168 lines
3.4 KiB
C
168 lines
3.4 KiB
C
/*
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* arch/arm/common/clkdev.c
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*
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* Copyright (C) 2008 Russell King.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Helper for the clk API to assist looking up a struct clk.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/device.h>
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#include <linux/list.h>
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#include <linux/errno.h>
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#include <linux/err.h>
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#include <linux/string.h>
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#include <linux/mutex.h>
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#include <linux/clk.h>
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#include <asm/clkdev.h>
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#include <mach/clkdev.h>
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static LIST_HEAD(clocks);
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static DEFINE_MUTEX(clocks_mutex);
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/*
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* Find the correct struct clk for the device and connection ID.
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* We do slightly fuzzy matching here:
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* An entry with a NULL ID is assumed to be a wildcard.
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* If an entry has a device ID, it must match
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* If an entry has a connection ID, it must match
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* Then we take the most specific entry - with the following
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* order of precidence: dev+con > dev only > con only.
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*/
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static struct clk *clk_find(const char *dev_id, const char *con_id)
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{
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struct clk_lookup *p;
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struct clk *clk = NULL;
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int match, best = 0;
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list_for_each_entry(p, &clocks, node) {
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match = 0;
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if (p->dev_id) {
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if (!dev_id || strcmp(p->dev_id, dev_id))
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continue;
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match += 2;
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}
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if (p->con_id) {
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if (!con_id || strcmp(p->con_id, con_id))
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continue;
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match += 1;
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}
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if (match == 0)
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continue;
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if (match > best) {
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clk = p->clk;
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best = match;
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}
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}
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return clk;
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}
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struct clk *clk_get_sys(const char *dev_id, const char *con_id)
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{
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struct clk *clk;
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mutex_lock(&clocks_mutex);
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clk = clk_find(dev_id, con_id);
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if (clk && !__clk_get(clk))
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clk = NULL;
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mutex_unlock(&clocks_mutex);
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return clk ? clk : ERR_PTR(-ENOENT);
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}
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EXPORT_SYMBOL(clk_get_sys);
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struct clk *clk_get(struct device *dev, const char *con_id)
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{
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const char *dev_id = dev ? dev_name(dev) : NULL;
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return clk_get_sys(dev_id, con_id);
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}
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EXPORT_SYMBOL(clk_get);
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void clk_put(struct clk *clk)
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{
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__clk_put(clk);
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}
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EXPORT_SYMBOL(clk_put);
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void clkdev_add(struct clk_lookup *cl)
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{
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mutex_lock(&clocks_mutex);
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list_add_tail(&cl->node, &clocks);
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mutex_unlock(&clocks_mutex);
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}
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EXPORT_SYMBOL(clkdev_add);
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#define MAX_DEV_ID 20
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#define MAX_CON_ID 16
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struct clk_lookup_alloc {
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struct clk_lookup cl;
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char dev_id[MAX_DEV_ID];
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char con_id[MAX_CON_ID];
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};
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struct clk_lookup *clkdev_alloc(struct clk *clk, const char *con_id,
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const char *dev_fmt, ...)
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{
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struct clk_lookup_alloc *cla;
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cla = kzalloc(sizeof(*cla), GFP_KERNEL);
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if (!cla)
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return NULL;
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cla->cl.clk = clk;
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if (con_id) {
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strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
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cla->cl.con_id = cla->con_id;
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}
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if (dev_fmt) {
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va_list ap;
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va_start(ap, dev_fmt);
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vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
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cla->cl.dev_id = cla->dev_id;
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va_end(ap);
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}
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return &cla->cl;
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}
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EXPORT_SYMBOL(clkdev_alloc);
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int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
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struct device *dev)
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{
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struct clk *r = clk_get(dev, id);
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struct clk_lookup *l;
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if (IS_ERR(r))
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return PTR_ERR(r);
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l = clkdev_alloc(r, alias, alias_dev_name);
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clk_put(r);
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if (!l)
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return -ENODEV;
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clkdev_add(l);
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return 0;
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}
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EXPORT_SYMBOL(clk_add_alias);
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/*
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* clkdev_drop - remove a clock dynamically allocated
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*/
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void clkdev_drop(struct clk_lookup *cl)
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{
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mutex_lock(&clocks_mutex);
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list_del(&cl->node);
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mutex_unlock(&clocks_mutex);
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kfree(cl);
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}
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EXPORT_SYMBOL(clkdev_drop);
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