->con_id) {
123 if (!con_id || strcmp(p->con_id, con_id))
124 continue;
125 match += 1;
126 }
Russell King0318e692008-11-09 16:32:46 +0000127
viresh kumar67b50872012-04-19 04:23:25 +0100128 if (match > best_found) {
Russell Kinge8bf8df2011-04-30 10:14:08 +0100129 cl = p;
viresh kumar67b50872012-04-19 04:23:25 +0100130 if (match != best_possible)
131 best_found = match;
viresh kumare4bf5be2010-03-09 11:54:30 +0100132 else
133 break;
Russell King0318e692008-11-09 16:32:46 +0000134 }
135 }
Russell Kinge8bf8df2011-04-30 10:14:08 +0100136 return cl;
Russell King0318e692008-11-09 16:32:46 +0000137}
138
Sascha Hauer05fd8e72009-03-07 12:55:49 +0100139struct clk *clk_get_sys(const char *dev_id, const char *con_id)
Russell King0318e692008-11-09 16:32:46 +0000140{
Russell Kinge8bf8df2011-04-30 10:14:08 +0100141 struct clk_lookup *cl;
Russell King0318e692008-11-09 16:32:46 +0000142
143 mutex_lock(&clocks_mutex);
Russell Kinge8bf8df2011-04-30 10:14:08 +0100144 cl = clk_find(dev_id, con_id);
145 if (cl && !__clk_get(cl->clk))
146 cl = NULL;
Russell King0318e692008-11-09 16:32:46 +0000147 mutex_unlock(&clocks_mutex);
148
Russell Kinge8bf8df2011-04-30 10:14:08 +0100149 return cl ? cl->clk : ERR_PTR(-ENOENT);
Russell King0318e692008-11-09 16:32:46 +0000150}
Sascha Hauer05fd8e72009-03-07 12:55:49 +0100151EXPORT_SYMBOL(clk_get_sys);
152
153struct clk *clk_get(struct device *dev, const char *con_id)
154{
155 const char *dev_id = dev ? dev_name(dev) : NULL;
Grant Likely766e6a42012-04-09 14:50:06 -0500156 struct clk *clk;
157
158 if (dev) {
159 clk = of_clk_get_by_name(dev->of_node, con_id);
Shawn Guo9f1612d2012-07-18 11:52:22 +0800160 if (!IS_ERR(clk) && __clk_get(clk))
Grant Likely766e6a42012-04-09 14:50:06 -0500161 return clk;
162 }
Sascha Hauer05fd8e72009-03-07 12:55:49 +0100163
164 return clk_get_sys(dev_id, con_id);
165}
Russell King0318e692008-11-09 16:32:46 +0000166EXPORT_SYMBOL(clk_get);
167
168void clk_put(struct clk *clk)
169{
170 __clk_put(clk);
171}
172EXPORT_SYMBOL(clk_put);
173
174void clkdev_add(struct clk_lookup *cl)
175{
176 mutex_lock(&clocks_mutex);
177 list_add_tail(&cl->node, &clocks);
178 mutex_unlock(&clocks_mutex);
179}
180EXPORT_SYMBOL(clkdev_add);
181
Russell King0a0300d2010-01-12 12:28:00 +0000182void __init clkdev_add_table(struct clk_lookup *cl, size_t num)
183{
184 mutex_lock(&clocks_mutex);
185 while (num--) {
186 list_add_tail(&cl->node, &clocks);
187 cl++;
188 }
189 mutex_unlock(&clocks_mutex);
190}
191
Russell King0318e692008-11-09 16:32:46 +0000192#define MAX_DEV_ID 20
193#define MAX_CON_ID 16
194
195struct clk_lookup_alloc {
196 struct clk_lookup cl;
197 char dev_id[MAX_DEV_ID];
198 char con_id[MAX_CON_ID];
199};
200
Russell Kinge9d7f402012-05-02 09:30:32 +0100201static struct clk_lookup * __init_refok
202vclkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt,
203 va_list ap)
Russell King0318e692008-11-09 16:32:46 +0000204{
205 struct clk_lookup_alloc *cla;
206
Jean-Christop PLAGNIOL-VILLARD6d803ba2010-11-17 10:04:33 +0100207 cla = __clkdev_alloc(sizeof(*cla));
Russell King0318e692008-11-09 16:32:46 +0000208 if (!cla)
209 return NULL;
210
211 cla->cl.clk = clk;
212 if (con_id) {
213 strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
214 cla->cl.con_id = cla->con_id;
215 }
216
217 if (dev_fmt) {
Russell King0318e692008-11-09 16:32:46 +0000218 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
219 cla->cl.dev_id = cla->dev_id;
Russell King0318e692008-11-09 16:32:46 +0000220 }
221
222 return &cla->cl;
223}
Russell Kinge9d7f402012-05-02 09:30:32 +0100224
225struct clk_lookup * __init_refok
226clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...)
227{
228 struct clk_lookup *cl;
229 va_list ap;
230
231 va_start(ap, dev_fmt);
232 cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
233 va_end(ap);
234
235 return cl;
236}
Russell King0318e692008-11-09 16:32:46 +0000237EXPORT_SYMBOL(clkdev_alloc);
238
Tony Lindgrenc0683032009-06-03 17:43:14 +0100239int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
240 struct device *dev)
241{
242 struct clk *r = clk_get(dev, id);
243 struct clk_lookup *l;
244
245 if (IS_ERR(r))
246 return PTR_ERR(r);
247
248 l = clkdev_alloc(r, alias, alias_dev_name);
249 clk_put(r);
250 if (!l)
251 return -ENODEV;
252 clkdev_add(l);
253 return 0;
254}
255EXPORT_SYMBOL(clk_add_alias);
256
Russell King0318e692008-11-09 16:32:46 +0000257/*
258 * clkdev_drop - remove a clock dynamically allocated
259 */
260void clkdev_drop(struct clk_lookup *cl)
261{
262 mutex_lock(&clocks_mutex);
263 list_del(&cl->node);
264 mutex_unlock(&clocks_mutex);
265 kfree(cl);
266}
267EXPORT_SYMBOL(clkdev_drop);
Russell Kinge9d7f402012-05-02 09:30:32 +0100268
269/**
270 * clk_register_clkdev - register one clock lookup for a struct clk
271 * @clk: struct clk to associate with all clk_lookups
272 * @con_id: connection ID string on device
273 * @dev_id: format string describing device name
274 *
275 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
276 * clkdev.
277 *
278 * To make things easier for mass registration, we detect error clks
279 * from a previous clk_register() call, and return the error code for
280 * those. This is to permit this function to be called immediately
281 * after clk_register().
282 */
283int clk_register_clkdev(struct clk *clk, const char *con_id,
284 const char *dev_fmt, ...)
285{
286 struct clk_lookup *cl;
287 va_list ap;
288
289 if (IS_ERR(clk))
290 return PTR_ERR(clk);
291
292 va_start(ap, dev_fmt);
293 cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
294 va_end(ap);
295
296 if (!cl)
297 return -ENOMEM;
298
299 clkdev_add(cl);
300
301 return 0;
302}
303
304/**
305 * clk_register_clkdevs - register a set of clk_lookup for a struct clk
306 * @clk: struct clk to associate with all clk_lookups
307 * @cl: array of clk_lookup structures with con_id and dev_id pre-initialized
308 * @num: number of clk_lookup structures to register
309 *
310 * To make things easier for mass registration, we detect error clks
311 * from a previous clk_register() call, and return the error code for
312 * those. This is to permit this function to be called immediately
313 * after clk_register().
314 */
315int clk_register_clkdevs(struct clk *clk, struct clk_lookup *cl, size_t num)
316{
317 unsigned i;
318
319 if (IS_ERR(clk))
320 return PTR_ERR(clk);
321
322 for (i = 0; i < num; i++, cl++) {
323 cl->clk = clk;
324 clkdev_add(cl);
325 }
326
327 return 0;
328}
329EXPORT_SYMBOL(clk_register_clkdevs);