forked from Minki/linux
83 lines
2.1 KiB
C
83 lines
2.1 KiB
C
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/*
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* Copyright 2013 Emilio López
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*
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* Emilio López <emilio@elopez.com.ar>
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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 "clk-factors.h"
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/**
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* sun4i_get_mod0_factors() - calculates m, n factors for MOD0-style clocks
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* MOD0 rate is calculated as follows
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* rate = (parent_rate >> p) / (m + 1);
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*/
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static void sun4i_a10_get_mod0_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, calcm, calcp;
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/* These clocks can only divide, so we will never be able to achieve
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* frequencies higher than the parent frequency */
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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 < 16)
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calcp = 0;
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else if (div / 2 < 16)
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calcp = 1;
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else if (div / 4 < 16)
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calcp = 2;
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else
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calcp = 3;
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calcm = DIV_ROUND_UP(div, 1 << calcp);
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*freq = (parent_rate >> calcp) / calcm;
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/* we were called to round the frequency, we can now return */
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if (n == NULL)
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return;
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*m = calcm - 1;
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*p = calcp;
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}
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/* user manual says "n" but it's really "p" */
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static struct clk_factors_config sun4i_a10_mod0_config = {
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.mshift = 0,
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.mwidth = 4,
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.pshift = 16,
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.pwidth = 2,
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};
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static const struct factors_data sun4i_a10_mod0_data __initconst = {
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.enable = 31,
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.mux = 24,
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.table = &sun4i_a10_mod0_config,
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.getter = sun4i_a10_get_mod0_factors,
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};
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static DEFINE_SPINLOCK(sun4i_a10_mod0_lock);
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static void __init sun4i_a10_mod0_setup(struct device_node *node)
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{
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sunxi_factors_register(node, &sun4i_a10_mod0_data, &sun4i_a10_mod0_lock);
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}
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CLK_OF_DECLARE(sun4i_a10_mod0, "allwinner,sun4i-a10-mod0-clk", sun4i_a10_mod0_setup);
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