434 lines
8.8 KiB
C
434 lines
8.8 KiB
C
/*
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* clk.c - generic barebox clock support. Based on Linux clk support
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*
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* Copyright (c) 2012 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <common.h>
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#include <errno.h>
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#include <malloc.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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static LIST_HEAD(clks);
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static int clk_parent_enable(struct clk *clk)
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{
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struct clk *parent = clk_get_parent(clk);
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if (!IS_ERR_OR_NULL(parent))
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return clk_enable(parent);
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return 0;
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}
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static void clk_parent_disable(struct clk *clk)
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{
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struct clk *parent = clk_get_parent(clk);
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if (!IS_ERR_OR_NULL(parent))
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clk_disable(parent);
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}
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int clk_enable(struct clk *clk)
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{
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int ret;
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if (IS_ERR(clk))
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return PTR_ERR(clk);
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if (!clk->enable_count) {
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ret = clk_parent_enable(clk);
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if (ret)
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return ret;
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if (clk->ops->enable) {
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ret = clk->ops->enable(clk);
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if (ret) {
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clk_parent_disable(clk);
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return ret;
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}
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}
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}
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clk->enable_count++;
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return 0;
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}
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void clk_disable(struct clk *clk)
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{
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if (IS_ERR(clk))
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return;
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if (!clk->enable_count)
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return;
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clk->enable_count--;
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if (!clk->enable_count) {
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if (clk->ops->disable)
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clk->ops->disable(clk);
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clk_parent_disable(clk);
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}
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}
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unsigned long clk_get_rate(struct clk *clk)
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{
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struct clk *parent;
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unsigned long parent_rate = 0;
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if (IS_ERR(clk))
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return 0;
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parent = clk_get_parent(clk);
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if (!IS_ERR_OR_NULL(parent))
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parent_rate = clk_get_rate(parent);
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if (clk->ops->recalc_rate)
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return clk->ops->recalc_rate(clk, parent_rate);
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return parent_rate;
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}
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long clk_round_rate(struct clk *clk, unsigned long rate)
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{
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if (IS_ERR(clk))
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return 0;
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return clk_get_rate(clk);
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}
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int clk_set_rate(struct clk *clk, unsigned long rate)
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{
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struct clk *parent;
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unsigned long parent_rate = 0;
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if (IS_ERR(clk))
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return PTR_ERR(clk);
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parent = clk_get_parent(clk);
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if (parent)
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parent_rate = clk_get_rate(parent);
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if (clk->ops->set_rate)
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return clk->ops->set_rate(clk, rate, parent_rate);
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return -ENOSYS;
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}
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struct clk *clk_lookup(const char *name)
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{
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struct clk *c;
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if (!name)
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return ERR_PTR(-ENODEV);
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list_for_each_entry(c, &clks, list) {
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if (!strcmp(c->name, name))
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return c;
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}
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return ERR_PTR(-ENODEV);
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}
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int clk_set_parent(struct clk *clk, struct clk *parent)
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{
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int i;
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if (IS_ERR(clk))
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return PTR_ERR(clk);
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if (IS_ERR(parent))
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return PTR_ERR(parent);
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if (!clk->num_parents)
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return -EINVAL;
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if (!clk->ops->set_parent)
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return -EINVAL;
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for (i = 0; i < clk->num_parents; i++) {
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if (IS_ERR_OR_NULL(clk->parents[i]))
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clk->parents[i] = clk_lookup(clk->parent_names[i]);
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if (!IS_ERR_OR_NULL(clk->parents[i]))
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if (clk->parents[i] == parent)
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break;
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}
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if (i == clk->num_parents)
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return -EINVAL;
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return clk->ops->set_parent(clk, i);
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}
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struct clk *clk_get_parent(struct clk *clk)
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{
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int idx;
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if (IS_ERR(clk))
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return clk;
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if (!clk->num_parents)
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return ERR_PTR(-ENODEV);
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if (clk->num_parents != 1) {
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if (!clk->ops->get_parent)
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return ERR_PTR(-EINVAL);
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idx = clk->ops->get_parent(clk);
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if (idx >= clk->num_parents)
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return ERR_PTR(-ENODEV);
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} else {
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idx = 0;
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}
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if (IS_ERR_OR_NULL(clk->parents[idx]))
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clk->parents[idx] = clk_lookup(clk->parent_names[idx]);
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return clk->parents[idx];
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}
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int clk_register(struct clk *clk)
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{
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clk->parents = xzalloc(sizeof(struct clk *) * clk->num_parents);
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list_add_tail(&clk->list, &clks);
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return 0;
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}
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int clk_is_enabled(struct clk *clk)
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{
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int enabled;
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if (IS_ERR(clk))
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return 0;
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if (clk->ops->is_enabled) {
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/*
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* If we can ask a clk, do it
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*/
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enabled = clk->ops->is_enabled(clk);
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} else {
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if (clk->ops->enable) {
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/*
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* If we can't ask a clk, but it can be enabled,
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* depend on the enable_count.
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*/
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enabled = clk->enable_count;
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} else {
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/*
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* We can't ask a clk, it has no enable op,
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* so assume it's enabled and go on and ask
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* the parent.
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*/
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enabled = 1;
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}
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}
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if (!enabled)
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return 0;
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clk = clk_get_parent(clk);
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if (IS_ERR(clk))
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return 1;
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return clk_is_enabled(clk);
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}
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int clk_is_enabled_always(struct clk *clk)
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{
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return 1;
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}
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#if defined(CONFIG_OFTREE) && defined(CONFIG_COMMON_CLK_OF_PROVIDER)
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/**
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* struct of_clk_provider - Clock provider registration structure
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* @link: Entry in global list of clock providers
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* @node: Pointer to device tree node of clock provider
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* @get: Get clock callback. Returns NULL or a struct clk for the
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* given clock specifier
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* @data: context pointer to be passed into @get callback
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*/
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struct of_clk_provider {
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struct list_head link;
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struct device_node *node;
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struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
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void *data;
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};
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extern struct of_device_id __clk_of_table_start[];
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const struct of_device_id __clk_of_table_sentinel
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__attribute__ ((unused,section (".__clk_of_table_end")));
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static LIST_HEAD(of_clk_providers);
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struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
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void *data)
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{
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return data;
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}
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EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
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struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
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{
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struct clk_onecell_data *clk_data = data;
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unsigned int idx = clkspec->args[0];
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if (idx >= clk_data->clk_num) {
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pr_err("%s: invalid clock index %d\n", __func__, idx);
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return ERR_PTR(-EINVAL);
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}
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return clk_data->clks[idx];
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}
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EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
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/**
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* of_clk_add_provider() - Register a clock provider for a node
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* @np: Device node pointer associated with clock provider
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* @clk_src_get: callback for decoding clock
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* @data: context pointer for @clk_src_get callback.
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*/
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int of_clk_add_provider(struct device_node *np,
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struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
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void *data),
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void *data)
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{
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struct of_clk_provider *cp;
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cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
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if (!cp)
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return -ENOMEM;
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cp->node = np;
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cp->data = data;
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cp->get = clk_src_get;
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list_add(&cp->link, &of_clk_providers);
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pr_debug("Added clock from %s\n", np->full_name);
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return 0;
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}
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EXPORT_SYMBOL_GPL(of_clk_add_provider);
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/**
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* of_clk_del_provider() - Remove a previously registered clock provider
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* @np: Device node pointer associated with clock provider
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*/
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void of_clk_del_provider(struct device_node *np)
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{
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struct of_clk_provider *cp;
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list_for_each_entry(cp, &of_clk_providers, link) {
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if (cp->node == np) {
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list_del(&cp->link);
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kfree(cp);
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break;
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}
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}
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}
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EXPORT_SYMBOL_GPL(of_clk_del_provider);
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struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
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{
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struct of_clk_provider *provider;
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struct clk *clk = ERR_PTR(-ENOENT);
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/* Check if we have such a provider in our array */
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list_for_each_entry(provider, &of_clk_providers, link) {
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if (provider->node == clkspec->np)
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clk = provider->get(clkspec, provider->data);
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if (!IS_ERR(clk))
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break;
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}
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return clk;
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}
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/**
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* of_clk_init() - Scan and init clock providers from the DT
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* @root: parent of the first level to probe or NULL for the root of the tree
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* @matches: array of compatible values and init functions for providers.
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*
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* This function scans the device tree for matching clock providers and
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* calls their initialization functions
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*
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* Returns 0 on success, < 0 on failure.
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*/
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int of_clk_init(struct device_node *root, const struct of_device_id *matches)
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{
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const struct of_device_id *match;
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int rc;
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if (!root)
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root = of_find_node_by_path("/");
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if (!root)
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return -EINVAL;
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if (!matches)
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matches = __clk_of_table_start;
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for_each_matching_node_and_match(root, matches, &match) {
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of_clk_init_cb_t clk_init_cb = (of_clk_init_cb_t)match->data;
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rc = clk_init_cb(root);
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if (rc)
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pr_err("%s: failed to init clock for %s: %d\n",
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__func__, root->full_name, rc);
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}
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return 0;
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}
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#endif
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static void dump_one(struct clk *clk, int verbose, int indent)
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{
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struct clk *c;
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printf("%*s%s (rate %ld, %sabled)\n", indent * 4, "", clk->name, clk_get_rate(clk),
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clk_is_enabled(clk) ? "en" : "dis");
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if (verbose) {
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if (clk->num_parents > 1) {
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int i;
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printf("%*s`---- possible parents: ", indent * 4, "");
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for (i = 0; i < clk->num_parents; i++)
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printf("%s ", clk->parent_names[i]);
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printf("\n");
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}
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}
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list_for_each_entry(c, &clks, list) {
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struct clk *parent = clk_get_parent(c);
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if (parent == clk) {
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dump_one(c, verbose, indent + 1);
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}
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}
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}
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void clk_dump(int verbose)
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{
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struct clk *c;
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list_for_each_entry(c, &clks, list) {
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struct clk *parent = clk_get_parent(c);
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if (IS_ERR_OR_NULL(parent))
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dump_one(c, verbose, 0);
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}
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}
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