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/*
* clk-divider-table.c - generic barebox clock support. Based on Linux clk support
*
* Copyright (c) 2012 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include <common.h>
#include <io.h>
#include <malloc.h>
#include <linux/clk.h>
#include <linux/err.h>
struct clk_divider_table {
struct clk clk;
u8 shift;
u8 width;
void __iomem *reg;
const char *parent;
const struct clk_div_table *table;
int table_size;
int max_div_index;
};
static int clk_divider_set_rate(struct clk *clk, unsigned long rate,
unsigned long parent_rate)
{
struct clk_divider_table *div =
container_of(clk, struct clk_divider_table, clk);
unsigned int val;
int i, div_index = -1;
unsigned long best = 0;
if (rate > parent_rate)
rate = parent_rate;
if (rate < parent_rate / div->table[div->max_div_index].div)
rate = parent_rate / div->table[div->max_div_index].div;
for (i = 0; i < div->table_size; i++) {
unsigned long now = parent_rate / div->table[i].div;
if (now <= rate && now >= best) {
best = now;
div_index = i;
}
}
val = readl(div->reg);
val &= ~(((1 << div->width) - 1) << div->shift);
val |= div_index << div->shift;
writel(val, div->reg);
return 0;
}
static unsigned long clk_divider_recalc_rate(struct clk *clk,
unsigned long parent_rate)
{
struct clk_divider_table *div =
container_of(clk, struct clk_divider_table, clk);
unsigned int val;
val = readl(div->reg) >> div->shift;
val &= (1 << div->width) - 1;
if (val >= div->table_size)
return 0;
return parent_rate / div->table[val].div;
}
static struct clk_ops clk_divider_table_ops = {
.set_rate = clk_divider_set_rate,
.recalc_rate = clk_divider_recalc_rate,
};
struct clk *clk_divider_table(const char *name,
const char *parent, void __iomem *reg, u8 shift, u8 width,
const struct clk_div_table *table)
{
struct clk_divider_table *div = xzalloc(sizeof(*div));
const struct clk_div_table *clkt;
int ret, max_div = 0;
div->shift = shift;
div->reg = reg;
div->width = width;
div->parent = parent;
div->clk.ops = &clk_divider_table_ops;
div->clk.name = name;
div->clk.parent_names = &div->parent;
div->clk.num_parents = 1;
div->table = table;
for (clkt = div->table; clkt->div; clkt++) {
if (clkt->div > max_div) {
max_div = clkt->div;
div->max_div_index = div->table_size;
}
div->table_size++;
}
ret = clk_register(&div->clk);
if (ret) {
free(div);
return ERR_PTR(ret);
}
return &div->clk;
}
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