[linux.git] / drivers / clk / clk-multiplier.c

/*
 * Copyright (C) 2015 Maxime Ripard <[email protected]>
 *
 * 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.
 */

#include <linux/bitops.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/slab.h>

static unsigned long __get_mult(struct clk_multiplier *mult,
				unsigned long rate,
				unsigned long parent_rate)
{
	if (mult->flags & CLK_MULTIPLIER_ROUND_CLOSEST)
		return DIV_ROUND_CLOSEST(rate, parent_rate);

	return rate / parent_rate;
}

static unsigned long clk_multiplier_recalc_rate(struct clk_hw *hw,
						unsigned long parent_rate)
{
	struct clk_multiplier *mult = to_clk_multiplier(hw);
	unsigned long val;

	val = clk_readl(mult->reg) >> mult->shift;
	val &= GENMASK(mult->width - 1, 0);

	if (!val && mult->flags & CLK_MULTIPLIER_ZERO_BYPASS)
		val = 1;

	return parent_rate * val;
}

static bool __is_best_rate(unsigned long rate, unsigned long new,
			   unsigned long best, unsigned long flags)
{
	if (flags & CLK_MULTIPLIER_ROUND_CLOSEST)
		return abs(rate - new) < abs(rate - best);

	return new >= rate && new < best;
}

static unsigned long __bestmult(struct clk_hw *hw, unsigned long rate,
				unsigned long *best_parent_rate,
				u8 width, unsigned long flags)
{
	struct clk_multiplier *mult = to_clk_multiplier(hw);
	unsigned long orig_parent_rate = *best_parent_rate;
	unsigned long parent_rate, current_rate, best_rate = ~0;
	unsigned int i, bestmult = 0;
	unsigned int maxmult = (1 << width) - 1;

	if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
		bestmult = rate / orig_parent_rate;

		/* Make sure we don't end up with a 0 multiplier */
		if ((bestmult == 0) &&
		    !(mult->flags & CLK_MULTIPLIER_ZERO_BYPASS))
			bestmult = 1;

		/* Make sure we don't overflow the multiplier */
		if (bestmult > maxmult)
			bestmult = maxmult;

		return bestmult;
	}

	for (i = 1; i < maxmult; i++) {
		if (rate == orig_parent_rate * i) {
			/*
			 * This is the best case for us if we have a
			 * perfect match without changing the parent
			 * rate.
			 */
			*best_parent_rate = orig_parent_rate;
			return i;
		}

		parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw),
						rate / i);
		current_rate = parent_rate * i;

		if (__is_best_rate(rate, current_rate, best_rate, flags)) {
			bestmult = i;
			best_rate = current_rate;
			*best_parent_rate = parent_rate;
		}
	}

	return bestmult;
}

static long clk_multiplier_round_rate(struct clk_hw *hw, unsigned long rate,
				  unsigned long *parent_rate)
{
	struct clk_multiplier *mult = to_clk_multiplier(hw);
	unsigned long factor = __bestmult(hw, rate, parent_rate,
					  mult->width, mult->flags);

	return *parent_rate * factor;
}

static int clk_multiplier_set_rate(struct clk_hw *hw, unsigned long rate,
			       unsigned long parent_rate)
{
	struct clk_multiplier *mult = to_clk_multiplier(hw);
	unsigned long factor = __get_mult(mult, rate, parent_rate);
	unsigned long flags = 0;
	unsigned long val;

	if (mult->lock)
		spin_lock_irqsave(mult->lock, flags);
	else
		__acquire(mult->lock);

	val = clk_readl(mult->reg);
	val &= ~GENMASK(mult->width + mult->shift - 1, mult->shift);
	val |= factor << mult->shift;
	clk_writel(val, mult->reg);

	if (mult->lock)
		spin_unlock_irqrestore(mult->lock, flags);
	else
		__release(mult->lock);

	return 0;
}

const struct clk_ops clk_multiplier_ops = {
	.recalc_rate	= clk_multiplier_recalc_rate,
	.round_rate	= clk_multiplier_round_rate,
	.set_rate	= clk_multiplier_set_rate,
};
EXPORT_SYMBOL_GPL(clk_multiplier_ops);
Commit	Line	Data
f2e0a532 MR	1	/*
	2	* Copyright (C) 2015 Maxime Ripard <[email protected]>
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*/
	8
	9	#include <linux/bitops.h>
	10	#include <linux/clk-provider.h>
	11	#include <linux/err.h>
	12	#include <linux/export.h>
	13	#include <linux/kernel.h>
	14	#include <linux/of.h>
	15	#include <linux/slab.h>
	16
f2e0a532 MR	17	static unsigned long __get_mult(struct clk_multiplier *mult,
	18	unsigned long rate,
	19	unsigned long parent_rate)
	20	{
	21	if (mult->flags & CLK_MULTIPLIER_ROUND_CLOSEST)
	22	return DIV_ROUND_CLOSEST(rate, parent_rate);
	23
	24	return rate / parent_rate;
	25	}
	26
	27	static unsigned long clk_multiplier_recalc_rate(struct clk_hw *hw,
	28	unsigned long parent_rate)
	29	{
	30	struct clk_multiplier *mult = to_clk_multiplier(hw);
	31	unsigned long val;
	32
	33	val = clk_readl(mult->reg) >> mult->shift;
	34	val &= GENMASK(mult->width - 1, 0);
	35
	36	if (!val && mult->flags & CLK_MULTIPLIER_ZERO_BYPASS)
	37	val = 1;
	38
	39	return parent_rate * val;
	40	}
	41
	42	static bool __is_best_rate(unsigned long rate, unsigned long new,
	43	unsigned long best, unsigned long flags)
	44	{
	45	if (flags & CLK_MULTIPLIER_ROUND_CLOSEST)
	46	return abs(rate - new) < abs(rate - best);
	47
	48	return new >= rate && new < best;
	49	}
	50
	51	static unsigned long __bestmult(struct clk_hw *hw, unsigned long rate,
	52	unsigned long *best_parent_rate,
	53	u8 width, unsigned long flags)
	54	{
25f77a3a	55	struct clk_multiplier *mult = to_clk_multiplier(hw);
f2e0a532 MR	56	unsigned long orig_parent_rate = *best_parent_rate;
	57	unsigned long parent_rate, current_rate, best_rate = ~0;
	58	unsigned int i, bestmult = 0;
25f77a3a MR	59	unsigned int maxmult = (1 << width) - 1;
	60
	61	if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
	62	bestmult = rate / orig_parent_rate;
	63
	64	/* Make sure we don't end up with a 0 multiplier */
	65	if ((bestmult == 0) &&
	66	!(mult->flags & CLK_MULTIPLIER_ZERO_BYPASS))
	67	bestmult = 1;
f2e0a532	68
25f77a3a MR	69	/* Make sure we don't overflow the multiplier */
	70	if (bestmult > maxmult)
	71	bestmult = maxmult;
	72
	73	return bestmult;
	74	}
f2e0a532	75
25f77a3a	76	for (i = 1; i < maxmult; i++) {
f2e0a532 MR	77	if (rate == orig_parent_rate * i) {
	78	/*
	79	* This is the best case for us if we have a
	80	* perfect match without changing the parent
	81	* rate.
	82	*/
	83	*best_parent_rate = orig_parent_rate;
	84	return i;
	85	}
	86
	87	parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw),
	88	rate / i);
	89	current_rate = parent_rate * i;
	90
	91	if (__is_best_rate(rate, current_rate, best_rate, flags)) {
	92	bestmult = i;
	93	best_rate = current_rate;
	94	*best_parent_rate = parent_rate;
	95	}
	96	}
	97
	98	return bestmult;
	99	}
	100
	101	static long clk_multiplier_round_rate(struct clk_hw *hw, unsigned long rate,
	102	unsigned long *parent_rate)
	103	{
	104	struct clk_multiplier *mult = to_clk_multiplier(hw);
	105	unsigned long factor = __bestmult(hw, rate, parent_rate,
	106	mult->width, mult->flags);
	107
	108	return parent_rate factor;
	109	}
	110
	111	static int clk_multiplier_set_rate(struct clk_hw *hw, unsigned long rate,
	112	unsigned long parent_rate)
	113	{
	114	struct clk_multiplier *mult = to_clk_multiplier(hw);
	115	unsigned long factor = __get_mult(mult, rate, parent_rate);
	116	unsigned long flags = 0;
	117	unsigned long val;
	118
	119	if (mult->lock)
	120	spin_lock_irqsave(mult->lock, flags);
	121	else
	122	__acquire(mult->lock);
	123
	124	val = clk_readl(mult->reg);
	125	val &= ~GENMASK(mult->width + mult->shift - 1, mult->shift);
	126	val \|= factor << mult->shift;
	127	clk_writel(val, mult->reg);
	128
	129	if (mult->lock)
	130	spin_unlock_irqrestore(mult->lock, flags);
	131	else
	132	__release(mult->lock);
	133
	134	return 0;
	135	}
	136
	137	const struct clk_ops clk_multiplier_ops = {
	138	.recalc_rate = clk_multiplier_recalc_rate,
	139	.round_rate = clk_multiplier_round_rate,
	140	.set_rate = clk_multiplier_set_rate,
141	};
142	EXPORT_SYMBOL_GPL(clk_multiplier_ops);