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         spinlock_t                      lock;
  44         struct clk_hw_onecell_data      clk_data;
  45 };
  46
  47 static void __init clps711x_clk_init_dt(struct device_node *np)
  48 {
  49         u32 tmp, f_cpu, f_pll, f_bus, f_tim, f_pwm, f_spi, fref = 0;
  50         struct clps711x_clk *clps711x_clk;
  51         void __iomem *base;
  52
  53         WARN_ON(of_property_read_u32(np, "startup-frequency", &fref));
  54
  55         base = of_iomap(np, 0);
  56         BUG_ON(!base);
  57
  58         clps711x_clk = kzalloc(struct_size(clps711x_clk, clk_data.hws,
  59                                            CLPS711X_CLK_MAX),
  60                                GFP_KERNEL);
  61         BUG_ON(!clps711x_clk);
  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->clk_data.hws[CLPS711X_CLK_DUMMY] =
 111                 clk_hw_register_fixed_rate(NULL, "dummy", NULL, 0, 0);
 112         clps711x_clk->clk_data.hws[CLPS711X_CLK_CPU] =
 113                 clk_hw_register_fixed_rate(NULL, "cpu", NULL, 0, f_cpu);
 114         clps711x_clk->clk_data.hws[CLPS711X_CLK_BUS] =
 115                 clk_hw_register_fixed_rate(NULL, "bus", NULL, 0, f_bus);
 116         clps711x_clk->clk_data.hws[CLPS711X_CLK_PLL] =
 117                 clk_hw_register_fixed_rate(NULL, "pll", NULL, 0, f_pll);
 118         clps711x_clk->clk_data.hws[CLPS711X_CLK_TIMERREF] =
 119                 clk_hw_register_fixed_rate(NULL, "timer_ref", NULL, 0, f_tim);
 120         clps711x_clk->clk_data.hws[CLPS711X_CLK_TIMER1] =
 121                 clk_hw_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->clk_data.hws[CLPS711X_CLK_TIMER2] =
 125                 clk_hw_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->clk_data.hws[CLPS711X_CLK_PWM] =
 129                 clk_hw_register_fixed_rate(NULL, "pwm", NULL, 0, f_pwm);
 130         clps711x_clk->clk_data.hws[CLPS711X_CLK_SPIREF] =
 131                 clk_hw_register_fixed_rate(NULL, "spi_ref", NULL, 0, f_spi);
 132         clps711x_clk->clk_data.hws[CLPS711X_CLK_SPI] =
 133                 clk_hw_register_divider_table(NULL, "spi", "spi_ref", 0,
 134                                            base + CLPS711X_SYSCON1, 16, 2, 0,
 135                                            spi_div_table, &clps711x_clk->lock);
 136         clps711x_clk->clk_data.hws[CLPS711X_CLK_UART] =
 137                 clk_hw_register_fixed_factor(NULL, "uart", "bus", 0, 1, 10);
 138         clps711x_clk->clk_data.hws[CLPS711X_CLK_TICK] =
 139                 clk_hw_register_fixed_rate(NULL, "tick", NULL, 0, 64);
 140         for (tmp = 0; tmp < CLPS711X_CLK_MAX; tmp++)
 141                 if (IS_ERR(clps711x_clk->clk_data.hws[tmp]))
 142                         pr_err("clk %i: register failed with %ld\n",
 143                                tmp, PTR_ERR(clps711x_clk->clk_data.hws[tmp]));
 144
 145         clps711x_clk->clk_data.num = CLPS711X_CLK_MAX;
 146         of_clk_add_hw_provider(np, of_clk_hw_onecell_get,
 147                                &clps711x_clk->clk_data);
 148 }
 149 CLK_OF_DECLARE(clps711x, "cirrus,ep7209-clk", clps711x_clk_init_dt);