path: root/drivers/clk/sunxi/clk-sunxi.c

/*
 * Copyright 2013 Emilio López
 *
 * Emilio López <emilio@elopez.com.ar>
 *
 * 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-provider.h>
#include <linux/clkdev.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/reset-controller.h>

#include "clk-factors.h"

static DEFINE_SPINLOCK(clk_lock);

/* Maximum number of parents our clocks have */
#define SUNXI_MAX_PARENTS	5

/**
 * sun4i_get_pll1_factors() - calculates n, k, m, p factors for PLL1
 * PLL1 rate is calculated as follows
 * rate = (parent_rate * n * (k + 1) >> p) / (m + 1);
 * parent_rate is always 24Mhz
 */

static void sun4i_get_pll1_factors(u32 *freq, u32 parent_rate,
				   u8 *n, u8 *k, u8 *m, u8 *p)
{
	u8 div;

	/* Normalize value to a 6M multiple */
	div = *freq / 6000000;
	*freq = 6000000 * div;

	/* we were called to round the frequency, we can now return */
	if (n == NULL)
		return;

	/* m is always zero for pll1 */
	*m = 0;

	/* k is 1 only on these cases */
	if (*freq >= 768000000 || *freq == 42000000 || *freq == 54000000)
		*k = 1;
	else
		*k = 0;

	/* p will be 3 for divs under 10 */
	if (div < 10)
		*p = 3;

	/* p will be 2 for divs between 10 - 20 and odd divs under 32 */
	else if (div < 20 || (div < 32 && (div & 1)))
		*p = 2;

	/* p will be 1 for even divs under 32, divs under 40 and odd pairs
	 * of divs between 40-62 */
	else if (div < 40 || (div < 64 && (div & 2)))
		*p = 1;

	/* any other entries have p = 0 */
	else
		*p = 0;

	/* calculate a suitable n based on k and p */
	div <<= *p;
	div /= (*k + 1);
	*n = div / 4;
}

/**
 * sun6i_a31_get_pll1_factors() - calculates n, k and m factors for PLL1
 * PLL1 rate is calculated as follows
 * rate = parent_rate * (n + 1) * (k + 1) / (m + 1);
 * parent_rate should always be 24MHz
 */
static void sun6i_a31_get_pll1_factors(u32 *freq, u32 parent_rate,
				       u8 *n, u8 *k, u8 *m, u8 *p)
{
	/*
	 * We can operate only on MHz, this will make our life easier
	 * later.
	 */
	u32 freq_mhz = *freq / 1000000;
	u32 parent_freq_mhz = parent_rate / 1000000;

	/*
	 * Round down the frequency to the closest multiple of either
	 * 6 or 16
	 */
	u32 round_freq_6 = round_down(freq_mhz, 6);
	u32 round_freq_16 = round_down(freq_mhz, 16);

	if (round_freq_6 > round_freq_16)
		freq_mhz = round_freq_6;
	else
		freq_mhz = round_freq_16;

	*freq = freq_mhz * 1000000;

	/*
	 * If the factors pointer are null, we were just called to
	 * round down the frequency.
	 * Exit.
	 */
	if (n == NULL)
		return;

	/* If the frequency is a multiple of 32 MHz, k is always 3 */
	if (</