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kernel/linux-rt-4.4.41/drivers/clk/mmp/clk-apbc.c 3.33 KB
5113f6f70   김현기   kernel add
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  /*
   * mmp APB clock operation source file
   *
   * Copyright (C) 2012 Marvell
   * Chao Xie <xiechao.mail@gmail.com>
   *
   * This file is licensed under the terms of the GNU General Public
   * License version 2. This program is licensed "as is" without any
   * warranty of any kind, whether express or implied.
   */
  
  #include <linux/kernel.h>
  #include <linux/io.h>
  #include <linux/err.h>
  #include <linux/delay.h>
  #include <linux/slab.h>
  
  #include "clk.h"
  
  /* Common APB clock register bit definitions */
  #define APBC_APBCLK	(1 << 0)  /* APB Bus Clock Enable */
  #define APBC_FNCLK	(1 << 1)  /* Functional Clock Enable */
  #define APBC_RST	(1 << 2)  /* Reset Generation */
  #define APBC_POWER	(1 << 7)  /* Reset Generation */
  
  #define to_clk_apbc(hw) container_of(hw, struct clk_apbc, hw)
  struct clk_apbc {
  	struct clk_hw		hw;
  	void __iomem		*base;
  	unsigned int		delay;
  	unsigned int		flags;
  	spinlock_t		*lock;
  };
  
  static int clk_apbc_prepare(struct clk_hw *hw)
  {
  	struct clk_apbc *apbc = to_clk_apbc(hw);
  	unsigned int data;
  	unsigned long flags = 0;
  
  	/*
  	 * It may share same register as MUX clock,
  	 * and it will impact FNCLK enable. Spinlock is needed
  	 */
  	if (apbc->lock)
  		spin_lock_irqsave(apbc->lock, flags);
  
  	data = readl_relaxed(apbc->base);
  	if (apbc->flags & APBC_POWER_CTRL)
  		data |= APBC_POWER;
  	data |= APBC_FNCLK;
  	writel_relaxed(data, apbc->base);
  
  	if (apbc->lock)
  		spin_unlock_irqrestore(apbc->lock, flags);
  
  	udelay(apbc->delay);
  
  	if (apbc->lock)
  		spin_lock_irqsave(apbc->lock, flags);
  
  	data = readl_relaxed(apbc->base);
  	data |= APBC_APBCLK;
  	writel_relaxed(data, apbc->base);
  
  	if (apbc->lock)
  		spin_unlock_irqrestore(apbc->lock, flags);
  
  	udelay(apbc->delay);
  
  	if (!(apbc->flags & APBC_NO_BUS_CTRL)) {
  		if (apbc->lock)
  			spin_lock_irqsave(apbc->lock, flags);
  
  		data = readl_relaxed(apbc->base);
  		data &= ~APBC_RST;
  		writel_relaxed(data, apbc->base);
  
  		if (apbc->lock)
  			spin_unlock_irqrestore(apbc->lock, flags);
  	}
  
  	return 0;
  }
  
  static void clk_apbc_unprepare(struct clk_hw *hw)
  {
  	struct clk_apbc *apbc = to_clk_apbc(hw);
  	unsigned long data;
  	unsigned long flags = 0;
  
  	if (apbc->lock)
  		spin_lock_irqsave(apbc->lock, flags);
  
  	data = readl_relaxed(apbc->base);
  	if (apbc->flags & APBC_POWER_CTRL)
  		data &= ~APBC_POWER;
  	data &= ~APBC_FNCLK;
  	writel_relaxed(data, apbc->base);
  
  	if (apbc->lock)
  		spin_unlock_irqrestore(apbc->lock, flags);
  
  	udelay(10);
  
  	if (apbc->lock)
  		spin_lock_irqsave(apbc->lock, flags);
  
  	data = readl_relaxed(apbc->base);
  	data &= ~APBC_APBCLK;
  	writel_relaxed(data, apbc->base);
  
  	if (apbc->lock)
  		spin_unlock_irqrestore(apbc->lock, flags);
  }
  
  static struct clk_ops clk_apbc_ops = {
  	.prepare = clk_apbc_prepare,
  	.unprepare = clk_apbc_unprepare,
  };
  
  struct clk *mmp_clk_register_apbc(const char *name, const char *parent_name,
  		void __iomem *base, unsigned int delay,
  		unsigned int apbc_flags, spinlock_t *lock)
  {
  	struct clk_apbc *apbc;
  	struct clk *clk;
  	struct clk_init_data init;
  
  	apbc = kzalloc(sizeof(*apbc), GFP_KERNEL);
  	if (!apbc)
  		return NULL;
  
  	init.name = name;
  	init.ops = &clk_apbc_ops;
  	init.flags = CLK_SET_RATE_PARENT;
  	init.parent_names = (parent_name ? &parent_name : NULL);
  	init.num_parents = (parent_name ? 1 : 0);
  
  	apbc->base = base;
  	apbc->delay = delay;
  	apbc->flags = apbc_flags;
  	apbc->lock = lock;
  	apbc->hw.init = &init;
  
  	clk = clk_register(NULL, &apbc->hw);
  	if (IS_ERR(clk))
  		kfree(apbc);
  
  	return clk;
  }