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/*
* clk-divider.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>
static unsigned int clk_divider_maxdiv(struct clk_divider *div)
{
if (div->flags & CLK_DIVIDER_ONE_BASED)
return (1 << div->width) - 1;
return 1 << div->width;
}
static int clk_divider_set_rate(struct clk *clk, unsigned long rate,
unsigned long parent_rate)
{
struct clk_divider *div = container_of(clk, struct clk_divider, clk);
unsigned int val, divval;
if (rate > parent_rate)
rate = parent_rate;
if (!rate)
rate = 1;
divval = DIV_ROUND_UP(parent_rate, rate);
if (divval > clk_divider_maxdiv(div))
divval = clk_divider_maxdiv(div);
if (!(div->flags & CLK_DIVIDER_ONE_BASED))
divval--;
val = readl(div->reg);
val &= ~(((1 << div->width) - 1) << div->shift);
val |= divval << 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 *div = container_of(clk, struct clk_divider, clk);
unsigned int val;
val = readl(div->reg) >> div->shift;
val &= (1 << div->width) - 1;
if (div->flags & CLK_DIVIDER_ONE_BASED) {
if (!val)
val++;
} else {
val++;
}
return parent_rate / val;
}
struct clk_ops clk_divider_ops = {
.set_rate = clk_divider_set_rate,
.recalc_rate = clk_divider_recalc_rate,
};
struct clk *clk_divider(const char *name, const char *parent,
void __iomem *reg, u8 shift, u8 width)
{
struct clk_divider *div = xzalloc(sizeof(*div));
int ret;
div->shift = shift;
div->reg = reg;
div->width = width;
div->parent = parent;
div->clk.ops = &clk_divider_ops;
div->clk.name = name;
div->clk.parent_names = &div->parent;
div->clk.num_parents = 1;
ret = clk_register(&div->clk);
if (ret) {
free(div);
return ERR_PTR(ret);
}
return &div->clk;
}
struct clk *clk_divider_one_based(const char *name, const char *parent,
void __iomem *reg, u8 shift, u8 width)
{
struct clk_divider *div;
struct clk *clk;
clk = clk_divider(name, parent, reg, shift, width);
if (IS_ERR(clk))
return clk;
div = container_of(clk, struct clk_divider, clk);
div->flags |= CLK_DIVIDER_ONE_BASED;
return clk;
}
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