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/*
* Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
*
* 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.
*
*/
#include <linux/clk-provider.h>
#include <linux/clkdev.h>
#include <linux/clk/at91_pmc.h>
#include <linux/of.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include "pmc.h"
#define MASTER_PRES_MASK 0x7
#define MASTER_PRES_MAX MASTER_PRES_MASK
#define MASTER_DIV_SHIFT 8
#define MASTER_DIV_MASK 0x3
#define to_clk_master(hw) container_of(hw, struct clk_master, hw)
struct clk_master {
struct clk_hw hw;
struct regmap *regmap;
const struct clk_master_layout *layout;
const struct clk_master_characteristics *characteristics;
u32 mckr;
};
static inline bool clk_master_ready(struct regmap *regmap)
{
unsigned int status;
regmap_read(regmap, AT91_PMC_SR, &status);
return status & AT91_PMC_MCKRDY ? 1 : 0;
}
static int clk_master_prepare(struct clk_hw *hw)
{
struct clk_master *master = to_clk_master(hw);
while (!clk_master_ready(master->regmap))
cpu_relax();
return 0;
}
static int clk_master_is_prepared(struct clk_hw *hw)
{
struct clk_master *master = to_clk_master(hw);
return clk_master_ready(master->regmap);
}
static unsigned long clk_master_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
u8 pres;
u8 div;
unsigned long rate = parent_rate;
struct clk_master *master = to_clk_master(hw);
const struct clk_master_layout *layout = master->layout;
const struct clk_master_characteristics *characteristics =
master->characteristics;
unsigned int mckr;
regmap_read(master->regmap, master->layout->offset, &mckr);
mckr &= layout->mask;
pres = (mckr >> layout->pres_shift) & MASTER_PRES_MASK;
div = (mckr >> MASTER_DIV_SHIFT) & MASTER_DIV_MASK;
if (characteristics->have_div3_pres && pres == MASTER_PRES_MAX)
rate /= 3;
else
rate >>= pres;
rate /= characteristics->divisors[div];
if (rate < characteristics->output.min)
pr_warn("master clk is underclocked");
else if (rate > characteristics->output.max)
pr_warn("master clk is overclocked");
return rate;
}
static u8 clk_master_get_parent(struct clk_hw *hw)
{
struct clk_master *master = to_clk_master(hw);
unsigned int mckr;
regmap_read(master->regmap, master->layout->offset, &mckr);
return mckr & AT91_PMC_CSS;
}
static const struct clk_ops master_ops = {
.prepare = clk_master_prepare,
.is_prepared = clk_master_is_prepared,
.recalc_rate = clk_master_recalc_rate,
.get_parent = clk_master_get_parent,
};
struct clk_hw * __init
at91_clk_register_master(struct regmap *regmap,
const char *name, int num_parents,
const char **parent_names,
const struct clk_master_layout *layout,
const struct clk_master_characteristics *characteristics)
{
struct clk_master *master;
struct clk_init_data init;
struct clk_hw *hw;
int ret;
if (!name || !num_parents || !parent_names)
return ERR_PTR(-EINVAL);
master = kzalloc(sizeof(*master), GFP_KERNEL);
if (!master)
return ERR_PTR(-ENOMEM);
init.name = name;
init.ops = &master_ops;
init.parent_names = parent_names;
init.num_parents = num_parents;
init.flags = 0;
master->hw.init = &init;
master->layout = layout;
master->characteristics = characteristics;
master->regmap = regmap;
hw = &master->hw;
ret = clk_hw_register(NULL, &master->hw);
if (ret) {
kfree(master);
hw = ERR_PTR(ret);
}
return hw;
}
const struct clk_master_layout at91rm9200_master_layout = {
.mask = 0x31F,
.pres_shift = 2,
.offset = AT91_PMC_MCKR,
};
const struct clk_master_layout at91sam9x5_master_layout = {
.mask = 0x373,
.pres_shift = 4,
.offset = AT91_PMC_MCKR,
};
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