/* * 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/of.h> static LIST_HEAD(clocks); static DEFINE_MUTEX(clocks_mutex); #if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) struct clk *of_clk_get(struct device_node *np, int index) { struct of_phandle_args clkspec; struct clk *clk; int rc; if (index < 0) return ERR_PTR(-EINVAL); rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index, &clkspec); if (rc) return ERR_PTR(rc); clk = of_clk_get_from_provider(&clkspec); of_node_put(clkspec.np); return clk; } EXPORT_SYMBOL(of_clk_get); /** * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node * @np: pointer to clock consumer node * @name: name of consumer's clock input, or NULL for the first clock reference * * This function parses the clocks and clock-names properties, * and uses them to look up the struct clk from the registered list of clock * providers. */ struct clk *of_clk_get_by_name(struct device_node *np, const char *name) { struct clk *clk = ERR_PTR(-ENOENT); /* Walk up the tree of devices looking for a clock that matches */ while (np) { int index = 0; /* * For named clocks, first look up the name in the * "clock-names" property. If it cannot be found, then * index will be an error code, and of_clk_get() will fail. */ if (name) index = of_property_match_string(np, "clock-names", name); clk = of_clk_get(np, index); if (!IS_ERR(clk)) break; else if (name && index >= 0) { pr_err("ERROR: could not get clock %s:%s(%i)\n", np->full_name, name ? name : "", index); return clk; } /* * No matching clock found on this node. If the parent node * has a "clock-ranges" property, then we can try one of its * clocks. */ np = np->parent; if (np && !of_get_property(np, "clock-ranges", NULL)) break; } return clk; } EXPORT_SYMBOL(of_clk_get_by_name); #endif /* * 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; 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 *clk_get_sys(const char *dev_id, const char *con_id) { struct clk_lookup *cl; mutex_lock(&clocks_mutex); cl = clk_find(dev_id, con_id); if (cl && !__clk_get(cl->clk)) cl = NULL; mutex_unlock(&clocks_mutex); return cl ? cl->clk : ERR_PTR(-ENOENT); } 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 *clk; if (dev) { clk = of_clk_get_by_name(dev->of_node, con_id); if (!IS_ERR(clk) && __clk_get(clk)) return clk; } return clk_get_sys(dev_id, con_id); } EXPORT_SYMBOL(clk_get); void clk_put(struct clk *clk) { __clk_put(clk); } EXPORT_SYMBOL(clk_put); static void devm_clk_release(struct device *dev, void *res) { clk_put(*(struct clk **)res); } struct clk *devm_clk_get(struct device *dev, const char *id) { struct clk **ptr, *clk; ptr = devres_alloc(devm_clk_release, sizeof(*ptr), GFP_KERNEL); if (!ptr) return ERR_PTR(-ENOMEM); clk = clk_get(dev, id); if (!IS_ERR(clk)) { *ptr = clk; devres_add(dev, ptr); } else { devres_free(ptr); } return clk; } EXPORT_SYMBOL(devm_clk_get); static int devm_clk_match(struct device *dev, void *res, void *data) { struct clk **c = res; if (!c || !*c) { WARN_ON(!c || !*c); return 0; } return *c == data; } void devm_clk_put(struct device *dev, struct clk *clk) { int ret; ret = devres_destroy(dev, devm_clk_release, devm_clk_match, clk); WARN_ON(ret); } EXPORT_SYMBOL(devm_clk_put); void clkdev_add(struct clk_lookup *cl) { mutex_lock(&clocks_mutex); list_add_tail(&cl->node, &clocks); mutex_unlock(&clocks_mutex); } EXPORT_SYMBOL(clkdev_add); void __init clkdev_add_table(struct clk_lookup *cl, size_t num) { mutex_lock(&clocks_mutex); while (num--) { 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 * __init_refok vclkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, va_list ap) { struct clk_lookup_alloc *cla; cla = __clkdev_alloc(sizeof(*cla)); if (!cla) return NULL; cla->cl.clk = clk; 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; } struct clk_lookup * __init_refok 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, con_id, dev_fmt, ap); va_end(ap); return cl; } EXPORT_SYMBOL(clkdev_alloc); int clk_add_alias(const char *alias, const char *alias_dev_name, char *id, struct device *dev) { struct clk *r = clk_get(dev, id); struct clk_lookup *l; if (IS_ERR(r)) return PTR_ERR(r); l = clkdev_alloc(r, alias, alias_dev_name); clk_put(r); if (!l) return -ENODEV; clkdev_add(l); return 0; } 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); /** * 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: 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 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_fmt, ...) { struct clk_lookup *cl; va_list ap; if (IS_ERR(clk)) return PTR_ERR(clk); va_start(ap, dev_fmt); cl = vclkdev_alloc(clk, con_id, dev_fmt, ap); va_end(ap); if (!cl) return -ENOMEM; clkdev_add(cl); return 0; } /** * clk_register_clkdevs - register a set of clk_lookup for a struct clk * @clk: struct clk to associate with all clk_lookups * @cl: array of clk_lookup structures with con_id and dev_id pre-initialized * @num: number of clk_lookup structures to register * * 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_clkdevs(struct clk *clk, struct clk_lookup *cl, size_t num) { unsigned i; if (IS_ERR(clk)) return PTR_ERR(clk); for (i = 0; i < num; i++, cl++) { cl->clk = clk; clkdev_add(cl); } return 0; } EXPORT_SYMBOL(clk_register_clkdevs);