drivers/clk/clk-nspire.c

   1 /*
   2  *
   3  *  Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2, as
   7  * published by the Free Software Foundation.
   8  *
   9  */
  10
  11 #include <linux/clk-provider.h>
  12 #include <linux/err.h>
  13 #include <linux/io.h>
  14 #include <linux/of.h>
  15 #include <linux/of_address.h>
  16
  17 #define MHZ (1000 * 1000)
  18
  19 #define BASE_CPU_SHIFT          1
  20 #define BASE_CPU_MASK           0x7F
  21
  22 #define CPU_AHB_SHIFT           12
  23 #define CPU_AHB_MASK            0x07
  24
  25 #define FIXED_BASE_SHIFT        8
  26 #define FIXED_BASE_MASK         0x01
  27
  28 #define CLASSIC_BASE_SHIFT      16
  29 #define CLASSIC_BASE_MASK       0x1F
  30
  31 #define CX_BASE_SHIFT           15
  32 #define CX_BASE_MASK            0x3F
  33
  34 #define CX_UNKNOWN_SHIFT        21
  35 #define CX_UNKNOWN_MASK         0x03
  36
  37 struct nspire_clk_info {
  38         u32 base_clock;
  39         u16 base_cpu_ratio;
  40         u16 base_ahb_ratio;
  41 };
  42
  43
  44 #define EXTRACT(var, prop) (((var)>>prop##_SHIFT) & prop##_MASK)
  45 static void nspire_clkinfo_cx(u32 val, struct nspire_clk_info *clk)
  46 {
  47         if (EXTRACT(val, FIXED_BASE))
  48                 clk->base_clock = 48 * MHZ;
  49         else
  50                 clk->base_clock = 6 * EXTRACT(val, CX_BASE) * MHZ;
  51
  52         clk->base_cpu_ratio = EXTRACT(val, BASE_CPU) * EXTRACT(val, CX_UNKNOWN);
  53         clk->base_ahb_ratio = clk->base_cpu_ratio * (EXTRACT(val, CPU_AHB) + 1);
  54 }
  55
  56 static void nspire_clkinfo_classic(u32 val, struct nspire_clk_info *clk)
  57 {
  58         if (EXTRACT(val, FIXED_BASE))
  59                 clk->base_clock = 27 * MHZ;
  60         else
  61                 clk->base_clock = (300 - 6 * EXTRACT(val, CLASSIC_BASE)) * MHZ;
  62
  63         clk->base_cpu_ratio = EXTRACT(val, BASE_CPU) * 2;
  64         clk->base_ahb_ratio = clk->base_cpu_ratio * (EXTRACT(val, CPU_AHB) + 1);
  65 }
  66
  67 static void __init nspire_ahbdiv_setup(struct device_node *node,
  68                 void (*get_clkinfo)(u32, struct nspire_clk_info *))
  69 {
  70         u32 val;
  71         void __iomem *io;
  72         struct clk *clk;
  73         const char *clk_name = node->name;
  74         const char *parent_name;
  75         struct nspire_clk_info info;
  76
  77         io = of_iomap(node, 0);
  78         if (!io)
  79                 return;
  80         val = readl(io);
  81         iounmap(io);
  82
  83         get_clkinfo(val, &info);
  84
  85         of_property_read_string(node, "clock-output-names", &clk_name);
  86         parent_name = of_clk_get_parent_name(node, 0);
  87
  88         clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,
  89                                         1, info.base_ahb_ratio);
  90         if (!IS_ERR(clk))
  91                 of_clk_add_provider(node, of_clk_src_simple_get, clk);
  92 }
  93
  94 static void __init nspire_ahbdiv_setup_cx(struct device_node *node)
  95 {
  96         nspire_ahbdiv_setup(node, nspire_clkinfo_cx);
  97 }
  98
  99 static void __init nspire_ahbdiv_setup_classic(struct device_node *node)
 100 {
 101         nspire_ahbdiv_setup(node, nspire_clkinfo_classic);
 102 }
 103
 104 CLK_OF_DECLARE(nspire_ahbdiv_cx, "lsi,nspire-cx-ahb-divider",
 105                 nspire_ahbdiv_setup_cx);
 106 CLK_OF_DECLARE(nspire_ahbdiv_classic, "lsi,nspire-classic-ahb-divider",
 107                 nspire_ahbdiv_setup_classic);
 108
 109 static void __init nspire_clk_setup(struct device_node *node,
 110                 void (*get_clkinfo)(u32, struct nspire_clk_info *))
 111 {
 112         u32 val;
 113         void __iomem *io;
 114         struct clk *clk;
 115         const char *clk_name = node->name;
 116         struct nspire_clk_info info;
 117
 118         io = of_iomap(node, 0);
 119         if (!io)
 120                 return;
 121         val = readl(io);
 122         iounmap(io);
 123
 124         get_clkinfo(val, &info);
 125
 126         of_property_read_string(node, "clock-output-names", &clk_name);
 127
 128         clk = clk_register_fixed_rate(NULL, clk_name, NULL, CLK_IS_ROOT,
 129                         info.base_clock);
 130         if (!IS_ERR(clk))
 131                 of_clk_add_provider(node, of_clk_src_simple_get, clk);
 132         else
 133                 return;
 134
 135         pr_info("TI-NSPIRE Base: %uMHz CPU: %uMHz AHB: %uMHz\n",
 136                 info.base_clock / MHZ,
 137                 info.base_clock / info.base_cpu_ratio / MHZ,
 138                 info.base_clock / info.base_ahb_ratio / MHZ);
 139 }
 140
 141 static void __init nspire_clk_setup_cx(struct device_node *node)
 142 {
 143         nspire_clk_setup(node, nspire_clkinfo_cx);
 144 }
 145
 146 static void __init nspire_clk_setup_classic(struct device_node *node)
 147 {
 148         nspire_clk_setup(node, nspire_clkinfo_classic);
 149 }
 150
 151 CLK_OF_DECLARE(nspire_clk_cx, "lsi,nspire-cx-clock", nspire_clk_setup_cx);
 152 CLK_OF_DECLARE(nspire_clk_classic, "lsi,nspire-classic-clock",
 153                 nspire_clk_setup_classic);