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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: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Michael Turquette <mturquette@baylibre.com> Link: lkml.kernel.org/r/20160629190535.11855-4-maxime.ripard@free-electrons.com
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config SUNXI_CCU
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bool "Clock support for Allwinner SoCs"
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default ARCH_SUNXI
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if SUNXI_CCU
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# Base clock types
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config SUNXI_CCU_FRAC
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bool
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endif
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# Common objects
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obj-$(CONFIG_SUNXI_CCU) += ccu_common.o
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obj-$(CONFIG_SUNXI_CCU) += ccu_reset.o
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# Base clock types
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obj-$(CONFIG_SUNXI_CCU_FRAC) += ccu_frac.o
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110
drivers/clk/sunxi-ng/ccu_frac.c
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110
drivers/clk/sunxi-ng/ccu_frac.c
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/*
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* Copyright (C) 2016 Maxime Ripard
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* Maxime Ripard <maxime.ripard@free-electrons.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*/
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#include <linux/clk-provider.h>
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#include <linux/spinlock.h>
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#include "ccu_frac.h"
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bool ccu_frac_helper_is_enabled(struct ccu_common *common,
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struct _ccu_frac *cf)
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{
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if (!(common->features & CCU_FEATURE_FRACTIONAL))
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return false;
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return !(readl(common->base + common->reg) & cf->enable);
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}
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void ccu_frac_helper_enable(struct ccu_common *common,
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struct _ccu_frac *cf)
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{
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unsigned long flags;
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u32 reg;
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if (!(common->features & CCU_FEATURE_FRACTIONAL))
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return;
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spin_lock_irqsave(common->lock, flags);
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reg = readl(common->base + common->reg);
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writel(reg & ~cf->enable, common->base + common->reg);
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spin_unlock_irqrestore(common->lock, flags);
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}
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void ccu_frac_helper_disable(struct ccu_common *common,
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struct _ccu_frac *cf)
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{
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unsigned long flags;
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u32 reg;
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if (!(common->features & CCU_FEATURE_FRACTIONAL))
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return;
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spin_lock_irqsave(common->lock, flags);
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reg = readl(common->base + common->reg);
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writel(reg | cf->enable, common->base + common->reg);
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spin_unlock_irqrestore(common->lock, flags);
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}
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bool ccu_frac_helper_has_rate(struct ccu_common *common,
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struct _ccu_frac *cf,
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unsigned long rate)
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{
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if (!(common->features & CCU_FEATURE_FRACTIONAL))
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return false;
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return (cf->rates[0] == rate) || (cf->rates[1] == rate);
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}
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unsigned long ccu_frac_helper_read_rate(struct ccu_common *common,
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struct _ccu_frac *cf)
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{
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u32 reg;
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printk("%s: Read fractional\n", clk_hw_get_name(&common->hw));
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if (!(common->features & CCU_FEATURE_FRACTIONAL))
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return 0;
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printk("%s: clock is fractional (rates %lu and %lu)\n",
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clk_hw_get_name(&common->hw), cf->rates[0], cf->rates[1]);
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reg = readl(common->base + common->reg);
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printk("%s: clock reg is 0x%x (select is 0x%x)\n",
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clk_hw_get_name(&common->hw), reg, cf->select);
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return (reg & cf->select) ? cf->rates[1] : cf->rates[0];
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}
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int ccu_frac_helper_set_rate(struct ccu_common *common,
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struct _ccu_frac *cf,
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unsigned long rate)
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{
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unsigned long flags;
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u32 reg, sel;
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if (!(common->features & CCU_FEATURE_FRACTIONAL))
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return -EINVAL;
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if (cf->rates[0] == rate)
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sel = 0;
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else if (cf->rates[1] == rate)
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sel = cf->select;
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else
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return -EINVAL;
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spin_lock_irqsave(common->lock, flags);
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reg = readl(common->base + common->reg);
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reg &= ~cf->select;
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writel(reg | sel, common->base + common->reg);
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spin_unlock_irqrestore(common->lock, flags);
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return 0;
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}
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53
drivers/clk/sunxi-ng/ccu_frac.h
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53
drivers/clk/sunxi-ng/ccu_frac.h
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/*
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* Copyright (c) 2016 Maxime Ripard. All rights reserved.
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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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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#ifndef _CCU_FRAC_H_
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#define _CCU_FRAC_H_
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#include <linux/clk-provider.h>
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#include "ccu_common.h"
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struct _ccu_frac {
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u32 enable;
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u32 select;
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unsigned long rates[2];
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};
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#define _SUNXI_CCU_FRAC(_enable, _select, _rate1, _rate2) \
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{ \
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.enable = _enable, \
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.select = _select, \
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.rates = { _rate1, _rate2 }, \
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}
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bool ccu_frac_helper_is_enabled(struct ccu_common *common,
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struct _ccu_frac *cf);
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void ccu_frac_helper_enable(struct ccu_common *common,
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struct _ccu_frac *cf);
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void ccu_frac_helper_disable(struct ccu_common *common,
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struct _ccu_frac *cf);
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bool ccu_frac_helper_has_rate(struct ccu_common *common,
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struct _ccu_frac *cf,
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unsigned long rate);
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unsigned long ccu_frac_helper_read_rate(struct ccu_common *common,
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struct _ccu_frac *cf);
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int ccu_frac_helper_set_rate(struct ccu_common *common,
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struct _ccu_frac *cf,
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unsigned long rate);
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#endif /* _CCU_FRAC_H_ */
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