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kernel add
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/*
* Copyright 2014 Chen-Yu Tsai
*
* Chen-Yu Tsai <wens@csie.org>
*
* 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.
*
* 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.h>
#include <linux/clk-provider.h>
#include <linux/of_address.h>
#include "clk-factors.h"
/**
* sun8i_a23_get_mbus_factors() - calculates m factor for MBUS clocks
* MBUS rate is calculated as follows
* rate = parent_rate / (m + 1);
*/
static void sun8i_a23_get_mbus_factors(u32 *freq, u32 parent_rate,
u8 *n, u8 *k, u8 *m, u8 *p)
{
u8 div;
/*
* These clocks can only divide, so we will never be able to
* achieve frequencies higher than the parent frequency
*/
if (*freq > parent_rate)
*freq = parent_rate;
div = DIV_ROUND_UP(parent_rate, *freq);
if (div > 8)
div = 8;
*freq = parent_rate / div;
/* we were called to round the frequency, we can now return */
if (m == NULL)
return;
*m = div - 1;
}
static struct clk_factors_config sun8i_a23_mbus_config = {
.mshift = 0,
.mwidth = 3,
};
static const struct factors_data sun8i_a23_mbus_data __initconst = {
.enable = 31,
.mux = 24,
.muxmask = BIT(1) | BIT(0),
.table = &sun8i_a23_mbus_config,
.getter = sun8i_a23_get_mbus_factors,
};
static DEFINE_SPINLOCK(sun8i_a23_mbus_lock);
static void __init sun8i_a23_mbus_setup(struct device_node *node)
{
struct clk *mbus;
void __iomem *reg;
reg = of_iomap(node, 0);
if (!reg) {
pr_err("Could not get registers for a23-mbus-clk
");
return;
}
mbus = sunxi_factors_register(node, &sun8i_a23_mbus_data,
&sun8i_a23_mbus_lock, reg);
/* The MBUS clocks needs to be always enabled */
__clk_get(mbus);
clk_prepare_enable(mbus);
}
CLK_OF_DECLARE(sun8i_a23_mbus, "allwinner,sun8i-a23-mbus-clk", sun8i_a23_mbus_setup);
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