drivers/clk/bcm/clk-iproc-asiu.c

   1 /*
   2  * Copyright (C) 2014 Broadcom Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation version 2.
   7  *
   8  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
   9  * kind, whether express or implied; without even the implied warranty
  10  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/err.h>
  16 #include <linux/clk-provider.h>
  17 #include <linux/io.h>
  18 #include <linux/of.h>
  19 #include <linux/clkdev.h>
  20 #include <linux/of_address.h>
  21 #include <linux/delay.h>
  22
  23 #include "clk-iproc.h"
  24
  25 struct iproc_asiu;
  26
  27 struct iproc_asiu_clk {
  28         struct clk_hw hw;
  29         const char *name;
  30         struct iproc_asiu *asiu;
  31         unsigned long rate;
  32         struct iproc_asiu_div div;
  33         struct iproc_asiu_gate gate;
  34 };
  35
  36 struct iproc_asiu {
  37         void __iomem *div_base;
  38         void __iomem *gate_base;
  39
  40         struct clk_hw_onecell_data *clk_data;
  41         struct iproc_asiu_clk *clks;
  42 };
  43
  44 #define to_asiu_clk(hw) container_of(hw, struct iproc_asiu_clk, hw)
  45
  46 static int iproc_asiu_clk_enable(struct clk_hw *hw)
  47 {
  48         struct iproc_asiu_clk *clk = to_asiu_clk(hw);
  49         struct iproc_asiu *asiu = clk->asiu;
  50         u32 val;
  51
  52         /* some clocks at the ASIU level are always enabled */
  53         if (clk->gate.offset == IPROC_CLK_INVALID_OFFSET)
  54                 return 0;
  55
  56         val = readl(asiu->gate_base + clk->gate.offset);
  57         val |= (1 << clk->gate.en_shift);
  58         writel(val, asiu->gate_base + clk->gate.offset);
  59
  60         return 0;
  61 }
  62
  63 static void iproc_asiu_clk_disable(struct clk_hw *hw)
  64 {
  65         struct iproc_asiu_clk *clk = to_asiu_clk(hw);
  66         struct iproc_asiu *asiu = clk->asiu;
  67         u32 val;
  68
  69         /* some clocks at the ASIU level are always enabled */
  70         if (clk->gate.offset == IPROC_CLK_INVALID_OFFSET)
  71                 return;
  72
  73         val = readl(asiu->gate_base + clk->gate.offset);
  74         val &= ~(1 << clk->gate.en_shift);
  75         writel(val, asiu->gate_base + clk->gate.offset);
  76 }
  77
  78 static unsigned long iproc_asiu_clk_recalc_rate(struct clk_hw *hw,
  79                                                 unsigned long parent_rate)
  80 {
  81         struct iproc_asiu_clk *clk = to_asiu_clk(hw);
  82         struct iproc_asiu *asiu = clk->asiu;
  83         u32 val;
  84         unsigned int div_h, div_l;
  85
  86         if (parent_rate == 0) {
  87                 clk->rate = 0;
  88                 return 0;
  89         }
  90
  91         /* if clock divisor is not enabled, simply return parent rate */
  92         val = readl(asiu->div_base + clk->div.offset);
  93         if ((val & (1 << clk->div.en_shift)) == 0) {
  94                 clk->rate = parent_rate;
  95                 return parent_rate;
  96         }
  97
  98         /* clock rate = parent rate / (high_div + 1) + (low_div + 1) */
  99         div_h = (val >> clk->div.high_shift) & bit_mask(clk->div.high_width);
 100         div_h++;
 101         div_l = (val >> clk->div.low_shift) & bit_mask(clk->div.low_width);
 102         div_l++;
 103
 104         clk->rate = parent_rate / (div_h + div_l);
 105         pr_debug("%s: rate: %lu. parent rate: %lu div_h: %u div_l: %u\n",
 106                  __func__, clk->rate, parent_rate, div_h, div_l);
 107
 108         return clk->rate;
 109 }
 110
 111 static long iproc_asiu_clk_round_rate(struct clk_hw *hw, unsigned long rate,
 112                                       unsigned long *parent_rate)
 113 {
 114         unsigned int div;
 115
 116         if (rate == 0 || *parent_rate == 0)
 117                 return -EINVAL;
 118
 119         if (rate == *parent_rate)
 120                 return *parent_rate;
 121
 122         div = DIV_ROUND_UP(*parent_rate, rate);
 123         if (div < 2)
 124                 return *parent_rate;
 125
 126         return *parent_rate / div;
 127 }
 128
 129 static int iproc_asiu_clk_set_rate(struct clk_hw *hw, unsigned long rate,
 130                                    unsigned long parent_rate)
 131 {
 132         struct iproc_asiu_clk *clk = to_asiu_clk(hw);
 133         struct iproc_asiu *asiu = clk->asiu;
 134         unsigned int div, div_h, div_l;
 135         u32 val;
 136
 137         if (rate == 0 || parent_rate == 0)
 138                 return -EINVAL;
 139
 140         /* simply disable the divisor if one wants the same rate as parent */
 141         if (rate == parent_rate) {
 142                 val = readl(asiu->div_base + clk->div.offset);
 143                 val &= ~(1 << clk->div.en_shift);
 144                 writel(val, asiu->div_base + clk->div.offset);
 145                 return 0;
 146         }
 147
 148         div = DIV_ROUND_UP(parent_rate, rate);
 149         if (div < 2)
 150                 return -EINVAL;
 151
 152         div_h = div_l = div >> 1;
 153         div_h--;
 154         div_l--;
 155
 156         val = readl(asiu->div_base + clk->div.offset);
 157         val |= 1 << clk->div.en_shift;
 158         if (div_h) {
 159                 val &= ~(bit_mask(clk->div.high_width)
 160                          << clk->div.high_shift);
 161                 val |= div_h << clk->div.high_shift;
 162         } else {
 163                 val &= ~(bit_mask(clk->div.high_width)
 164                          << clk->div.high_shift);
 165         }
 166         if (div_l) {
 167                 val &= ~(bit_mask(clk->div.low_width) << clk->div.low_shift);
 168                 val |= div_l << clk->div.low_shift;
 169         } else {
 170                 val &= ~(bit_mask(clk->div.low_width) << clk->div.low_shift);
 171         }
 172         writel(val, asiu->div_base + clk->div.offset);
 173
 174         return 0;
 175 }
 176
 177 static const struct clk_ops iproc_asiu_ops = {
 178         .enable = iproc_asiu_clk_enable,
 179         .disable = iproc_asiu_clk_disable,
 180         .recalc_rate = iproc_asiu_clk_recalc_rate,
 181         .round_rate = iproc_asiu_clk_round_rate,
 182         .set_rate = iproc_asiu_clk_set_rate,
 183 };
 184
 185 void __init iproc_asiu_setup(struct device_node *node,
 186                              const struct iproc_asiu_div *div,
 187                              const struct iproc_asiu_gate *gate,
 188                              unsigned int num_clks)
 189 {
 190         int i, ret;
 191         struct iproc_asiu *asiu;
 192
 193         if (WARN_ON(!gate || !div))
 194                 return;
 195
 196         asiu = kzalloc(sizeof(*asiu), GFP_KERNEL);
 197         if (WARN_ON(!asiu))
 198                 return;
 199
 200         asiu->clk_data = kzalloc(struct_size(asiu->clk_data, hws, num_clks),
 201                                  GFP_KERNEL);
 202         if (WARN_ON(!asiu->clk_data))
 203                 goto err_clks;
 204         asiu->clk_data->num = num_clks;
 205
 206         asiu->clks = kcalloc(num_clks, sizeof(*asiu->clks), GFP_KERNEL);
 207         if (WARN_ON(!asiu->clks))
 208                 goto err_asiu_clks;
 209
 210         asiu->div_base = of_iomap(node, 0);
 211         if (WARN_ON(!asiu->div_base))
 212                 goto err_iomap_div;
 213
 214         asiu->gate_base = of_iomap(node, 1);
 215         if (WARN_ON(!asiu->gate_base))
 216                 goto err_iomap_gate;
 217
 218         for (i = 0; i < num_clks; i++) {
 219                 struct clk_init_data init;
 220                 const char *parent_name;
 221                 struct iproc_asiu_clk *asiu_clk;
 222                 const char *clk_name;
 223
 224                 ret = of_property_read_string_index(node, "clock-output-names",
 225                                                     i, &clk_name);
 226                 if (WARN_ON(ret))
 227                         goto err_clk_register;
 228
 229                 asiu_clk = &asiu->clks[i];
 230                 asiu_clk->name = clk_name;
 231                 asiu_clk->asiu = asiu;
 232                 asiu_clk->div = div[i];
 233                 asiu_clk->gate = gate[i];
 234                 init.name = clk_name;
 235                 init.ops = &iproc_asiu_ops;
 236                 init.flags = 0;
 237                 parent_name = of_clk_get_parent_name(node, 0);
 238                 init.parent_names = (parent_name ? &parent_name : NULL);
 239                 init.num_parents = (parent_name ? 1 : 0);
 240                 asiu_clk->hw.init = &init;
 241
 242                 ret = clk_hw_register(NULL, &asiu_clk->hw);
 243                 if (WARN_ON(ret))
 244                         goto err_clk_register;
 245                 asiu->clk_data->hws[i] = &asiu_clk->hw;
 246         }
 247
 248         ret = of_clk_add_hw_provider(node, of_clk_hw_onecell_get,
 249                                      asiu->clk_data);
 250         if (WARN_ON(ret))
 251                 goto err_clk_register;
 252
 253         return;
 254
 255 err_clk_register:
 256         while (--i >= 0)
 257                 clk_hw_unregister(asiu->clk_data->hws[i]);
 258         iounmap(asiu->gate_base);
 259
 260 err_iomap_gate:
 261         iounmap(asiu->div_base);
 262
 263 err_iomap_div:
 264         kfree(asiu->clks);
 265
 266 err_asiu_clks:
 267         kfree(asiu->clk_data);
 268
 269 err_clks:
 270         kfree(asiu);
 271 }