drivers/clk/clk-axi-clkgen.c

   1 /*
   2  * AXI clkgen driver
   3  *
   4  * Copyright 2012-2013 Analog Devices Inc.
   5  *  Author: Lars-Peter Clausen <lars@metafoo.de>
   6  *
   7  * Licensed under the GPL-2.
   8  *
   9  */
  10
  11 #include <linux/platform_device.h>
  12 #include <linux/clk-provider.h>
  13 #include <linux/slab.h>
  14 #include <linux/io.h>
  15 #include <linux/of.h>
  16 #include <linux/module.h>
  17 #include <linux/err.h>
  18
  19 #define AXI_CLKGEN_V2_REG_RESET         0x40
  20 #define AXI_CLKGEN_V2_REG_CLKSEL        0x44
  21 #define AXI_CLKGEN_V2_REG_DRP_CNTRL     0x70
  22 #define AXI_CLKGEN_V2_REG_DRP_STATUS    0x74
  23
  24 #define AXI_CLKGEN_V2_RESET_MMCM_ENABLE BIT(1)
  25 #define AXI_CLKGEN_V2_RESET_ENABLE      BIT(0)
  26
  27 #define AXI_CLKGEN_V2_DRP_CNTRL_SEL     BIT(29)
  28 #define AXI_CLKGEN_V2_DRP_CNTRL_READ    BIT(28)
  29
  30 #define AXI_CLKGEN_V2_DRP_STATUS_BUSY   BIT(16)
  31
  32 #define MMCM_REG_CLKOUT0_1      0x08
  33 #define MMCM_REG_CLKOUT0_2      0x09
  34 #define MMCM_REG_CLK_FB1        0x14
  35 #define MMCM_REG_CLK_FB2        0x15
  36 #define MMCM_REG_CLK_DIV        0x16
  37 #define MMCM_REG_LOCK1          0x18
  38 #define MMCM_REG_LOCK2          0x19
  39 #define MMCM_REG_LOCK3          0x1a
  40 #define MMCM_REG_FILTER1        0x4e
  41 #define MMCM_REG_FILTER2        0x4f
  42
  43 struct axi_clkgen {
  44         void __iomem *base;
  45         struct clk_hw clk_hw;
  46 };
  47
  48 static uint32_t axi_clkgen_lookup_filter(unsigned int m)
  49 {
  50         switch (m) {
  51         case 0:
  52                 return 0x01001990;
  53         case 1:
  54                 return 0x01001190;
  55         case 2:
  56                 return 0x01009890;
  57         case 3:
  58                 return 0x01001890;
  59         case 4:
  60                 return 0x01008890;
  61         case 5 ... 8:
  62                 return 0x01009090;
  63         case 9 ... 11:
  64                 return 0x01000890;
  65         case 12:
  66                 return 0x08009090;
  67         case 13 ... 22:
  68                 return 0x01001090;
  69         case 23 ... 36:
  70                 return 0x01008090;
  71         case 37 ... 46:
  72                 return 0x08001090;
  73         default:
  74                 return 0x08008090;
  75         }
  76 }
  77
  78 static const uint32_t axi_clkgen_lock_table[] = {
  79         0x060603e8, 0x060603e8, 0x080803e8, 0x0b0b03e8,
  80         0x0e0e03e8, 0x111103e8, 0x131303e8, 0x161603e8,
  81         0x191903e8, 0x1c1c03e8, 0x1f1f0384, 0x1f1f0339,
  82         0x1f1f02ee, 0x1f1f02bc, 0x1f1f028a, 0x1f1f0271,
  83         0x1f1f023f, 0x1f1f0226, 0x1f1f020d, 0x1f1f01f4,
  84         0x1f1f01db, 0x1f1f01c2, 0x1f1f01a9, 0x1f1f0190,
  85         0x1f1f0190, 0x1f1f0177, 0x1f1f015e, 0x1f1f015e,
  86         0x1f1f0145, 0x1f1f0145, 0x1f1f012c, 0x1f1f012c,
  87         0x1f1f012c, 0x1f1f0113, 0x1f1f0113, 0x1f1f0113,
  88 };
  89
  90 static uint32_t axi_clkgen_lookup_lock(unsigned int m)
  91 {
  92         if (m < ARRAY_SIZE(axi_clkgen_lock_table))
  93                 return axi_clkgen_lock_table[m];
  94         return 0x1f1f00fa;
  95 }
  96
  97 static const unsigned int fpfd_min = 10000;
  98 static const unsigned int fpfd_max = 300000;
  99 static const unsigned int fvco_min = 600000;
 100 static const unsigned int fvco_max = 1200000;
 101
 102 static void axi_clkgen_calc_params(unsigned long fin, unsigned long fout,
 103         unsigned int *best_d, unsigned int *best_m, unsigned int *best_dout)
 104 {
 105         unsigned long d, d_min, d_max, _d_min, _d_max;
 106         unsigned long m, m_min, m_max;
 107         unsigned long f, dout, best_f, fvco;
 108
 109         fin /= 1000;
 110         fout /= 1000;
 111
 112         best_f = ULONG_MAX;
 113         *best_d = 0;
 114         *best_m = 0;
 115         *best_dout = 0;
 116
 117         d_min = max_t(unsigned long, DIV_ROUND_UP(fin, fpfd_max), 1);
 118         d_max = min_t(unsigned long, fin / fpfd_min, 80);
 119
 120         m_min = max_t(unsigned long, DIV_ROUND_UP(fvco_min, fin) * d_min, 1);
 121         m_max = min_t(unsigned long, fvco_max * d_max / fin, 64);
 122
 123         for (m = m_min; m <= m_max; m++) {
 124                 _d_min = max(d_min, DIV_ROUND_UP(fin * m, fvco_max));
 125                 _d_max = min(d_max, fin * m / fvco_min);
 126
 127                 for (d = _d_min; d <= _d_max; d++) {
 128                         fvco = fin * m / d;
 129
 130                         dout = DIV_ROUND_CLOSEST(fvco, fout);
 131                         dout = clamp_t(unsigned long, dout, 1, 128);
 132                         f = fvco / dout;
 133                         if (abs(f - fout) < abs(best_f - fout)) {
 134                                 best_f = f;
 135                                 *best_d = d;
 136                                 *best_m = m;
 137                                 *best_dout = dout;
 138                                 if (best_f == fout)
 139                                         return;
 140                         }
 141                 }
 142         }
 143 }
 144
 145 static void axi_clkgen_calc_clk_params(unsigned int divider, unsigned int *low,
 146         unsigned int *high, unsigned int *edge, unsigned int *nocount)
 147 {
 148         if (divider == 1)
 149                 *nocount = 1;
 150         else
 151                 *nocount = 0;
 152
 153         *high = divider / 2;
 154         *edge = divider % 2;
 155         *low = divider - *high;
 156 }
 157
 158 static void axi_clkgen_write(struct axi_clkgen *axi_clkgen,
 159         unsigned int reg, unsigned int val)
 160 {
 161         writel(val, axi_clkgen->base + reg);
 162 }
 163
 164 static void axi_clkgen_read(struct axi_clkgen *axi_clkgen,
 165         unsigned int reg, unsigned int *val)
 166 {
 167         *val = readl(axi_clkgen->base + reg);
 168 }
 169
 170 static int axi_clkgen_wait_non_busy(struct axi_clkgen *axi_clkgen)
 171 {
 172         unsigned int timeout = 10000;
 173         unsigned int val;
 174
 175         do {
 176                 axi_clkgen_read(axi_clkgen, AXI_CLKGEN_V2_REG_DRP_STATUS, &val);
 177         } while ((val & AXI_CLKGEN_V2_DRP_STATUS_BUSY) && --timeout);
 178
 179         if (val & AXI_CLKGEN_V2_DRP_STATUS_BUSY)
 180                 return -EIO;
 181
 182         return val & 0xffff;
 183 }
 184
 185 static int axi_clkgen_mmcm_read(struct axi_clkgen *axi_clkgen,
 186         unsigned int reg, unsigned int *val)
 187 {
 188         unsigned int reg_val;
 189         int ret;
 190
 191         ret = axi_clkgen_wait_non_busy(axi_clkgen);
 192         if (ret < 0)
 193                 return ret;
 194
 195         reg_val = AXI_CLKGEN_V2_DRP_CNTRL_SEL | AXI_CLKGEN_V2_DRP_CNTRL_READ;
 196         reg_val |= (reg << 16);
 197
 198         axi_clkgen_write(axi_clkgen, AXI_CLKGEN_V2_REG_DRP_CNTRL, reg_val);
 199
 200         ret = axi_clkgen_wait_non_busy(axi_clkgen);
 201         if (ret < 0)
 202                 return ret;
 203
 204         *val = ret;
 205
 206         return 0;
 207 }
 208
 209 static int axi_clkgen_mmcm_write(struct axi_clkgen *axi_clkgen,
 210         unsigned int reg, unsigned int val, unsigned int mask)
 211 {
 212         unsigned int reg_val = 0;
 213         int ret;
 214
 215         ret = axi_clkgen_wait_non_busy(axi_clkgen);
 216         if (ret < 0)
 217                 return ret;
 218
 219         if (mask != 0xffff) {
 220                 axi_clkgen_mmcm_read(axi_clkgen, reg, &reg_val);
 221                 reg_val &= ~mask;
 222         }
 223
 224         reg_val |= AXI_CLKGEN_V2_DRP_CNTRL_SEL | (reg << 16) | (val & mask);
 225
 226         axi_clkgen_write(axi_clkgen, AXI_CLKGEN_V2_REG_DRP_CNTRL, reg_val);
 227
 228         return 0;
 229 }
 230
 231 static void axi_clkgen_mmcm_enable(struct axi_clkgen *axi_clkgen,
 232         bool enable)
 233 {
 234         unsigned int val = AXI_CLKGEN_V2_RESET_ENABLE;
 235
 236         if (enable)
 237                 val |= AXI_CLKGEN_V2_RESET_MMCM_ENABLE;
 238
 239         axi_clkgen_write(axi_clkgen, AXI_CLKGEN_V2_REG_RESET, val);
 240 }
 241
 242 static struct axi_clkgen *clk_hw_to_axi_clkgen(struct clk_hw *clk_hw)
 243 {
 244         return container_of(clk_hw, struct axi_clkgen, clk_hw);
 245 }
 246
 247 static int axi_clkgen_set_rate(struct clk_hw *clk_hw,
 248         unsigned long rate, unsigned long parent_rate)
 249 {
 250         struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
 251         unsigned int d, m, dout;
 252         unsigned int nocount;
 253         unsigned int high;
 254         unsigned int edge;
 255         unsigned int low;
 256         uint32_t filter;
 257         uint32_t lock;
 258
 259         if (parent_rate == 0 || rate == 0)
 260                 return -EINVAL;
 261
 262         axi_clkgen_calc_params(parent_rate, rate, &d, &m, &dout);
 263
 264         if (d == 0 || dout == 0 || m == 0)
 265                 return -EINVAL;
 266
 267         filter = axi_clkgen_lookup_filter(m - 1);
 268         lock = axi_clkgen_lookup_lock(m - 1);
 269
 270         axi_clkgen_calc_clk_params(dout, &low, &high, &edge, &nocount);
 271         axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_CLKOUT0_1,
 272                 (high << 6) | low, 0xefff);
 273         axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_CLKOUT0_2,
 274                 (edge << 7) | (nocount << 6), 0x03ff);
 275
 276         axi_clkgen_calc_clk_params(d, &low, &high, &edge, &nocount);
 277         axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_CLK_DIV,
 278                 (edge << 13) | (nocount << 12) | (high << 6) | low, 0x3fff);
 279
 280         axi_clkgen_calc_clk_params(m, &low, &high, &edge, &nocount);
 281         axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_CLK_FB1,
 282                 (high << 6) | low, 0xefff);
 283         axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_CLK_FB2,
 284                 (edge << 7) | (nocount << 6), 0x03ff);
 285
 286         axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_LOCK1, lock & 0x3ff, 0x3ff);
 287         axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_LOCK2,
 288                 (((lock >> 16) & 0x1f) << 10) | 0x1, 0x7fff);
 289         axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_LOCK3,
 290                 (((lock >> 24) & 0x1f) << 10) | 0x3e9, 0x7fff);
 291         axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_FILTER1, filter >> 16, 0x9900);
 292         axi_clkgen_mmcm_write(axi_clkgen, MMCM_REG_FILTER2, filter, 0x9900);
 293
 294         return 0;
 295 }
 296
 297 static long axi_clkgen_round_rate(struct clk_hw *hw, unsigned long rate,
 298         unsigned long *parent_rate)
 299 {
 300         unsigned int d, m, dout;
 301
 302         axi_clkgen_calc_params(*parent_rate, rate, &d, &m, &dout);
 303
 304         if (d == 0 || dout == 0 || m == 0)
 305                 return -EINVAL;
 306
 307         return *parent_rate / d * m / dout;
 308 }
 309
 310 static unsigned long axi_clkgen_recalc_rate(struct clk_hw *clk_hw,
 311         unsigned long parent_rate)
 312 {
 313         struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
 314         unsigned int d, m, dout;
 315         unsigned int reg;
 316         unsigned long long tmp;
 317
 318         axi_clkgen_mmcm_read(axi_clkgen, MMCM_REG_CLKOUT0_1, &reg);
 319         dout = (reg & 0x3f) + ((reg >> 6) & 0x3f);
 320         axi_clkgen_mmcm_read(axi_clkgen, MMCM_REG_CLK_DIV, &reg);
 321         d = (reg & 0x3f) + ((reg >> 6) & 0x3f);
 322         axi_clkgen_mmcm_read(axi_clkgen, MMCM_REG_CLK_FB1, &reg);
 323         m = (reg & 0x3f) + ((reg >> 6) & 0x3f);
 324
 325         if (d == 0 || dout == 0)
 326                 return 0;
 327
 328         tmp = (unsigned long long)(parent_rate / d) * m;
 329         do_div(tmp, dout);
 330
 331         return min_t(unsigned long long, tmp, ULONG_MAX);
 332 }
 333
 334 static int axi_clkgen_enable(struct clk_hw *clk_hw)
 335 {
 336         struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
 337
 338         axi_clkgen_mmcm_enable(axi_clkgen, true);
 339
 340         return 0;
 341 }
 342
 343 static void axi_clkgen_disable(struct clk_hw *clk_hw)
 344 {
 345         struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
 346
 347         axi_clkgen_mmcm_enable(axi_clkgen, false);
 348 }
 349
 350 static int axi_clkgen_set_parent(struct clk_hw *clk_hw, u8 index)
 351 {
 352         struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
 353
 354         axi_clkgen_write(axi_clkgen, AXI_CLKGEN_V2_REG_CLKSEL, index);
 355
 356         return 0;
 357 }
 358
 359 static u8 axi_clkgen_get_parent(struct clk_hw *clk_hw)
 360 {
 361         struct axi_clkgen *axi_clkgen = clk_hw_to_axi_clkgen(clk_hw);
 362         unsigned int parent;
 363
 364         axi_clkgen_read(axi_clkgen, AXI_CLKGEN_V2_REG_CLKSEL, &parent);
 365
 366         return parent;
 367 }
 368
 369 static const struct clk_ops axi_clkgen_ops = {
 370         .recalc_rate = axi_clkgen_recalc_rate,
 371         .round_rate = axi_clkgen_round_rate,
 372         .set_rate = axi_clkgen_set_rate,
 373         .enable = axi_clkgen_enable,
 374         .disable = axi_clkgen_disable,
 375         .set_parent = axi_clkgen_set_parent,
 376         .get_parent = axi_clkgen_get_parent,
 377 };
 378
 379 static const struct of_device_id axi_clkgen_ids[] = {
 380         {
 381                 .compatible = "adi,axi-clkgen-2.00.a",
 382         },
 383         { },
 384 };
 385 MODULE_DEVICE_TABLE(of, axi_clkgen_ids);
 386
 387 static int axi_clkgen_probe(struct platform_device *pdev)
 388 {
 389         const struct of_device_id *id;
 390         struct axi_clkgen *axi_clkgen;
 391         struct clk_init_data init;
 392         const char *parent_names[2];
 393         const char *clk_name;
 394         struct resource *mem;
 395         struct clk *clk;
 396         unsigned int i;
 397
 398         if (!pdev->dev.of_node)
 399                 return -ENODEV;
 400
 401         id = of_match_node(axi_clkgen_ids, pdev->dev.of_node);
 402         if (!id)
 403                 return -ENODEV;
 404
 405         axi_clkgen = devm_kzalloc(&pdev->dev, sizeof(*axi_clkgen), GFP_KERNEL);
 406         if (!axi_clkgen)
 407                 return -ENOMEM;
 408
 409         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 410         axi_clkgen->base = devm_ioremap_resource(&pdev->dev, mem);
 411         if (IS_ERR(axi_clkgen->base))
 412                 return PTR_ERR(axi_clkgen->base);
 413
 414         init.num_parents = of_clk_get_parent_count(pdev->dev.of_node);
 415         if (init.num_parents < 1 || init.num_parents > 2)
 416                 return -EINVAL;
 417
 418         for (i = 0; i < init.num_parents; i++) {
 419                 parent_names[i] = of_clk_get_parent_name(pdev->dev.of_node, i);
 420                 if (!parent_names[i])
 421                         return -EINVAL;
 422         }
 423
 424         clk_name = pdev->dev.of_node->name;
 425         of_property_read_string(pdev->dev.of_node, "clock-output-names",
 426                 &clk_name);
 427
 428         init.name = clk_name;
 429         init.ops = &axi_clkgen_ops;
 430         init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
 431         init.parent_names = parent_names;
 432
 433         axi_clkgen_mmcm_enable(axi_clkgen, false);
 434
 435         axi_clkgen->clk_hw.init = &init;
 436         clk = devm_clk_register(&pdev->dev, &axi_clkgen->clk_hw);
 437         if (IS_ERR(clk))
 438                 return PTR_ERR(clk);
 439
 440         return of_clk_add_provider(pdev->dev.of_node, of_clk_src_simple_get,
 441                                     clk);
 442 }
 443
 444 static int axi_clkgen_remove(struct platform_device *pdev)
 445 {
 446         of_clk_del_provider(pdev->dev.of_node);
 447
 448         return 0;
 449 }
 450
 451 static struct platform_driver axi_clkgen_driver = {
 452         .driver = {
 453                 .name = "adi-axi-clkgen",
 454                 .of_match_table = axi_clkgen_ids,
 455         },
 456         .probe = axi_clkgen_probe,
 457         .remove = axi_clkgen_remove,
 458 };
 459 module_platform_driver(axi_clkgen_driver);
 460
 461 MODULE_LICENSE("GPL v2");
 462 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 463 MODULE_DESCRIPTION("Driver for the Analog Devices' AXI clkgen pcore clock generator");