drivers/clk/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
  24 static LIST_HEAD(clocks);
  25 static 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  */
  36 static 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
  72 struct 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
  86 static 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
  94 struct clk *clk_get_sys(const char *dev_id, const char *con_id)
  95 {
  96         return __clk_get_sys(NULL, dev_id, con_id);
  97 }
  98 EXPORT_SYMBOL(clk_get_sys);
  99
 100 struct 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 }
 113 EXPORT_SYMBOL(clk_get);
 114
 115 void clk_put(struct clk *clk)
 116 {
 117         __clk_put(clk);
 118 }
 119 EXPORT_SYMBOL(clk_put);
 120
 121 static 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
 128 void 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 }
 134 EXPORT_SYMBOL(clkdev_add);
 135
 136 void 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      20
 148 #define MAX_CON_ID      16
 149
 150 struct clk_lookup_alloc {
 151         struct clk_lookup cl;
 152         char    dev_id[MAX_DEV_ID];
 153         char    con_id[MAX_CON_ID];
 154 };
 155
 156 static struct clk_lookup * __ref
 157 vclkdev_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
 162         cla = kzalloc(sizeof(*cla), GFP_KERNEL);
 163         if (!cla)
 164                 return NULL;
 165
 166         cla->cl.clk_hw = hw;
 167         if (con_id) {
 168                 strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
 169                 cla->cl.con_id = cla->con_id;
 170         }
 171
 172         if (dev_fmt) {
 173                 vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
 174                 cla->cl.dev_id = cla->dev_id;
 175         }
 176
 177         return &cla->cl;
 178 }
 179
 180 static struct clk_lookup *
 181 vclkdev_create(struct clk_hw *hw, const char *con_id, const char *dev_fmt,
 182         va_list ap)
 183 {
 184         struct clk_lookup *cl;
 185
 186         cl = vclkdev_alloc(hw, con_id, dev_fmt, ap);
 187         if (cl)
 188                 __clkdev_add(cl);
 189
 190         return cl;
 191 }
 192
 193 /**
 194  * clkdev_create - allocate and add a clkdev lookup structure
 195  * @clk: struct clk to associate with all clk_lookups
 196  * @con_id: connection ID string on device
 197  * @dev_fmt: format string describing device name
 198  *
 199  * Returns a clk_lookup structure, which can be later unregistered and
 200  * freed.
 201  */
 202 struct clk_lookup *clkdev_create(struct clk *clk, const char *con_id,
 203         const char *dev_fmt, ...)
 204 {
 205         struct clk_lookup *cl;
 206         va_list ap;
 207
 208         va_start(ap, dev_fmt);
 209         cl = vclkdev_create(__clk_get_hw(clk), con_id, dev_fmt, ap);
 210         va_end(ap);
 211
 212         return cl;
 213 }
 214 EXPORT_SYMBOL_GPL(clkdev_create);
 215
 216 /**
 217  * clkdev_hw_create - allocate and add a clkdev lookup structure
 218  * @hw: struct clk_hw to associate with all clk_lookups
 219  * @con_id: connection ID string on device
 220  * @dev_fmt: format string describing device name
 221  *
 222  * Returns a clk_lookup structure, which can be later unregistered and
 223  * freed.
 224  */
 225 struct clk_lookup *clkdev_hw_create(struct clk_hw *hw, const char *con_id,
 226         const char *dev_fmt, ...)
 227 {
 228         struct clk_lookup *cl;
 229         va_list ap;
 230
 231         va_start(ap, dev_fmt);
 232         cl = vclkdev_create(hw, con_id, dev_fmt, ap);
 233         va_end(ap);
 234
 235         return cl;
 236 }
 237 EXPORT_SYMBOL_GPL(clkdev_hw_create);
 238
 239 int clk_add_alias(const char *alias, const char *alias_dev_name,
 240         const char *con_id, struct device *dev)
 241 {
 242         struct clk *r = clk_get(dev, con_id);
 243         struct clk_lookup *l;
 244
 245         if (IS_ERR(r))
 246                 return PTR_ERR(r);
 247
 248         l = clkdev_create(r, alias, alias_dev_name ? "%s" : NULL,
 249                           alias_dev_name);
 250         clk_put(r);
 251
 252         return l ? 0 : -ENODEV;
 253 }
 254 EXPORT_SYMBOL(clk_add_alias);
 255
 256 /*
 257  * clkdev_drop - remove a clock dynamically allocated
 258  */
 259 void clkdev_drop(struct clk_lookup *cl)
 260 {
 261         mutex_lock(&clocks_mutex);
 262         list_del(&cl->node);
 263         mutex_unlock(&clocks_mutex);
 264         kfree(cl);
 265 }
 266 EXPORT_SYMBOL(clkdev_drop);
 267
 268 static struct clk_lookup *__clk_register_clkdev(struct clk_hw *hw,
 269                                                 const char *con_id,
 270                                                 const char *dev_id, ...)
 271 {
 272         struct clk_lookup *cl;
 273         va_list ap;
 274
 275         va_start(ap, dev_id);
 276         cl = vclkdev_create(hw, con_id, dev_id, ap);
 277         va_end(ap);
 278
 279         return cl;
 280 }
 281
 282 static int do_clk_register_clkdev(struct clk_hw *hw,
 283         struct clk_lookup **cl, const char *con_id, const char *dev_id)
 284 {
 285         if (IS_ERR(hw))
 286                 return PTR_ERR(hw);
 287         /*
 288          * Since dev_id can be NULL, and NULL is handled specially, we must
 289          * pass it as either a NULL format string, or with "%s".
 290          */
 291         if (dev_id)
 292                 *cl = __clk_register_clkdev(hw, con_id, "%s", dev_id);
 293         else
 294                 *cl = __clk_register_clkdev(hw, con_id, NULL);
 295
 296         return *cl ? 0 : -ENOMEM;
 297 }
 298
 299 /**
 300  * clk_register_clkdev - register one clock lookup for a struct clk
 301  * @clk: struct clk to associate with all clk_lookups
 302  * @con_id: connection ID string on device
 303  * @dev_id: string describing device name
 304  *
 305  * con_id or dev_id may be NULL as a wildcard, just as in the rest of
 306  * clkdev.
 307  *
 308  * To make things easier for mass registration, we detect error clks
 309  * from a previous clk_register() call, and return the error code for
 310  * those.  This is to permit this function to be called immediately
 311  * after clk_register().
 312  */
 313 int clk_register_clkdev(struct clk *clk, const char *con_id,
 314         const char *dev_id)
 315 {
 316         struct clk_lookup *cl;
 317
 318         if (IS_ERR(clk))
 319                 return PTR_ERR(clk);
 320
 321         return do_clk_register_clkdev(__clk_get_hw(clk), &cl, con_id,
 322                                               dev_id);
 323 }
 324 EXPORT_SYMBOL(clk_register_clkdev);
 325
 326 /**
 327  * clk_hw_register_clkdev - register one clock lookup for a struct clk_hw
 328  * @hw: struct clk_hw to associate with all clk_lookups
 329  * @con_id: connection ID string on device
 330  * @dev_id: format string describing device name
 331  *
 332  * con_id or dev_id may be NULL as a wildcard, just as in the rest of
 333  * clkdev.
 334  *
 335  * To make things easier for mass registration, we detect error clk_hws
 336  * from a previous clk_hw_register_*() call, and return the error code for
 337  * those.  This is to permit this function to be called immediately
 338  * after clk_hw_register_*().
 339  */
 340 int clk_hw_register_clkdev(struct clk_hw *hw, const char *con_id,
 341         const char *dev_id)
 342 {
 343         struct clk_lookup *cl;
 344
 345         return do_clk_register_clkdev(hw, &cl, con_id, dev_id);
 346 }
 347 EXPORT_SYMBOL(clk_hw_register_clkdev);
 348
 349 static void devm_clkdev_release(struct device *dev, void *res)
 350 {
 351         clkdev_drop(*(struct clk_lookup **)res);
 352 }
 353
 354 static int devm_clk_match_clkdev(struct device *dev, void *res, void *data)
 355 {
 356         struct clk_lookup **l = res;
 357
 358         return *l == data;
 359 }
 360
 361 /**
 362  * devm_clk_release_clkdev - Resource managed clkdev lookup release
 363  * @dev: device this lookup is bound
 364  * @con_id: connection ID string on device
 365  * @dev_id: format string describing device name
 366  *
 367  * Drop the clkdev lookup created with devm_clk_hw_register_clkdev.
 368  * Normally this function will not need to be called and the resource
 369  * management code will ensure that the resource is freed.
 370  */
 371 void devm_clk_release_clkdev(struct device *dev, const char *con_id,
 372                              const char *dev_id)
 373 {
 374         struct clk_lookup *cl;
 375         int rval;
 376
 377         mutex_lock(&clocks_mutex);
 378         cl = clk_find(dev_id, con_id);
 379         mutex_unlock(&clocks_mutex);
 380
 381         WARN_ON(!cl);
 382         rval = devres_release(dev, devm_clkdev_release,
 383                               devm_clk_match_clkdev, cl);
 384         WARN_ON(rval);
 385 }
 386 EXPORT_SYMBOL(devm_clk_release_clkdev);
 387
 388 /**
 389  * devm_clk_hw_register_clkdev - managed clk lookup registration for clk_hw
 390  * @dev: device this lookup is bound
 391  * @hw: struct clk_hw to associate with all clk_lookups
 392  * @con_id: connection ID string on device
 393  * @dev_id: format string describing device name
 394  *
 395  * con_id or dev_id may be NULL as a wildcard, just as in the rest of
 396  * clkdev.
 397  *
 398  * To make things easier for mass registration, we detect error clk_hws
 399  * from a previous clk_hw_register_*() call, and return the error code for
 400  * those.  This is to permit this function to be called immediately
 401  * after clk_hw_register_*().
 402  */
 403 int devm_clk_hw_register_clkdev(struct device *dev, struct clk_hw *hw,
 404                                 const char *con_id, const char *dev_id)
 405 {
 406         int rval = -ENOMEM;
 407         struct clk_lookup **cl;
 408
 409         cl = devres_alloc(devm_clkdev_release, sizeof(*cl), GFP_KERNEL);
 410         if (cl) {
 411                 rval = do_clk_register_clkdev(hw, cl, con_id, dev_id);
 412                 if (!rval)
 413                         devres_add(dev, cl);
 414                 else
 415                         devres_free(cl);
 416         }
 417         return rval;
 418 }
 419 EXPORT_SYMBOL(devm_clk_hw_register_clkdev);