This adds barebox common clk support loosely based on the Kernel common clk support. differences are: - barebox does not need prepare/unprepare - no parent rate propagation for set_rate - struct clk is not really encapsulated from the drivers Along with the clk support we have support for some basic clk building blocks: - clk-fixed - clk-fixed-factor - clk-mux - clk-divider clk-fixed and clk-fixed-factor are completely generic, clk-mux and clk-divider are currently the way i.MX muxes/dividers are implemented. Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
225 lines
4.2 KiB
C
225 lines
4.2 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 <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 (!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 (!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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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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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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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 (!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 (!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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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->enable_count ? "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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