drivers/clk/clk-clps711x.c

   1 /*
   2  *  Cirrus Logic CLPS711X CLK driver
   3  *
   4  *  Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  */
  11
  12 #include <linux/clk-provider.h>
  13 #include <linux/clkdev.h>
  14 #include <linux/io.h>
  15 #include <linux/ioport.h>
  16 #include <linux/of_address.h>
  17 #include <linux/slab.h>
  18 #include <linux/mfd/syscon/clps711x.h>
  19
  20 #include <dt-bindings/clock/clps711x-clock.h>
  21
  22 #define CLPS711X_SYSCON1        (0x0100)
  23 #define CLPS711X_SYSCON2        (0x1100)
  24 #define CLPS711X_SYSFLG2        (CLPS711X_SYSCON2 + SYSFLG_OFFSET)
  25 #define CLPS711X_PLLR           (0xa5a8)
  26
  27 #define CLPS711X_EXT_FREQ       (13000000)
  28 #define CLPS711X_OSC_FREQ       (3686400)
  29
  30 static const struct clk_div_table spi_div_table[] = {
  31         { .val = 0, .div = 32, },
  32         { .val = 1, .div = 8, },
  33         { .val = 2, .div = 2, },
  34         { .val = 3, .div = 1, },
  35 };
  36
  37 static const struct clk_div_table timer_div_table[] = {
  38         { .val = 0, .div = 256, },
  39         { .val = 1, .div = 1, },
  40 };
  41
  42 struct clps711x_clk {
  43         struct clk_onecell_data clk_data;
  44         spinlock_t              lock;
  45         struct clk              *clks[CLPS711X_CLK_MAX];
  46 };
  47
  48 static struct clps711x_clk * __init _clps711x_clk_init(void __iomem *base,
  49                                                        u32 fref)
  50 {
  51         u32 tmp, f_cpu, f_pll, f_bus, f_tim, f_pwm, f_spi;
  52         struct clps711x_clk *clps711x_clk;
  53         unsigned i;
  54
  55         if (!base)
  56                 return ERR_PTR(-ENOMEM);
  57
  58         clps711x_clk = kzalloc(sizeof(*clps711x_clk), GFP_KERNEL);
  59         if (!clps711x_clk)
  60                 return ERR_PTR(-ENOMEM);
  61
  62         spin_lock_init(&clps711x_clk->lock);
  63
  64         /* Read PLL multiplier value and sanity check */
  65         tmp = readl(base + CLPS711X_PLLR) >> 24;
  66         if (((tmp >= 10) && (tmp <= 50)) || !fref)
  67                 f_pll = DIV_ROUND_UP(CLPS711X_OSC_FREQ * tmp, 2);
  68         else
  69                 f_pll = fref;
  70
  71         tmp = readl(base + CLPS711X_SYSFLG2);
  72         if (tmp & SYSFLG2_CKMODE) {
  73                 f_cpu = CLPS711X_EXT_FREQ;
  74                 f_bus = CLPS711X_EXT_FREQ;
  75                 f_spi = DIV_ROUND_CLOSEST(CLPS711X_EXT_FREQ, 96);
  76                 f_pll = 0;
  77                 f_pwm = DIV_ROUND_CLOSEST(CLPS711X_EXT_FREQ, 128);
  78         } else {
  79                 f_cpu = f_pll;
  80                 if (f_cpu > 36864000)
  81                         f_bus = DIV_ROUND_UP(f_cpu, 2);
  82                 else
  83                         f_bus = 36864000 / 2;
  84                 f_spi = DIV_ROUND_CLOSEST(f_cpu, 576);
  85                 f_pwm = DIV_ROUND_CLOSEST(f_cpu, 768);
  86         }
  87
  88         if (tmp & SYSFLG2_CKMODE) {
  89                 if (readl(base + CLPS711X_SYSCON2) & SYSCON2_OSTB)
  90                         f_tim = DIV_ROUND_CLOSEST(CLPS711X_EXT_FREQ, 26);
  91                 else
  92                         f_tim = DIV_ROUND_CLOSEST(CLPS711X_EXT_FREQ, 24);
  93         } else
  94                 f_tim = DIV_ROUND_CLOSEST(f_cpu, 144);
  95
  96         tmp = readl(base + CLPS711X_SYSCON1);
  97         /* Timer1 in free running mode.
  98          * Counter will wrap around to 0xffff when it underflows
  99          * and will continue to count down.
 100          */
 101         tmp &= ~(SYSCON1_TC1M | SYSCON1_TC1S);
 102         /* Timer2 in prescale mode.
 103          * Value writen is automatically re-loaded when
 104          * the counter underflows.
 105          */
 106         tmp |= SYSCON1_TC2M | SYSCON1_TC2S;
 107         writel(tmp, base + CLPS711X_SYSCON1);
 108
 109         clps711x_clk->clks[CLPS711X_CLK_DUMMY] =
 110                 clk_register_fixed_rate(NULL, "dummy", NULL, CLK_IS_ROOT, 0);
 111         clps711x_clk->clks[CLPS711X_CLK_CPU] =
 112                 clk_register_fixed_rate(NULL, "cpu", NULL, CLK_IS_ROOT, f_cpu);
 113         clps711x_clk->clks[CLPS711X_CLK_BUS] =
 114                 clk_register_fixed_rate(NULL, "bus", NULL, CLK_IS_ROOT, f_bus);
 115         clps711x_clk->clks[CLPS711X_CLK_PLL] =
 116                 clk_register_fixed_rate(NULL, "pll", NULL, CLK_IS_ROOT, f_pll);
 117         clps711x_clk->clks[CLPS711X_CLK_TIMERREF] =
 118                 clk_register_fixed_rate(NULL, "timer_ref", NULL, CLK_IS_ROOT,
 119                                         f_tim);
 120         clps711x_clk->clks[CLPS711X_CLK_TIMER1] =
 121                 clk_register_divider_table(NULL, "timer1", "timer_ref", 0,
 122                                            base + CLPS711X_SYSCON1, 5, 1, 0,
 123                                            timer_div_table, &clps711x_clk->lock);
 124         clps711x_clk->clks[CLPS711X_CLK_TIMER2] =
 125                 clk_register_divider_table(NULL, "timer2", "timer_ref", 0,
 126                                            base + CLPS711X_SYSCON1, 7, 1, 0,
 127                                            timer_div_table, &clps711x_clk->lock);
 128         clps711x_clk->clks[CLPS711X_CLK_PWM] =
 129                 clk_register_fixed_rate(NULL, "pwm", NULL, CLK_IS_ROOT, f_pwm);
 130         clps711x_clk->clks[CLPS711X_CLK_SPIREF] =
 131                 clk_register_fixed_rate(NULL, "spi_ref", NULL, CLK_IS_ROOT,
 132                                         f_spi);
 133         clps711x_clk->clks[CLPS711X_CLK_SPI] =
 134                 clk_register_divider_table(NULL, "spi", "spi_ref", 0,
 135                                            base + CLPS711X_SYSCON1, 16, 2, 0,
 136                                            spi_div_table, &clps711x_clk->lock);
 137         clps711x_clk->clks[CLPS711X_CLK_UART] =
 138                 clk_register_fixed_factor(NULL, "uart", "bus", 0, 1, 10);
 139         clps711x_clk->clks[CLPS711X_CLK_TICK] =
 140                 clk_register_fixed_rate(NULL, "tick", NULL, CLK_IS_ROOT, 64);
 141
 142         for (i = 0; i < CLPS711X_CLK_MAX; i++)
 143                 if (IS_ERR(clps711x_clk->clks[i]))
 144                         pr_err("clk %i: register failed with %ld\n",
 145                                i, PTR_ERR(clps711x_clk->clks[i]));
 146
 147         return clps711x_clk;
 148 }
 149
 150 void __init clps711x_clk_init(void __iomem *base)
 151 {
 152         struct clps711x_clk *clps711x_clk;
 153
 154         clps711x_clk = _clps711x_clk_init(base, 73728000);
 155
 156         BUG_ON(IS_ERR(clps711x_clk));
 157
 158         /* Clocksource */
 159         clk_register_clkdev(clps711x_clk->clks[CLPS711X_CLK_TIMER1],
 160                             NULL, "clps711x-timer.0");
 161         clk_register_clkdev(clps711x_clk->clks[CLPS711X_CLK_TIMER2],
 162                             NULL, "clps711x-timer.1");
 163
 164         /* Drivers */
 165         clk_register_clkdev(clps711x_clk->clks[CLPS711X_CLK_PWM],
 166                             NULL, "clps711x-pwm");
 167         clk_register_clkdev(clps711x_clk->clks[CLPS711X_CLK_UART],
 168                             NULL, "clps711x-uart.0");
 169         clk_register_clkdev(clps711x_clk->clks[CLPS711X_CLK_UART],
 170                             NULL, "clps711x-uart.1");
 171 }
 172
 173 #ifdef CONFIG_OF
 174 static void __init clps711x_clk_init_dt(struct device_node *np)
 175 {
 176         void __iomem *base = of_iomap(np, 0);
 177         struct clps711x_clk *clps711x_clk;
 178         u32 fref = 0;
 179
 180         WARN_ON(of_property_read_u32(np, "startup-frequency", &fref));
 181
 182         clps711x_clk = _clps711x_clk_init(base, fref);
 183         BUG_ON(IS_ERR(clps711x_clk));
 184
 185         clps711x_clk->clk_data.clks = clps711x_clk->clks;
 186         clps711x_clk->clk_data.clk_num = CLPS711X_CLK_MAX;
 187         of_clk_add_provider(np, of_clk_src_onecell_get,
 188                             &clps711x_clk->clk_data);
 189 }
 190 CLK_OF_DECLARE(clps711x, "cirrus,clps711x-clk", clps711x_clk_init_dt);
 191 #endif