kernel/drivers/clk/at91/clk-peripheral.c

   1 /*
   2  *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  */
  10
  11 #include <linux/clk-provider.h>
  12 #include <linux/clkdev.h>
  13 #include <linux/clk/at91_pmc.h>
  14 #include <linux/of.h>
  15 #include <linux/of_address.h>
  16 #include <linux/io.h>
  17
  18 #include "pmc.h"
  19
  20 #define PERIPHERAL_MAX          64
  21
  22 #define PERIPHERAL_AT91RM9200   0
  23 #define PERIPHERAL_AT91SAM9X5   1
  24
  25 #define PERIPHERAL_ID_MIN       2
  26 #define PERIPHERAL_ID_MAX       31
  27 #define PERIPHERAL_MASK(id)     (1 << ((id) & PERIPHERAL_ID_MAX))
  28
  29 #define PERIPHERAL_RSHIFT_MASK  0x3
  30 #define PERIPHERAL_RSHIFT(val)  (((val) >> 16) & PERIPHERAL_RSHIFT_MASK)
  31
  32 #define PERIPHERAL_MAX_SHIFT    3
  33
  34 struct clk_peripheral {
  35         struct clk_hw hw;
  36         struct at91_pmc *pmc;
  37         u32 id;
  38 };
  39
  40 #define to_clk_peripheral(hw) container_of(hw, struct clk_peripheral, hw)
  41
  42 struct clk_sam9x5_peripheral {
  43         struct clk_hw hw;
  44         struct at91_pmc *pmc;
  45         struct clk_range range;
  46         u32 id;
  47         u32 div;
  48         bool auto_div;
  49 };
  50
  51 #define to_clk_sam9x5_peripheral(hw) \
  52         container_of(hw, struct clk_sam9x5_peripheral, hw)
  53
  54 static int clk_peripheral_enable(struct clk_hw *hw)
  55 {
  56         struct clk_peripheral *periph = to_clk_peripheral(hw);
  57         struct at91_pmc *pmc = periph->pmc;
  58         int offset = AT91_PMC_PCER;
  59         u32 id = periph->id;
  60
  61         if (id < PERIPHERAL_ID_MIN)
  62                 return 0;
  63         if (id > PERIPHERAL_ID_MAX)
  64                 offset = AT91_PMC_PCER1;
  65         pmc_write(pmc, offset, PERIPHERAL_MASK(id));
  66         return 0;
  67 }
  68
  69 static void clk_peripheral_disable(struct clk_hw *hw)
  70 {
  71         struct clk_peripheral *periph = to_clk_peripheral(hw);
  72         struct at91_pmc *pmc = periph->pmc;
  73         int offset = AT91_PMC_PCDR;
  74         u32 id = periph->id;
  75
  76         if (id < PERIPHERAL_ID_MIN)
  77                 return;
  78         if (id > PERIPHERAL_ID_MAX)
  79                 offset = AT91_PMC_PCDR1;
  80         pmc_write(pmc, offset, PERIPHERAL_MASK(id));
  81 }
  82
  83 static int clk_peripheral_is_enabled(struct clk_hw *hw)
  84 {
  85         struct clk_peripheral *periph = to_clk_peripheral(hw);
  86         struct at91_pmc *pmc = periph->pmc;
  87         int offset = AT91_PMC_PCSR;
  88         u32 id = periph->id;
  89
  90         if (id < PERIPHERAL_ID_MIN)
  91                 return 1;
  92         if (id > PERIPHERAL_ID_MAX)
  93                 offset = AT91_PMC_PCSR1;
  94         return !!(pmc_read(pmc, offset) & PERIPHERAL_MASK(id));
  95 }
  96
  97 static const struct clk_ops peripheral_ops = {
  98         .enable = clk_peripheral_enable,
  99         .disable = clk_peripheral_disable,
 100         .is_enabled = clk_peripheral_is_enabled,
 101 };
 102
 103 static struct clk * __init
 104 at91_clk_register_peripheral(struct at91_pmc *pmc, const char *name,
 105                              const char *parent_name, u32 id)
 106 {
 107         struct clk_peripheral *periph;
 108         struct clk *clk = NULL;
 109         struct clk_init_data init;
 110
 111         if (!pmc || !name || !parent_name || id > PERIPHERAL_ID_MAX)
 112                 return ERR_PTR(-EINVAL);
 113
 114         periph = kzalloc(sizeof(*periph), GFP_KERNEL);
 115         if (!periph)
 116                 return ERR_PTR(-ENOMEM);
 117
 118         init.name = name;
 119         init.ops = &peripheral_ops;
 120         init.parent_names = (parent_name ? &parent_name : NULL);
 121         init.num_parents = (parent_name ? 1 : 0);
 122         init.flags = 0;
 123
 124         periph->id = id;
 125         periph->hw.init = &init;
 126         periph->pmc = pmc;
 127
 128         clk = clk_register(NULL, &periph->hw);
 129         if (IS_ERR(clk))
 130                 kfree(periph);
 131
 132         return clk;
 133 }
 134
 135 static void clk_sam9x5_peripheral_autodiv(struct clk_sam9x5_peripheral *periph)
 136 {
 137         struct clk *parent;
 138         unsigned long parent_rate;
 139         int shift = 0;
 140
 141         if (!periph->auto_div)
 142                 return;
 143
 144         if (periph->range.max) {
 145                 parent = clk_get_parent_by_index(periph->hw.clk, 0);
 146                 parent_rate = __clk_get_rate(parent);
 147                 if (!parent_rate)
 148                         return;
 149
 150                 for (; shift < PERIPHERAL_MAX_SHIFT; shift++) {
 151                         if (parent_rate >> shift <= periph->range.max)
 152                                 break;
 153                 }
 154         }
 155
 156         periph->auto_div = false;
 157         periph->div = shift;
 158 }
 159
 160 static int clk_sam9x5_peripheral_enable(struct clk_hw *hw)
 161 {
 162         struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
 163         struct at91_pmc *pmc = periph->pmc;
 164
 165         if (periph->id < PERIPHERAL_ID_MIN)
 166                 return 0;
 167
 168         pmc_write(pmc, AT91_PMC_PCR, (periph->id & AT91_PMC_PCR_PID) |
 169                                      AT91_PMC_PCR_CMD |
 170                                      AT91_PMC_PCR_DIV(periph->div) |
 171                                      AT91_PMC_PCR_EN);
 172         return 0;
 173 }
 174
 175 static void clk_sam9x5_peripheral_disable(struct clk_hw *hw)
 176 {
 177         struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
 178         struct at91_pmc *pmc = periph->pmc;
 179
 180         if (periph->id < PERIPHERAL_ID_MIN)
 181                 return;
 182
 183         pmc_write(pmc, AT91_PMC_PCR, (periph->id & AT91_PMC_PCR_PID) |
 184                                      AT91_PMC_PCR_CMD);
 185 }
 186
 187 static int clk_sam9x5_peripheral_is_enabled(struct clk_hw *hw)
 188 {
 189         struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
 190         struct at91_pmc *pmc = periph->pmc;
 191         int ret;
 192
 193         if (periph->id < PERIPHERAL_ID_MIN)
 194                 return 1;
 195
 196         pmc_lock(pmc);
 197         pmc_write(pmc, AT91_PMC_PCR, (periph->id & AT91_PMC_PCR_PID));
 198         ret = !!(pmc_read(pmc, AT91_PMC_PCR) & AT91_PMC_PCR_EN);
 199         pmc_unlock(pmc);
 200
 201         return ret;
 202 }
 203
 204 static unsigned long
 205 clk_sam9x5_peripheral_recalc_rate(struct clk_hw *hw,
 206                                   unsigned long parent_rate)
 207 {
 208         struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
 209         struct at91_pmc *pmc = periph->pmc;
 210         u32 tmp;
 211
 212         if (periph->id < PERIPHERAL_ID_MIN)
 213                 return parent_rate;
 214
 215         pmc_lock(pmc);
 216         pmc_write(pmc, AT91_PMC_PCR, (periph->id & AT91_PMC_PCR_PID));
 217         tmp = pmc_read(pmc, AT91_PMC_PCR);
 218         pmc_unlock(pmc);
 219
 220         if (tmp & AT91_PMC_PCR_EN) {
 221                 periph->div = PERIPHERAL_RSHIFT(tmp);
 222                 periph->auto_div = false;
 223         } else {
 224                 clk_sam9x5_peripheral_autodiv(periph);
 225         }
 226
 227         return parent_rate >> periph->div;
 228 }
 229
 230 static long clk_sam9x5_peripheral_round_rate(struct clk_hw *hw,
 231                                              unsigned long rate,
 232                                              unsigned long *parent_rate)
 233 {
 234         int shift = 0;
 235         unsigned long best_rate;
 236         unsigned long best_diff;
 237         unsigned long cur_rate = *parent_rate;
 238         unsigned long cur_diff;
 239         struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
 240
 241         if (periph->id < PERIPHERAL_ID_MIN || !periph->range.max)
 242                 return *parent_rate;
 243
 244         if (periph->range.max) {
 245                 for (; shift <= PERIPHERAL_MAX_SHIFT; shift++) {
 246                         cur_rate = *parent_rate >> shift;
 247                         if (cur_rate <= periph->range.max)
 248                                 break;
 249                 }
 250         }
 251
 252         if (rate >= cur_rate)
 253                 return cur_rate;
 254
 255         best_diff = cur_rate - rate;
 256         best_rate = cur_rate;
 257         for (; shift <= PERIPHERAL_MAX_SHIFT; shift++) {
 258                 cur_rate = *parent_rate >> shift;
 259                 if (cur_rate < rate)
 260                         cur_diff = rate - cur_rate;
 261                 else
 262                         cur_diff = cur_rate - rate;
 263
 264                 if (cur_diff < best_diff) {
 265                         best_diff = cur_diff;
 266                         best_rate = cur_rate;
 267                 }
 268
 269                 if (!best_diff || cur_rate < rate)
 270                         break;
 271         }
 272
 273         return best_rate;
 274 }
 275
 276 static int clk_sam9x5_peripheral_set_rate(struct clk_hw *hw,
 277                                           unsigned long rate,
 278                                           unsigned long parent_rate)
 279 {
 280         int shift;
 281         struct clk_sam9x5_peripheral *periph = to_clk_sam9x5_peripheral(hw);
 282         if (periph->id < PERIPHERAL_ID_MIN || !periph->range.max) {
 283                 if (parent_rate == rate)
 284                         return 0;
 285                 else
 286                         return -EINVAL;
 287         }
 288
 289         if (periph->range.max && rate > periph->range.max)
 290                 return -EINVAL;
 291
 292         for (shift = 0; shift <= PERIPHERAL_MAX_SHIFT; shift++) {
 293                 if (parent_rate >> shift == rate) {
 294                         periph->auto_div = false;
 295                         periph->div = shift;
 296                         return 0;
 297                 }
 298         }
 299
 300         return -EINVAL;
 301 }
 302
 303 static const struct clk_ops sam9x5_peripheral_ops = {
 304         .enable = clk_sam9x5_peripheral_enable,
 305         .disable = clk_sam9x5_peripheral_disable,
 306         .is_enabled = clk_sam9x5_peripheral_is_enabled,
 307         .recalc_rate = clk_sam9x5_peripheral_recalc_rate,
 308         .round_rate = clk_sam9x5_peripheral_round_rate,
 309         .set_rate = clk_sam9x5_peripheral_set_rate,
 310 };
 311
 312 static struct clk * __init
 313 at91_clk_register_sam9x5_peripheral(struct at91_pmc *pmc, const char *name,
 314                                     const char *parent_name, u32 id,
 315                                     const struct clk_range *range)
 316 {
 317         struct clk_sam9x5_peripheral *periph;
 318         struct clk *clk = NULL;
 319         struct clk_init_data init;
 320
 321         if (!pmc || !name || !parent_name)
 322                 return ERR_PTR(-EINVAL);
 323
 324         periph = kzalloc(sizeof(*periph), GFP_KERNEL);
 325         if (!periph)
 326                 return ERR_PTR(-ENOMEM);
 327
 328         init.name = name;
 329         init.ops = &sam9x5_peripheral_ops;
 330         init.parent_names = (parent_name ? &parent_name : NULL);
 331         init.num_parents = (parent_name ? 1 : 0);
 332         init.flags = 0;
 333
 334         periph->id = id;
 335         periph->hw.init = &init;
 336         periph->div = 0;
 337         periph->pmc = pmc;
 338         periph->auto_div = true;
 339         periph->range = *range;
 340
 341         clk = clk_register(NULL, &periph->hw);
 342         if (IS_ERR(clk))
 343                 kfree(periph);
 344         else
 345                 clk_sam9x5_peripheral_autodiv(periph);
 346
 347         return clk;
 348 }
 349
 350 static void __init
 351 of_at91_clk_periph_setup(struct device_node *np, struct at91_pmc *pmc, u8 type)
 352 {
 353         int num;
 354         u32 id;
 355         struct clk *clk;
 356         const char *parent_name;
 357         const char *name;
 358         struct device_node *periphclknp;
 359
 360         parent_name = of_clk_get_parent_name(np, 0);
 361         if (!parent_name)
 362                 return;
 363
 364         num = of_get_child_count(np);
 365         if (!num || num > PERIPHERAL_MAX)
 366                 return;
 367
 368         for_each_child_of_node(np, periphclknp) {
 369                 if (of_property_read_u32(periphclknp, "reg", &id))
 370                         continue;
 371
 372                 if (id >= PERIPHERAL_MAX)
 373                         continue;
 374
 375                 if (of_property_read_string(np, "clock-output-names", &name))
 376                         name = periphclknp->name;
 377
 378                 if (type == PERIPHERAL_AT91RM9200) {
 379                         clk = at91_clk_register_peripheral(pmc, name,
 380                                                            parent_name, id);
 381                 } else {
 382                         struct clk_range range = CLK_RANGE(0, 0);
 383
 384                         of_at91_get_clk_range(periphclknp,
 385                                               "atmel,clk-output-range",
 386                                               &range);
 387
 388                         clk = at91_clk_register_sam9x5_peripheral(pmc, name,
 389                                                                   parent_name,
 390                                                                   id, &range);
 391                 }
 392
 393                 if (IS_ERR(clk))
 394                         continue;
 395
 396                 of_clk_add_provider(periphclknp, of_clk_src_simple_get, clk);
 397         }
 398 }
 399
 400 void __init of_at91rm9200_clk_periph_setup(struct device_node *np,
 401                                            struct at91_pmc *pmc)
 402 {
 403         of_at91_clk_periph_setup(np, pmc, PERIPHERAL_AT91RM9200);
 404 }
 405
 406 void __init of_at91sam9x5_clk_periph_setup(struct device_node *np,
 407                                            struct at91_pmc *pmc)
 408 {
 409         of_at91_clk_periph_setup(np, pmc, PERIPHERAL_AT91SAM9X5);
 410 }