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kernel/linux-rt-4.4.41/drivers/clk/imx/clk.c 2.56 KB
5113f6f70   김현기   kernel add
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  #include <linux/clk.h>
  #include <linux/err.h>
  #include <linux/of.h>
  #include <linux/slab.h>
  #include <linux/spinlock.h>
  #include "clk.h"
  
  DEFINE_SPINLOCK(imx_ccm_lock);
  
  void __init imx_check_clocks(struct clk *clks[], unsigned int count)
  {
  	unsigned i;
  
  	for (i = 0; i < count; i++)
  		if (IS_ERR(clks[i]))
  			pr_err("i.MX clk %u: register failed with %ld
  ",
  			       i, PTR_ERR(clks[i]));
  }
  
  static struct clk * __init imx_obtain_fixed_clock_from_dt(const char *name)
  {
  	struct of_phandle_args phandle;
  	struct clk *clk = ERR_PTR(-ENODEV);
  	char *path;
  
  	path = kasprintf(GFP_KERNEL, "/clocks/%s", name);
  	if (!path)
  		return ERR_PTR(-ENOMEM);
  
  	phandle.np = of_find_node_by_path(path);
  	kfree(path);
  
  	if (phandle.np) {
  		clk = of_clk_get_from_provider(&phandle);
  		of_node_put(phandle.np);
  	}
  	return clk;
  }
  
  struct clk * __init imx_obtain_fixed_clock(
  			const char *name, unsigned long rate)
  {
  	struct clk *clk;
  
  	clk = imx_obtain_fixed_clock_from_dt(name);
  	if (IS_ERR(clk))
  		clk = imx_clk_fixed(name, rate);
  	return clk;
  }
  
  /*
   * This fixups the register CCM_CSCMR1 write value.
   * The write/read/divider values of the aclk_podf field
   * of that register have the relationship described by
   * the following table:
   *
   * write value       read value        divider
   * 3b'000            3b'110            7
   * 3b'001            3b'111            8
   * 3b'010            3b'100            5
   * 3b'011            3b'101            6
   * 3b'100            3b'010            3
   * 3b'101            3b'011            4
   * 3b'110            3b'000            1
   * 3b'111            3b'001            2(default)
   *
   * That's why we do the xor operation below.
   */
  #define CSCMR1_FIXUP	0x00600000
  
  void imx_cscmr1_fixup(u32 *val)
  {
  	*val ^= CSCMR1_FIXUP;
  	return;
  }
  
  static int imx_keep_uart_clocks __initdata;
  static struct clk ** const *imx_uart_clocks __initdata;
  
  static int __init imx_keep_uart_clocks_param(char *str)
  {
  	imx_keep_uart_clocks = 1;
  
  	return 0;
  }
  __setup_param("earlycon", imx_keep_uart_earlycon,
  	      imx_keep_uart_clocks_param, 0);
  __setup_param("earlyprintk", imx_keep_uart_earlyprintk,
  	      imx_keep_uart_clocks_param, 0);
  
  void __init imx_register_uart_clocks(struct clk ** const clks[])
  {
  	if (imx_keep_uart_clocks) {
  		int i;
  
  		imx_uart_clocks = clks;
  		for (i = 0; imx_uart_clocks[i]; i++)
  			clk_prepare_enable(*imx_uart_clocks[i]);
  	}
  }
  
  static int __init imx_clk_disable_uart(void)
  {
  	if (imx_keep_uart_clocks && imx_uart_clocks) {
  		int i;
  
  		for (i = 0; imx_uart_clocks[i]; i++)
  			clk_disable_unprepare(*imx_uart_clocks[i]);
  	}
  
  	return 0;
  }
  late_initcall_sync(imx_clk_disable_uart);