/* * 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> 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 = 0; 	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) {			cl = p;			if (match != 3)				best = 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; 	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];}; struct clk_lookup * __init_refokclkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...){	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) {		va_list ap; 		va_start(ap, dev_fmt);		vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);		cla->cl.dev_id = cla->dev_id;		va_end(ap);	} 	return &cla->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);