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79 lines
2.0 KiB
C
79 lines
2.0 KiB
C
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/*
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* Copyright 2014 Chen-Yu Tsai
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*
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* Chen-Yu Tsai <wens@csie.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/clk-provider.h>
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#include <linux/clkdev.h>
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#include <linux/of_address.h>
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#include "clk-factors.h"
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/**
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* sun8i_a23_get_mbus_factors() - calculates m factor for MBUS clocks
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* MBUS rate is calculated as follows
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* rate = parent_rate / (m + 1);
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*/
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static void sun8i_a23_get_mbus_factors(u32 *freq, u32 parent_rate,
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u8 *n, u8 *k, u8 *m, u8 *p)
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{
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u8 div;
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/*
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* These clocks can only divide, so we will never be able to
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* achieve frequencies higher than the parent frequency
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*/
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if (*freq > parent_rate)
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*freq = parent_rate;
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div = DIV_ROUND_UP(parent_rate, *freq);
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if (div > 8)
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div = 8;
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*freq = parent_rate / div;
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/* we were called to round the frequency, we can now return */
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if (m == NULL)
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return;
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*m = div - 1;
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}
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static struct clk_factors_config sun8i_a23_mbus_config = {
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.mshift = 0,
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.mwidth = 3,
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};
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static const struct factors_data sun8i_a23_mbus_data __initconst = {
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.enable = 31,
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.mux = 24,
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.table = &sun8i_a23_mbus_config,
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.getter = sun8i_a23_get_mbus_factors,
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};
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static DEFINE_SPINLOCK(sun8i_a23_mbus_lock);
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static void __init sun8i_a23_mbus_setup(struct device_node *node)
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{
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struct clk *mbus = sunxi_factors_register(node, &sun8i_a23_mbus_data,
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&sun8i_a23_mbus_lock);
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/* The MBUS clocks needs to be always enabled */
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__clk_get(mbus);
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clk_prepare_enable(mbus);
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}
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CLK_OF_DECLARE(sun8i_a23_mbus, "allwinner,sun8i-a23-mbus-clk", sun8i_a23_mbus_setup);
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