clkdev.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * drivers/clk/clkdev.c
  4 *
  5 *  Copyright (C) 2008 Russell King.
  6 *
  7 * Helper for the clk API to assist looking up a struct clk.
  8 */
  9#include <linux/module.h>
 10#include <linux/kernel.h>
 11#include <linux/device.h>
 12#include <linux/list.h>
 13#include <linux/errno.h>
 14#include <linux/err.h>
 15#include <linux/string.h>
 16#include <linux/mutex.h>
 17#include <linux/clk.h>
 18#include <linux/clkdev.h>
 19#include <linux/clk-provider.h>
 20#include <linux/of.h>
 21
 22#include "clk.h"
 23
 24static LIST_HEAD(clocks);
 25static DEFINE_MUTEX(clocks_mutex);
 26
 27/*
 28 * Find the correct struct clk for the device and connection ID.
 29 * We do slightly fuzzy matching here:
 30 *  An entry with a NULL ID is assumed to be a wildcard.
 31 *  If an entry has a device ID, it must match
 32 *  If an entry has a connection ID, it must match
 33 * Then we take the most specific entry - with the following
 34 * order of precedence: dev+con > dev only > con only.
 35 */
 36static struct clk_lookup *clk_find(const char *dev_id, const char *con_id)
 37{
 38	struct clk_lookup *p, *cl = NULL;
 39	int match, best_found = 0, best_possible = 0;
 40
 41	if (dev_id)
 42		best_possible += 2;
 43	if (con_id)
 44		best_possible += 1;
 45
 46	lockdep_assert_held(&clocks_mutex);
 47
 48	list_for_each_entry(p, &clocks, node) {
 49		match = 0;
 50		if (p->dev_id) {
 51			if (!dev_id || strcmp(p->dev_id, dev_id))
 52				continue;
 53			match += 2;
 54		}
 55		if (p->con_id) {
 56			if (!con_id || strcmp(p->con_id, con_id))
 57				continue;
 58			match += 1;
 59		}
 60
 61		if (match > best_found) {
 62			cl = p;
 63			if (match != best_possible)
 64				best_found = match;
 65			else
 66				break;
 67		}
 68	}
 69	return cl;
 70}
 71
 72struct clk_hw *clk_find_hw(const char *dev_id, const char *con_id)
 73{
 74	struct clk_lookup *cl;
 75	struct clk_hw *hw = ERR_PTR(-ENOENT);
 76
 77	mutex_lock(&clocks_mutex);
 78	cl = clk_find(dev_id, con_id);
 79	if (cl)
 80		hw = cl->clk_hw;
 81	mutex_unlock(&clocks_mutex);
 82
 83	return hw;
 84}
 85
 86static struct clk *__clk_get_sys(struct device *dev, const char *dev_id,
 87				 const char *con_id)
 88{
 89	struct clk_hw *hw = clk_find_hw(dev_id, con_id);
 90
 91	return clk_hw_create_clk(dev, hw, dev_id, con_id);
 92}
 93
 94struct clk *clk_get_sys(const char *dev_id, const char *con_id)
 95{
 96	return __clk_get_sys(NULL, dev_id, con_id);
 97}
 98EXPORT_SYMBOL(clk_get_sys);
 99
100struct clk *clk_get(struct device *dev, const char *con_id)
101{
102	const char *dev_id = dev ? dev_name(dev) : NULL;
103	struct clk_hw *hw;
104
105	if (dev && dev->of_node) {
106		hw = of_clk_get_hw(dev->of_node, 0, con_id);
107		if (!IS_ERR(hw) || PTR_ERR(hw) == -EPROBE_DEFER)
108			return clk_hw_create_clk(dev, hw, dev_id, con_id);
109	}
110
111	return __clk_get_sys(dev, dev_id, con_id);
112}
113EXPORT_SYMBOL(clk_get);
114
115void clk_put(struct clk *clk)
116{
117	__clk_put(clk);
118}
119EXPORT_SYMBOL(clk_put);
120
121static void __clkdev_add(struct clk_lookup *cl)
122{
123	mutex_lock(&clocks_mutex);
124	list_add_tail(&cl->node, &clocks);
125	mutex_unlock(&clocks_mutex);
126}
127
128void clkdev_add(struct clk_lookup *cl)
129{
130	if (!cl->clk_hw)
131		cl->clk_hw = __clk_get_hw(cl->clk);
132	__clkdev_add(cl);
133}
134EXPORT_SYMBOL(clkdev_add);
135
136void clkdev_add_table(struct clk_lookup *cl, size_t num)
137{
138	mutex_lock(&clocks_mutex);
139	while (num--) {
140		cl->clk_hw = __clk_get_hw(cl->clk);
141		list_add_tail(&cl->node, &clocks);
142		cl++;
143	}
144	mutex_unlock(&clocks_mutex);
145}
146
147#define MAX_DEV_ID	24
148#define MAX_CON_ID	16
149
150struct clk_lookup_alloc {
151	struct clk_lookup cl;
152	char	dev_id[MAX_DEV_ID];
153	char	con_id[MAX_CON_ID];
154};
155
156static __printf(3, 0) struct clk_lookup * __ref
157vclkdev_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt,
158	va_list ap)
159{
160	struct clk_lookup_alloc *cla;
161	struct va_format vaf;
162	const char *failure;
163	va_list ap_copy;
164	size_t max_size;
165	ssize_t res;
166
167	cla = kzalloc(sizeof(*cla), GFP_KERNEL);
168	if (!cla)
169		return NULL;
170
171	va_copy(ap_copy, ap);
172
173	cla->cl.clk_hw = hw;
174	if (con_id) {
175		res = strscpy(cla->con_id, con_id, sizeof(cla->con_id));
176		if (res < 0) {
177			max_size = sizeof(cla->con_id);
178			failure = "connection";
179			goto fail;
180		}
181		cla->cl.con_id = cla->con_id;
182	}
183
184	if (dev_fmt) {
185		res = vsnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
186		if (res >= sizeof(cla->dev_id)) {
187			max_size = sizeof(cla->dev_id);
188			failure = "device";
189			goto fail;
190		}
191		cla->cl.dev_id = cla->dev_id;
192	}
193
194	va_end(ap_copy);
195
196	return &cla->cl;
197
198fail:
199	if (dev_fmt)
200		vaf.fmt = dev_fmt;
201	else
202		vaf.fmt = "null-device";
203	vaf.va = &ap_copy;
204	pr_err("%pV:%s: %s ID is greater than %zu\n",
205	       &vaf, con_id, failure, max_size);
206	va_end(ap_copy);
207
208	/*
209	 * Don't fail in this case, but as the entry won't ever match just
210	 * fill it with something that also won't match.
211	 */
212	strscpy(cla->con_id, "bad", sizeof(cla->con_id));
213	strscpy(cla->dev_id, "bad", sizeof(cla->dev_id));
214
215	return &cla->cl;
216}
217
218static __printf(3, 0) struct clk_lookup *
219vclkdev_create(struct clk_hw *hw, const char *con_id, const char *dev_fmt,
220	va_list ap)
221{
222	struct clk_lookup *cl;
223
224	cl = vclkdev_alloc(hw, con_id, dev_fmt, ap);
225	if (cl)
226		__clkdev_add(cl);
227
228	return cl;
229}
230
231/**
232 * clkdev_create - allocate and add a clkdev lookup structure
233 * @clk: struct clk to associate with all clk_lookups
234 * @con_id: connection ID string on device
235 * @dev_fmt: format string describing device name
236 *
237 * Returns a clk_lookup structure, which can be later unregistered and
238 * freed.
239 */
240struct clk_lookup *clkdev_create(struct clk *clk, const char *con_id,
241	const char *dev_fmt, ...)
242{
243	struct clk_lookup *cl;
244	va_list ap;
245
246	va_start(ap, dev_fmt);
247	cl = vclkdev_create(__clk_get_hw(clk), con_id, dev_fmt, ap);
248	va_end(ap);
249
250	return cl;
251}
252EXPORT_SYMBOL_GPL(clkdev_create);
253
254/**
255 * clkdev_hw_create - allocate and add a clkdev lookup structure
256 * @hw: struct clk_hw to associate with all clk_lookups
257 * @con_id: connection ID string on device
258 * @dev_fmt: format string describing device name
259 *
260 * Returns a clk_lookup structure, which can be later unregistered and
261 * freed.
262 */
263struct clk_lookup *clkdev_hw_create(struct clk_hw *hw, const char *con_id,
264	const char *dev_fmt, ...)
265{
266	struct clk_lookup *cl;
267	va_list ap;
268
269	va_start(ap, dev_fmt);
270	cl = vclkdev_create(hw, con_id, dev_fmt, ap);
271	va_end(ap);
272
273	return cl;
274}
275EXPORT_SYMBOL_GPL(clkdev_hw_create);
276
277int clk_add_alias(const char *alias, const char *alias_dev_name,
278	const char *con_id, struct device *dev)
279{
280	struct clk *r = clk_get(dev, con_id);
281	struct clk_lookup *l;
282
283	if (IS_ERR(r))
284		return PTR_ERR(r);
285
286	l = clkdev_create(r, alias, alias_dev_name ? "%s" : NULL,
287			  alias_dev_name);
288	clk_put(r);
289
290	return l ? 0 : -ENODEV;
291}
292EXPORT_SYMBOL(clk_add_alias);
293
294/*
295 * clkdev_drop - remove a clock dynamically allocated
296 */
297void clkdev_drop(struct clk_lookup *cl)
298{
299	mutex_lock(&clocks_mutex);
300	list_del(&cl->node);
301	mutex_unlock(&clocks_mutex);
302	kfree(cl);
303}
304EXPORT_SYMBOL(clkdev_drop);
305
306static __printf(3, 4) struct clk_lookup *
307__clk_register_clkdev(struct clk_hw *hw, const char *con_id, const char *dev_id, ...)
308{
309	struct clk_lookup *cl;
310	va_list ap;
311
312	va_start(ap, dev_id);
313	cl = vclkdev_create(hw, con_id, dev_id, ap);
314	va_end(ap);
315
316	return cl;
317}
318
319static int do_clk_register_clkdev(struct clk_hw *hw,
320	struct clk_lookup **cl, const char *con_id, const char *dev_id)
321{
322	if (IS_ERR(hw))
323		return PTR_ERR(hw);
324	/*
325	 * Since dev_id can be NULL, and NULL is handled specially, we must
326	 * pass it as either a NULL format string, or with "%s".
327	 */
328	if (dev_id)
329		*cl = __clk_register_clkdev(hw, con_id, "%s", dev_id);
330	else
331		*cl = __clk_register_clkdev(hw, con_id, NULL);
332
333	return *cl ? 0 : -ENOMEM;
334}
335
336/**
337 * clk_register_clkdev - register one clock lookup for a struct clk
338 * @clk: struct clk to associate with all clk_lookups
339 * @con_id: connection ID string on device
340 * @dev_id: string describing device name
341 *
342 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
343 * clkdev.
344 *
345 * To make things easier for mass registration, we detect error clks
346 * from a previous clk_register() call, and return the error code for
347 * those.  This is to permit this function to be called immediately
348 * after clk_register().
349 */
350int clk_register_clkdev(struct clk *clk, const char *con_id,
351	const char *dev_id)
352{
353	struct clk_lookup *cl;
354
355	if (IS_ERR(clk))
356		return PTR_ERR(clk);
357
358	return do_clk_register_clkdev(__clk_get_hw(clk), &cl, con_id,
359					      dev_id);
360}
361EXPORT_SYMBOL(clk_register_clkdev);
362
363/**
364 * clk_hw_register_clkdev - register one clock lookup for a struct clk_hw
365 * @hw: struct clk_hw to associate with all clk_lookups
366 * @con_id: connection ID string on device
367 * @dev_id: format string describing device name
368 *
369 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
370 * clkdev.
371 *
372 * To make things easier for mass registration, we detect error clk_hws
373 * from a previous clk_hw_register_*() call, and return the error code for
374 * those.  This is to permit this function to be called immediately
375 * after clk_hw_register_*().
376 */
377int clk_hw_register_clkdev(struct clk_hw *hw, const char *con_id,
378	const char *dev_id)
379{
380	struct clk_lookup *cl;
381
382	return do_clk_register_clkdev(hw, &cl, con_id, dev_id);
383}
384EXPORT_SYMBOL(clk_hw_register_clkdev);
385
386static void devm_clkdev_release(void *res)
387{
388	clkdev_drop(res);
389}
390
391/**
392 * devm_clk_hw_register_clkdev - managed clk lookup registration for clk_hw
393 * @dev: device this lookup is bound
394 * @hw: struct clk_hw to associate with all clk_lookups
395 * @con_id: connection ID string on device
396 * @dev_id: format string describing device name
397 *
398 * con_id or dev_id may be NULL as a wildcard, just as in the rest of
399 * clkdev.
400 *
401 * To make things easier for mass registration, we detect error clk_hws
402 * from a previous clk_hw_register_*() call, and return the error code for
403 * those.  This is to permit this function to be called immediately
404 * after clk_hw_register_*().
405 */
406int devm_clk_hw_register_clkdev(struct device *dev, struct clk_hw *hw,
407				const char *con_id, const char *dev_id)
408{
409	struct clk_lookup *cl;
410	int rval;
411
412	rval = do_clk_register_clkdev(hw, &cl, con_id, dev_id);
413	if (rval)
414		return rval;
415
416	return devm_add_action_or_reset(dev, devm_clkdev_release, cl);
417}
418EXPORT_SYMBOL(devm_clk_hw_register_clkdev);