arch/arm/mach-ep93xx/clock.c

   1 /*
   2  * arch/arm/mach-ep93xx/clock.c
   3  * Clock control for Cirrus EP93xx chips.
   4  *
   5  * Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
   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 as published by
   9  * the Free Software Foundation; either version 2 of the License, or (at
  10  * your option) any later version.
  11  */
  12
  13 #define pr_fmt(fmt) "ep93xx " KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/kernel.h>
  16 #include <linux/clk.h>
  17 #include <linux/err.h>
  18 #include <linux/module.h>
  19 #include <linux/string.h>
  20 #include <linux/io.h>
  21 #include <linux/spinlock.h>
  22
  23 #include <mach/hardware.h>
  24
  25 #include <asm/clkdev.h>
  26 #include <asm/div64.h>
  27
  28
  29 struct clk {
  30         struct clk      *parent;
  31         unsigned long   rate;
  32         int             users;
  33         int             sw_locked;
  34         void __iomem    *enable_reg;
  35         u32             enable_mask;
  36
  37         unsigned long   (*get_rate)(struct clk *clk);
  38         int             (*set_rate)(struct clk *clk, unsigned long rate);
  39 };
  40
  41
  42 static unsigned long get_uart_rate(struct clk *clk);
  43
  44 static int set_keytchclk_rate(struct clk *clk, unsigned long rate);
  45 static int set_div_rate(struct clk *clk, unsigned long rate);
  46
  47
  48 static struct clk clk_xtali = {
  49         .rate           = EP93XX_EXT_CLK_RATE,
  50 };
  51 static struct clk clk_uart1 = {
  52         .parent         = &clk_xtali,
  53         .sw_locked      = 1,
  54         .enable_reg     = EP93XX_SYSCON_DEVCFG,
  55         .enable_mask    = EP93XX_SYSCON_DEVCFG_U1EN,
  56         .get_rate       = get_uart_rate,
  57 };
  58 static struct clk clk_uart2 = {
  59         .parent         = &clk_xtali,
  60         .sw_locked      = 1,
  61         .enable_reg     = EP93XX_SYSCON_DEVCFG,
  62         .enable_mask    = EP93XX_SYSCON_DEVCFG_U2EN,
  63         .get_rate       = get_uart_rate,
  64 };
  65 static struct clk clk_uart3 = {
  66         .parent         = &clk_xtali,
  67         .sw_locked      = 1,
  68         .enable_reg     = EP93XX_SYSCON_DEVCFG,
  69         .enable_mask    = EP93XX_SYSCON_DEVCFG_U3EN,
  70         .get_rate       = get_uart_rate,
  71 };
  72 static struct clk clk_pll1 = {
  73         .parent         = &clk_xtali,
  74 };
  75 static struct clk clk_f = {
  76         .parent         = &clk_pll1,
  77 };
  78 static struct clk clk_h = {
  79         .parent         = &clk_pll1,
  80 };
  81 static struct clk clk_p = {
  82         .parent         = &clk_pll1,
  83 };
  84 static struct clk clk_pll2 = {
  85         .parent         = &clk_xtali,
  86 };
  87 static struct clk clk_usb_host = {
  88         .parent         = &clk_pll2,
  89         .enable_reg     = EP93XX_SYSCON_PWRCNT,
  90         .enable_mask    = EP93XX_SYSCON_PWRCNT_USH_EN,
  91 };
  92 static struct clk clk_keypad = {
  93         .parent         = &clk_xtali,
  94         .sw_locked      = 1,
  95         .enable_reg     = EP93XX_SYSCON_KEYTCHCLKDIV,
  96         .enable_mask    = EP93XX_SYSCON_KEYTCHCLKDIV_KEN,
  97         .set_rate       = set_keytchclk_rate,
  98 };
  99 static struct clk clk_pwm = {
 100         .parent         = &clk_xtali,
 101         .rate           = EP93XX_EXT_CLK_RATE,
 102 };
 103
 104 static struct clk clk_video = {
 105         .sw_locked      = 1,
 106         .enable_reg     = EP93XX_SYSCON_VIDCLKDIV,
 107         .enable_mask    = EP93XX_SYSCON_CLKDIV_ENABLE,
 108         .set_rate       = set_div_rate,
 109 };
 110
 111 /* DMA Clocks */
 112 static struct clk clk_m2p0 = {
 113         .parent         = &clk_h,
 114         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 115         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P0,
 116 };
 117 static struct clk clk_m2p1 = {
 118         .parent         = &clk_h,
 119         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 120         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P1,
 121 };
 122 static struct clk clk_m2p2 = {
 123         .parent         = &clk_h,
 124         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 125         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P2,
 126 };
 127 static struct clk clk_m2p3 = {
 128         .parent         = &clk_h,
 129         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 130         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P3,
 131 };
 132 static struct clk clk_m2p4 = {
 133         .parent         = &clk_h,
 134         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 135         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P4,
 136 };
 137 static struct clk clk_m2p5 = {
 138         .parent         = &clk_h,
 139         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 140         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P5,
 141 };
 142 static struct clk clk_m2p6 = {
 143         .parent         = &clk_h,
 144         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 145         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P6,
 146 };
 147 static struct clk clk_m2p7 = {
 148         .parent         = &clk_h,
 149         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 150         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P7,
 151 };
 152 static struct clk clk_m2p8 = {
 153         .parent         = &clk_h,
 154         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 155         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P8,
 156 };
 157 static struct clk clk_m2p9 = {
 158         .parent         = &clk_h,
 159         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 160         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P9,
 161 };
 162 static struct clk clk_m2m0 = {
 163         .parent         = &clk_h,
 164         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 165         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2M0,
 166 };
 167 static struct clk clk_m2m1 = {
 168         .parent         = &clk_h,
 169         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 170         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2M1,
 171 };
 172
 173 #define INIT_CK(dev,con,ck)                                     \
 174         { .dev_id = dev, .con_id = con, .clk = ck }
 175
 176 static struct clk_lookup clocks[] = {
 177         INIT_CK(NULL,                   "xtali",        &clk_xtali),
 178         INIT_CK("apb:uart1",            NULL,           &clk_uart1),
 179         INIT_CK("apb:uart2",            NULL,           &clk_uart2),
 180         INIT_CK("apb:uart3",            NULL,           &clk_uart3),
 181         INIT_CK(NULL,                   "pll1",         &clk_pll1),
 182         INIT_CK(NULL,                   "fclk",         &clk_f),
 183         INIT_CK(NULL,                   "hclk",         &clk_h),
 184         INIT_CK(NULL,                   "pclk",         &clk_p),
 185         INIT_CK(NULL,                   "pll2",         &clk_pll2),
 186         INIT_CK("ep93xx-ohci",          NULL,           &clk_usb_host),
 187         INIT_CK("ep93xx-keypad",        NULL,           &clk_keypad),
 188         INIT_CK("ep93xx-fb",            NULL,           &clk_video),
 189         INIT_CK(NULL,                   "pwm_clk",      &clk_pwm),
 190         INIT_CK(NULL,                   "m2p0",         &clk_m2p0),
 191         INIT_CK(NULL,                   "m2p1",         &clk_m2p1),
 192         INIT_CK(NULL,                   "m2p2",         &clk_m2p2),
 193         INIT_CK(NULL,                   "m2p3",         &clk_m2p3),
 194         INIT_CK(NULL,                   "m2p4",         &clk_m2p4),
 195         INIT_CK(NULL,                   "m2p5",         &clk_m2p5),
 196         INIT_CK(NULL,                   "m2p6",         &clk_m2p6),
 197         INIT_CK(NULL,                   "m2p7",         &clk_m2p7),
 198         INIT_CK(NULL,                   "m2p8",         &clk_m2p8),
 199         INIT_CK(NULL,                   "m2p9",         &clk_m2p9),
 200         INIT_CK(NULL,                   "m2m0",         &clk_m2m0),
 201         INIT_CK(NULL,                   "m2m1",         &clk_m2m1),
 202 };
 203
 204 static DEFINE_SPINLOCK(clk_lock);
 205
 206 static void __clk_enable(struct clk *clk)
 207 {
 208         if (!clk->users++) {
 209                 if (clk->parent)
 210                         __clk_enable(clk->parent);
 211
 212                 if (clk->enable_reg) {
 213                         u32 v;
 214
 215                         v = __raw_readl(clk->enable_reg);
 216                         v |= clk->enable_mask;
 217                         if (clk->sw_locked)
 218                                 ep93xx_syscon_swlocked_write(v, clk->enable_reg);
 219                         else
 220                                 __raw_writel(v, clk->enable_reg);
 221                 }
 222         }
 223 }
 224
 225 int clk_enable(struct clk *clk)
 226 {
 227         unsigned long flags;
 228
 229         if (!clk)
 230                 return -EINVAL;
 231
 232         spin_lock_irqsave(&clk_lock, flags);
 233         __clk_enable(clk);
 234         spin_unlock_irqrestore(&clk_lock, flags);
 235
 236         return 0;
 237 }
 238 EXPORT_SYMBOL(clk_enable);
 239
 240 static void __clk_disable(struct clk *clk)
 241 {
 242         if (!--clk->users) {
 243                 if (clk->enable_reg) {
 244                         u32 v;
 245
 246                         v = __raw_readl(clk->enable_reg);
 247                         v &= ~clk->enable_mask;
 248                         if (clk->sw_locked)
 249                                 ep93xx_syscon_swlocked_write(v, clk->enable_reg);
 250                         else
 251                                 __raw_writel(v, clk->enable_reg);
 252                 }
 253
 254                 if (clk->parent)
 255                         __clk_disable(clk->parent);
 256         }
 257 }
 258
 259 void clk_disable(struct clk *clk)
 260 {
 261         unsigned long flags;
 262
 263         if (!clk)
 264                 return;
 265
 266         spin_lock_irqsave(&clk_lock, flags);
 267         __clk_disable(clk);
 268         spin_unlock_irqrestore(&clk_lock, flags);
 269 }
 270 EXPORT_SYMBOL(clk_disable);
 271
 272 static unsigned long get_uart_rate(struct clk *clk)
 273 {
 274         unsigned long rate = clk_get_rate(clk->parent);
 275         u32 value;
 276
 277         value = __raw_readl(EP93XX_SYSCON_PWRCNT);
 278         if (value & EP93XX_SYSCON_PWRCNT_UARTBAUD)
 279                 return rate;
 280         else
 281                 return rate / 2;
 282 }
 283
 284 unsigned long clk_get_rate(struct clk *clk)
 285 {
 286         if (clk->get_rate)
 287                 return clk->get_rate(clk);
 288
 289         return clk->rate;
 290 }
 291 EXPORT_SYMBOL(clk_get_rate);
 292
 293 static int set_keytchclk_rate(struct clk *clk, unsigned long rate)
 294 {
 295         u32 val;
 296         u32 div_bit;
 297
 298         val = __raw_readl(clk->enable_reg);
 299
 300         /*
 301          * The Key Matrix and ADC clocks are configured using the same
 302          * System Controller register.  The clock used will be either
 303          * 1/4 or 1/16 the external clock rate depending on the
 304          * EP93XX_SYSCON_KEYTCHCLKDIV_KDIV/EP93XX_SYSCON_KEYTCHCLKDIV_ADIV
 305          * bit being set or cleared.
 306          */
 307         div_bit = clk->enable_mask >> 15;
 308
 309         if (rate == EP93XX_KEYTCHCLK_DIV4)
 310                 val |= div_bit;
 311         else if (rate == EP93XX_KEYTCHCLK_DIV16)
 312                 val &= ~div_bit;
 313         else
 314                 return -EINVAL;
 315
 316         ep93xx_syscon_swlocked_write(val, clk->enable_reg);
 317         clk->rate = rate;
 318         return 0;
 319 }
 320
 321 static int calc_clk_div(struct clk *clk, unsigned long rate,
 322                         int *psel, int *esel, int *pdiv, int *div)
 323 {
 324         struct clk *mclk;
 325         unsigned long max_rate, actual_rate, mclk_rate, rate_err = -1;
 326         int i, found = 0, __div = 0, __pdiv = 0;
 327
 328         /* Don't exceed the maximum rate */
 329         max_rate = max(max(clk_pll1.rate / 4, clk_pll2.rate / 4),
 330                        clk_xtali.rate / 4);
 331         rate = min(rate, max_rate);
 332
 333         /*
 334          * Try the two pll's and the external clock
 335          * Because the valid predividers are 2, 2.5 and 3, we multiply
 336          * all the clocks by 2 to avoid floating point math.
 337          *
 338          * This is based on the algorithm in the ep93xx raster guide:
 339          * http://be-a-maverick.com/en/pubs/appNote/AN269REV1.pdf
 340          *
 341          */
 342         for (i = 0; i < 3; i++) {
 343                 if (i == 0)
 344                         mclk = &clk_xtali;
 345                 else if (i == 1)
 346                         mclk = &clk_pll1;
 347                 else
 348                         mclk = &clk_pll2;
 349                 mclk_rate = mclk->rate * 2;
 350
 351                 /* Try each predivider value */
 352                 for (__pdiv = 4; __pdiv <= 6; __pdiv++) {
 353                         __div = mclk_rate / (rate * __pdiv);
 354                         if (__div < 2 || __div > 127)
 355                                 continue;
 356
 357                         actual_rate = mclk_rate / (__pdiv * __div);
 358
 359                         if (!found || abs(actual_rate - rate) < rate_err) {
 360                                 *pdiv = __pdiv - 3;
 361                                 *div = __div;
 362                                 *psel = (i == 2);
 363                                 *esel = (i != 0);
 364                                 clk->parent = mclk;
 365                                 clk->rate = actual_rate;
 366                                 rate_err = abs(actual_rate - rate);
 367                                 found = 1;
 368                         }
 369                 }
 370         }
 371
 372         if (!found)
 373                 return -EINVAL;
 374
 375         return 0;
 376 }
 377
 378 static int set_div_rate(struct clk *clk, unsigned long rate)
 379 {
 380         int err, psel = 0, esel = 0, pdiv = 0, div = 0;
 381         u32 val;
 382
 383         err = calc_clk_div(clk, rate, &psel, &esel, &pdiv, &div);
 384         if (err)
 385                 return err;
 386
 387         /* Clear the esel, psel, pdiv and div bits */
 388         val = __raw_readl(clk->enable_reg);
 389         val &= ~0x7fff;
 390
 391         /* Set the new esel, psel, pdiv and div bits for the new clock rate */
 392         val |= (esel ? EP93XX_SYSCON_CLKDIV_ESEL : 0) |
 393                 (psel ? EP93XX_SYSCON_CLKDIV_PSEL : 0) |
 394                 (pdiv << EP93XX_SYSCON_CLKDIV_PDIV_SHIFT) | div;
 395         ep93xx_syscon_swlocked_write(val, clk->enable_reg);
 396         return 0;
 397 }
 398
 399 int clk_set_rate(struct clk *clk, unsigned long rate)
 400 {
 401         if (clk->set_rate)
 402                 return clk->set_rate(clk, rate);
 403
 404         return -EINVAL;
 405 }
 406 EXPORT_SYMBOL(clk_set_rate);
 407
 408
 409 static char fclk_divisors[] = { 1, 2, 4, 8, 16, 1, 1, 1 };
 410 static char hclk_divisors[] = { 1, 2, 4, 5, 6, 8, 16, 32 };
 411 static char pclk_divisors[] = { 1, 2, 4, 8 };
 412
 413 /*
 414  * PLL rate = 14.7456 MHz * (X1FBD + 1) * (X2FBD + 1) / (X2IPD + 1) / 2^PS
 415  */
 416 static unsigned long calc_pll_rate(u32 config_word)
 417 {
 418         unsigned long long rate;
 419         int i;
 420
 421         rate = clk_xtali.rate;
 422         rate *= ((config_word >> 11) & 0x1f) + 1;               /* X1FBD */
 423         rate *= ((config_word >> 5) & 0x3f) + 1;                /* X2FBD */
 424         do_div(rate, (config_word & 0x1f) + 1);                 /* X2IPD */
 425         for (i = 0; i < ((config_word >> 16) & 3); i++)         /* PS */
 426                 rate >>= 1;
 427
 428         return (unsigned long)rate;
 429 }
 430
 431 static void __init ep93xx_dma_clock_init(void)
 432 {
 433         clk_m2p0.rate = clk_h.rate;
 434         clk_m2p1.rate = clk_h.rate;
 435         clk_m2p2.rate = clk_h.rate;
 436         clk_m2p3.rate = clk_h.rate;
 437         clk_m2p4.rate = clk_h.rate;
 438         clk_m2p5.rate = clk_h.rate;
 439         clk_m2p6.rate = clk_h.rate;
 440         clk_m2p7.rate = clk_h.rate;
 441         clk_m2p8.rate = clk_h.rate;
 442         clk_m2p9.rate = clk_h.rate;
 443         clk_m2m0.rate = clk_h.rate;
 444         clk_m2m1.rate = clk_h.rate;
 445 }
 446
 447 static int __init ep93xx_clock_init(void)
 448 {
 449         u32 value;
 450
 451         /* Determine the bootloader configured pll1 rate */
 452         value = __raw_readl(EP93XX_SYSCON_CLKSET1);
 453         if (!(value & EP93XX_SYSCON_CLKSET1_NBYP1))
 454                 clk_pll1.rate = clk_xtali.rate;
 455         else
 456                 clk_pll1.rate = calc_pll_rate(value);
 457
 458         /* Initialize the pll1 derived clocks */
 459         clk_f.rate = clk_pll1.rate / fclk_divisors[(value >> 25) & 0x7];
 460         clk_h.rate = clk_pll1.rate / hclk_divisors[(value >> 20) & 0x7];
 461         clk_p.rate = clk_h.rate / pclk_divisors[(value >> 18) & 0x3];
 462         ep93xx_dma_clock_init();
 463
 464         /* Determine the bootloader configured pll2 rate */
 465         value = __raw_readl(EP93XX_SYSCON_CLKSET2);
 466         if (!(value & EP93XX_SYSCON_CLKSET2_NBYP2))
 467                 clk_pll2.rate = clk_xtali.rate;
 468         else if (value & EP93XX_SYSCON_CLKSET2_PLL2_EN)
 469                 clk_pll2.rate = calc_pll_rate(value);
 470         else
 471                 clk_pll2.rate = 0;
 472
 473         /* Initialize the pll2 derived clocks */
 474         clk_usb_host.rate = clk_pll2.rate / (((value >> 28) & 0xf) + 1);
 475
 476         pr_info("PLL1 running at %ld MHz, PLL2 at %ld MHz\n",
 477                 clk_pll1.rate / 1000000, clk_pll2.rate / 1000000);
 478         pr_info("FCLK %ld MHz, HCLK %ld MHz, PCLK %ld MHz\n",
 479                 clk_f.rate / 1000000, clk_h.rate / 1000000,
 480                 clk_p.rate / 1000000);
 481
 482         clkdev_add_table(clocks, ARRAY_SIZE(clocks));
 483         return 0;
 484 }
 485 arch_initcall(ep93xx_clock_init);