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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2017 BayLibre, SAS
* Author: Neil Armstrong <narmstrong@baylibre.com>
* Author: Jerome Brunet <jbrunet@baylibre.com>
*/
/*
* The AO Domain embeds a dual/divider to generate a more precise
* 32,768KHz clock for low-power suspend mode and CEC.
* ______ ______
* | | | |
* | Div1 |-| Cnt1 |
* /|______| |______|\
* -| ______ ______ X--> Out
* \| | | |/
* | Div2 |-| Cnt2 |
* |______| |______|
*
* The dividing can be switched to single or dual, with a counter
* for each divider to set when the switching is done.
*/
#include <linux/clk-provider.h>
#include <linux/module.h>
#include "clk-regmap.h"
#include "clk-dualdiv.h"
static inline struct meson_clk_dualdiv_data *
meson_clk_dualdiv_data(struct clk_regmap *clk)
{
return (struct meson_clk_dualdiv_data *)clk->data;
}
static unsigned long
__dualdiv_param_to_rate(unsigned long parent_rate,
const struct meson_clk_dualdiv_param *p)
{
if (!p->dual)
return DIV_ROUND_CLOSEST(parent_rate, p->n1);
return DIV_ROUND_CLOSEST(parent_rate * (p->m1 + p->m2),
p->n1 * p->m1 + p->n2 * p->m2);
}
static unsigned long meson_clk_dualdiv_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_regmap *clk = to_clk_regmap(hw);
struct meson_clk_dualdiv_data *dualdiv = meson_clk_dualdiv_data(clk);
struct meson_clk_dualdiv_param setting;
setting.dual = meson_parm_read(clk->map, &dualdiv->dual);
setting.n1 = meson_parm_read(clk->map, &dualdiv->n1) + 1;
setting.m1 = meson_parm_read(clk->map, &dualdiv->m1) + 1;
setting.n2 = meson_parm_read(clk->map, &dualdiv->n2) + 1;
setting.m2 = meson_parm_read(clk->map, &dualdiv->m2) + 1;
return __dualdiv_param_to_rate(parent_rate, &setting);
}
static const struct meson_clk_dualdiv_param *
__dualdiv_get_setting(unsigned long rate, unsigned long parent_rate,
struct meson_clk_dualdiv_data *dualdiv)
{
const struct meson_clk_dualdiv_param *table = dualdiv->table;
unsigned long best = 0, now = 0;
unsigned int i, best_i = 0;
if (!table)
return NULL;
for (i = 0; table[i].n1; i++) {
now = __dualdiv_param_to_rate(parent_rate, &table[i]);
/* If we get an exact match, don't bother any further */
if (now == rate) {
return &table[i];
} else if (abs(now - rate) < abs(best - rate)) {
best = now;
best_i = i;
}
}
return (struct meson_clk_dualdiv_param *)&table[best_i];
}
static int meson_clk_dualdiv_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
struct clk_regmap *clk = to_clk_regmap(hw);
struct meson_clk_dualdiv_data *dualdiv = meson_clk_dualdiv_data(clk);
const struct meson_clk_dualdiv_param *setting;
setting = __dualdiv_get_setting(req->rate, req->best_parent_rate,
dualdiv);
if (setting)
req->rate = __dualdiv_param_to_rate(req->best_parent_rate,
setting);
else
req->rate = meson_clk_dualdiv_recalc_rate(hw,
req->best_parent_rate);
return 0;
}
static int meson_clk_dualdiv_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct clk_regmap *clk = to_clk_regmap(hw);
struct meson_clk_dualdiv_data *dualdiv = meson_clk_dualdiv_data(clk);
const struct meson_clk_dualdiv_param *setting =
__dualdiv_get_setting(rate, parent_rate, dualdiv);
if (!setting)
return -EINVAL;
meson_parm_write(clk->map, &dualdiv->dual, setting->dual);
meson_parm_write(clk->map, &dualdiv->n1, setting->n1 - 1);
meson_parm_write(clk->map, &dualdiv->m1, setting->m1 - 1);
meson_parm_write(clk->map, &dualdiv->n2, setting->n2 - 1);
meson_parm_write(clk->map, &dualdiv->m2, setting->m2 - 1);
return 0;
}
const struct clk_ops meson_clk_dualdiv_ops = {
.recalc_rate = meson_clk_dualdiv_recalc_rate,
.determine_rate = meson_clk_dualdiv_determine_rate,
.set_rate = meson_clk_dualdiv_set_rate,
};
EXPORT_SYMBOL_GPL(meson_clk_dualdiv_ops);
const struct clk_ops meson_clk_dualdiv_ro_ops = {
.recalc_rate = meson_clk_dualdiv_recalc_rate,
};
EXPORT_SYMBOL_GPL(meson_clk_dualdiv_ro_ops);
MODULE_DESCRIPTION("Amlogic dual divider driver");
MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
MODULE_LICENSE("GPL");
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