/* * drivers/clk/clkdev.c * * Copyright (C) 2008 Russell King. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * Helper for the clk API to assist looking up a struct clk. */ #include <linux/module.h> #include <linux/kernel.h> #include <linux/device.h> #include <linux/list.h> #include <linux/errno.h> #include <linux/err.h> #include <linux/string.h> #include <linux/mutex.h> #include <linux/clk.h> #include <linux/clkdev.h> #include <linux/clk-provider.h> #include <linux/of.h> #include "clk.h" static LIST_HEAD(clocks); static DEFINE_MUTEX(clocks_mutex); /* * Find the correct struct clk for the device and connection ID. * We do slightly fuzzy matching here: * An entry with a NULL ID is assumed to be a wildcard. * If an entry has a device ID, it must match * If an entry has a connection ID, it must match * Then we take the most specific entry - with the following * order of precedence: dev+con > dev only > con only. */ static struct clk_lookup *clk_find(const char *dev_id, const char *con_id) { struct clk_lookup *p, *cl = NULL; int match, best_found = 0, best_possible = 0; if (dev_id) best_possible += 2; if (con_id) best_possible += 1; lockdep_assert_held(&clocks_mutex); list_for_each_entry(p, &clocks, node) { match = 0; if (p->dev_id) { if (!dev_id || strcmp(p->dev_id, dev_id)) continue; match += 2; } if (p->con_id) { if (!con_id || strcmp(p->con_id, con_id)) continue; match += 1; } if (match > best_found) { cl = p; if (match != best_possible) best_found = match; else break; } } return cl; } struct clk_hw *clk_find_hw(const char *dev_id, const char *con_id) { struct clk_lookup *cl; struct clk_hw *hw = ERR_PTR(-ENOENT); mutex_lock(&clocks_mutex); cl = clk_find(dev_id, con_id); if (cl) hw = cl->clk_hw; mutex_unlock(&clocks_mutex); return hw; } static struct clk *__clk_get_sys(struct device *dev, const char *dev_id, const char *con_id) { struct clk_hw *hw = clk_find_hw(dev_id, con_id); return clk_hw_create_clk(dev, hw, dev_id, con_id); } struct clk *clk_get_sys(const char *dev_id, const char *con_id) { return __clk_get_sys(NULL, dev_id, con_id); } EXPORT_SYMBOL(clk_get_sys); struct clk *clk_get(struct device *dev, const char *con_id) { const char *dev_id = dev ? dev_name(dev) : NULL; struct clk_hw *hw; if (dev && dev->of_node) { hw = of_clk_get_hw(dev->of_node, 0, con_id); if (!IS_ERR(hw) || PTR_ERR(hw) == -EPROBE_DEFER) return clk_hw_create_clk(dev, hw, dev_id, con_id); } return __clk_get_sys(dev, dev_id, con_id); } EXPORT_SYMBOL(clk_get); void clk_put(struct clk *clk) { __clk_put(clk); } EXPORT_SYMBOL(clk_put); static void __clkdev_add(struct clk_lookup *cl) { mutex_lock(&clocks_mutex); list_add_tail(&cl->node, &clocks); mutex_unlock(&clocks_mutex); } void clkdev_add(struct clk_lookup *cl) { if (!cl->clk_hw) cl->clk_hw = __clk_get_hw(cl->clk); __clkdev_add(cl); } EXPORT_SYMBOL(clkdev_add); void clkdev_add_table(struct clk_lookup *cl, size_t num) { mutex_lock(&clocks_mutex); while (num--) { cl->clk_hw = __clk_get_hw(cl->clk); list_add_tail(&cl->node, &clocks); cl++; } mutex_unlock(&clocks_mutex); } #define MAX_DEV_ID 20 #define MAX_CON_ID 16 struct clk_lookup_alloc { struct clk_lookup cl; char dev_id[MAX_DEV_ID]; char con_id[MAX_CON_ID]; }; static struct clk_lookup * __ref vclkdev_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt, va_list ap) { struct clk_lookup_alloc *cla; cla = kzalloc(sizeof(*cla), GFP_KERNEL); if (!cla) return NULL; cla->cl.clk_hw = hw; if (con_id) { strlcpy(cla->con_id, con_id, sizeof(cla->con_id)); cla->cl.con_id = cla->con_id; } if (dev_fmt) { vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap); cla->cl.dev_id = cla->dev_id; } return &cla->cl; } static struct clk_lookup * vclkdev_create(struct clk_hw *hw, const char *con_id, const char *dev_fmt, va_list ap) { struct clk_lookup *cl; cl = vclkdev_alloc(hw, con_id, dev_fmt, ap); if (cl) __clkdev_add(cl); return cl; } struct clk_lookup * __ref clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...) { struct clk_lookup *cl; va_list ap; va_start(ap, dev_fmt); cl = vclkdev_alloc(__clk_get_hw(clk), con_id, dev_fmt, ap); va_end(ap); return cl; } EXPORT_SYMBOL(clkdev_alloc); struct clk_lookup * clkdev_hw_alloc(struct clk_hw *hw, const char *con_id, const char *dev_fmt, ...) { struct clk_lookup *cl; va_list ap; va_start(ap, dev_fmt); cl = vclkdev_alloc(hw, con_id, dev_fmt, ap); va_end(ap); return cl; } EXPORT_SYMBOL(clkdev_hw_alloc); /** * clkdev_create - allocate and add a clkdev lookup structure * @clk: struct clk to associate with all clk_lookups * @con_id: connection ID string on device * @dev_fmt: format string describing device name * * Returns a clk_lookup structure, which can be later unregistered and * freed. */ struct clk_lookup *clkdev_create(struct clk *clk, const char *con_id, const char *dev_fmt, ...) { struct clk_lookup *cl; va_list ap; va_start(ap, dev_fmt); cl = vclkdev_create(__clk_get_hw(clk), con_id, dev_fmt, ap); va_end(ap); return cl; } EXPORT_SYMBOL_GPL(clkdev_create); /** * clkdev_hw_create - allocate and add a clkdev lookup structure * @hw: struct clk_hw to associate with all clk_lookups * @con_id: connection ID string on device * @dev_fmt: format string describing device name * * Returns a clk_lookup structure, which can be later unregistered and * freed. */ struct clk_lookup *clkdev_hw_create(struct clk_hw *hw, const char *con_id, const char *dev_fmt, ...) { struct clk_lookup *cl; va_list ap; va_start(ap, dev_fmt); cl = vclkdev_create(hw, con_id, dev_fmt, ap); va_end(ap); return cl; } EXPORT_SYMBOL_GPL(clkdev_hw_create); int clk_add_alias(const char *alias, const char *alias_dev_name, const char *con_id, struct device *dev) { struct clk *r = clk_get(dev, con_id); struct clk_lookup *l; if (IS_ERR(r)) return PTR_ERR(r); l = clkdev_create(r, alias, alias_dev_name ? "%s" : NULL, alias_dev_name); clk_put(r); return l ? 0 : -ENODEV; } EXPORT_SYMBOL(clk_add_alias); /* * clkdev_drop - remove a clock dynamically allocated */ void clkdev_drop(struct clk_lookup *cl) { mutex_lock(&clocks_mutex); list_del(&cl->node); mutex_unlock(&clocks_mutex); kfree(cl); } EXPORT_SYMBOL(clkdev_drop); static struct clk_lookup *__clk_register_clkdev(struct clk_hw *hw, const char *con_id, const char *dev_id, ...) { struct clk_lookup *cl; va_list ap; va_start(ap, dev_id); cl = vclkdev_create(hw, con_id, dev_id, ap); va_end(ap); return cl; } static int do_clk_register_clkdev(struct clk_hw *hw, struct clk_lookup **cl, const char *con_id, const char *dev_id) { if (IS_ERR(hw)) return PTR_ERR(hw); /* * Since dev_id can be NULL, and NULL is handled specially, we must * pass it as either a NULL format string, or with "%s". */ if (dev_id) *cl = __clk_register_clkdev(hw, con_id, "%s", dev_id); else *cl = __clk_register_clkdev(hw, con_id, NULL); return *cl ? 0 : -ENOMEM; } /** * clk_register_clkdev - register one clock lookup for a struct clk * @clk: struct clk to associate with all clk_lookups * @con_id: connection ID string on device * @dev_id: string describing device name * * con_id or dev_id may be NULL as a wildcard, just as in the rest of * clkdev. * * To make things easier for mass registration, we detect error clks * from a previous clk_register() call, and return the error code for * those. This is to permit this function to be called immediately * after clk_register(). */ int clk_register_clkdev(struct clk *clk, const char *con_id, const char *dev_id) { struct clk_lookup *cl; if (IS_ERR(clk)) return PTR_ERR(clk); return do_clk_register_clkdev(__clk_get_hw(clk), &cl, con_id, dev_id); } EXPORT_SYMBOL(clk_register_clkdev); /** * clk_hw_register_clkdev - register one clock lookup for a struct clk_hw * @hw: struct clk_hw to associate with all clk_lookups * @con_id: connection ID string on device * @dev_id: format string describing device name * * con_id or dev_id may be NULL as a wildcard, just as in the rest of * clkdev. * * To make things easier for mass registration, we detect error clk_hws * from a previous clk_hw_register_*() call, and return the error code for * those. This is to permit this function to be called immediately * after clk_hw_register_*(). */ int clk_hw_register_clkdev(struct clk_hw *hw, const char *con_id, const char *dev_id) { struct clk_lookup *cl; return do_clk_register_clkdev(hw, &cl, con_id, dev_id); } EXPORT_SYMBOL(clk_hw_register_clkdev); static void devm_clkdev_release(struct device *dev, void *res) { clkdev_drop(*(struct clk_lookup **)res); } static int devm_clk_match_clkdev(struct device *dev, void *res, void *data) { struct clk_lookup **l = res; return *l == data; } /** * devm_clk_release_clkdev - Resource managed clkdev lookup release * @dev: device this lookup is bound * @con_id: connection ID string on device * @dev_id: format string describing device name * * Drop the clkdev lookup created with devm_clk_hw_register_clkdev. * Normally this function will not need to be called and the resource * management code will ensure that the resource is freed. */ void devm_clk_release_clkdev(struct device *dev, const char *con_id, const char *dev_id) { struct clk_lookup *cl; int rval; mutex_lock(&clocks_mutex); cl = clk_find(dev_id, con_id); mutex_unlock(&clocks_mutex); WARN_ON(!cl); rval = devres_release(dev, devm_clkdev_release, devm_clk_match_clkdev, cl); WARN_ON(rval); } EXPORT_SYMBOL(devm_clk_release_clkdev); /** * devm_clk_hw_register_clkdev - managed clk lookup registration for clk_hw * @dev: device this lookup is bound * @hw: struct clk_hw to associate with all clk_lookups * @con_id: connection ID string on device * @dev_id: format string describing device name * * con_id or dev_id may be NULL as a wildcard, just as in the rest of * clkdev. * * To make things easier for mass registration, we detect error clk_hws * from a previous clk_hw_register_*() call, and return the error code for * those. This is to permit this function to be called immediately * after clk_hw_register_*(). */ int devm_clk_hw_register_clkdev(struct device *dev, struct clk_hw *hw, const char *con_id, const char *dev_id) { int rval = -ENOMEM; struct clk_lookup **cl; cl = devres_alloc(devm_clkdev_release, sizeof(*cl), GFP_KERNEL); if (cl) { rval = do_clk_register_clkdev(hw, cl, con_id, dev_id); if (!rval) devres_add(dev, cl); else devres_free(cl); } return rval; } EXPORT_SYMBOL(devm_clk_hw_register_clkdev);