drivers/clk/clk-ls1x.c

   1 /*
   2  * Copyright (c) 2012 Zhang, Keguang <keguang.zhang@gmail.com>
   3  *
   4  * This program is free software; you can redistribute  it and/or modify it
   5  * under  the terms of  the GNU General  Public License as published by the
   6  * Free Software Foundation;  either version 2 of the  License, or (at your
   7  * option) any later version.
   8  */
   9
  10 #include <linux/clkdev.h>
  11 #include <linux/clk-provider.h>
  12 #include <linux/io.h>
  13 #include <linux/slab.h>
  14 #include <linux/err.h>
  15
  16 #include <loongson1.h>
  17
  18 #define OSC             (33 * 1000000)
  19 #define DIV_APB         2
  20
  21 static DEFINE_SPINLOCK(_lock);
  22
  23 static int ls1x_pll_clk_enable(struct clk_hw *hw)
  24 {
  25         return 0;
  26 }
  27
  28 static void ls1x_pll_clk_disable(struct clk_hw *hw)
  29 {
  30 }
  31
  32 static unsigned long ls1x_pll_recalc_rate(struct clk_hw *hw,
  33                                           unsigned long parent_rate)
  34 {
  35         u32 pll, rate;
  36
  37         pll = __raw_readl(LS1X_CLK_PLL_FREQ);
  38         rate = 12 + (pll & 0x3f) + (((pll >> 8) & 0x3ff) >> 10);
  39         rate *= OSC;
  40         rate >>= 1;
  41
  42         return rate;
  43 }
  44
  45 static const struct clk_ops ls1x_pll_clk_ops = {
  46         .enable = ls1x_pll_clk_enable,
  47         .disable = ls1x_pll_clk_disable,
  48         .recalc_rate = ls1x_pll_recalc_rate,
  49 };
  50
  51 static struct clk *__init clk_register_pll(struct device *dev,
  52                                            const char *name,
  53                                            const char *parent_name,
  54                                            unsigned long flags)
  55 {
  56         struct clk_hw *hw;
  57         struct clk *clk;
  58         struct clk_init_data init;
  59
  60         /* allocate the divider */
  61         hw = kzalloc(sizeof(struct clk_hw), GFP_KERNEL);
  62         if (!hw) {
  63                 pr_err("%s: could not allocate clk_hw\n", __func__);
  64                 return ERR_PTR(-ENOMEM);
  65         }
  66
  67         init.name = name;
  68         init.ops = &ls1x_pll_clk_ops;
  69         init.flags = flags | CLK_IS_BASIC;
  70         init.parent_names = (parent_name ? &parent_name : NULL);
  71         init.num_parents = (parent_name ? 1 : 0);
  72         hw->init = &init;
  73
  74         /* register the clock */
  75         clk = clk_register(dev, hw);
  76
  77         if (IS_ERR(clk))
  78                 kfree(hw);
  79
  80         return clk;
  81 }
  82
  83 static const char * const cpu_parents[] = { "cpu_clk_div", "osc_33m_clk", };
  84 static const char * const ahb_parents[] = { "ahb_clk_div", "osc_33m_clk", };
  85 static const char * const dc_parents[] = { "dc_clk_div", "osc_33m_clk", };
  86
  87 void __init ls1x_clk_init(void)
  88 {
  89         struct clk *clk;
  90
  91         clk = clk_register_fixed_rate(NULL, "osc_33m_clk", NULL, 0, OSC);
  92         clk_register_clkdev(clk, "osc_33m_clk", NULL);
  93
  94         /* clock derived from 33 MHz OSC clk */
  95         clk = clk_register_pll(NULL, "pll_clk", "osc_33m_clk", 0);
  96         clk_register_clkdev(clk, "pll_clk", NULL);
  97
  98         /* clock derived from PLL clk */
  99         /*                                 _____
 100          *         _______________________|     |
 101          * OSC ___/                       | MUX |___ CPU CLK
 102          *        \___ PLL ___ CPU DIV ___|     |
 103          *                                |_____|
 104          */
 105         clk = clk_register_divider(NULL, "cpu_clk_div", "pll_clk",
 106                                    CLK_GET_RATE_NOCACHE, LS1X_CLK_PLL_DIV,
 107                                    DIV_CPU_SHIFT, DIV_CPU_WIDTH,
 108                                    CLK_DIVIDER_ONE_BASED |
 109                                    CLK_DIVIDER_ROUND_CLOSEST, &_lock);
 110         clk_register_clkdev(clk, "cpu_clk_div", NULL);
 111         clk = clk_register_mux(NULL, "cpu_clk", cpu_parents,
 112                                ARRAY_SIZE(cpu_parents),
 113                                CLK_SET_RATE_NO_REPARENT, LS1X_CLK_PLL_DIV,
 114                                BYPASS_CPU_SHIFT, BYPASS_CPU_WIDTH, 0, &_lock);
 115         clk_register_clkdev(clk, "cpu_clk", NULL);
 116
 117         /*                                 _____
 118          *         _______________________|     |
 119          * OSC ___/                       | MUX |___ DC  CLK
 120          *        \___ PLL ___ DC  DIV ___|     |
 121          *                                |_____|
 122          */
 123         clk = clk_register_divider(NULL, "dc_clk_div", "pll_clk",
 124                                    0, LS1X_CLK_PLL_DIV, DIV_DC_SHIFT,
 125                                    DIV_DC_WIDTH, CLK_DIVIDER_ONE_BASED, &_lock);
 126         clk_register_clkdev(clk, "dc_clk_div", NULL);
 127         clk = clk_register_mux(NULL, "dc_clk", dc_parents,
 128                                ARRAY_SIZE(dc_parents),
 129                                CLK_SET_RATE_NO_REPARENT, LS1X_CLK_PLL_DIV,
 130                                BYPASS_DC_SHIFT, BYPASS_DC_WIDTH, 0, &_lock);
 131         clk_register_clkdev(clk, "dc_clk", NULL);
 132
 133         /*                                 _____
 134          *         _______________________|     |
 135          * OSC ___/                       | MUX |___ DDR CLK
 136          *        \___ PLL ___ DDR DIV ___|     |
 137          *                                |_____|
 138          */
 139         clk = clk_register_divider(NULL, "ahb_clk_div", "pll_clk",
 140                                    0, LS1X_CLK_PLL_DIV, DIV_DDR_SHIFT,
 141                                    DIV_DDR_WIDTH, CLK_DIVIDER_ONE_BASED,
 142                                    &_lock);
 143         clk_register_clkdev(clk, "ahb_clk_div", NULL);
 144         clk = clk_register_mux(NULL, "ahb_clk", ahb_parents,
 145                                ARRAY_SIZE(ahb_parents),
 146                                CLK_SET_RATE_NO_REPARENT, LS1X_CLK_PLL_DIV,
 147                                BYPASS_DDR_SHIFT, BYPASS_DDR_WIDTH, 0, &_lock);
 148         clk_register_clkdev(clk, "ahb_clk", NULL);
 149         clk_register_clkdev(clk, "stmmaceth", NULL);
 150
 151         /* clock derived from AHB clk */
 152         /* APB clk is always half of the AHB clk */
 153         clk = clk_register_fixed_factor(NULL, "apb_clk", "ahb_clk", 0, 1,
 154                                         DIV_APB);
 155         clk_register_clkdev(clk, "apb_clk", NULL);
 156         clk_register_clkdev(clk, "ls1x_i2c", NULL);
 157         clk_register_clkdev(clk, "ls1x_pwmtimer", NULL);
 158         clk_register_clkdev(clk, "ls1x_spi", NULL);
 159         clk_register_clkdev(clk, "ls1x_wdt", NULL);
 160         clk_register_clkdev(clk, "serial8250", NULL);
 161 }