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kernel/linux-imx6_3.14.28/arch/arm/mach-sa1100/clock.c 2.11 KB
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  /*
   *  linux/arch/arm/mach-sa1100/clock.c
   */
  #include <linux/module.h>
  #include <linux/kernel.h>
  #include <linux/device.h>
  #include <linux/list.h>
  #include <linux/errno.h>
  #include <linux/err.h>
  #include <linux/string.h>
  #include <linux/clk.h>
  #include <linux/spinlock.h>
  #include <linux/mutex.h>
  #include <linux/io.h>
  #include <linux/clkdev.h>
  
  #include <mach/hardware.h>
  
  struct clkops {
  	void			(*enable)(struct clk *);
  	void			(*disable)(struct clk *);
  };
  
  struct clk {
  	const struct clkops	*ops;
  	unsigned int		enabled;
  };
  
  #define DEFINE_CLK(_name, _ops)				\
  struct clk clk_##_name = {				\
  		.ops	= _ops,				\
  	}
  
  static DEFINE_SPINLOCK(clocks_lock);
  
  /* Dummy clk routine to build generic kernel parts that may be using them */
  unsigned long clk_get_rate(struct clk *clk)
  {
  	return 0;
  }
  EXPORT_SYMBOL(clk_get_rate);
  
  static void clk_gpio27_enable(struct clk *clk)
  {
  	/*
  	 * First, set up the 3.6864MHz clock on GPIO 27 for the SA-1111:
  	 * (SA-1110 Developer's Manual, section 9.1.2.1)
  	 */
  	GAFR |= GPIO_32_768kHz;
  	GPDR |= GPIO_32_768kHz;
  	TUCR = TUCR_3_6864MHz;
  }
  
  static void clk_gpio27_disable(struct clk *clk)
  {
  	TUCR = 0;
  	GPDR &= ~GPIO_32_768kHz;
  	GAFR &= ~GPIO_32_768kHz;
  }
  
  int clk_enable(struct clk *clk)
  {
  	unsigned long flags;
  
  	if (clk) {
  		spin_lock_irqsave(&clocks_lock, flags);
  		if (clk->enabled++ == 0)
  			clk->ops->enable(clk);
  		spin_unlock_irqrestore(&clocks_lock, flags);
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL(clk_enable);
  
  void clk_disable(struct clk *clk)
  {
  	unsigned long flags;
  
  	if (clk) {
  		WARN_ON(clk->enabled == 0);
  		spin_lock_irqsave(&clocks_lock, flags);
  		if (--clk->enabled == 0)
  			clk->ops->disable(clk);
  		spin_unlock_irqrestore(&clocks_lock, flags);
  	}
  }
  EXPORT_SYMBOL(clk_disable);
  
  const struct clkops clk_gpio27_ops = {
  	.enable		= clk_gpio27_enable,
  	.disable	= clk_gpio27_disable,
  };
  
  static DEFINE_CLK(gpio27, &clk_gpio27_ops);
  
  static struct clk_lookup sa11xx_clkregs[] = {
  	CLKDEV_INIT("sa1111.0", NULL, &clk_gpio27),
  	CLKDEV_INIT("sa1100-rtc", NULL, NULL),
  };
  
  static int __init sa11xx_clk_init(void)
  {
  	clkdev_add_table(sa11xx_clkregs, ARRAY_SIZE(sa11xx_clkregs));
  	return 0;
  }
  core_initcall(sa11xx_clk_init);