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