drivers/clk/loongson1/clk-loongson1b.c

   1 /*
   2  * Copyright (c) 2012-2016 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/err.h>
  14
  15 #include <loongson1.h>
  16 #include "clk.h"
  17
  18 #define OSC             (33 * 1000000)
  19 #define DIV_APB         2
  20
  21 static DEFINE_SPINLOCK(_lock);
  22
  23 static unsigned long ls1x_pll_recalc_rate(struct clk_hw *hw,
  24                                           unsigned long parent_rate)
  25 {
  26         u32 pll, rate;
  27
  28         pll = __raw_readl(LS1X_CLK_PLL_FREQ);
  29         rate = 12 + (pll & GENMASK(5, 0));
  30         rate *= OSC;
  31         rate >>= 1;
  32
  33         return rate;
  34 }
  35
  36 static const struct clk_ops ls1x_pll_clk_ops = {
  37         .recalc_rate = ls1x_pll_recalc_rate,
  38 };
  39
  40 static const char *const cpu_parents[] = { "cpu_clk_div", "osc_clk", };
  41 static const char *const ahb_parents[] = { "ahb_clk_div", "osc_clk", };
  42 static const char *const dc_parents[] = { "dc_clk_div", "osc_clk", };
  43
  44 void __init ls1x_clk_init(void)
  45 {
  46         struct clk_hw *hw;
  47
  48         hw = clk_hw_register_fixed_rate(NULL, "osc_clk", NULL, 0, OSC);
  49         clk_hw_register_clkdev(hw, "osc_clk", NULL);
  50
  51         /* clock derived from 33 MHz OSC clk */
  52         hw = clk_hw_register_pll(NULL, "pll_clk", "osc_clk",
  53                                  &ls1x_pll_clk_ops, 0);
  54         clk_hw_register_clkdev(hw, "pll_clk", NULL);
  55
  56         /* clock derived from PLL clk */
  57         /*                                 _____
  58          *         _______________________|     |
  59          * OSC ___/                       | MUX |___ CPU CLK
  60          *        \___ PLL ___ CPU DIV ___|     |
  61          *                                |_____|
  62          */
  63         hw = clk_hw_register_divider(NULL, "cpu_clk_div", "pll_clk",
  64                                    CLK_GET_RATE_NOCACHE, LS1X_CLK_PLL_DIV,
  65                                    DIV_CPU_SHIFT, DIV_CPU_WIDTH,
  66                                    CLK_DIVIDER_ONE_BASED |
  67                                    CLK_DIVIDER_ROUND_CLOSEST, &_lock);
  68         clk_hw_register_clkdev(hw, "cpu_clk_div", NULL);
  69         hw = clk_hw_register_mux(NULL, "cpu_clk", cpu_parents,
  70                                ARRAY_SIZE(cpu_parents),
  71                                CLK_SET_RATE_NO_REPARENT, LS1X_CLK_PLL_DIV,
  72                                BYPASS_CPU_SHIFT, BYPASS_CPU_WIDTH, 0, &_lock);
  73         clk_hw_register_clkdev(hw, "cpu_clk", NULL);
  74
  75         /*                                 _____
  76          *         _______________________|     |
  77          * OSC ___/                       | MUX |___ DC  CLK
  78          *        \___ PLL ___ DC  DIV ___|     |
  79          *                                |_____|
  80          */
  81         hw = clk_hw_register_divider(NULL, "dc_clk_div", "pll_clk",
  82                                    0, LS1X_CLK_PLL_DIV, DIV_DC_SHIFT,
  83                                    DIV_DC_WIDTH, CLK_DIVIDER_ONE_BASED, &_lock);
  84         clk_hw_register_clkdev(hw, "dc_clk_div", NULL);
  85         hw = clk_hw_register_mux(NULL, "dc_clk", dc_parents,
  86                                ARRAY_SIZE(dc_parents),
  87                                CLK_SET_RATE_NO_REPARENT, LS1X_CLK_PLL_DIV,
  88                                BYPASS_DC_SHIFT, BYPASS_DC_WIDTH, 0, &_lock);
  89         clk_hw_register_clkdev(hw, "dc_clk", NULL);
  90
  91         /*                                 _____
  92          *         _______________________|     |
  93          * OSC ___/                       | MUX |___ DDR CLK
  94          *        \___ PLL ___ DDR DIV ___|     |
  95          *                                |_____|
  96          */
  97         hw = clk_hw_register_divider(NULL, "ahb_clk_div", "pll_clk",
  98                                    0, LS1X_CLK_PLL_DIV, DIV_DDR_SHIFT,
  99                                    DIV_DDR_WIDTH, CLK_DIVIDER_ONE_BASED,
 100                                    &_lock);
 101         clk_hw_register_clkdev(hw, "ahb_clk_div", NULL);
 102         hw = clk_hw_register_mux(NULL, "ahb_clk", ahb_parents,
 103                                ARRAY_SIZE(ahb_parents),
 104                                CLK_SET_RATE_NO_REPARENT, LS1X_CLK_PLL_DIV,
 105                                BYPASS_DDR_SHIFT, BYPASS_DDR_WIDTH, 0, &_lock);
 106         clk_hw_register_clkdev(hw, "ahb_clk", NULL);
 107         clk_hw_register_clkdev(hw, "ls1x-dma", NULL);
 108         clk_hw_register_clkdev(hw, "stmmaceth", NULL);
 109
 110         /* clock derived from AHB clk */
 111         /* APB clk is always half of the AHB clk */
 112         hw = clk_hw_register_fixed_factor(NULL, "apb_clk", "ahb_clk", 0, 1,
 113                                         DIV_APB);
 114         clk_hw_register_clkdev(hw, "apb_clk", NULL);
 115         clk_hw_register_clkdev(hw, "ls1x-ac97", NULL);
 116         clk_hw_register_clkdev(hw, "ls1x-i2c", NULL);
 117         clk_hw_register_clkdev(hw, "ls1x-nand", NULL);
 118         clk_hw_register_clkdev(hw, "ls1x-pwmtimer", NULL);
 119         clk_hw_register_clkdev(hw, "ls1x-spi", NULL);
 120         clk_hw_register_clkdev(hw, "ls1x-wdt", NULL);
 121         clk_hw_register_clkdev(hw, "serial8250", NULL);
 122 }