linux/drivers/clk/clk-nspire.c
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   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
  37struct 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)
  45static 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
  56static 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
  67static 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
  94static void __init nspire_ahbdiv_setup_cx(struct device_node *node)
  95{
  96        nspire_ahbdiv_setup(node, nspire_clkinfo_cx);
  97}
  98
  99static void __init nspire_ahbdiv_setup_classic(struct device_node *node)
 100{
 101        nspire_ahbdiv_setup(node, nspire_clkinfo_classic);
 102}
 103
 104CLK_OF_DECLARE(nspire_ahbdiv_cx, "lsi,nspire-cx-ahb-divider",
 105                nspire_ahbdiv_setup_cx);
 106CLK_OF_DECLARE(nspire_ahbdiv_classic, "lsi,nspire-classic-ahb-divider",
 107                nspire_ahbdiv_setup_classic);
 108
 109static 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
 141static void __init nspire_clk_setup_cx(struct device_node *node)
 142{
 143        nspire_clk_setup(node, nspire_clkinfo_cx);
 144}
 145
 146static void __init nspire_clk_setup_classic(struct device_node *node)
 147{
 148        nspire_clk_setup(node, nspire_clkinfo_classic);
 149}
 150
 151CLK_OF_DECLARE(nspire_clk_cx, "lsi,nspire-cx-clock", nspire_clk_setup_cx);
 152CLK_OF_DECLARE(nspire_clk_classic, "lsi,nspire-classic-clock",
 153                nspire_clk_setup_classic);
 154
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