/* * 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); 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_refokvclkdev_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_refokclkdev_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);