drivers/sh/clk/cpg.c

   1 /*
   2  * Helper routines for SuperH Clock Pulse Generator blocks (CPG).
   3  *
   4  *  Copyright (C) 2010  Magnus Damm
   5  *  Copyright (C) 2010 - 2012  Paul Mundt
   6  *
   7  * This file is subject to the terms and conditions of the GNU General Public
   8  * License.  See the file "COPYING" in the main directory of this archive
   9  * for more details.
  10  */
  11 #include <linux/clk.h>
  12 #include <linux/compiler.h>
  13 #include <linux/slab.h>
  14 #include <linux/io.h>
  15 #include <linux/sh_clk.h>
  16
  17 #define CPG_CKSTP_BIT   BIT(8)
  18
  19 static unsigned int sh_clk_read(struct clk *clk)
  20 {
  21         if (clk->flags & CLK_ENABLE_REG_8BIT)
  22                 return ioread8(clk->mapped_reg);
  23         else if (clk->flags & CLK_ENABLE_REG_16BIT)
  24                 return ioread16(clk->mapped_reg);
  25
  26         return ioread32(clk->mapped_reg);
  27 }
  28
  29 static void sh_clk_write(int value, struct clk *clk)
  30 {
  31         if (clk->flags & CLK_ENABLE_REG_8BIT)
  32                 iowrite8(value, clk->mapped_reg);
  33         else if (clk->flags & CLK_ENABLE_REG_16BIT)
  34                 iowrite16(value, clk->mapped_reg);
  35         else
  36                 iowrite32(value, clk->mapped_reg);
  37 }
  38
  39 static int sh_clk_mstp_enable(struct clk *clk)
  40 {
  41         sh_clk_write(sh_clk_read(clk) & ~(1 << clk->enable_bit), clk);
  42         return 0;
  43 }
  44
  45 static void sh_clk_mstp_disable(struct clk *clk)
  46 {
  47         sh_clk_write(sh_clk_read(clk) | (1 << clk->enable_bit), clk);
  48 }
  49
  50 static struct sh_clk_ops sh_clk_mstp_clk_ops = {
  51         .enable         = sh_clk_mstp_enable,
  52         .disable        = sh_clk_mstp_disable,
  53         .recalc         = followparent_recalc,
  54 };
  55
  56 int __init sh_clk_mstp_register(struct clk *clks, int nr)
  57 {
  58         struct clk *clkp;
  59         int ret = 0;
  60         int k;
  61
  62         for (k = 0; !ret && (k < nr); k++) {
  63                 clkp = clks + k;
  64                 clkp->ops = &sh_clk_mstp_clk_ops;
  65                 ret |= clk_register(clkp);
  66         }
  67
  68         return ret;
  69 }
  70
  71 /*
  72  * Div/mult table lookup helpers
  73  */
  74 static inline struct clk_div_table *clk_to_div_table(struct clk *clk)
  75 {
  76         return clk->priv;
  77 }
  78
  79 static inline struct clk_div_mult_table *clk_to_div_mult_table(struct clk *clk)
  80 {
  81         return clk_to_div_table(clk)->div_mult_table;
  82 }
  83
  84 /*
  85  * Common div ops
  86  */
  87 static long sh_clk_div_round_rate(struct clk *clk, unsigned long rate)
  88 {
  89         return clk_rate_table_round(clk, clk->freq_table, rate);
  90 }
  91
  92 static unsigned long sh_clk_div_recalc(struct clk *clk)
  93 {
  94         struct clk_div_mult_table *table = clk_to_div_mult_table(clk);
  95         unsigned int idx;
  96
  97         clk_rate_table_build(clk, clk->freq_table, table->nr_divisors,
  98                              table, clk->arch_flags ? &clk->arch_flags : NULL);
  99
 100         idx = (sh_clk_read(clk) >> clk->enable_bit) & clk->div_mask;
 101
 102         return clk->freq_table[idx].frequency;
 103 }
 104
 105 static int sh_clk_div_set_rate(struct clk *clk, unsigned long rate)
 106 {
 107         struct clk_div_table *dt = clk_to_div_table(clk);
 108         unsigned long value;
 109         int idx;
 110
 111         idx = clk_rate_table_find(clk, clk->freq_table, rate);
 112         if (idx < 0)
 113                 return idx;
 114
 115         value = sh_clk_read(clk);
 116         value &= ~(clk->div_mask << clk->enable_bit);
 117         value |= (idx << clk->enable_bit);
 118         sh_clk_write(value, clk);
 119
 120         /* XXX: Should use a post-change notifier */
 121         if (dt->kick)
 122                 dt->kick(clk);
 123
 124         return 0;
 125 }
 126
 127 static int sh_clk_div_enable(struct clk *clk)
 128 {
 129         sh_clk_write(sh_clk_read(clk) & ~CPG_CKSTP_BIT, clk);
 130         return 0;
 131 }
 132
 133 static void sh_clk_div_disable(struct clk *clk)
 134 {
 135         unsigned int val;
 136
 137         val = sh_clk_read(clk);
 138         val |= CPG_CKSTP_BIT;
 139
 140         /*
 141          * div6 clocks require the divisor field to be non-zero or the
 142          * above CKSTP toggle silently fails. Ensure that the divisor
 143          * array is reset to its initial state on disable.
 144          */
 145         if (clk->flags & CLK_MASK_DIV_ON_DISABLE)
 146                 val |= clk->div_mask;
 147
 148         sh_clk_write(val, clk);
 149 }
 150
 151 static struct sh_clk_ops sh_clk_div_clk_ops = {
 152         .recalc         = sh_clk_div_recalc,
 153         .set_rate       = sh_clk_div_set_rate,
 154         .round_rate     = sh_clk_div_round_rate,
 155 };
 156
 157 static struct sh_clk_ops sh_clk_div_enable_clk_ops = {
 158         .recalc         = sh_clk_div_recalc,
 159         .set_rate       = sh_clk_div_set_rate,
 160         .round_rate     = sh_clk_div_round_rate,
 161         .enable         = sh_clk_div_enable,
 162         .disable        = sh_clk_div_disable,
 163 };
 164
 165 static int __init sh_clk_init_parent(struct clk *clk)
 166 {
 167         u32 val;
 168
 169         if (clk->parent)
 170                 return 0;
 171
 172         if (!clk->parent_table || !clk->parent_num)
 173                 return 0;
 174
 175         if (!clk->src_width) {
 176                 pr_err("sh_clk_init_parent: cannot select parent clock\n");
 177                 return -EINVAL;
 178         }
 179
 180         val  = (sh_clk_read(clk) >> clk->src_shift);
 181         val &= (1 << clk->src_width) - 1;
 182
 183         if (val >= clk->parent_num) {
 184                 pr_err("sh_clk_init_parent: parent table size failed\n");
 185                 return -EINVAL;
 186         }
 187
 188         clk_reparent(clk, clk->parent_table[val]);
 189         if (!clk->parent) {
 190                 pr_err("sh_clk_init_parent: unable to set parent");
 191                 return -EINVAL;
 192         }
 193
 194         return 0;
 195 }
 196
 197 static int __init sh_clk_div_register_ops(struct clk *clks, int nr,
 198                         struct clk_div_table *table, struct sh_clk_ops *ops)
 199 {
 200         struct clk *clkp;
 201         void *freq_table;
 202         int nr_divs = table->div_mult_table->nr_divisors;
 203         int freq_table_size = sizeof(struct cpufreq_frequency_table);
 204         int ret = 0;
 205         int k;
 206
 207         freq_table_size *= (nr_divs + 1);
 208         freq_table = kzalloc(freq_table_size * nr, GFP_KERNEL);
 209         if (!freq_table) {
 210                 pr_err("%s: unable to alloc memory\n", __func__);
 211                 return -ENOMEM;
 212         }
 213
 214         for (k = 0; !ret && (k < nr); k++) {
 215                 clkp = clks + k;
 216
 217                 clkp->ops = ops;
 218                 clkp->priv = table;
 219
 220                 clkp->freq_table = freq_table + (k * freq_table_size);
 221                 clkp->freq_table[nr_divs].frequency = CPUFREQ_TABLE_END;
 222
 223                 ret = clk_register(clkp);
 224                 if (ret == 0)
 225                         ret = sh_clk_init_parent(clkp);
 226         }
 227
 228         return ret;
 229 }
 230
 231 /*
 232  * div6 support
 233  */
 234 static int sh_clk_div6_divisors[64] = {
 235         1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
 236         17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32,
 237         33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
 238         49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64
 239 };
 240
 241 static struct clk_div_mult_table div6_div_mult_table = {
 242         .divisors = sh_clk_div6_divisors,
 243         .nr_divisors = ARRAY_SIZE(sh_clk_div6_divisors),
 244 };
 245
 246 static struct clk_div_table sh_clk_div6_table = {
 247         .div_mult_table = &div6_div_mult_table,
 248 };
 249
 250 static int sh_clk_div6_set_parent(struct clk *clk, struct clk *parent)
 251 {
 252         struct clk_div_mult_table *table = clk_to_div_mult_table(clk);
 253         u32 value;
 254         int ret, i;
 255
 256         if (!clk->parent_table || !clk->parent_num)
 257                 return -EINVAL;
 258
 259         /* Search the parent */
 260         for (i = 0; i < clk->parent_num; i++)
 261                 if (clk->parent_table[i] == parent)
 262                         break;
 263
 264         if (i == clk->parent_num)
 265                 return -ENODEV;
 266
 267         ret = clk_reparent(clk, parent);
 268         if (ret < 0)
 269                 return ret;
 270
 271         value = sh_clk_read(clk) &
 272                 ~(((1 << clk->src_width) - 1) << clk->src_shift);
 273
 274         sh_clk_write(value | (i << clk->src_shift), clk);
 275
 276         /* Rebuild the frequency table */
 277         clk_rate_table_build(clk, clk->freq_table, table->nr_divisors,
 278                              table, NULL);
 279
 280         return 0;
 281 }
 282
 283 static struct sh_clk_ops sh_clk_div6_reparent_clk_ops = {
 284         .recalc         = sh_clk_div_recalc,
 285         .round_rate     = sh_clk_div_round_rate,
 286         .set_rate       = sh_clk_div_set_rate,
 287         .enable         = sh_clk_div_enable,
 288         .disable        = sh_clk_div_disable,
 289         .set_parent     = sh_clk_div6_set_parent,
 290 };
 291
 292 int __init sh_clk_div6_register(struct clk *clks, int nr)
 293 {
 294         return sh_clk_div_register_ops(clks, nr, &sh_clk_div6_table,
 295                                        &sh_clk_div_enable_clk_ops);
 296 }
 297
 298 int __init sh_clk_div6_reparent_register(struct clk *clks, int nr)
 299 {
 300         return sh_clk_div_register_ops(clks, nr, &sh_clk_div6_table,
 301                                        &sh_clk_div6_reparent_clk_ops);
 302 }
 303
 304 /*
 305  * div4 support
 306  */
 307 static int sh_clk_div4_set_parent(struct clk *clk, struct clk *parent)
 308 {
 309         struct clk_div_mult_table *table = clk_to_div_mult_table(clk);
 310         u32 value;
 311         int ret;
 312
 313         /* we really need a better way to determine parent index, but for
 314          * now assume internal parent comes with CLK_ENABLE_ON_INIT set,
 315          * no CLK_ENABLE_ON_INIT means external clock...
 316          */
 317
 318         if (parent->flags & CLK_ENABLE_ON_INIT)
 319                 value = sh_clk_read(clk) & ~(1 << 7);
 320         else
 321                 value = sh_clk_read(clk) | (1 << 7);
 322
 323         ret = clk_reparent(clk, parent);
 324         if (ret < 0)
 325                 return ret;
 326
 327         sh_clk_write(value, clk);
 328
 329         /* Rebiuld the frequency table */
 330         clk_rate_table_build(clk, clk->freq_table, table->nr_divisors,
 331                              table, &clk->arch_flags);
 332
 333         return 0;
 334 }
 335
 336 static struct sh_clk_ops sh_clk_div4_reparent_clk_ops = {
 337         .recalc         = sh_clk_div_recalc,
 338         .set_rate       = sh_clk_div_set_rate,
 339         .round_rate     = sh_clk_div_round_rate,
 340         .enable         = sh_clk_div_enable,
 341         .disable        = sh_clk_div_disable,
 342         .set_parent     = sh_clk_div4_set_parent,
 343 };
 344
 345 int __init sh_clk_div4_register(struct clk *clks, int nr,
 346                                 struct clk_div4_table *table)
 347 {
 348         return sh_clk_div_register_ops(clks, nr, table, &sh_clk_div_clk_ops);
 349 }
 350
 351 int __init sh_clk_div4_enable_register(struct clk *clks, int nr,
 352                                 struct clk_div4_table *table)
 353 {
 354         return sh_clk_div_register_ops(clks, nr, table,
 355                                        &sh_clk_div_enable_clk_ops);
 356 }
 357
 358 int __init sh_clk_div4_reparent_register(struct clk *clks, int nr,
 359                                 struct clk_div4_table *table)
 360 {
 361         return sh_clk_div_register_ops(clks, nr, table,
 362                                        &sh_clk_div4_reparent_clk_ops);
 363 }