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