drivers/clk/clk-cs2000-cp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * CS2000  --  CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
   4  *
   5  * Copyright (C) 2015 Renesas Electronics Corporation
   6  * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
   7  */
   8 #include <linux/clk-provider.h>
   9 #include <linux/delay.h>
  10 #include <linux/clk.h>
  11 #include <linux/i2c.h>
  12 #include <linux/of.h>
  13 #include <linux/module.h>
  14 #include <linux/regmap.h>
  15
  16 #define CH_MAX 4
  17 #define RATIO_REG_SIZE 4
  18
  19 #define DEVICE_ID       0x1
  20 #define DEVICE_CTRL     0x2
  21 #define DEVICE_CFG1     0x3
  22 #define DEVICE_CFG2     0x4
  23 #define GLOBAL_CFG      0x5
  24 #define Ratio_Add(x, nth)       (6 + (x * 4) + (nth))
  25 #define Ratio_Val(x, nth)       ((x >> (24 - (8 * nth))) & 0xFF)
  26 #define Val_Ratio(x, nth)       ((x & 0xFF) << (24 - (8 * nth)))
  27 #define FUNC_CFG1       0x16
  28 #define FUNC_CFG2       0x17
  29
  30 /* DEVICE_ID */
  31 #define REVISION_MASK   (0x7)
  32 #define REVISION_B2_B3  (0x4)
  33 #define REVISION_C1     (0x6)
  34
  35 /* DEVICE_CTRL */
  36 #define PLL_UNLOCK      (1 << 7)
  37 #define AUXOUTDIS       (1 << 1)
  38 #define CLKOUTDIS       (1 << 0)
  39
  40 /* DEVICE_CFG1 */
  41 #define RSEL(x)         (((x) & 0x3) << 3)
  42 #define RSEL_MASK       RSEL(0x3)
  43 #define AUXOUTSRC(x)    (((x) & 0x3) << 1)
  44 #define AUXOUTSRC_MASK  AUXOUTSRC(0x3)
  45 #define ENDEV1          (0x1)
  46
  47 /* DEVICE_CFG2 */
  48 #define AUTORMOD        (1 << 3)
  49 #define LOCKCLK(x)      (((x) & 0x3) << 1)
  50 #define LOCKCLK_MASK    LOCKCLK(0x3)
  51 #define FRACNSRC_MASK   (1 << 0)
  52 #define FRACNSRC_STATIC         (0 << 0)
  53 #define FRACNSRC_DYNAMIC        (1 << 0)
  54
  55 /* GLOBAL_CFG */
  56 #define FREEZE          (1 << 7)
  57 #define ENDEV2          (0x1)
  58
  59 /* FUNC_CFG1 */
  60 #define CLKSKIPEN       (1 << 7)
  61 #define REFCLKDIV(x)    (((x) & 0x3) << 3)
  62 #define REFCLKDIV_MASK  REFCLKDIV(0x3)
  63
  64 /* FUNC_CFG2 */
  65 #define LFRATIO_MASK    (1 << 3)
  66 #define LFRATIO_20_12   (0 << 3)
  67 #define LFRATIO_12_20   (1 << 3)
  68
  69 #define CH_SIZE_ERR(ch)         ((ch < 0) || (ch >= CH_MAX))
  70 #define hw_to_priv(_hw)         container_of(_hw, struct cs2000_priv, hw)
  71 #define priv_to_client(priv)    (priv->client)
  72 #define priv_to_dev(priv)       (&(priv_to_client(priv)->dev))
  73
  74 #define CLK_IN  0
  75 #define REF_CLK 1
  76 #define CLK_MAX 2
  77
  78 static bool cs2000_readable_reg(struct device *dev, unsigned int reg)
  79 {
  80         return reg > 0;
  81 }
  82
  83 static bool cs2000_writeable_reg(struct device *dev, unsigned int reg)
  84 {
  85         return reg != DEVICE_ID;
  86 }
  87
  88 static bool cs2000_volatile_reg(struct device *dev, unsigned int reg)
  89 {
  90         return reg == DEVICE_CTRL;
  91 }
  92
  93 static const struct regmap_config cs2000_regmap_config = {
  94         .reg_bits       = 8,
  95         .val_bits       = 8,
  96         .max_register   = FUNC_CFG2,
  97         .readable_reg   = cs2000_readable_reg,
  98         .writeable_reg  = cs2000_writeable_reg,
  99         .volatile_reg   = cs2000_volatile_reg,
 100 };
 101
 102 struct cs2000_priv {
 103         struct clk_hw hw;
 104         struct i2c_client *client;
 105         struct clk *clk_in;
 106         struct clk *ref_clk;
 107         struct regmap *regmap;
 108
 109         bool dynamic_mode;
 110         bool lf_ratio;
 111         bool clk_skip;
 112
 113         /* suspend/resume */
 114         unsigned long saved_rate;
 115         unsigned long saved_parent_rate;
 116 };
 117
 118 static const struct of_device_id cs2000_of_match[] = {
 119         { .compatible = "cirrus,cs2000-cp", },
 120         {},
 121 };
 122 MODULE_DEVICE_TABLE(of, cs2000_of_match);
 123
 124 static const struct i2c_device_id cs2000_id[] = {
 125         { "cs2000-cp", },
 126         {}
 127 };
 128 MODULE_DEVICE_TABLE(i2c, cs2000_id);
 129
 130 static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)
 131 {
 132         int ret;
 133
 134         ret = regmap_update_bits(priv->regmap, DEVICE_CFG1, ENDEV1,
 135                                  enable ? ENDEV1 : 0);
 136         if (ret < 0)
 137                 return ret;
 138
 139         ret = regmap_update_bits(priv->regmap, GLOBAL_CFG,  ENDEV2,
 140                                  enable ? ENDEV2 : 0);
 141         if (ret < 0)
 142                 return ret;
 143
 144         ret = regmap_update_bits(priv->regmap, FUNC_CFG1, CLKSKIPEN,
 145                                  (enable && priv->clk_skip) ? CLKSKIPEN : 0);
 146         if (ret < 0)
 147                 return ret;
 148
 149         return 0;
 150 }
 151
 152 static int cs2000_ref_clk_bound_rate(struct cs2000_priv *priv,
 153                                      u32 rate_in)
 154 {
 155         u32 val;
 156
 157         if (rate_in >= 32000000 && rate_in < 56000000)
 158                 val = 0x0;
 159         else if (rate_in >= 16000000 && rate_in < 28000000)
 160                 val = 0x1;
 161         else if (rate_in >= 8000000 && rate_in < 14000000)
 162                 val = 0x2;
 163         else
 164                 return -EINVAL;
 165
 166         return regmap_update_bits(priv->regmap, FUNC_CFG1,
 167                                   REFCLKDIV_MASK,
 168                                   REFCLKDIV(val));
 169 }
 170
 171 static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
 172 {
 173         struct device *dev = priv_to_dev(priv);
 174         unsigned int i, val;
 175         int ret;
 176
 177         for (i = 0; i < 256; i++) {
 178                 ret = regmap_read(priv->regmap, DEVICE_CTRL, &val);
 179                 if (ret < 0)
 180                         return ret;
 181                 if (!(val & PLL_UNLOCK))
 182                         return 0;
 183                 udelay(1);
 184         }
 185
 186         dev_err(dev, "pll lock failed\n");
 187
 188         return -ETIMEDOUT;
 189 }
 190
 191 static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
 192 {
 193         /* enable both AUX_OUT, CLK_OUT */
 194         return regmap_update_bits(priv->regmap, DEVICE_CTRL,
 195                                   (AUXOUTDIS | CLKOUTDIS),
 196                                   enable ? 0 :
 197                                   (AUXOUTDIS | CLKOUTDIS));
 198 }
 199
 200 static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out, bool lf_ratio)
 201 {
 202         u64 ratio;
 203         u32 multiplier = lf_ratio ? 12 : 20;
 204
 205         /*
 206          * ratio = rate_out / rate_in * 2^multiplier
 207          *
 208          * To avoid over flow, rate_out is u64.
 209          * The result should be u32.
 210          */
 211         ratio = (u64)rate_out << multiplier;
 212         do_div(ratio, rate_in);
 213
 214         return ratio;
 215 }
 216
 217 static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in, bool lf_ratio)
 218 {
 219         u64 rate_out;
 220         u32 multiplier = lf_ratio ? 12 : 20;
 221
 222         /*
 223          * ratio = rate_out / rate_in * 2^multiplier
 224          *
 225          * To avoid over flow, rate_out is u64.
 226          * The result should be u32 or unsigned long.
 227          */
 228
 229         rate_out = (u64)ratio * rate_in;
 230         return rate_out >> multiplier;
 231 }
 232
 233 static int cs2000_ratio_set(struct cs2000_priv *priv,
 234                             int ch, u32 rate_in, u32 rate_out)
 235 {
 236         u32 val;
 237         unsigned int i;
 238         int ret;
 239
 240         if (CH_SIZE_ERR(ch))
 241                 return -EINVAL;
 242
 243         val = cs2000_rate_to_ratio(rate_in, rate_out, priv->lf_ratio);
 244         for (i = 0; i < RATIO_REG_SIZE; i++) {
 245                 ret = regmap_write(priv->regmap,
 246                                    Ratio_Add(ch, i),
 247                                    Ratio_Val(val, i));
 248                 if (ret < 0)
 249                         return ret;
 250         }
 251
 252         return 0;
 253 }
 254
 255 static u32 cs2000_ratio_get(struct cs2000_priv *priv, int ch)
 256 {
 257         unsigned int tmp, i;
 258         u32 val;
 259         int ret;
 260
 261         val = 0;
 262         for (i = 0; i < RATIO_REG_SIZE; i++) {
 263                 ret = regmap_read(priv->regmap, Ratio_Add(ch, i), &tmp);
 264                 if (ret < 0)
 265                         return 0;
 266
 267                 val |= Val_Ratio(tmp, i);
 268         }
 269
 270         return val;
 271 }
 272
 273 static int cs2000_ratio_select(struct cs2000_priv *priv, int ch)
 274 {
 275         int ret;
 276         u8 fracnsrc;
 277
 278         if (CH_SIZE_ERR(ch))
 279                 return -EINVAL;
 280
 281         ret = regmap_update_bits(priv->regmap, DEVICE_CFG1, RSEL_MASK, RSEL(ch));
 282         if (ret < 0)
 283                 return ret;
 284
 285         fracnsrc = priv->dynamic_mode ? FRACNSRC_DYNAMIC : FRACNSRC_STATIC;
 286
 287         ret = regmap_update_bits(priv->regmap, DEVICE_CFG2,
 288                                  AUTORMOD | LOCKCLK_MASK | FRACNSRC_MASK,
 289                                  LOCKCLK(ch) | fracnsrc);
 290         if (ret < 0)
 291                 return ret;
 292
 293         return 0;
 294 }
 295
 296 static unsigned long cs2000_recalc_rate(struct clk_hw *hw,
 297                                         unsigned long parent_rate)
 298 {
 299         struct cs2000_priv *priv = hw_to_priv(hw);
 300         int ch = 0; /* it uses ch0 only at this point */
 301         u32 ratio;
 302
 303         ratio = cs2000_ratio_get(priv, ch);
 304
 305         return cs2000_ratio_to_rate(ratio, parent_rate, priv->lf_ratio);
 306 }
 307
 308 static long cs2000_round_rate(struct clk_hw *hw, unsigned long rate,
 309                               unsigned long *parent_rate)
 310 {
 311         struct cs2000_priv *priv = hw_to_priv(hw);
 312         u32 ratio;
 313
 314         ratio = cs2000_rate_to_ratio(*parent_rate, rate, priv->lf_ratio);
 315
 316         return cs2000_ratio_to_rate(ratio, *parent_rate, priv->lf_ratio);
 317 }
 318
 319 static int cs2000_select_ratio_mode(struct cs2000_priv *priv,
 320                                     unsigned long rate,
 321                                     unsigned long parent_rate)
 322 {
 323         /*
 324          * From the datasheet:
 325          *
 326          * | It is recommended that the 12.20 High-Resolution format be
 327          * | utilized whenever the desired ratio is less than 4096 since
 328          * | the output frequency accuracy of the PLL is directly proportional
 329          * | to the accuracy of the timing reference clock and the resolution
 330          * | of the R_UD.
 331          *
 332          * This mode is only available in dynamic mode.
 333          */
 334         priv->lf_ratio = priv->dynamic_mode && ((rate / parent_rate) > 4096);
 335
 336         return regmap_update_bits(priv->regmap, FUNC_CFG2, LFRATIO_MASK,
 337                                   priv->lf_ratio ? LFRATIO_20_12 : LFRATIO_12_20);
 338 }
 339
 340 static int __cs2000_set_rate(struct cs2000_priv *priv, int ch,
 341                              unsigned long rate, unsigned long parent_rate)
 342
 343 {
 344         int ret;
 345
 346         ret = regmap_update_bits(priv->regmap, GLOBAL_CFG, FREEZE, FREEZE);
 347         if (ret < 0)
 348                 return ret;
 349
 350         ret = cs2000_select_ratio_mode(priv, rate, parent_rate);
 351         if (ret < 0)
 352                 return ret;
 353
 354         ret = cs2000_ratio_set(priv, ch, parent_rate, rate);
 355         if (ret < 0)
 356                 return ret;
 357
 358         ret = cs2000_ratio_select(priv, ch);
 359         if (ret < 0)
 360                 return ret;
 361
 362         ret = regmap_update_bits(priv->regmap, GLOBAL_CFG, FREEZE, 0);
 363         if (ret < 0)
 364                 return ret;
 365
 366         priv->saved_rate        = rate;
 367         priv->saved_parent_rate = parent_rate;
 368
 369         return 0;
 370 }
 371
 372 static int cs2000_set_rate(struct clk_hw *hw,
 373                            unsigned long rate, unsigned long parent_rate)
 374 {
 375         struct cs2000_priv *priv = hw_to_priv(hw);
 376         int ch = 0; /* it uses ch0 only at this point */
 377
 378         return __cs2000_set_rate(priv, ch, rate, parent_rate);
 379 }
 380
 381 static int cs2000_set_saved_rate(struct cs2000_priv *priv)
 382 {
 383         int ch = 0; /* it uses ch0 only at this point */
 384
 385         return __cs2000_set_rate(priv, ch,
 386                                  priv->saved_rate,
 387                                  priv->saved_parent_rate);
 388 }
 389
 390 static int cs2000_enable(struct clk_hw *hw)
 391 {
 392         struct cs2000_priv *priv = hw_to_priv(hw);
 393         int ret;
 394
 395         ret = cs2000_enable_dev_config(priv, true);
 396         if (ret < 0)
 397                 return ret;
 398
 399         ret = cs2000_clk_out_enable(priv, true);
 400         if (ret < 0)
 401                 return ret;
 402
 403         ret = cs2000_wait_pll_lock(priv);
 404         if (ret < 0)
 405                 return ret;
 406
 407         return ret;
 408 }
 409
 410 static void cs2000_disable(struct clk_hw *hw)
 411 {
 412         struct cs2000_priv *priv = hw_to_priv(hw);
 413
 414         cs2000_enable_dev_config(priv, false);
 415
 416         cs2000_clk_out_enable(priv, false);
 417 }
 418
 419 static u8 cs2000_get_parent(struct clk_hw *hw)
 420 {
 421         struct cs2000_priv *priv = hw_to_priv(hw);
 422
 423         /*
 424          * In dynamic mode, output rates are derived from CLK_IN.
 425          * In static mode, CLK_IN is ignored, so we return REF_CLK instead.
 426          */
 427         return priv->dynamic_mode ? CLK_IN : REF_CLK;
 428 }
 429
 430 static const struct clk_ops cs2000_ops = {
 431         .get_parent     = cs2000_get_parent,
 432         .recalc_rate    = cs2000_recalc_rate,
 433         .round_rate     = cs2000_round_rate,
 434         .set_rate       = cs2000_set_rate,
 435         .prepare        = cs2000_enable,
 436         .unprepare      = cs2000_disable,
 437 };
 438
 439 static int cs2000_clk_get(struct cs2000_priv *priv)
 440 {
 441         struct device *dev = priv_to_dev(priv);
 442         struct clk *clk_in, *ref_clk;
 443
 444         clk_in = devm_clk_get(dev, "clk_in");
 445         /* not yet provided */
 446         if (IS_ERR(clk_in))
 447                 return -EPROBE_DEFER;
 448
 449         ref_clk = devm_clk_get(dev, "ref_clk");
 450         /* not yet provided */
 451         if (IS_ERR(ref_clk))
 452                 return -EPROBE_DEFER;
 453
 454         priv->clk_in    = clk_in;
 455         priv->ref_clk   = ref_clk;
 456
 457         return 0;
 458 }
 459
 460 static int cs2000_clk_register(struct cs2000_priv *priv)
 461 {
 462         struct device *dev = priv_to_dev(priv);
 463         struct device_node *np = dev->of_node;
 464         struct clk_init_data init;
 465         const char *name = np->name;
 466         static const char *parent_names[CLK_MAX];
 467         u32 aux_out = 0;
 468         int ref_clk_rate;
 469         int ch = 0; /* it uses ch0 only at this point */
 470         int ret;
 471
 472         of_property_read_string(np, "clock-output-names", &name);
 473
 474         priv->dynamic_mode = of_property_read_bool(np, "cirrus,dynamic-mode");
 475         dev_info(dev, "operating in %s mode\n",
 476                  priv->dynamic_mode ? "dynamic" : "static");
 477
 478         of_property_read_u32(np, "cirrus,aux-output-source", &aux_out);
 479         ret = regmap_update_bits(priv->regmap, DEVICE_CFG1,
 480                                  AUXOUTSRC_MASK, AUXOUTSRC(aux_out));
 481         if (ret < 0)
 482                 return ret;
 483
 484         priv->clk_skip = of_property_read_bool(np, "cirrus,clock-skip");
 485
 486         ref_clk_rate = clk_get_rate(priv->ref_clk);
 487         ret = cs2000_ref_clk_bound_rate(priv, ref_clk_rate);
 488         if (ret < 0)
 489                 return ret;
 490
 491         if (priv->dynamic_mode) {
 492                 /* Default to low-frequency mode to allow for large ratios */
 493                 priv->lf_ratio = true;
 494         } else {
 495                 /*
 496                  * set default rate as 1/1.
 497                  * otherwise .set_rate which setup ratio
 498                  * is never called if user requests 1/1 rate
 499                  */
 500                 ret = __cs2000_set_rate(priv, ch, ref_clk_rate, ref_clk_rate);
 501                 if (ret < 0)
 502                         return ret;
 503         }
 504
 505         parent_names[CLK_IN]    = __clk_get_name(priv->clk_in);
 506         parent_names[REF_CLK]   = __clk_get_name(priv->ref_clk);
 507
 508         init.name               = name;
 509         init.ops                = &cs2000_ops;
 510         init.flags              = CLK_SET_RATE_GATE;
 511         init.parent_names       = parent_names;
 512         init.num_parents        = ARRAY_SIZE(parent_names);
 513
 514         priv->hw.init = &init;
 515
 516         ret = clk_hw_register(dev, &priv->hw);
 517         if (ret)
 518                 return ret;
 519
 520         ret = of_clk_add_hw_provider(np, of_clk_hw_simple_get, &priv->hw);
 521         if (ret < 0) {
 522                 clk_hw_unregister(&priv->hw);
 523                 return ret;
 524         }
 525
 526         return 0;
 527 }
 528
 529 static int cs2000_version_print(struct cs2000_priv *priv)
 530 {
 531         struct device *dev = priv_to_dev(priv);
 532         const char *revision;
 533         unsigned int val;
 534         int ret;
 535
 536         ret = regmap_read(priv->regmap, DEVICE_ID, &val);
 537         if (ret < 0)
 538                 return ret;
 539
 540         /* CS2000 should be 0x0 */
 541         if (val >> 3)
 542                 return -EIO;
 543
 544         switch (val & REVISION_MASK) {
 545         case REVISION_B2_B3:
 546                 revision = "B2 / B3";
 547                 break;
 548         case REVISION_C1:
 549                 revision = "C1";
 550                 break;
 551         default:
 552                 return -EIO;
 553         }
 554
 555         dev_info(dev, "revision - %s\n", revision);
 556
 557         return 0;
 558 }
 559
 560 static void cs2000_remove(struct i2c_client *client)
 561 {
 562         struct cs2000_priv *priv = i2c_get_clientdata(client);
 563         struct device *dev = priv_to_dev(priv);
 564         struct device_node *np = dev->of_node;
 565
 566         of_clk_del_provider(np);
 567
 568         clk_hw_unregister(&priv->hw);
 569 }
 570
 571 static int cs2000_probe(struct i2c_client *client)
 572 {
 573         struct cs2000_priv *priv;
 574         struct device *dev = &client->dev;
 575         int ret;
 576
 577         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 578         if (!priv)
 579                 return -ENOMEM;
 580
 581         priv->client = client;
 582         i2c_set_clientdata(client, priv);
 583
 584         priv->regmap = devm_regmap_init_i2c(client, &cs2000_regmap_config);
 585         if (IS_ERR(priv->regmap))
 586                 return PTR_ERR(priv->regmap);
 587
 588         ret = cs2000_clk_get(priv);
 589         if (ret < 0)
 590                 return ret;
 591
 592         ret = cs2000_clk_register(priv);
 593         if (ret < 0)
 594                 return ret;
 595
 596         ret = cs2000_version_print(priv);
 597         if (ret < 0)
 598                 goto probe_err;
 599
 600         return 0;
 601
 602 probe_err:
 603         cs2000_remove(client);
 604
 605         return ret;
 606 }
 607
 608 static int __maybe_unused cs2000_resume(struct device *dev)
 609 {
 610         struct cs2000_priv *priv = dev_get_drvdata(dev);
 611
 612         return cs2000_set_saved_rate(priv);
 613 }
 614
 615 static const struct dev_pm_ops cs2000_pm_ops = {
 616         SET_LATE_SYSTEM_SLEEP_PM_OPS(NULL, cs2000_resume)
 617 };
 618
 619 static struct i2c_driver cs2000_driver = {
 620         .driver = {
 621                 .name = "cs2000-cp",
 622                 .pm     = &cs2000_pm_ops,
 623                 .of_match_table = cs2000_of_match,
 624         },
 625         .probe          = cs2000_probe,
 626         .remove         = cs2000_remove,
 627         .id_table       = cs2000_id,
 628 };
 629
 630 module_i2c_driver(cs2000_driver);
 631
 632 MODULE_DESCRIPTION("CS2000-CP driver");
 633 MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");
 634 MODULE_LICENSE("GPL v2");