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kernel/linux-imx6_3.14.28/drivers/clk/clk-nspire.c 3.77 KB
6b13f685e   김민수   BSP 최초 추가
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  /*
   *
   *  Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2, as
   * published by the Free Software Foundation.
   *
   */
  
  #include <linux/clk-provider.h>
  #include <linux/err.h>
  #include <linux/io.h>
  #include <linux/of.h>
  #include <linux/of_address.h>
  
  #define MHZ (1000 * 1000)
  
  #define BASE_CPU_SHIFT		1
  #define BASE_CPU_MASK		0x7F
  
  #define CPU_AHB_SHIFT		12
  #define CPU_AHB_MASK		0x07
  
  #define FIXED_BASE_SHIFT	8
  #define FIXED_BASE_MASK		0x01
  
  #define CLASSIC_BASE_SHIFT	16
  #define CLASSIC_BASE_MASK	0x1F
  
  #define CX_BASE_SHIFT		15
  #define CX_BASE_MASK		0x3F
  
  #define CX_UNKNOWN_SHIFT	21
  #define CX_UNKNOWN_MASK		0x03
  
  struct nspire_clk_info {
  	u32 base_clock;
  	u16 base_cpu_ratio;
  	u16 base_ahb_ratio;
  };
  
  
  #define EXTRACT(var, prop) (((var)>>prop##_SHIFT) & prop##_MASK)
  static void nspire_clkinfo_cx(u32 val, struct nspire_clk_info *clk)
  {
  	if (EXTRACT(val, FIXED_BASE))
  		clk->base_clock = 48 * MHZ;
  	else
  		clk->base_clock = 6 * EXTRACT(val, CX_BASE) * MHZ;
  
  	clk->base_cpu_ratio = EXTRACT(val, BASE_CPU) * EXTRACT(val, CX_UNKNOWN);
  	clk->base_ahb_ratio = clk->base_cpu_ratio * (EXTRACT(val, CPU_AHB) + 1);
  }
  
  static void nspire_clkinfo_classic(u32 val, struct nspire_clk_info *clk)
  {
  	if (EXTRACT(val, FIXED_BASE))
  		clk->base_clock = 27 * MHZ;
  	else
  		clk->base_clock = (300 - 6 * EXTRACT(val, CLASSIC_BASE)) * MHZ;
  
  	clk->base_cpu_ratio = EXTRACT(val, BASE_CPU) * 2;
  	clk->base_ahb_ratio = clk->base_cpu_ratio * (EXTRACT(val, CPU_AHB) + 1);
  }
  
  static void __init nspire_ahbdiv_setup(struct device_node *node,
  		void (*get_clkinfo)(u32, struct nspire_clk_info *))
  {
  	u32 val;
  	void __iomem *io;
  	struct clk *clk;
  	const char *clk_name = node->name;
  	const char *parent_name;
  	struct nspire_clk_info info;
  
  	io = of_iomap(node, 0);
  	if (!io)
  		return;
  	val = readl(io);
  	iounmap(io);
  
  	get_clkinfo(val, &info);
  
  	of_property_read_string(node, "clock-output-names", &clk_name);
  	parent_name = of_clk_get_parent_name(node, 0);
  
  	clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,
  					1, info.base_ahb_ratio);
  	if (!IS_ERR(clk))
  		of_clk_add_provider(node, of_clk_src_simple_get, clk);
  }
  
  static void __init nspire_ahbdiv_setup_cx(struct device_node *node)
  {
  	nspire_ahbdiv_setup(node, nspire_clkinfo_cx);
  }
  
  static void __init nspire_ahbdiv_setup_classic(struct device_node *node)
  {
  	nspire_ahbdiv_setup(node, nspire_clkinfo_classic);
  }
  
  CLK_OF_DECLARE(nspire_ahbdiv_cx, "lsi,nspire-cx-ahb-divider",
  		nspire_ahbdiv_setup_cx);
  CLK_OF_DECLARE(nspire_ahbdiv_classic, "lsi,nspire-classic-ahb-divider",
  		nspire_ahbdiv_setup_classic);
  
  static void __init nspire_clk_setup(struct device_node *node,
  		void (*get_clkinfo)(u32, struct nspire_clk_info *))
  {
  	u32 val;
  	void __iomem *io;
  	struct clk *clk;
  	const char *clk_name = node->name;
  	struct nspire_clk_info info;
  
  	io = of_iomap(node, 0);
  	if (!io)
  		return;
  	val = readl(io);
  	iounmap(io);
  
  	get_clkinfo(val, &info);
  
  	of_property_read_string(node, "clock-output-names", &clk_name);
  
  	clk = clk_register_fixed_rate(NULL, clk_name, NULL, CLK_IS_ROOT,
  			info.base_clock);
  	if (!IS_ERR(clk))
  		of_clk_add_provider(node, of_clk_src_simple_get, clk);
  	else
  		return;
  
  	pr_info("TI-NSPIRE Base: %uMHz CPU: %uMHz AHB: %uMHz
  ",
  		info.base_clock / MHZ,
  		info.base_clock / info.base_cpu_ratio / MHZ,
  		info.base_clock / info.base_ahb_ratio / MHZ);
  }
  
  static void __init nspire_clk_setup_cx(struct device_node *node)
  {
  	nspire_clk_setup(node, nspire_clkinfo_cx);
  }
  
  static void __init nspire_clk_setup_classic(struct device_node *node)
  {
  	nspire_clk_setup(node, nspire_clkinfo_classic);
  }
  
  CLK_OF_DECLARE(nspire_clk_cx, "lsi,nspire-cx-clock", nspire_clk_setup_cx);
  CLK_OF_DECLARE(nspire_clk_classic, "lsi,nspire-classic-clock",
  		nspire_clk_setup_classic);