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/*
* Clock Driver for HiFiBerry DAC Pro
*
* Author: Stuart MacLean
* Copyright 2015
*
* 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.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <linux/clk-provider.h>
#include <linux/clkdev.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
/* Clock rate of CLK44EN attached to GPIO6 pin */
#define CLK_44EN_RATE 22579200UL
/* Clock rate of CLK48EN attached to GPIO3 pin */
#define CLK_48EN_RATE 24576000UL
/**
* struct hifiberry_dacpro_clk - Common struct to the HiFiBerry DAC Pro
* @hw: clk_hw for the common clk framework
* @mode: 0 => CLK44EN, 1 => CLK48EN
*/
struct clk_hifiberry_hw {
struct clk_hw hw;
uint8_t mode;
};
#define to_hifiberry_clk(_hw) container_of(_hw, struct clk_hifiberry_hw, hw)
static const struct of_device_id clk_hifiberry_dacpro_dt_ids[] = {
{ .compatible = "hifiberry,dacpro-clk",},
{ }
};
MODULE_DEVICE_TABLE(of, clk_hifiberry_dacpro_dt_ids);
static unsigned long clk_hifiberry_dacpro_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
return (to_hifiberry_clk(hw)->mode == 0) ? CLK_44EN_RATE :
CLK_48EN_RATE;
}
static long clk_hifiberry_dacpro_round_rate(struct clk_hw *hw,
unsigned long rate, unsigned long *parent_rate)
{
long actual_rate;
if (rate <= CLK_44EN_RATE) {
actual_rate = (long)CLK_44EN_RATE;
} else if (rate >= CLK_48EN_RATE) {
actual_rate = (long)CLK_48EN_RATE;
} else {
long diff44Rate = (long)(rate - CLK_44EN_RATE);
long diff48Rate = (long)(CLK_48EN_RATE - rate);
if (diff44Rate < diff48Rate)
actual_rate = (long)CLK_44EN_RATE;
else
actual_rate = (long)CLK_48EN_RATE;
}
return actual_rate;
}
static int clk_hifiberry_dacpro_set_rate(struct clk_hw *hw,
unsigned long rate, unsigned long parent_rate)
{
unsigned long actual_rate;
struct clk_hifiberry_hw *clk = to_hifiberry_clk(hw);
actual_rate = (unsigned long)clk_hifiberry_dacpro_round_rate(hw, rate,
&parent_rate);
clk->mode = (actual_rate == CLK_44EN_RATE) ? 0 : 1;
return 0;
}
const struct clk_ops clk_hifiberry_dacpro_rate_ops = {
.recalc_rate = clk_hifiberry_dacpro_recalc_rate,
.round_rate = clk_hifiberry_dacpro_round_rate,
.set_rate = clk_hifiberry_dacpro_set_rate,
};
static int clk_hifiberry_dacpro_probe(struct platform_device *pdev)
{
int ret;
struct clk_hifiberry_hw *proclk;
struct clk *clk;
struct device *dev;
struct clk_init_data init;
dev = &pdev->dev;
proclk = kzalloc(sizeof(struct clk_hifiberry_hw), GFP_KERNEL);
if (!proclk)
return -ENOMEM;
init.name = "clk-hifiberry-dacpro";
init.ops = &clk_hifiberry_dacpro_rate_ops;
init.flags = CLK_IS_ROOT | CLK_IS_BASIC;
init.parent_names = NULL;
init.num_parents = 0;
proclk->mode = 0;
proclk->hw.init = &init;
clk = devm_clk_register(dev, &proclk->hw);
if (!IS_ERR(clk)) {
ret = of_clk_add_provider(dev->of_node, of_clk_src_simple_get,
clk);
} else {
dev_err(dev, "Fail to register clock driver\n");
kfree(proclk);
ret = PTR_ERR(clk);
}
return ret;
}
static int clk_hifiberry_dacpro_remove(struct platform_device *pdev)
{
of_clk_del_provider(pdev->dev.of_node);
return 0;
}
static struct platform_driver clk_hifiberry_dacpro_driver = {
.probe = clk_hifiberry_dacpro_probe,
.remove = clk_hifiberry_dacpro_remove,
.driver = {
.name = "clk-hifiberry-dacpro",
.of_match_table = clk_hifiberry_dacpro_dt_ids,
},
};
static int __init clk_hifiberry_dacpro_init(void)
{
return platform_driver_register(&clk_hifiberry_dacpro_driver);
}
core_initcall(clk_hifiberry_dacpro_init);
static void __exit clk_hifiberry_dacpro_exit(void)
{
platform_driver_unregister(&clk_hifiberry_dacpro_driver);
}
module_exit(clk_hifiberry_dacpro_exit);
MODULE_DESCRIPTION("HiFiBerry DAC Pro clock driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:clk-hifiberry-dacpro");
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