drivers/clk/at91/clk-pll.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/mfd/syscon.h>
  16 #include <linux/regmap.h>
  17
  18 #include "pmc.h"
  19
  20 #define PLL_STATUS_MASK(id)     (1 << (1 + (id)))
  21 #define PLL_REG(id)             (AT91_CKGR_PLLAR + ((id) * 4))
  22 #define PLL_DIV_MASK            0xff
  23 #define PLL_DIV_MAX             PLL_DIV_MASK
  24 #define PLL_DIV(reg)            ((reg) & PLL_DIV_MASK)
  25 #define PLL_MUL(reg, layout)    (((reg) >> (layout)->mul_shift) & \
  26                                  (layout)->mul_mask)
  27 #define PLL_MUL_MIN             2
  28 #define PLL_MUL_MASK(layout)    ((layout)->mul_mask)
  29 #define PLL_MUL_MAX(layout)     (PLL_MUL_MASK(layout) + 1)
  30 #define PLL_ICPR_SHIFT(id)      ((id) * 16)
  31 #define PLL_ICPR_MASK(id)       (0xffff << PLL_ICPR_SHIFT(id))
  32 #define PLL_MAX_COUNT           0x3f
  33 #define PLL_COUNT_SHIFT         8
  34 #define PLL_OUT_SHIFT           14
  35 #define PLL_MAX_ID              1
  36
  37 struct clk_pll_characteristics {
  38         struct clk_range input;
  39         int num_output;
  40         struct clk_range *output;
  41         u16 *icpll;
  42         u8 *out;
  43 };
  44
  45 struct clk_pll_layout {
  46         u32 pllr_mask;
  47         u16 mul_mask;
  48         u8 mul_shift;
  49 };
  50
  51 #define to_clk_pll(hw) container_of(hw, struct clk_pll, hw)
  52
  53 struct clk_pll {
  54         struct clk_hw hw;
  55         struct regmap *regmap;
  56         u8 id;
  57         u8 div;
  58         u8 range;
  59         u16 mul;
  60         const struct clk_pll_layout *layout;
  61         const struct clk_pll_characteristics *characteristics;
  62 };
  63
  64 static inline bool clk_pll_ready(struct regmap *regmap, int id)
  65 {
  66         unsigned int status;
  67
  68         regmap_read(regmap, AT91_PMC_SR, &status);
  69
  70         return status & PLL_STATUS_MASK(id) ? 1 : 0;
  71 }
  72
  73 static int clk_pll_prepare(struct clk_hw *hw)
  74 {
  75         struct clk_pll *pll = to_clk_pll(hw);
  76         struct regmap *regmap = pll->regmap;
  77         const struct clk_pll_layout *layout = pll->layout;
  78         const struct clk_pll_characteristics *characteristics =
  79                                                         pll->characteristics;
  80         u8 id = pll->id;
  81         u32 mask = PLL_STATUS_MASK(id);
  82         int offset = PLL_REG(id);
  83         u8 out = 0;
  84         unsigned int pllr;
  85         unsigned int status;
  86         u8 div;
  87         u16 mul;
  88
  89         regmap_read(regmap, offset, &pllr);
  90         div = PLL_DIV(pllr);
  91         mul = PLL_MUL(pllr, layout);
  92
  93         regmap_read(regmap, AT91_PMC_SR, &status);
  94         if ((status & mask) &&
  95             (div == pll->div && mul == pll->mul))
  96                 return 0;
  97
  98         if (characteristics->out)
  99                 out = characteristics->out[pll->range];
 100
 101         if (characteristics->icpll)
 102                 regmap_update_bits(regmap, AT91_PMC_PLLICPR, PLL_ICPR_MASK(id),
 103                         characteristics->icpll[pll->range] << PLL_ICPR_SHIFT(id));
 104
 105         regmap_update_bits(regmap, offset, layout->pllr_mask,
 106                         pll->div | (PLL_MAX_COUNT << PLL_COUNT_SHIFT) |
 107                         (out << PLL_OUT_SHIFT) |
 108                         ((pll->mul & layout->mul_mask) << layout->mul_shift));
 109
 110         while (!clk_pll_ready(regmap, pll->id))
 111                 cpu_relax();
 112
 113         return 0;
 114 }
 115
 116 static int clk_pll_is_prepared(struct clk_hw *hw)
 117 {
 118         struct clk_pll *pll = to_clk_pll(hw);
 119
 120         return clk_pll_ready(pll->regmap, pll->id);
 121 }
 122
 123 static void clk_pll_unprepare(struct clk_hw *hw)
 124 {
 125         struct clk_pll *pll = to_clk_pll(hw);
 126         unsigned int mask = pll->layout->pllr_mask;
 127
 128         regmap_update_bits(pll->regmap, PLL_REG(pll->id), mask, ~mask);
 129 }
 130
 131 static unsigned long clk_pll_recalc_rate(struct clk_hw *hw,
 132                                          unsigned long parent_rate)
 133 {
 134         struct clk_pll *pll = to_clk_pll(hw);
 135
 136         return (parent_rate / pll->div) * (pll->mul + 1);
 137 }
 138
 139 static long clk_pll_get_best_div_mul(struct clk_pll *pll, unsigned long rate,
 140                                      unsigned long parent_rate,
 141                                      u32 *div, u32 *mul,
 142                                      u32 *index) {
 143         const struct clk_pll_layout *layout = pll->layout;
 144         const struct clk_pll_characteristics *characteristics =
 145                                                         pll->characteristics;
 146         unsigned long bestremainder = ULONG_MAX;
 147         unsigned long maxdiv, mindiv, tmpdiv;
 148         long bestrate = -ERANGE;
 149         unsigned long bestdiv;
 150         unsigned long bestmul;
 151         int i = 0;
 152
 153         /* Check if parent_rate is a valid input rate */
 154         if (parent_rate < characteristics->input.min)
 155                 return -ERANGE;
 156
 157         /*
 158          * Calculate minimum divider based on the minimum multiplier, the
 159          * parent_rate and the requested rate.
 160          * Should always be 2 according to the input and output characteristics
 161          * of the PLL blocks.
 162          */
 163         mindiv = (parent_rate * PLL_MUL_MIN) / rate;
 164         if (!mindiv)
 165                 mindiv = 1;
 166
 167         if (parent_rate > characteristics->input.max) {
 168                 tmpdiv = DIV_ROUND_UP(parent_rate, characteristics->input.max);
 169                 if (tmpdiv > PLL_DIV_MAX)
 170                         return -ERANGE;
 171
 172                 if (tmpdiv > mindiv)
 173                         mindiv = tmpdiv;
 174         }
 175
 176         /*
 177          * Calculate the maximum divider which is limited by PLL register
 178          * layout (limited by the MUL or DIV field size).
 179          */
 180         maxdiv = DIV_ROUND_UP(parent_rate * PLL_MUL_MAX(layout), rate);
 181         if (maxdiv > PLL_DIV_MAX)
 182                 maxdiv = PLL_DIV_MAX;
 183
 184         /*
 185          * Iterate over the acceptable divider values to find the best
 186          * divider/multiplier pair (the one that generates the closest
 187          * rate to the requested one).
 188          */
 189         for (tmpdiv = mindiv; tmpdiv <= maxdiv; tmpdiv++) {
 190                 unsigned long remainder;
 191                 unsigned long tmprate;
 192                 unsigned long tmpmul;
 193
 194                 /*
 195                  * Calculate the multiplier associated with the current
 196                  * divider that provide the closest rate to the requested one.
 197                  */
 198                 tmpmul = DIV_ROUND_CLOSEST(rate, parent_rate / tmpdiv);
 199                 tmprate = (parent_rate / tmpdiv) * tmpmul;
 200                 if (tmprate > rate)
 201                         remainder = tmprate - rate;
 202                 else
 203                         remainder = rate - tmprate;
 204
 205                 /*
 206                  * Compare the remainder with the best remainder found until
 207                  * now and elect a new best multiplier/divider pair if the
 208                  * current remainder is smaller than the best one.
 209                  */
 210                 if (remainder < bestremainder) {
 211                         bestremainder = remainder;
 212                         bestdiv = tmpdiv;
 213                         bestmul = tmpmul;
 214                         bestrate = tmprate;
 215                 }
 216
 217                 /*
 218                  * We've found a perfect match!
 219                  * Stop searching now and use this multiplier/divider pair.
 220                  */
 221                 if (!remainder)
 222                         break;
 223         }
 224
 225         /* We haven't found any multiplier/divider pair => return -ERANGE */
 226         if (bestrate < 0)
 227                 return bestrate;
 228
 229         /* Check if bestrate is a valid output rate  */
 230         for (i = 0; i < characteristics->num_output; i++) {
 231                 if (bestrate >= characteristics->output[i].min &&
 232                     bestrate <= characteristics->output[i].max)
 233                         break;
 234         }
 235
 236         if (i >= characteristics->num_output)
 237                 return -ERANGE;
 238
 239         if (div)
 240                 *div = bestdiv;
 241         if (mul)
 242                 *mul = bestmul - 1;
 243         if (index)
 244                 *index = i;
 245
 246         return bestrate;
 247 }
 248
 249 static long clk_pll_round_rate(struct clk_hw *hw, unsigned long rate,
 250                                         unsigned long *parent_rate)
 251 {
 252         struct clk_pll *pll = to_clk_pll(hw);
 253
 254         return clk_pll_get_best_div_mul(pll, rate, *parent_rate,
 255                                         NULL, NULL, NULL);
 256 }
 257
 258 static int clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 259                             unsigned long parent_rate)
 260 {
 261         struct clk_pll *pll = to_clk_pll(hw);
 262         long ret;
 263         u32 div;
 264         u32 mul;
 265         u32 index;
 266
 267         ret = clk_pll_get_best_div_mul(pll, rate, parent_rate,
 268                                        &div, &mul, &index);
 269         if (ret < 0)
 270                 return ret;
 271
 272         pll->range = index;
 273         pll->div = div;
 274         pll->mul = mul;
 275
 276         return 0;
 277 }
 278
 279 static const struct clk_ops pll_ops = {
 280         .prepare = clk_pll_prepare,
 281         .unprepare = clk_pll_unprepare,
 282         .is_prepared = clk_pll_is_prepared,
 283         .recalc_rate = clk_pll_recalc_rate,
 284         .round_rate = clk_pll_round_rate,
 285         .set_rate = clk_pll_set_rate,
 286 };
 287
 288 static struct clk_hw * __init
 289 at91_clk_register_pll(struct regmap *regmap, const char *name,
 290                       const char *parent_name, u8 id,
 291                       const struct clk_pll_layout *layout,
 292                       const struct clk_pll_characteristics *characteristics)
 293 {
 294         struct clk_pll *pll;
 295         struct clk_hw *hw;
 296         struct clk_init_data init;
 297         int offset = PLL_REG(id);
 298         unsigned int pllr;
 299         int ret;
 300
 301         if (id > PLL_MAX_ID)
 302                 return ERR_PTR(-EINVAL);
 303
 304         pll = kzalloc(sizeof(*pll), GFP_KERNEL);
 305         if (!pll)
 306                 return ERR_PTR(-ENOMEM);
 307
 308         init.name = name;
 309         init.ops = &pll_ops;
 310         init.parent_names = &parent_name;
 311         init.num_parents = 1;
 312         init.flags = CLK_SET_RATE_GATE;
 313
 314         pll->id = id;
 315         pll->hw.init = &init;
 316         pll->layout = layout;
 317         pll->characteristics = characteristics;
 318         pll->regmap = regmap;
 319         regmap_read(regmap, offset, &pllr);
 320         pll->div = PLL_DIV(pllr);
 321         pll->mul = PLL_MUL(pllr, layout);
 322
 323         hw = &pll->hw;
 324         ret = clk_hw_register(NULL, &pll->hw);
 325         if (ret) {
 326                 kfree(pll);
 327                 hw = ERR_PTR(ret);
 328         }
 329
 330         return hw;
 331 }
 332
 333
 334 static const struct clk_pll_layout at91rm9200_pll_layout = {
 335         .pllr_mask = 0x7FFFFFF,
 336         .mul_shift = 16,
 337         .mul_mask = 0x7FF,
 338 };
 339
 340 static const struct clk_pll_layout at91sam9g45_pll_layout = {
 341         .pllr_mask = 0xFFFFFF,
 342         .mul_shift = 16,
 343         .mul_mask = 0xFF,
 344 };
 345
 346 static const struct clk_pll_layout at91sam9g20_pllb_layout = {
 347         .pllr_mask = 0x3FFFFF,
 348         .mul_shift = 16,
 349         .mul_mask = 0x3F,
 350 };
 351
 352 static const struct clk_pll_layout sama5d3_pll_layout = {
 353         .pllr_mask = 0x1FFFFFF,
 354         .mul_shift = 18,
 355         .mul_mask = 0x7F,
 356 };
 357
 358
 359 static struct clk_pll_characteristics * __init
 360 of_at91_clk_pll_get_characteristics(struct device_node *np)
 361 {
 362         int i;
 363         int offset;
 364         u32 tmp;
 365         int num_output;
 366         u32 num_cells;
 367         struct clk_range input;
 368         struct clk_range *output;
 369         u8 *out = NULL;
 370         u16 *icpll = NULL;
 371         struct clk_pll_characteristics *characteristics;
 372
 373         if (of_at91_get_clk_range(np, "atmel,clk-input-range", &input))
 374                 return NULL;
 375
 376         if (of_property_read_u32(np, "#atmel,pll-clk-output-range-cells",
 377                                  &num_cells))
 378                 return NULL;
 379
 380         if (num_cells < 2 || num_cells > 4)
 381                 return NULL;
 382
 383         if (!of_get_property(np, "atmel,pll-clk-output-ranges", &tmp))
 384                 return NULL;
 385         num_output = tmp / (sizeof(u32) * num_cells);
 386
 387         characteristics = kzalloc(sizeof(*characteristics), GFP_KERNEL);
 388         if (!characteristics)
 389                 return NULL;
 390
 391         output = kcalloc(num_output, sizeof(*output), GFP_KERNEL);
 392         if (!output)
 393                 goto out_free_characteristics;
 394
 395         if (num_cells > 2) {
 396                 out = kcalloc(num_output, sizeof(*out), GFP_KERNEL);
 397                 if (!out)
 398                         goto out_free_output;
 399         }
 400
 401         if (num_cells > 3) {
 402                 icpll = kcalloc(num_output, sizeof(*icpll), GFP_KERNEL);
 403                 if (!icpll)
 404                         goto out_free_output;
 405         }
 406
 407         for (i = 0; i < num_output; i++) {
 408                 offset = i * num_cells;
 409                 if (of_property_read_u32_index(np,
 410                                                "atmel,pll-clk-output-ranges",
 411                                                offset, &tmp))
 412                         goto out_free_output;
 413                 output[i].min = tmp;
 414                 if (of_property_read_u32_index(np,
 415                                                "atmel,pll-clk-output-ranges",
 416                                                offset + 1, &tmp))
 417                         goto out_free_output;
 418                 output[i].max = tmp;
 419
 420                 if (num_cells == 2)
 421                         continue;
 422
 423                 if (of_property_read_u32_index(np,
 424                                                "atmel,pll-clk-output-ranges",
 425                                                offset + 2, &tmp))
 426                         goto out_free_output;
 427                 out[i] = tmp;
 428
 429                 if (num_cells == 3)
 430                         continue;
 431
 432                 if (of_property_read_u32_index(np,
 433                                                "atmel,pll-clk-output-ranges",
 434                                                offset + 3, &tmp))
 435                         goto out_free_output;
 436                 icpll[i] = tmp;
 437         }
 438
 439         characteristics->input = input;
 440         characteristics->num_output = num_output;
 441         characteristics->output = output;
 442         characteristics->out = out;
 443         characteristics->icpll = icpll;
 444         return characteristics;
 445
 446 out_free_output:
 447         kfree(icpll);
 448         kfree(out);
 449         kfree(output);
 450 out_free_characteristics:
 451         kfree(characteristics);
 452         return NULL;
 453 }
 454
 455 static void __init
 456 of_at91_clk_pll_setup(struct device_node *np,
 457                       const struct clk_pll_layout *layout)
 458 {
 459         u32 id;
 460         struct clk_hw *hw;
 461         struct regmap *regmap;
 462         const char *parent_name;
 463         const char *name = np->name;
 464         struct clk_pll_characteristics *characteristics;
 465
 466         if (of_property_read_u32(np, "reg", &id))
 467                 return;
 468
 469         parent_name = of_clk_get_parent_name(np, 0);
 470
 471         of_property_read_string(np, "clock-output-names", &name);
 472
 473         regmap = syscon_node_to_regmap(of_get_parent(np));
 474         if (IS_ERR(regmap))
 475                 return;
 476
 477         characteristics = of_at91_clk_pll_get_characteristics(np);
 478         if (!characteristics)
 479                 return;
 480
 481         hw = at91_clk_register_pll(regmap, name, parent_name, id, layout,
 482                                     characteristics);
 483         if (IS_ERR(hw))
 484                 goto out_free_characteristics;
 485
 486         of_clk_add_hw_provider(np, of_clk_hw_simple_get, hw);
 487         return;
 488
 489 out_free_characteristics:
 490         kfree(characteristics);
 491 }
 492
 493 static void __init of_at91rm9200_clk_pll_setup(struct device_node *np)
 494 {
 495         of_at91_clk_pll_setup(np, &at91rm9200_pll_layout);
 496 }
 497 CLK_OF_DECLARE(at91rm9200_clk_pll, "atmel,at91rm9200-clk-pll",
 498                of_at91rm9200_clk_pll_setup);
 499
 500 static void __init of_at91sam9g45_clk_pll_setup(struct device_node *np)
 501 {
 502         of_at91_clk_pll_setup(np, &at91sam9g45_pll_layout);
 503 }
 504 CLK_OF_DECLARE(at91sam9g45_clk_pll, "atmel,at91sam9g45-clk-pll",
 505                of_at91sam9g45_clk_pll_setup);
 506
 507 static void __init of_at91sam9g20_clk_pllb_setup(struct device_node *np)
 508 {
 509         of_at91_clk_pll_setup(np, &at91sam9g20_pllb_layout);
 510 }
 511 CLK_OF_DECLARE(at91sam9g20_clk_pllb, "atmel,at91sam9g20-clk-pllb",
 512                of_at91sam9g20_clk_pllb_setup);
 513
 514 static void __init of_sama5d3_clk_pll_setup(struct device_node *np)
 515 {
 516         of_at91_clk_pll_setup(np, &sama5d3_pll_layout);
 517 }
 518 CLK_OF_DECLARE(sama5d3_clk_pll, "atmel,sama5d3-clk-pll",
 519                of_sama5d3_clk_pll_setup);