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kernel add
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/*
* Copyright (c) 2014 Lucas Stach <l.stach@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 version 2 as
* published by the Free Software Foundation.
*
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*/
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/slab.h>
#include "clk.h"
struct clk_cpu {
struct clk_hw hw;
struct clk *div;
struct clk *mux;
struct clk *pll;
struct clk *step;
};
static inline struct clk_cpu *to_clk_cpu(struct clk_hw *hw)
{
return container_of(hw, struct clk_cpu, hw);
}
static unsigned long clk_cpu_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct clk_cpu *cpu = to_clk_cpu(hw);
return clk_get_rate(cpu->div);
}
static long clk_cpu_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *prate)
{
struct clk_cpu *cpu = to_clk_cpu(hw);
return clk_round_rate(cpu->pll, rate);
}
static int clk_cpu_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct clk_cpu *cpu = to_clk_cpu(hw);
int ret;
/* switch to PLL bypass clock */
ret = clk_set_parent(cpu->mux, cpu->step);
if (ret)
return ret;
/* reprogram PLL */
ret = clk_set_rate(cpu->pll, rate);
if (ret) {
clk_set_parent(cpu->mux, cpu->pll);
return ret;
}
/* switch back to PLL clock */
clk_set_parent(cpu->mux, cpu->pll);
/* Ensure the divider is what we expect */
clk_set_rate(cpu->div, rate);
return 0;
}
static const struct clk_ops clk_cpu_ops = {
.recalc_rate = clk_cpu_recalc_rate,
.round_rate = clk_cpu_round_rate,
.set_rate = clk_cpu_set_rate,
};
struct clk *imx_clk_cpu(const char *name, const char *parent_name,
struct clk *div, struct clk *mux, struct clk *pll,
struct clk *step)
{
struct clk_cpu *cpu;
struct clk *clk;
struct clk_init_data init;
cpu = kzalloc(sizeof(*cpu), GFP_KERNEL);
if (!cpu)
return ERR_PTR(-ENOMEM);
cpu->div = div;
cpu->mux = mux;
cpu->pll = pll;
cpu->step = step;
init.name = name;
init.ops = &clk_cpu_ops;
init.flags = 0;
init.parent_names = &parent_name;
init.num_parents = 1;
cpu->hw.init = &init;
clk = clk_register(NULL, &cpu->hw);
if (IS_ERR(clk))
kfree(cpu);
return clk;
}
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