clk-frac.c
3.62 KB
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/*
* mmp factor clock operation source file
*
* Copyright (C) 2012 Marvell
* Chao Xie <xiechao.mail@gmail.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/clk-provider.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/err.h>
#include "clk.h"
/*
* It is M/N clock
*
* Fout from synthesizer can be given from two equations:
* numerator/denominator = Fin / (Fout * factor)
*/
#define to_clk_factor(hw) container_of(hw, struct clk_factor, hw)
struct clk_factor {
struct clk_hw hw;
void __iomem *base;
struct clk_factor_masks *masks;
struct clk_factor_tbl *ftbl;
unsigned int ftbl_cnt;
};
static long clk_factor_round_rate(struct clk_hw *hw, unsigned long drate,
unsigned long *prate)
{
struct clk_factor *factor = to_clk_factor(hw);
unsigned long rate = 0, prev_rate;
int i;
for (i = 0; i < factor->ftbl_cnt; i++) {
prev_rate = rate;
rate = (((*prate / 10000) * factor->ftbl[i].num) /
(factor->ftbl[i].den * factor->masks->factor)) * 10000;
if (rate > drate)
break;
}
if (i == 0)
return rate;
else
return prev_rate;
}
static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_factor *factor = to_clk_factor(hw);
struct clk_factor_masks *masks = factor->masks;
unsigned int val, num, den;
val = readl_relaxed(factor->base);
/* calculate numerator */
num = (val >> masks->num_shift) & masks->num_mask;
/* calculate denominator */
den = (val >> masks->den_shift) & masks->num_mask;
if (!den)
return 0;
return (((parent_rate / 10000) * den) /
(num * factor->masks->factor)) * 10000;
}
/* Configures new clock rate*/
static int clk_factor_set_rate(struct clk_hw *hw, unsigned long drate,
unsigned long prate)
{
struct clk_factor *factor = to_clk_factor(hw);
struct clk_factor_masks *masks = factor->masks;
int i;
unsigned long val;
unsigned long prev_rate, rate = 0;
for (i = 0; i < factor->ftbl_cnt; i++) {
prev_rate = rate;
rate = (((prate / 10000) * factor->ftbl[i].num) /
(factor->ftbl[i].den * factor->masks->factor)) * 10000;
if (rate > drate)
break;
}
if (i > 0)
i--;
val = readl_relaxed(factor->base);
val &= ~(masks->num_mask << masks->num_shift);
val |= (factor->ftbl[i].num & masks->num_mask) << masks->num_shift;
val &= ~(masks->den_mask << masks->den_shift);
val |= (factor->ftbl[i].den & masks->den_mask) << masks->den_shift;
writel_relaxed(val, factor->base);
return 0;
}
static struct clk_ops clk_factor_ops = {
.recalc_rate = clk_factor_recalc_rate,
.round_rate = clk_factor_round_rate,
.set_rate = clk_factor_set_rate,
};
struct clk *mmp_clk_register_factor(const char *name, const char *parent_name,
unsigned long flags, void __iomem *base,
struct clk_factor_masks *masks, struct clk_factor_tbl *ftbl,
unsigned int ftbl_cnt)
{
struct clk_factor *factor;
struct clk_init_data init;
struct clk *clk;
if (!masks) {
pr_err("%s: must pass a clk_factor_mask\n", __func__);
return ERR_PTR(-EINVAL);
}
factor = kzalloc(sizeof(*factor), GFP_KERNEL);
if (!factor) {
pr_err("%s: could not allocate factor clk\n", __func__);
return ERR_PTR(-ENOMEM);
}
/* struct clk_aux assignments */
factor->base = base;
factor->masks = masks;
factor->ftbl = ftbl;
factor->ftbl_cnt = ftbl_cnt;
factor->hw.init = &init;
init.name = name;
init.ops = &clk_factor_ops;
init.flags = flags;
init.parent_names = &parent_name;
init.num_parents = 1;
clk = clk_register(NULL, &factor->hw);
if (IS_ERR_OR_NULL(clk))
kfree(factor);
return clk;
}