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Commit 89a3dfb7 authored by Maxime Ripard's avatar Maxime Ripard Committed by Michael Turquette
Browse files

clk: sunxi-ng: Add fractional lib 



Some clocks can be switched to a mode called fractional that have two fixed
output rate you can choose from.

Add a small library to deal with those clocks.

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/20160629190535.11855-4-maxime.ripard@free-electrons.com
parent 1d80c142

drivers/clk/sunxi-ng/Kconfig

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Original line number Diff line number Diff line 
config SUNXI_CCU

	bool "Clock support for Allwinner SoCs"

	default ARCH_SUNXI



if SUNXI_CCU



# Base clock types



config SUNXI_CCU_FRAC

	bool



endif

drivers/clk/sunxi-ng/Makefile

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# Common objects

obj-$(CONFIG_SUNXI_CCU)		+= ccu_common.o

obj-$(CONFIG_SUNXI_CCU)		+= ccu_reset.o



# Base clock types

obj-$(CONFIG_SUNXI_CCU_FRAC)	+= ccu_frac.o

drivers/clk/sunxi-ng/ccu_frac.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/spinlock.h>



#include "ccu_frac.h"



bool ccu_frac_helper_is_enabled(struct ccu_common *common,

				struct _ccu_frac *cf)

{

	if (!(common->features & CCU_FEATURE_FRACTIONAL))

		return false;



	return !(readl(common->base + common->reg) & cf->enable);

}



void ccu_frac_helper_enable(struct ccu_common *common,

			    struct _ccu_frac *cf)

{

	unsigned long flags;

	u32 reg;



	if (!(common->features & CCU_FEATURE_FRACTIONAL))

		return;



	spin_lock_irqsave(common->lock, flags);

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

	writel(reg & ~cf->enable, common->base + common->reg);

	spin_unlock_irqrestore(common->lock, flags);

}



void ccu_frac_helper_disable(struct ccu_common *common,

			     struct _ccu_frac *cf)

{

	unsigned long flags;

	u32 reg;



	if (!(common->features & CCU_FEATURE_FRACTIONAL))

		return;



	spin_lock_irqsave(common->lock, flags);

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

	writel(reg | cf->enable, common->base + common->reg);

	spin_unlock_irqrestore(common->lock, flags);

}



bool ccu_frac_helper_has_rate(struct ccu_common *common,

			      struct _ccu_frac *cf,

			      unsigned long rate)

{

	if (!(common->features & CCU_FEATURE_FRACTIONAL))

		return false;



	return (cf->rates[0] == rate) || (cf->rates[1] == rate);

}



unsigned long ccu_frac_helper_read_rate(struct ccu_common *common,

					struct _ccu_frac *cf)

{

	u32 reg;



	printk("%s: Read fractional\n", clk_hw_get_name(&common->hw));



	if (!(common->features & CCU_FEATURE_FRACTIONAL))

		return 0;



	printk("%s: clock is fractional (rates %lu and %lu)\n",

	       clk_hw_get_name(&common->hw), cf->rates[0], cf->rates[1]);



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



	printk("%s: clock reg is 0x%x (select is 0x%x)\n",

	       clk_hw_get_name(&common->hw), reg, cf->select);



	return (reg & cf->select) ? cf->rates[1] : cf->rates[0];

}



int ccu_frac_helper_set_rate(struct ccu_common *common,

			     struct _ccu_frac *cf,

			     unsigned long rate)

{

	unsigned long flags;

	u32 reg, sel;



	if (!(common->features & CCU_FEATURE_FRACTIONAL))

		return -EINVAL;



	if (cf->rates[0] == rate)

		sel = 0;

	else if (cf->rates[1] == rate)

		sel = cf->select;

	else

		return -EINVAL;



	spin_lock_irqsave(common->lock, flags);

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

	reg &= ~cf->select;

	writel(reg | sel, common->base + common->reg);

	spin_unlock_irqrestore(common->lock, flags);



	return 0;

}

drivers/clk/sunxi-ng/ccu_frac.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_FRAC_H_

#define _CCU_FRAC_H_



#include <linux/clk-provider.h>



#include "ccu_common.h"



struct _ccu_frac {

	u32		enable;

	u32		select;



	unsigned long	rates[2];

};



#define _SUNXI_CCU_FRAC(_enable, _select, _rate1, _rate2)		\

	{								\

		.enable	= _enable,					\

		.select	= _select,					\

		.rates = { _rate1, _rate2 },				\

	}



bool ccu_frac_helper_is_enabled(struct ccu_common *common,

				struct _ccu_frac *cf);

void ccu_frac_helper_enable(struct ccu_common *common,

			    struct _ccu_frac *cf);

void ccu_frac_helper_disable(struct ccu_common *common,

			     struct _ccu_frac *cf);



bool ccu_frac_helper_has_rate(struct ccu_common *common,

			      struct _ccu_frac *cf,

			      unsigned long rate);



unsigned long ccu_frac_helper_read_rate(struct ccu_common *common,

					struct _ccu_frac *cf);



int ccu_frac_helper_set_rate(struct ccu_common *common,

			     struct _ccu_frac *cf,

			     unsigned long rate);



#endif /* _CCU_FRAC_H_ */