linux/drivers/clk/clk-fixed-rate.c

82 lines
2.2 KiB
C

/*
* Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
* Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
*
* 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.
*
* Fixed rate clock implementation
*/
#include <linux/clk-provider.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/err.h>
/*
* DOC: basic fixed-rate clock that cannot gate
*
* Traits of this clock:
* prepare - clk_(un)prepare only ensures parents are prepared
* enable - clk_enable only ensures parents are enabled
* rate - rate is always a fixed value. No clk_set_rate support
* parent - fixed parent. No clk_set_parent support
*/
#define to_clk_fixed_rate(_hw) container_of(_hw, struct clk_fixed_rate, hw)
static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
return to_clk_fixed_rate(hw)->fixed_rate;
}
const struct clk_ops clk_fixed_rate_ops = {
.recalc_rate = clk_fixed_rate_recalc_rate,
};
EXPORT_SYMBOL_GPL(clk_fixed_rate_ops);
/**
* clk_register_fixed_rate - register fixed-rate clock with the clock framework
* @dev: device that is registering this clock
* @name: name of this clock
* @parent_name: name of clock's parent
* @flags: framework-specific flags
* @fixed_rate: non-adjustable clock rate
*/
struct clk *clk_register_fixed_rate(struct device *dev, const char *name,
const char *parent_name, unsigned long flags,
unsigned long fixed_rate)
{
struct clk_fixed_rate *fixed;
struct clk *clk;
struct clk_init_data init;
/* allocate fixed-rate clock */
fixed = kzalloc(sizeof(struct clk_fixed_rate), GFP_KERNEL);
if (!fixed) {
pr_err("%s: could not allocate fixed clk\n", __func__);
return ERR_PTR(-ENOMEM);
}
init.name = name;
init.ops = &clk_fixed_rate_ops;
init.flags = flags;
init.parent_names = (parent_name ? &parent_name: NULL);
init.num_parents = (parent_name ? 1 : 0);
/* struct clk_fixed_rate assignments */
fixed->fixed_rate = fixed_rate;
fixed->hw.init = &init;
/* register the clock */
clk = clk_register(dev, &fixed->hw);
if (IS_ERR(clk))
kfree(fixed);
return clk;
}