drivers/clk/clk-wm831x.c

   1 /*
   2  * WM831x clock control
   3  *
   4  * Copyright 2011-2 Wolfson Microelectronics PLC.
   5  *
   6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   7  *
   8  *  This program is free software; you can redistribute  it and/or modify it
   9  *  under  the terms of  the GNU General  Public License as published by the
  10  *  Free Software Foundation;  either version 2 of the  License, or (at your
  11  *  option) any later version.
  12  *
  13  */
  14
  15 #include <linux/clk-provider.h>
  16 #include <linux/delay.h>
  17 #include <linux/module.h>
  18 #include <linux/slab.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/mfd/wm831x/core.h>
  21
  22 struct wm831x_clk {
  23         struct wm831x *wm831x;
  24         struct clk_hw xtal_hw;
  25         struct clk_hw fll_hw;
  26         struct clk_hw clkout_hw;
  27         struct clk *xtal;
  28         struct clk *fll;
  29         struct clk *clkout;
  30         bool xtal_ena;
  31 };
  32
  33 static int wm831x_xtal_is_prepared(struct clk_hw *hw)
  34 {
  35         struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
  36                                                   xtal_hw);
  37
  38         return clkdata->xtal_ena;
  39 }
  40
  41 static unsigned long wm831x_xtal_recalc_rate(struct clk_hw *hw,
  42                                              unsigned long parent_rate)
  43 {
  44         struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
  45                                                   xtal_hw);
  46
  47         if (clkdata->xtal_ena)
  48                 return 32768;
  49         else
  50                 return 0;
  51 }
  52
  53 static const struct clk_ops wm831x_xtal_ops = {
  54         .is_prepared = wm831x_xtal_is_prepared,
  55         .recalc_rate = wm831x_xtal_recalc_rate,
  56 };
  57
  58 static struct clk_init_data wm831x_xtal_init = {
  59         .name = "xtal",
  60         .ops = &wm831x_xtal_ops,
  61         .flags = CLK_IS_ROOT,
  62 };
  63
  64 static const unsigned long wm831x_fll_auto_rates[] = {
  65          2048000,
  66         11289600,
  67         12000000,
  68         12288000,
  69         19200000,
  70         22579600,
  71         24000000,
  72         24576000,
  73 };
  74
  75 static int wm831x_fll_is_prepared(struct clk_hw *hw)
  76 {
  77         struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
  78                                                   fll_hw);
  79         struct wm831x *wm831x = clkdata->wm831x;
  80         int ret;
  81
  82         ret = wm831x_reg_read(wm831x, WM831X_FLL_CONTROL_1);
  83         if (ret < 0) {
  84                 dev_err(wm831x->dev, "Unable to read FLL_CONTROL_1: %d\n",
  85                         ret);
  86                 return true;
  87         }
  88
  89         return (ret & WM831X_FLL_ENA) != 0;
  90 }
  91
  92 static int wm831x_fll_prepare(struct clk_hw *hw)
  93 {
  94         struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
  95                                                   fll_hw);
  96         struct wm831x *wm831x = clkdata->wm831x;
  97         int ret;
  98
  99         ret = wm831x_set_bits(wm831x, WM831X_FLL_CONTROL_1,
 100                               WM831X_FLL_ENA, WM831X_FLL_ENA);
 101         if (ret != 0)
 102                 dev_crit(wm831x->dev, "Failed to enable FLL: %d\n", ret);
 103
 104         usleep_range(2000, 2000);
 105
 106         return ret;
 107 }
 108
 109 static void wm831x_fll_unprepare(struct clk_hw *hw)
 110 {
 111         struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
 112                                                   fll_hw);
 113         struct wm831x *wm831x = clkdata->wm831x;
 114         int ret;
 115
 116         ret = wm831x_set_bits(wm831x, WM831X_FLL_CONTROL_1, WM831X_FLL_ENA, 0);
 117         if (ret != 0)
 118                 dev_crit(wm831x->dev, "Failed to disable FLL: %d\n", ret);
 119 }
 120
 121 static unsigned long wm831x_fll_recalc_rate(struct clk_hw *hw,
 122                                             unsigned long parent_rate)
 123 {
 124         struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
 125                                                   fll_hw);
 126         struct wm831x *wm831x = clkdata->wm831x;
 127         int ret;
 128
 129         ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_2);
 130         if (ret < 0) {
 131                 dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_2: %d\n",
 132                         ret);
 133                 return 0;
 134         }
 135
 136         if (ret & WM831X_FLL_AUTO)
 137                 return wm831x_fll_auto_rates[ret & WM831X_FLL_AUTO_FREQ_MASK];
 138
 139         dev_err(wm831x->dev, "FLL only supported in AUTO mode\n");
 140
 141         return 0;
 142 }
 143
 144 static long wm831x_fll_round_rate(struct clk_hw *hw, unsigned long rate,
 145                                   unsigned long *unused)
 146 {
 147         int best = 0;
 148         int i;
 149
 150         for (i = 0; i < ARRAY_SIZE(wm831x_fll_auto_rates); i++)
 151                 if (abs(wm831x_fll_auto_rates[i] - rate) <
 152                     abs(wm831x_fll_auto_rates[best] - rate))
 153                         best = i;
 154
 155         return wm831x_fll_auto_rates[best];
 156 }
 157
 158 static int wm831x_fll_set_rate(struct clk_hw *hw, unsigned long rate,
 159                                unsigned long parent_rate)
 160 {
 161         struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
 162                                                   fll_hw);
 163         struct wm831x *wm831x = clkdata->wm831x;
 164         int i;
 165
 166         for (i = 0; i < ARRAY_SIZE(wm831x_fll_auto_rates); i++)
 167                 if (wm831x_fll_auto_rates[i] == rate)
 168                         break;
 169         if (i == ARRAY_SIZE(wm831x_fll_auto_rates))
 170                 return -EINVAL;
 171
 172         if (wm831x_fll_is_prepared(hw))
 173                 return -EPERM;
 174
 175         return wm831x_set_bits(wm831x, WM831X_CLOCK_CONTROL_2,
 176                                WM831X_FLL_AUTO_FREQ_MASK, i);
 177 }
 178
 179 static const char *wm831x_fll_parents[] = {
 180         "xtal",
 181         "clkin",
 182 };
 183
 184 static u8 wm831x_fll_get_parent(struct clk_hw *hw)
 185 {
 186         struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
 187                                                   fll_hw);
 188         struct wm831x *wm831x = clkdata->wm831x;
 189         int ret;
 190
 191         /* AUTO mode is always clocked from the crystal */
 192         ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_2);
 193         if (ret < 0) {
 194                 dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_2: %d\n",
 195                         ret);
 196                 return 0;
 197         }
 198
 199         if (ret & WM831X_FLL_AUTO)
 200                 return 0;
 201
 202         ret = wm831x_reg_read(wm831x, WM831X_FLL_CONTROL_5);
 203         if (ret < 0) {
 204                 dev_err(wm831x->dev, "Unable to read FLL_CONTROL_5: %d\n",
 205                         ret);
 206                 return 0;
 207         }
 208
 209         switch (ret & WM831X_FLL_CLK_SRC_MASK) {
 210         case 0:
 211                 return 0;
 212         case 1:
 213                 return 1;
 214         default:
 215                 dev_err(wm831x->dev, "Unsupported FLL clock source %d\n",
 216                         ret & WM831X_FLL_CLK_SRC_MASK);
 217                 return 0;
 218         }
 219 }
 220
 221 static const struct clk_ops wm831x_fll_ops = {
 222         .is_prepared = wm831x_fll_is_prepared,
 223         .prepare = wm831x_fll_prepare,
 224         .unprepare = wm831x_fll_unprepare,
 225         .round_rate = wm831x_fll_round_rate,
 226         .recalc_rate = wm831x_fll_recalc_rate,
 227         .set_rate = wm831x_fll_set_rate,
 228         .get_parent = wm831x_fll_get_parent,
 229 };
 230
 231 static struct clk_init_data wm831x_fll_init = {
 232         .name = "fll",
 233         .ops = &wm831x_fll_ops,
 234         .parent_names = wm831x_fll_parents,
 235         .num_parents = ARRAY_SIZE(wm831x_fll_parents),
 236         .flags = CLK_SET_RATE_GATE,
 237 };
 238
 239 static int wm831x_clkout_is_prepared(struct clk_hw *hw)
 240 {
 241         struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
 242                                                   clkout_hw);
 243         struct wm831x *wm831x = clkdata->wm831x;
 244         int ret;
 245
 246         ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_1);
 247         if (ret < 0) {
 248                 dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_1: %d\n",
 249                         ret);
 250                 return false;
 251         }
 252
 253         return (ret & WM831X_CLKOUT_ENA) != 0;
 254 }
 255
 256 static int wm831x_clkout_prepare(struct clk_hw *hw)
 257 {
 258         struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
 259                                                   clkout_hw);
 260         struct wm831x *wm831x = clkdata->wm831x;
 261         int ret;
 262
 263         ret = wm831x_reg_unlock(wm831x);
 264         if (ret != 0) {
 265                 dev_crit(wm831x->dev, "Failed to lock registers: %d\n", ret);
 266                 return ret;
 267         }
 268
 269         ret = wm831x_set_bits(wm831x, WM831X_CLOCK_CONTROL_1,
 270                               WM831X_CLKOUT_ENA, WM831X_CLKOUT_ENA);
 271         if (ret != 0)
 272                 dev_crit(wm831x->dev, "Failed to enable CLKOUT: %d\n", ret);
 273
 274         wm831x_reg_lock(wm831x);
 275
 276         return ret;
 277 }
 278
 279 static void wm831x_clkout_unprepare(struct clk_hw *hw)
 280 {
 281         struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
 282                                                   clkout_hw);
 283         struct wm831x *wm831x = clkdata->wm831x;
 284         int ret;
 285
 286         ret = wm831x_reg_unlock(wm831x);
 287         if (ret != 0) {
 288                 dev_crit(wm831x->dev, "Failed to lock registers: %d\n", ret);
 289                 return;
 290         }
 291
 292         ret = wm831x_set_bits(wm831x, WM831X_CLOCK_CONTROL_1,
 293                               WM831X_CLKOUT_ENA, 0);
 294         if (ret != 0)
 295                 dev_crit(wm831x->dev, "Failed to disable CLKOUT: %d\n", ret);
 296
 297         wm831x_reg_lock(wm831x);
 298 }
 299
 300 static const char *wm831x_clkout_parents[] = {
 301         "fll",
 302         "xtal",
 303 };
 304
 305 static u8 wm831x_clkout_get_parent(struct clk_hw *hw)
 306 {
 307         struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
 308                                                   clkout_hw);
 309         struct wm831x *wm831x = clkdata->wm831x;
 310         int ret;
 311
 312         ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_1);
 313         if (ret < 0) {
 314                 dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_1: %d\n",
 315                         ret);
 316                 return 0;
 317         }
 318
 319         if (ret & WM831X_CLKOUT_SRC)
 320                 return 1;
 321         else
 322                 return 0;
 323 }
 324
 325 static int wm831x_clkout_set_parent(struct clk_hw *hw, u8 parent)
 326 {
 327         struct wm831x_clk *clkdata = container_of(hw, struct wm831x_clk,
 328                                                   clkout_hw);
 329         struct wm831x *wm831x = clkdata->wm831x;
 330
 331         return wm831x_set_bits(wm831x, WM831X_CLOCK_CONTROL_1,
 332                                WM831X_CLKOUT_SRC,
 333                                parent << WM831X_CLKOUT_SRC_SHIFT);
 334 }
 335
 336 static const struct clk_ops wm831x_clkout_ops = {
 337         .is_prepared = wm831x_clkout_is_prepared,
 338         .prepare = wm831x_clkout_prepare,
 339         .unprepare = wm831x_clkout_unprepare,
 340         .get_parent = wm831x_clkout_get_parent,
 341         .set_parent = wm831x_clkout_set_parent,
 342 };
 343
 344 static struct clk_init_data wm831x_clkout_init = {
 345         .name = "clkout",
 346         .ops = &wm831x_clkout_ops,
 347         .parent_names = wm831x_clkout_parents,
 348         .num_parents = ARRAY_SIZE(wm831x_clkout_parents),
 349         .flags = CLK_SET_RATE_PARENT,
 350 };
 351
 352 static int wm831x_clk_probe(struct platform_device *pdev)
 353 {
 354         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
 355         struct wm831x_clk *clkdata;
 356         int ret;
 357
 358         clkdata = devm_kzalloc(&pdev->dev, sizeof(*clkdata), GFP_KERNEL);
 359         if (!clkdata)
 360                 return -ENOMEM;
 361
 362         clkdata->wm831x = wm831x;
 363
 364         /* XTAL_ENA can only be set via OTP/InstantConfig so just read once */
 365         ret = wm831x_reg_read(wm831x, WM831X_CLOCK_CONTROL_2);
 366         if (ret < 0) {
 367                 dev_err(wm831x->dev, "Unable to read CLOCK_CONTROL_2: %d\n",
 368                         ret);
 369                 return ret;
 370         }
 371         clkdata->xtal_ena = ret & WM831X_XTAL_ENA;
 372
 373         clkdata->xtal_hw.init = &wm831x_xtal_init;
 374         clkdata->xtal = devm_clk_register(&pdev->dev, &clkdata->xtal_hw);
 375         if (IS_ERR(clkdata->xtal))
 376                 return PTR_ERR(clkdata->xtal);
 377
 378         clkdata->fll_hw.init = &wm831x_fll_init;
 379         clkdata->fll = devm_clk_register(&pdev->dev, &clkdata->fll_hw);
 380         if (IS_ERR(clkdata->fll))
 381                 return PTR_ERR(clkdata->fll);
 382
 383         clkdata->clkout_hw.init = &wm831x_clkout_init;
 384         clkdata->clkout = devm_clk_register(&pdev->dev, &clkdata->clkout_hw);
 385         if (IS_ERR(clkdata->clkout))
 386                 return PTR_ERR(clkdata->clkout);
 387
 388         platform_set_drvdata(pdev, clkdata);
 389
 390         return 0;
 391 }
 392
 393 static struct platform_driver wm831x_clk_driver = {
 394         .probe = wm831x_clk_probe,
 395         .driver         = {
 396                 .name   = "wm831x-clk",
 397         },
 398 };
 399
 400 module_platform_driver(wm831x_clk_driver);
 401
 402 /* Module information */
 403 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 404 MODULE_DESCRIPTION("WM831x clock driver");
 405 MODULE_LICENSE("GPL");
 406 MODULE_ALIAS("platform:wm831x-clk");