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
  40 /* DEVICE_CFG1 */
  41 #define RSEL(x)         (((x) & 0x3) << 3)
  42 #define RSEL_MASK       RSEL(0x3)
  43 #define ENDEV1          (0x1)
  44
  45 /* GLOBAL_CFG */
  46 #define ENDEV2          (0x1)
  47
  48 #define CH_SIZE_ERR(ch)         ((ch < 0) || (ch >= CH_MAX))
  49 #define hw_to_priv(_hw)         container_of(_hw, struct cs2000_priv, hw)
  50 #define priv_to_client(priv)    (priv->client)
  51 #define priv_to_dev(priv)       (&(priv_to_client(priv)->dev))
  52
  53 #define CLK_IN  0
  54 #define REF_CLK 1
  55 #define CLK_MAX 2
  56
  57 struct cs2000_priv {
  58         struct clk_hw hw;
  59         struct i2c_client *client;
  60         struct clk *clk_in;
  61         struct clk *ref_clk;
  62
  63         /* suspend/resume */
  64         unsigned long saved_rate;
  65         unsigned long saved_parent_rate;
  66 };
  67
  68 static const struct of_device_id cs2000_of_match[] = {
  69         { .compatible = "cirrus,cs2000-cp", },
  70         {},
  71 };
  72 MODULE_DEVICE_TABLE(of, cs2000_of_match);
  73
  74 static const struct i2c_device_id cs2000_id[] = {
  75         { "cs2000-cp", },
  76         {}
  77 };
  78 MODULE_DEVICE_TABLE(i2c, cs2000_id);
  79
  80 #define cs2000_read(priv, addr) \
  81         i2c_smbus_read_byte_data(priv_to_client(priv), addr)
  82 #define cs2000_write(priv, addr, val) \
  83         i2c_smbus_write_byte_data(priv_to_client(priv), addr, val)
  84
  85 static int cs2000_bset(struct cs2000_priv *priv, u8 addr, u8 mask, u8 val)
  86 {
  87         s32 data;
  88
  89         data = cs2000_read(priv, addr);
  90         if (data < 0)
  91                 return data;
  92
  93         data &= ~mask;
  94         data |= (val & mask);
  95
  96         return cs2000_write(priv, addr, data);
  97 }
  98
  99 static int cs2000_enable_dev_config(struct cs2000_priv *priv, bool enable)
 100 {
 101         int ret;
 102
 103         ret = cs2000_bset(priv, DEVICE_CFG1, ENDEV1,
 104                           enable ? ENDEV1 : 0);
 105         if (ret < 0)
 106                 return ret;
 107
 108         ret = cs2000_bset(priv, GLOBAL_CFG,  ENDEV2,
 109                           enable ? ENDEV2 : 0);
 110         if (ret < 0)
 111                 return ret;
 112
 113         return 0;
 114 }
 115
 116 static int cs2000_clk_in_bound_rate(struct cs2000_priv *priv,
 117                                     u32 rate_in)
 118 {
 119         u32 val;
 120
 121         if (rate_in >= 32000000 && rate_in < 56000000)
 122                 val = 0x0;
 123         else if (rate_in >= 16000000 && rate_in < 28000000)
 124                 val = 0x1;
 125         else if (rate_in >= 8000000 && rate_in < 14000000)
 126                 val = 0x2;
 127         else
 128                 return -EINVAL;
 129
 130         return cs2000_bset(priv, FUNC_CFG1, 0x3 << 3, val << 3);
 131 }
 132
 133 static int cs2000_wait_pll_lock(struct cs2000_priv *priv)
 134 {
 135         struct device *dev = priv_to_dev(priv);
 136         s32 val;
 137         unsigned int i;
 138
 139         for (i = 0; i < 256; i++) {
 140                 val = cs2000_read(priv, DEVICE_CTRL);
 141                 if (val < 0)
 142                         return val;
 143                 if (!(val & PLL_UNLOCK))
 144                         return 0;
 145                 udelay(1);
 146         }
 147
 148         dev_err(dev, "pll lock failed\n");
 149
 150         return -ETIMEDOUT;
 151 }
 152
 153 static int cs2000_clk_out_enable(struct cs2000_priv *priv, bool enable)
 154 {
 155         /* enable both AUX_OUT, CLK_OUT */
 156         return cs2000_write(priv, DEVICE_CTRL, enable ? 0 : 0x3);
 157 }
 158
 159 static u32 cs2000_rate_to_ratio(u32 rate_in, u32 rate_out)
 160 {
 161         u64 ratio;
 162
 163         /*
 164          * ratio = rate_out / rate_in * 2^20
 165          *
 166          * To avoid over flow, rate_out is u64.
 167          * The result should be u32.
 168          */
 169         ratio = (u64)rate_out << 20;
 170         do_div(ratio, rate_in);
 171
 172         return ratio;
 173 }
 174
 175 static unsigned long cs2000_ratio_to_rate(u32 ratio, u32 rate_in)
 176 {
 177         u64 rate_out;
 178
 179         /*
 180          * ratio = rate_out / rate_in * 2^20
 181          *
 182          * To avoid over flow, rate_out is u64.
 183          * The result should be u32 or unsigned long.
 184          */
 185
 186         rate_out = (u64)ratio * rate_in;
 187         return rate_out >> 20;
 188 }
 189
 190 static int cs2000_ratio_set(struct cs2000_priv *priv,
 191                             int ch, u32 rate_in, u32 rate_out)
 192 {
 193         u32 val;
 194         unsigned int i;
 195         int ret;
 196
 197         if (CH_SIZE_ERR(ch))
 198                 return -EINVAL;
 199
 200         val = cs2000_rate_to_ratio(rate_in, rate_out);
 201         for (i = 0; i < RATIO_REG_SIZE; i++) {
 202                 ret = cs2000_write(priv,
 203                                    Ratio_Add(ch, i),
 204                                    Ratio_Val(val, i));
 205                 if (ret < 0)
 206                         return ret;
 207         }
 208
 209         return 0;
 210 }
 211
 212 static u32 cs2000_ratio_get(struct cs2000_priv *priv, int ch)
 213 {
 214         s32 tmp;
 215         u32 val;
 216         unsigned int i;
 217
 218         val = 0;
 219         for (i = 0; i < RATIO_REG_SIZE; i++) {
 220                 tmp = cs2000_read(priv, Ratio_Add(ch, i));
 221                 if (tmp < 0)
 222                         return 0;
 223
 224                 val |= Val_Ratio(tmp, i);
 225         }
 226
 227         return val;
 228 }
 229
 230 static int cs2000_ratio_select(struct cs2000_priv *priv, int ch)
 231 {
 232         int ret;
 233
 234         if (CH_SIZE_ERR(ch))
 235                 return -EINVAL;
 236
 237         /*
 238          * FIXME
 239          *
 240          * this driver supports static ratio mode only at this point.
 241          */
 242         ret = cs2000_bset(priv, DEVICE_CFG1, RSEL_MASK, RSEL(ch));
 243         if (ret < 0)
 244                 return ret;
 245
 246         ret = cs2000_write(priv, DEVICE_CFG2, 0x0);
 247         if (ret < 0)
 248                 return ret;
 249
 250         return 0;
 251 }
 252
 253 static unsigned long cs2000_recalc_rate(struct clk_hw *hw,
 254                                         unsigned long parent_rate)
 255 {
 256         struct cs2000_priv *priv = hw_to_priv(hw);
 257         int ch = 0; /* it uses ch0 only at this point */
 258         u32 ratio;
 259
 260         ratio = cs2000_ratio_get(priv, ch);
 261
 262         return cs2000_ratio_to_rate(ratio, parent_rate);
 263 }
 264
 265 static long cs2000_round_rate(struct clk_hw *hw, unsigned long rate,
 266                               unsigned long *parent_rate)
 267 {
 268         u32 ratio;
 269
 270         ratio = cs2000_rate_to_ratio(*parent_rate, rate);
 271
 272         return cs2000_ratio_to_rate(ratio, *parent_rate);
 273 }
 274
 275 static int __cs2000_set_rate(struct cs2000_priv *priv, int ch,
 276                              unsigned long rate, unsigned long parent_rate)
 277
 278 {
 279         int ret;
 280
 281         ret = cs2000_clk_in_bound_rate(priv, parent_rate);
 282         if (ret < 0)
 283                 return ret;
 284
 285         ret = cs2000_ratio_set(priv, ch, parent_rate, rate);
 286         if (ret < 0)
 287                 return ret;
 288
 289         ret = cs2000_ratio_select(priv, ch);
 290         if (ret < 0)
 291                 return ret;
 292
 293         priv->saved_rate        = rate;
 294         priv->saved_parent_rate = parent_rate;
 295
 296         return 0;
 297 }
 298
 299 static int cs2000_set_rate(struct clk_hw *hw,
 300                            unsigned long rate, unsigned long parent_rate)
 301 {
 302         struct cs2000_priv *priv = hw_to_priv(hw);
 303         int ch = 0; /* it uses ch0 only at this point */
 304
 305         return __cs2000_set_rate(priv, ch, rate, parent_rate);
 306 }
 307
 308 static int cs2000_enable(struct clk_hw *hw)
 309 {
 310         struct cs2000_priv *priv = hw_to_priv(hw);
 311         int ret;
 312
 313         ret = cs2000_enable_dev_config(priv, true);
 314         if (ret < 0)
 315                 return ret;
 316
 317         ret = cs2000_clk_out_enable(priv, true);
 318         if (ret < 0)
 319                 return ret;
 320
 321         ret = cs2000_wait_pll_lock(priv);
 322         if (ret < 0)
 323                 return ret;
 324
 325         return ret;
 326 }
 327
 328 static void cs2000_disable(struct clk_hw *hw)
 329 {
 330         struct cs2000_priv *priv = hw_to_priv(hw);
 331
 332         cs2000_enable_dev_config(priv, false);
 333
 334         cs2000_clk_out_enable(priv, false);
 335 }
 336
 337 static u8 cs2000_get_parent(struct clk_hw *hw)
 338 {
 339         /* always return REF_CLK */
 340         return REF_CLK;
 341 }
 342
 343 static const struct clk_ops cs2000_ops = {
 344         .get_parent     = cs2000_get_parent,
 345         .recalc_rate    = cs2000_recalc_rate,
 346         .round_rate     = cs2000_round_rate,
 347         .set_rate       = cs2000_set_rate,
 348         .prepare        = cs2000_enable,
 349         .unprepare      = cs2000_disable,
 350 };
 351
 352 static int cs2000_clk_get(struct cs2000_priv *priv)
 353 {
 354         struct i2c_client *client = priv_to_client(priv);
 355         struct device *dev = &client->dev;
 356         struct clk *clk_in, *ref_clk;
 357
 358         clk_in = devm_clk_get(dev, "clk_in");
 359         /* not yet provided */
 360         if (IS_ERR(clk_in))
 361                 return -EPROBE_DEFER;
 362
 363         ref_clk = devm_clk_get(dev, "ref_clk");
 364         /* not yet provided */
 365         if (IS_ERR(ref_clk))
 366                 return -EPROBE_DEFER;
 367
 368         priv->clk_in    = clk_in;
 369         priv->ref_clk   = ref_clk;
 370
 371         return 0;
 372 }
 373
 374 static int cs2000_clk_register(struct cs2000_priv *priv)
 375 {
 376         struct device *dev = priv_to_dev(priv);
 377         struct device_node *np = dev->of_node;
 378         struct clk_init_data init;
 379         const char *name = np->name;
 380         static const char *parent_names[CLK_MAX];
 381         int ch = 0; /* it uses ch0 only at this point */
 382         int rate;
 383         int ret;
 384
 385         of_property_read_string(np, "clock-output-names", &name);
 386
 387         /*
 388          * set default rate as 1/1.
 389          * otherwise .set_rate which setup ratio
 390          * is never called if user requests 1/1 rate
 391          */
 392         rate = clk_get_rate(priv->ref_clk);
 393         ret = __cs2000_set_rate(priv, ch, rate, rate);
 394         if (ret < 0)
 395                 return ret;
 396
 397         parent_names[CLK_IN]    = __clk_get_name(priv->clk_in);
 398         parent_names[REF_CLK]   = __clk_get_name(priv->ref_clk);
 399
 400         init.name               = name;
 401         init.ops                = &cs2000_ops;
 402         init.flags              = CLK_SET_RATE_GATE;
 403         init.parent_names       = parent_names;
 404         init.num_parents        = ARRAY_SIZE(parent_names);
 405
 406         priv->hw.init = &init;
 407
 408         ret = clk_hw_register(dev, &priv->hw);
 409         if (ret)
 410                 return ret;
 411
 412         ret = of_clk_add_hw_provider(np, of_clk_hw_simple_get, &priv->hw);
 413         if (ret < 0) {
 414                 clk_hw_unregister(&priv->hw);
 415                 return ret;
 416         }
 417
 418         return 0;
 419 }
 420
 421 static int cs2000_version_print(struct cs2000_priv *priv)
 422 {
 423         struct i2c_client *client = priv_to_client(priv);
 424         struct device *dev = &client->dev;
 425         s32 val;
 426         const char *revision;
 427
 428         val = cs2000_read(priv, DEVICE_ID);
 429         if (val < 0)
 430                 return val;
 431
 432         /* CS2000 should be 0x0 */
 433         if (val >> 3)
 434                 return -EIO;
 435
 436         switch (val & REVISION_MASK) {
 437         case REVISION_B2_B3:
 438                 revision = "B2 / B3";
 439                 break;
 440         case REVISION_C1:
 441                 revision = "C1";
 442                 break;
 443         default:
 444                 return -EIO;
 445         }
 446
 447         dev_info(dev, "revision - %s\n", revision);
 448
 449         return 0;
 450 }
 451
 452 static int cs2000_remove(struct i2c_client *client)
 453 {
 454         struct cs2000_priv *priv = i2c_get_clientdata(client);
 455         struct device *dev = &client->dev;
 456         struct device_node *np = dev->of_node;
 457
 458         of_clk_del_provider(np);
 459
 460         clk_hw_unregister(&priv->hw);
 461
 462         return 0;
 463 }
 464
 465 static int cs2000_probe(struct i2c_client *client,
 466                         const struct i2c_device_id *id)
 467 {
 468         struct cs2000_priv *priv;
 469         struct device *dev = &client->dev;
 470         int ret;
 471
 472         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 473         if (!priv)
 474                 return -ENOMEM;
 475
 476         priv->client = client;
 477         i2c_set_clientdata(client, priv);
 478
 479         ret = cs2000_clk_get(priv);
 480         if (ret < 0)
 481                 return ret;
 482
 483         ret = cs2000_clk_register(priv);
 484         if (ret < 0)
 485                 return ret;
 486
 487         ret = cs2000_version_print(priv);
 488         if (ret < 0)
 489                 goto probe_err;
 490
 491         return 0;
 492
 493 probe_err:
 494         cs2000_remove(client);
 495
 496         return ret;
 497 }
 498
 499 static int cs2000_resume(struct device *dev)
 500 {
 501         struct cs2000_priv *priv = dev_get_drvdata(dev);
 502         int ch = 0; /* it uses ch0 only at this point */
 503
 504         return __cs2000_set_rate(priv, ch,
 505                                  priv->saved_rate,
 506                                  priv->saved_parent_rate);
 507 }
 508
 509 static const struct dev_pm_ops cs2000_pm_ops = {
 510         .resume_early   = cs2000_resume,
 511 };
 512
 513 static struct i2c_driver cs2000_driver = {
 514         .driver = {
 515                 .name = "cs2000-cp",
 516                 .pm     = &cs2000_pm_ops,
 517                 .of_match_table = cs2000_of_match,
 518         },
 519         .probe          = cs2000_probe,
 520         .remove         = cs2000_remove,
 521         .id_table       = cs2000_id,
 522 };
 523
 524 module_i2c_driver(cs2000_driver);
 525
 526 MODULE_DESCRIPTION("CS2000-CP driver");
 527 MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");
 528 MODULE_LICENSE("GPL v2");