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