drivers/clk/clk-cs2000-cp.c

   1 /*
   2  * CS2000  --  CIRRUS LOGIC Fractional-N Clock Synthesizer & Clock Multiplier
   3  *
   4  * Copyright (C) 2015 Renesas Electronics Corporation
   5  * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/clk-provider.h>
  12 #include <linux/delay.h>
  13 #include <linux/clk.h>
  14 #include <linux/i2c.h>
  15 #include <linux/of_device.h>
  16 #include <linux/module.h>
  17
  18 #define CH_MAX 4
  19 #define RATIO_REG_SIZE 4
  20
  21 #define DEVICE_ID       0x1
  22 #define DEVICE_CTRL     0x2
  23 #define DEVICE_CFG1     0x3
  24 #define DEVICE_CFG2     0x4
  25 #define GLOBAL_CFG      0x5
  26 #define Ratio_Add(x, nth)       (6 + (x * 4) + (nth))
  27 #define Ratio_Val(x, nth)       ((x >> (24 - (8 * nth))) & 0xFF)
  28 #define Val_Ratio(x, nth)       ((x & 0xFF) << (24 - (8 * nth)))
  29 #define FUNC_CFG1       0x16
  30 #define FUNC_CFG2       0x17
  31
  32 /* DEVICE_ID */
  33 #define REVISION_MASK   (0x7)
  34 #define REVISION_B2_B3  (0x4)
  35 #define REVISION_C1     (0x6)
  36
  37 /* DEVICE_CTRL */
  38 #define PLL_UNLOCK      (1 << 7)
  39 #define AUXOUTDIS       (1 << 1)
  40 #define CLKOUTDIS       (1 << 0)
  41
  42 /* DEVICE_CFG1 */
  43 #define RSEL(x)         (((x) & 0x3) << 3)
  44 #define RSEL_MASK       RSEL(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 << 1)
  54
  55 /* GLOBAL_CFG */
  56 #define ENDEV2          (0x1)
  57
  58 /* FUNC_CFG1 */
  59 #define CLKSKIPEN       (1 << 7)
  60 #define REFCLKDIV(x)    (((x) & 0x3) << 3)
  61 #define REFCLKDIV_MASK  REFCLKDIV(0x3)
  62
  63 /* FUNC_CFG2 */
  64 #define LFRATIO_MASK    (1 << 3)
  65 #define LFRATIO_20_12   (0 << 3)
  66 #define LFRATIO_12_20   (1 << 3)
  67
  68 #define CH_SIZE_ERR(ch)         ((ch < 0) || (ch >= CH_MAX))
  69 #define hw_to_priv(_hw)         container_of(_hw, struct cs2000_priv, hw)
  70 #define priv_to_client(priv)    (priv->client)
  71 #define priv_to_dev(priv)       (&(priv_to_client(priv)->dev))
  72
  73 #define CLK_IN  0
  74 #define REF_CLK 1
  75 #define CLK_MAX 2
  76
  77 struct cs2000_priv {
  78         struct clk_hw hw;
  79         struct i2c_client *client;
  80         struct clk *clk_in;
  81         struct clk *ref_clk;
  82
  83         /* suspend/resume */
  84         unsigned long saved_rate;
  85         unsigned long saved_parent_rate;
  86 };
  87
  88 static const struct of_device_id cs2000_of_match[] = {
  89         { .compatible = "cirrus,cs2000-cp", },
  90         {},
  91 };
  92 MODULE_DEVICE_TABLE(of, cs2000_of_match);
  93
  94 static const struct i2c_device_id cs2000_id[] = {
  95         { "cs2000-cp", },
  96         {}
  97 };
  98 MODULE_DEVICE_TABLE(i2c, cs2000_id);
  99
 100 #define cs2000_read(priv, addr) \
 101         i2c_smbus_read_byte_data(priv_to_client(priv), addr)
 102 #define cs2000_write(priv, addr, val) \
 103         i2c_smbus_write_byte_data(priv_to_client(priv), addr, val)
 104
 105 static int cs2000_bset(struct cs2000_priv *priv, u8 addr, u8 mask, u8 val)
 106 {
 107         s32 data;
 108
 109         data = cs2000_read(priv, addr);
 110         if (data < 0)
 111                 return data;
 112
 113         data &= ~mask;
 114         data |= (val & mask);
 115
 116         return cs2000_write(priv, addr, data);
 117 }
 118
 119 static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)
 120 {
 121         int ret;
 122
 123         ret = cs2000_bset(priv, DEVICE_CFG1, ENDEV1,
 124                           enable ? ENDEV1 : 0);
 125         if (ret < 0)
 126                 return ret;
 127
 128         ret = cs2000_bset(priv, GLOBAL_CFG,  ENDEV2,
 129                           enable ? ENDEV2 : 0);
 130         if (ret < 0)
 131                 return ret;
 132
 133         ret = cs2000_bset(priv, FUNC_CFG1, CLKSKIPEN,
 134                           enable ? CLKSKIPEN : 0);
 135         if (ret < 0)
 136                 return ret;
 137
 138         /* FIXME: for Static ratio mode */
 139         ret = cs2000_bset(priv, FUNC_CFG2, LFRATIO_MASK,
 140                           LFRATIO_12_20);
 141         if (ret < 0)
 142                 return ret;
 143
 144         return 0;
 145 }
 146
 147 static int cs2000_clk_in_bound_rate(struct cs2000_priv *priv,
 148                                     u32 rate_in)
 149 {
 150         u32 val;
 151
 152         if (rate_in >= 32000000 && rate_in < 56000000)
 153                 val = 0x0;
 154         else if (rate_in >= 16000000 && rate_in < 28000000)
 155                 val = 0x1;
 156         else if (rate_in >= 8000000 && rate_in < 14000000)
 157                 val = 0x2;
 158         else
 159                 return -EINVAL;
 160
 161         return cs2000_bset(priv, FUNC_CFG1,
 162                            REFCLKDIV_MASK,
 163                            REFCLKDIV(val));
 164 }
 165
 166 static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
 167 {
 168         struct device *dev = priv_to_dev(priv);
 169         s32 val;
 170         unsigned int i;
 171
 172         for (i = 0; i < 256; i++) {
 173                 val = cs2000_read(priv, DEVICE_CTRL);
 174                 if (val < 0)
 175                         return val;
 176                 if (!(val & PLL_UNLOCK))
 177                         return 0;
 178                 udelay(1);
 179         }
 180
 181         dev_err(dev, "pll lock failed\n");
 182
 183         return -ETIMEDOUT;
 184 }
 185
 186 static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
 187 {
 188         /* enable both AUX_OUT, CLK_OUT */
 189         return cs2000_bset(priv, DEVICE_CTRL,
 190                            (AUXOUTDIS | CLKOUTDIS),
 191                            enable ? 0 :
 192                            (AUXOUTDIS | CLKOUTDIS));
 193 }
 194
 195 static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out)
 196 {
 197         u64 ratio;
 198
 199         /*
 200          * ratio = rate_out / rate_in * 2^20
 201          *
 202          * To avoid over flow, rate_out is u64.
 203          * The result should be u32.
 204          */
 205         ratio = (u64)rate_out << 20;
 206         do_div(ratio, rate_in);
 207
 208         return ratio;
 209 }
 210
 211 static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in)
 212 {
 213         u64 rate_out;
 214
 215         /*
 216          * ratio = rate_out / rate_in * 2^20
 217          *
 218          * To avoid over flow, rate_out is u64.
 219          * The result should be u32 or unsigned long.
 220          */
 221
 222         rate_out = (u64)ratio * rate_in;
 223         return rate_out >> 20;
 224 }
 225
 226 static int cs2000_ratio_set(struct cs2000_priv *priv,
 227                             int ch, u32 rate_in, u32 rate_out)
 228 {
 229         u32 val;
 230         unsigned int i;
 231         int ret;
 232
 233         if (CH_SIZE_ERR(ch))
 234                 return -EINVAL;
 235
 236         val = cs2000_rate_to_ratio(rate_in, rate_out);
 237         for (i = 0; i < RATIO_REG_SIZE; i++) {
 238                 ret = cs2000_write(priv,
 239                                    Ratio_Add(ch, i),
 240                                    Ratio_Val(val, i));
 241                 if (ret < 0)
 242                         return ret;
 243         }
 244
 245         return 0;
 246 }
 247
 248 static u32 cs2000_ratio_get(struct cs2000_priv *priv, int ch)
 249 {
 250         s32 tmp;
 251         u32 val;
 252         unsigned int i;
 253
 254         val = 0;
 255         for (i = 0; i < RATIO_REG_SIZE; i++) {
 256                 tmp = cs2000_read(priv, Ratio_Add(ch, i));
 257                 if (tmp < 0)
 258                         return 0;
 259
 260                 val |= Val_Ratio(tmp, i);
 261         }
 262
 263         return val;
 264 }
 265
 266 static int cs2000_ratio_select(struct cs2000_priv *priv, int ch)
 267 {
 268         int ret;
 269
 270         if (CH_SIZE_ERR(ch))
 271                 return -EINVAL;
 272
 273         /*
 274          * FIXME
 275          *
 276          * this driver supports static ratio mode only at this point.
 277          */
 278         ret = cs2000_bset(priv, DEVICE_CFG1, RSEL_MASK, RSEL(ch));
 279         if (ret < 0)
 280                 return ret;
 281
 282         ret = cs2000_bset(priv, DEVICE_CFG2,
 283                           (AUTORMOD | LOCKCLK_MASK | FRACNSRC_MASK),
 284                           (LOCKCLK(ch) | FRACNSRC_STATIC));
 285         if (ret < 0)
 286                 return ret;
 287
 288         return 0;
 289 }
 290
 291 static unsigned long cs2000_recalc_rate(struct clk_hw *hw,
 292                                         unsigned long parent_rate)
 293 {
 294         struct cs2000_priv *priv = hw_to_priv(hw);
 295         int ch = 0; /* it uses ch0 only at this point */
 296         u32 ratio;
 297
 298         ratio = cs2000_ratio_get(priv, ch);
 299
 300         return cs2000_ratio_to_rate(ratio, parent_rate);
 301 }
 302
 303 static long cs2000_round_rate(struct clk_hw *hw, unsigned long rate,
 304                               unsigned long *parent_rate)
 305 {
 306         u32 ratio;
 307
 308         ratio = cs2000_rate_to_ratio(*parent_rate, rate);
 309
 310         return cs2000_ratio_to_rate(ratio, *parent_rate);
 311 }
 312
 313 static int __cs2000_set_rate(struct cs2000_priv *priv, int ch,
 314                              unsigned long rate, unsigned long parent_rate)
 315
 316 {
 317         int ret;
 318
 319         ret = cs2000_clk_in_bound_rate(priv, parent_rate);
 320         if (ret < 0)
 321                 return ret;
 322
 323         ret = cs2000_ratio_set(priv, ch, parent_rate, rate);
 324         if (ret < 0)
 325                 return ret;
 326
 327         ret = cs2000_ratio_select(priv, ch);
 328         if (ret < 0)
 329                 return ret;
 330
 331         priv->saved_rate        = rate;
 332         priv->saved_parent_rate = parent_rate;
 333
 334         return 0;
 335 }
 336
 337 static int cs2000_set_rate(struct clk_hw *hw,
 338                            unsigned long rate, unsigned long parent_rate)
 339 {
 340         struct cs2000_priv *priv = hw_to_priv(hw);
 341         int ch = 0; /* it uses ch0 only at this point */
 342
 343         return __cs2000_set_rate(priv, ch, rate, parent_rate);
 344 }
 345
 346 static int cs2000_enable(struct clk_hw *hw)
 347 {
 348         struct cs2000_priv *priv = hw_to_priv(hw);
 349         int ret;
 350
 351         ret = cs2000_enable_dev_config(priv, true);
 352         if (ret < 0)
 353                 return ret;
 354
 355         ret = cs2000_clk_out_enable(priv, true);
 356         if (ret < 0)
 357                 return ret;
 358
 359         ret = cs2000_wait_pll_lock(priv);
 360         if (ret < 0)
 361                 return ret;
 362
 363         return ret;
 364 }
 365
 366 static void cs2000_disable(struct clk_hw *hw)
 367 {
 368         struct cs2000_priv *priv = hw_to_priv(hw);
 369
 370         cs2000_enable_dev_config(priv, false);
 371
 372         cs2000_clk_out_enable(priv, false);
 373 }
 374
 375 static u8 cs2000_get_parent(struct clk_hw *hw)
 376 {
 377         /* always return REF_CLK */
 378         return REF_CLK;
 379 }
 380
 381 static const struct clk_ops cs2000_ops = {
 382         .get_parent     = cs2000_get_parent,
 383         .recalc_rate    = cs2000_recalc_rate,
 384         .round_rate     = cs2000_round_rate,
 385         .set_rate       = cs2000_set_rate,
 386         .prepare        = cs2000_enable,
 387         .unprepare      = cs2000_disable,
 388 };
 389
 390 static int cs2000_clk_get(struct cs2000_priv *priv)
 391 {
 392         struct device *dev = priv_to_dev(priv);
 393         struct clk *clk_in, *ref_clk;
 394
 395         clk_in = devm_clk_get(dev, "clk_in");
 396         /* not yet provided */
 397         if (IS_ERR(clk_in))
 398                 return -EPROBE_DEFER;
 399
 400         ref_clk = devm_clk_get(dev, "ref_clk");
 401         /* not yet provided */
 402         if (IS_ERR(ref_clk))
 403                 return -EPROBE_DEFER;
 404
 405         priv->clk_in    = clk_in;
 406         priv->ref_clk   = ref_clk;
 407
 408         return 0;
 409 }
 410
 411 static int cs2000_clk_register(struct cs2000_priv *priv)
 412 {
 413         struct device *dev = priv_to_dev(priv);
 414         struct device_node *np = dev->of_node;
 415         struct clk_init_data init;
 416         const char *name = np->name;
 417         static const char *parent_names[CLK_MAX];
 418         int ch = 0; /* it uses ch0 only at this point */
 419         int rate;
 420         int ret;
 421
 422         of_property_read_string(np, "clock-output-names", &name);
 423
 424         /*
 425          * set default rate as 1/1.
 426          * otherwise .set_rate which setup ratio
 427          * is never called if user requests 1/1 rate
 428          */
 429         rate = clk_get_rate(priv->ref_clk);
 430         ret = __cs2000_set_rate(priv, ch, rate, rate);
 431         if (ret < 0)
 432                 return ret;
 433
 434         parent_names[CLK_IN]    = __clk_get_name(priv->clk_in);
 435         parent_names[REF_CLK]   = __clk_get_name(priv->ref_clk);
 436
 437         init.name               = name;
 438         init.ops                = &cs2000_ops;
 439         init.flags              = CLK_SET_RATE_GATE;
 440         init.parent_names       = parent_names;
 441         init.num_parents        = ARRAY_SIZE(parent_names);
 442
 443         priv->hw.init = &init;
 444
 445         ret = clk_hw_register(dev, &priv->hw);
 446         if (ret)
 447                 return ret;
 448
 449         ret = of_clk_add_hw_provider(np, of_clk_hw_simple_get, &priv->hw);
 450         if (ret < 0) {
 451                 clk_hw_unregister(&priv->hw);
 452                 return ret;
 453         }
 454
 455         return 0;
 456 }
 457
 458 static int cs2000_version_print(struct cs2000_priv *priv)
 459 {
 460         struct device *dev = priv_to_dev(priv);
 461         s32 val;
 462         const char *revision;
 463
 464         val = cs2000_read(priv, DEVICE_ID);
 465         if (val < 0)
 466                 return val;
 467
 468         /* CS2000 should be 0x0 */
 469         if (val >> 3)
 470                 return -EIO;
 471
 472         switch (val & REVISION_MASK) {
 473         case REVISION_B2_B3:
 474                 revision = "B2 / B3";
 475                 break;
 476         case REVISION_C1:
 477                 revision = "C1";
 478                 break;
 479         default:
 480                 return -EIO;
 481         }
 482
 483         dev_info(dev, "revision - %s\n", revision);
 484
 485         return 0;
 486 }
 487
 488 static int cs2000_remove(struct i2c_client *client)
 489 {
 490         struct cs2000_priv *priv = i2c_get_clientdata(client);
 491         struct device *dev = priv_to_dev(priv);
 492         struct device_node *np = dev->of_node;
 493
 494         of_clk_del_provider(np);
 495
 496         clk_hw_unregister(&priv->hw);
 497
 498         return 0;
 499 }
 500
 501 static int cs2000_probe(struct i2c_client *client,
 502                         const struct i2c_device_id *id)
 503 {
 504         struct cs2000_priv *priv;
 505         struct device *dev = &client->dev;
 506         int ret;
 507
 508         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 509         if (!priv)
 510                 return -ENOMEM;
 511
 512         priv->client = client;
 513         i2c_set_clientdata(client, priv);
 514
 515         ret = cs2000_clk_get(priv);
 516         if (ret < 0)
 517                 return ret;
 518
 519         ret = cs2000_clk_register(priv);
 520         if (ret < 0)
 521                 return ret;
 522
 523         ret = cs2000_version_print(priv);
 524         if (ret < 0)
 525                 goto probe_err;
 526
 527         return 0;
 528
 529 probe_err:
 530         cs2000_remove(client);
 531
 532         return ret;
 533 }
 534
 535 static int cs2000_resume(struct device *dev)
 536 {
 537         struct cs2000_priv *priv = dev_get_drvdata(dev);
 538         int ch = 0; /* it uses ch0 only at this point */
 539
 540         return __cs2000_set_rate(priv, ch,
 541                                  priv->saved_rate,
 542                                  priv->saved_parent_rate);
 543 }
 544
 545 static const struct dev_pm_ops cs2000_pm_ops = {
 546         .resume_early   = cs2000_resume,
 547 };
 548
 549 static struct i2c_driver cs2000_driver = {
 550         .driver = {
 551                 .name = "cs2000-cp",
 552                 .pm     = &cs2000_pm_ops,
 553                 .of_match_table = cs2000_of_match,
 554         },
 555         .probe          = cs2000_probe,
 556         .remove         = cs2000_remove,
 557         .id_table       = cs2000_id,
 558 };
 559
 560 module_i2c_driver(cs2000_driver);
 561
 562 MODULE_DESCRIPTION("CS2000-CP driver");
 563 MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");
 564 MODULE_LICENSE("GPL v2");