Commit 4f728b5d authored by Maxime Ripard's avatar Maxime Ripard Committed by Michael Turquette
Browse files

clk: sunxi-ng: Add N-K-M-P factor clock 



Introduce support for clocks that use a combination of two linear
multipliers (N and K factors), one linear divider (M) and one power of two
divider (P).

Signed-off-by: default avatarMaxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: default avatarMichael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20160629190535.11855-13-maxime.ripard@free-electrons.com
parent df6561e6

drivers/clk/sunxi-ng/Kconfig

+5 −0
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@@ -33,6 +33,11 @@ config SUNXI_CCU_NKM 
	select RATIONAL

	select SUNXI_CCU_GATE



config SUNXI_CCU_NKMP

	bool

	select RATIONAL

	select SUNXI_CCU_GATE



config SUNXI_CCU_NM

	bool

	select RATIONAL

drivers/clk/sunxi-ng/Makefile

+1 −0
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@@ -12,5 +12,6 @@ obj-$(CONFIG_SUNXI_CCU_PHASE) += ccu_phase.o 
# Multi-factor clocks

obj-$(CONFIG_SUNXI_CCU_NK)	+= ccu_nk.o

obj-$(CONFIG_SUNXI_CCU_NKM)	+= ccu_nkm.o

obj-$(CONFIG_SUNXI_CCU_NKMP)	+= ccu_nkmp.o

obj-$(CONFIG_SUNXI_CCU_NM)	+= ccu_nm.o

obj-$(CONFIG_SUNXI_CCU_MP)	+= ccu_mp.o

drivers/clk/sunxi-ng/ccu_nkmp.c

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/*

 * Copyright (C) 2016 Maxime Ripard

 * Maxime Ripard <maxime.ripard@free-electrons.com>

 *

 * 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.

 */



#include <linux/clk-provider.h>

#include <linux/rational.h>



#include "ccu_gate.h"

#include "ccu_nkmp.h"



struct _ccu_nkmp {

	unsigned long	n, max_n;

	unsigned long	k, max_k;

	unsigned long	m, max_m;

	unsigned long	p, max_p;

};



static void ccu_nkmp_find_best(unsigned long parent, unsigned long rate,

			       struct _ccu_nkmp *nkmp)

{

	unsigned long best_rate = 0;

	unsigned long best_n = 0, best_k = 0, best_m = 0, best_p = 0;

	unsigned long _n, _k, _m, _p;



	for (_k = 1; _k <= nkmp->max_k; _k++) {

		for (_p = 0; _p <= nkmp->max_p; _p++) {

			unsigned long tmp_rate;



			rational_best_approximation(rate / _k, parent >> _p,

						    nkmp->max_n, nkmp->max_m,

						    &_n, &_m);



			tmp_rate = (parent * _n * _k >> _p) / _m;



			if (tmp_rate > rate)

				continue;



			if ((rate - tmp_rate) < (rate - best_rate)) {

				best_rate = tmp_rate;

				best_n = _n;

				best_k = _k;

				best_m = _m;

				best_p = _p;

			}

		}

	}



	nkmp->n = best_n;

	nkmp->k = best_k;

	nkmp->m = best_m;

	nkmp->p = best_p;

}



static void ccu_nkmp_disable(struct clk_hw *hw)

{

	struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);



	return ccu_gate_helper_disable(&nkmp->common, nkmp->enable);

}



static int ccu_nkmp_enable(struct clk_hw *hw)

{

	struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);



	return ccu_gate_helper_enable(&nkmp->common, nkmp->enable);

}



static int ccu_nkmp_is_enabled(struct clk_hw *hw)

{

	struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);



	return ccu_gate_helper_is_enabled(&nkmp->common, nkmp->enable);

}



static unsigned long ccu_nkmp_recalc_rate(struct clk_hw *hw,

					unsigned long parent_rate)

{

	struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);

	unsigned long n, m, k, p;

	u32 reg;



	reg = readl(nkmp->common.base + nkmp->common.reg);



	n = reg >> nkmp->n.shift;

	n &= (1 << nkmp->n.width) - 1;



	k = reg >> nkmp->k.shift;

	k &= (1 << nkmp->k.width) - 1;



	m = reg >> nkmp->m.shift;

	m &= (1 << nkmp->m.width) - 1;



	p = reg >> nkmp->p.shift;

	p &= (1 << nkmp->p.width) - 1;



	return (parent_rate * (n + 1) * (k + 1) >> p) / (m + 1);

}



static long ccu_nkmp_round_rate(struct clk_hw *hw, unsigned long rate,

			      unsigned long *parent_rate)

{

	struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);

	struct _ccu_nkmp _nkmp;



	_nkmp.max_n = 1 << nkmp->n.width;

	_nkmp.max_k = 1 << nkmp->k.width;

	_nkmp.max_m = 1 << nkmp->m.width;

	_nkmp.max_p = (1 << nkmp->p.width) - 1;



	ccu_nkmp_find_best(*parent_rate, rate,

			   &_nkmp);



	return (*parent_rate * _nkmp.n * _nkmp.k >> _nkmp.p) / _nkmp.m;

}



static int ccu_nkmp_set_rate(struct clk_hw *hw, unsigned long rate,

			   unsigned long parent_rate)

{

	struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);

	struct _ccu_nkmp _nkmp;

	unsigned long flags;

	u32 reg;



	_nkmp.max_n = 1 << nkmp->n.width;

	_nkmp.max_k = 1 << nkmp->k.width;

	_nkmp.max_m = 1 << nkmp->m.width;

	_nkmp.max_p = (1 << nkmp->p.width) - 1;



	ccu_nkmp_find_best(parent_rate, rate, &_nkmp);



	spin_lock_irqsave(nkmp->common.lock, flags);



	reg = readl(nkmp->common.base + nkmp->common.reg);

	reg &= ~GENMASK(nkmp->n.width + nkmp->n.shift - 1, nkmp->n.shift);

	reg &= ~GENMASK(nkmp->k.width + nkmp->k.shift - 1, nkmp->k.shift);

	reg &= ~GENMASK(nkmp->m.width + nkmp->m.shift - 1, nkmp->m.shift);

	reg &= ~GENMASK(nkmp->p.width + nkmp->p.shift - 1, nkmp->p.shift);



	reg |= (_nkmp.n - 1) << nkmp->n.shift;

	reg |= (_nkmp.k - 1) << nkmp->k.shift;

	reg |= (_nkmp.m - 1) << nkmp->m.shift;

	reg |= _nkmp.p << nkmp->p.shift;



	writel(reg, nkmp->common.base + nkmp->common.reg);



	spin_unlock_irqrestore(nkmp->common.lock, flags);



	ccu_helper_wait_for_lock(&nkmp->common, nkmp->lock);



	return 0;

}



const struct clk_ops ccu_nkmp_ops = {

	.disable	= ccu_nkmp_disable,

	.enable		= ccu_nkmp_enable,

	.is_enabled	= ccu_nkmp_is_enabled,



	.recalc_rate	= ccu_nkmp_recalc_rate,

	.round_rate	= ccu_nkmp_round_rate,

	.set_rate	= ccu_nkmp_set_rate,

};

drivers/clk/sunxi-ng/ccu_nkmp.h

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/*

 * Copyright (c) 2016 Maxime Ripard. All rights reserved.

 *

 * This software is licensed under the terms of the GNU General Public

 * License version 2, as published by the Free Software Foundation, and

 * may be copied, distributed, and modified under those terms.

 *

 * 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.

 */



#ifndef _CCU_NKMP_H_

#define _CCU_NKMP_H_



#include <linux/clk-provider.h>



#include "ccu_common.h"

#include "ccu_div.h"

#include "ccu_mult.h"



/*

 * struct ccu_nkmp - Definition of an N-K-M-P clock

 *

 * Clocks based on the formula parent * N * K >> P / M

 */

struct ccu_nkmp {

	u32			enable;

	u32			lock;



	struct _ccu_mult	n;

	struct _ccu_mult	k;

	struct _ccu_div		m;

	struct _ccu_div		p;



	struct ccu_common	common;

};



#define SUNXI_CCU_NKMP_WITH_GATE_LOCK(_struct, _name, _parent, _reg,	\

				      _nshift, _nwidth,			\

				      _kshift, _kwidth,			\

				      _mshift, _mwidth,			\

				      _pshift, _pwidth,			\

				      _gate, _lock, _flags)		\

	struct ccu_nkmp _struct = {					\

		.enable		= _gate,				\

		.lock		= _lock,				\

		.n		= _SUNXI_CCU_MULT(_nshift, _nwidth),	\

		.k		= _SUNXI_CCU_MULT(_kshift, _kwidth),	\

		.m		= _SUNXI_CCU_DIV(_mshift, _mwidth),	\

		.p		= _SUNXI_CCU_DIV(_pshift, _pwidth),	\

		.common		= {					\

			.reg		= _reg,				\

			.hw.init	= CLK_HW_INIT(_name,		\

						      _parent,		\

						      &ccu_nkmp_ops,	\

						      _flags),		\

		},							\

	}



static inline struct ccu_nkmp *hw_to_ccu_nkmp(struct clk_hw *hw)

{

	struct ccu_common *common = hw_to_ccu_common(hw);



	return container_of(common, struct ccu_nkmp, common);

}



extern const struct clk_ops ccu_nkmp_ops;



#endif /* _CCU_NKMP_H_ */

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