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 #include <linux/kernel.h>
  14 #include <linux/clk.h>
  15 #include <linux/err.h>
  16 #include <linux/module.h>
  17 #include <linux/string.h>
  18 #include <linux/io.h>
  19
  20 #include <asm/clkdev.h>
  21 #include <asm/div64.h>
  22 #include <mach/hardware.h>
  23
  24
  25 struct clk {
  26         unsigned long   rate;
  27         int             users;
  28         int             sw_locked;
  29         void __iomem    *enable_reg;
  30         u32             enable_mask;
  31
  32         unsigned long   (*get_rate)(struct clk *clk);
  33         int             (*set_rate)(struct clk *clk, unsigned long rate);
  34 };
  35
  36
  37 static unsigned long get_uart_rate(struct clk *clk);
  38
  39 static int set_keytchclk_rate(struct clk *clk, unsigned long rate);
  40 static int set_div_rate(struct clk *clk, unsigned long rate);
  41
  42 static struct clk clk_uart1 = {
  43         .sw_locked      = 1,
  44         .enable_reg     = EP93XX_SYSCON_DEVCFG,
  45         .enable_mask    = EP93XX_SYSCON_DEVCFG_U1EN,
  46         .get_rate       = get_uart_rate,
  47 };
  48 static struct clk clk_uart2 = {
  49         .sw_locked      = 1,
  50         .enable_reg     = EP93XX_SYSCON_DEVCFG,
  51         .enable_mask    = EP93XX_SYSCON_DEVCFG_U2EN,
  52         .get_rate       = get_uart_rate,
  53 };
  54 static struct clk clk_uart3 = {
  55         .sw_locked      = 1,
  56         .enable_reg     = EP93XX_SYSCON_DEVCFG,
  57         .enable_mask    = EP93XX_SYSCON_DEVCFG_U3EN,
  58         .get_rate       = get_uart_rate,
  59 };
  60 static struct clk clk_pll1;
  61 static struct clk clk_f;
  62 static struct clk clk_h;
  63 static struct clk clk_p;
  64 static struct clk clk_pll2;
  65 static struct clk clk_usb_host = {
  66         .enable_reg     = EP93XX_SYSCON_PWRCNT,
  67         .enable_mask    = EP93XX_SYSCON_PWRCNT_USH_EN,
  68 };
  69 static struct clk clk_keypad = {
  70         .sw_locked      = 1,
  71         .enable_reg     = EP93XX_SYSCON_KEYTCHCLKDIV,
  72         .enable_mask    = EP93XX_SYSCON_KEYTCHCLKDIV_KEN,
  73         .set_rate       = set_keytchclk_rate,
  74 };
  75 static struct clk clk_pwm = {
  76         .rate           = EP93XX_EXT_CLK_RATE,
  77 };
  78
  79 static struct clk clk_video = {
  80         .sw_locked      = 1,
  81         .enable_reg     = EP93XX_SYSCON_VIDCLKDIV,
  82         .enable_mask    = EP93XX_SYSCON_CLKDIV_ENABLE,
  83         .set_rate       = set_div_rate,
  84 };
  85
  86 /* DMA Clocks */
  87 static struct clk clk_m2p0 = {
  88         .enable_reg     = EP93XX_SYSCON_PWRCNT,
  89         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P0,
  90 };
  91 static struct clk clk_m2p1 = {
  92         .enable_reg     = EP93XX_SYSCON_PWRCNT,
  93         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P1,
  94 };
  95 static struct clk clk_m2p2 = {
  96         .enable_reg     = EP93XX_SYSCON_PWRCNT,
  97         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P2,
  98 };
  99 static struct clk clk_m2p3 = {
 100         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 101         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P3,
 102 };
 103 static struct clk clk_m2p4 = {
 104         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 105         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P4,
 106 };
 107 static struct clk clk_m2p5 = {
 108         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 109         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P5,
 110 };
 111 static struct clk clk_m2p6 = {
 112         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 113         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P6,
 114 };
 115 static struct clk clk_m2p7 = {
 116         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 117         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P7,
 118 };
 119 static struct clk clk_m2p8 = {
 120         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 121         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P8,
 122 };
 123 static struct clk clk_m2p9 = {
 124         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 125         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2P9,
 126 };
 127 static struct clk clk_m2m0 = {
 128         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 129         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2M0,
 130 };
 131 static struct clk clk_m2m1 = {
 132         .enable_reg     = EP93XX_SYSCON_PWRCNT,
 133         .enable_mask    = EP93XX_SYSCON_PWRCNT_DMA_M2M1,
 134 };
 135
 136 #define INIT_CK(dev,con,ck)                                     \
 137         { .dev_id = dev, .con_id = con, .clk = ck }
 138
 139 static struct clk_lookup clocks[] = {
 140         INIT_CK("apb:uart1",            NULL,           &clk_uart1),
 141         INIT_CK("apb:uart2",            NULL,           &clk_uart2),
 142         INIT_CK("apb:uart3",            NULL,           &clk_uart3),
 143         INIT_CK(NULL,                   "pll1",         &clk_pll1),
 144         INIT_CK(NULL,                   "fclk",         &clk_f),
 145         INIT_CK(NULL,                   "hclk",         &clk_h),
 146         INIT_CK(NULL,                   "pclk",         &clk_p),
 147         INIT_CK(NULL,                   "pll2",         &clk_pll2),
 148         INIT_CK("ep93xx-ohci",          NULL,           &clk_usb_host),
 149         INIT_CK("ep93xx-keypad",        NULL,           &clk_keypad),
 150         INIT_CK("ep93xx-fb",            NULL,           &clk_video),
 151         INIT_CK(NULL,                   "pwm_clk",      &clk_pwm),
 152         INIT_CK(NULL,                   "m2p0",         &clk_m2p0),
 153         INIT_CK(NULL,                   "m2p1",         &clk_m2p1),
 154         INIT_CK(NULL,                   "m2p2",         &clk_m2p2),
 155         INIT_CK(NULL,                   "m2p3",         &clk_m2p3),
 156         INIT_CK(NULL,                   "m2p4",         &clk_m2p4),
 157         INIT_CK(NULL,                   "m2p5",         &clk_m2p5),
 158         INIT_CK(NULL,                   "m2p6",         &clk_m2p6),
 159         INIT_CK(NULL,                   "m2p7",         &clk_m2p7),
 160         INIT_CK(NULL,                   "m2p8",         &clk_m2p8),
 161         INIT_CK(NULL,                   "m2p9",         &clk_m2p9),
 162         INIT_CK(NULL,                   "m2m0",         &clk_m2m0),
 163         INIT_CK(NULL,                   "m2m1",         &clk_m2m1),
 164 };
 165
 166
 167 int clk_enable(struct clk *clk)
 168 {
 169         if (!clk->users++ && clk->enable_reg) {
 170                 u32 value;
 171
 172                 value = __raw_readl(clk->enable_reg);
 173                 value |= clk->enable_mask;
 174                 if (clk->sw_locked)
 175                         ep93xx_syscon_swlocked_write(value, clk->enable_reg);
 176                 else
 177                         __raw_writel(value, clk->enable_reg);
 178         }
 179
 180         return 0;
 181 }
 182 EXPORT_SYMBOL(clk_enable);
 183
 184 void clk_disable(struct clk *clk)
 185 {
 186         if (!--clk->users && clk->enable_reg) {
 187                 u32 value;
 188
 189                 value = __raw_readl(clk->enable_reg);
 190                 value &= ~clk->enable_mask;
 191                 if (clk->sw_locked)
 192                         ep93xx_syscon_swlocked_write(value, clk->enable_reg);
 193                 else
 194                         __raw_writel(value, clk->enable_reg);
 195         }
 196 }
 197 EXPORT_SYMBOL(clk_disable);
 198
 199 static unsigned long get_uart_rate(struct clk *clk)
 200 {
 201         u32 value;
 202
 203         value = __raw_readl(EP93XX_SYSCON_PWRCNT);
 204         if (value & EP93XX_SYSCON_PWRCNT_UARTBAUD)
 205                 return EP93XX_EXT_CLK_RATE;
 206         else
 207                 return EP93XX_EXT_CLK_RATE / 2;
 208 }
 209
 210 unsigned long clk_get_rate(struct clk *clk)
 211 {
 212         if (clk->get_rate)
 213                 return clk->get_rate(clk);
 214
 215         return clk->rate;
 216 }
 217 EXPORT_SYMBOL(clk_get_rate);
 218
 219 static int set_keytchclk_rate(struct clk *clk, unsigned long rate)
 220 {
 221         u32 val;
 222         u32 div_bit;
 223
 224         val = __raw_readl(clk->enable_reg);
 225
 226         /*
 227          * The Key Matrix and ADC clocks are configured using the same
 228          * System Controller register.  The clock used will be either
 229          * 1/4 or 1/16 the external clock rate depending on the
 230          * EP93XX_SYSCON_KEYTCHCLKDIV_KDIV/EP93XX_SYSCON_KEYTCHCLKDIV_ADIV
 231          * bit being set or cleared.
 232          */
 233         div_bit = clk->enable_mask >> 15;
 234
 235         if (rate == EP93XX_KEYTCHCLK_DIV4)
 236                 val |= div_bit;
 237         else if (rate == EP93XX_KEYTCHCLK_DIV16)
 238                 val &= ~div_bit;
 239         else
 240                 return -EINVAL;
 241
 242         ep93xx_syscon_swlocked_write(val, clk->enable_reg);
 243         clk->rate = rate;
 244         return 0;
 245 }
 246
 247 static unsigned long calc_clk_div(unsigned long rate, int *psel, int *esel,
 248                                   int *pdiv, int *div)
 249 {
 250         unsigned long max_rate, best_rate = 0,
 251                 actual_rate = 0, mclk_rate = 0, rate_err = -1;
 252         int i, found = 0, __div = 0, __pdiv = 0;
 253
 254         /* Don't exceed the maximum rate */
 255         max_rate = max(max(clk_pll1.rate / 4, clk_pll2.rate / 4),
 256                        (unsigned long)EP93XX_EXT_CLK_RATE / 4);
 257         rate = min(rate, max_rate);
 258
 259         /*
 260          * Try the two pll's and the external clock
 261          * Because the valid predividers are 2, 2.5 and 3, we multiply
 262          * all the clocks by 2 to avoid floating point math.
 263          *
 264          * This is based on the algorithm in the ep93xx raster guide:
 265          * http://be-a-maverick.com/en/pubs/appNote/AN269REV1.pdf
 266          *
 267          */
 268         for (i = 0; i < 3; i++) {
 269                 if (i == 0)
 270                         mclk_rate = EP93XX_EXT_CLK_RATE * 2;
 271                 else if (i == 1)
 272                         mclk_rate = clk_pll1.rate * 2;
 273                 else if (i == 2)
 274                         mclk_rate = clk_pll2.rate * 2;
 275
 276                 /* Try each predivider value */
 277                 for (__pdiv = 4; __pdiv <= 6; __pdiv++) {
 278                         __div = mclk_rate / (rate * __pdiv);
 279                         if (__div < 2 || __div > 127)
 280                                 continue;
 281
 282                         actual_rate = mclk_rate / (__pdiv * __div);
 283
 284                         if (!found || abs(actual_rate - rate) < rate_err) {
 285                                 *pdiv = __pdiv - 3;
 286                                 *div = __div;
 287                                 *psel = (i == 2);
 288                                 *esel = (i != 0);
 289                                 best_rate = actual_rate;
 290                                 rate_err = abs(actual_rate - rate);
 291                                 found = 1;
 292                         }
 293                 }
 294         }
 295
 296         if (!found)
 297                 return 0;
 298
 299         return best_rate;
 300 }
 301
 302 static int set_div_rate(struct clk *clk, unsigned long rate)
 303 {
 304         unsigned long actual_rate;
 305         int psel = 0, esel = 0, pdiv = 0, div = 0;
 306         u32 val;
 307
 308         actual_rate = calc_clk_div(rate, &psel, &esel, &pdiv, &div);
 309         if (actual_rate == 0)
 310                 return -EINVAL;
 311         clk->rate = actual_rate;
 312
 313         /* Clear the esel, psel, pdiv and div bits */
 314         val = __raw_readl(clk->enable_reg);
 315         val &= ~0x7fff;
 316
 317         /* Set the new esel, psel, pdiv and div bits for the new clock rate */
 318         val |= (esel ? EP93XX_SYSCON_CLKDIV_ESEL : 0) |
 319                 (psel ? EP93XX_SYSCON_CLKDIV_PSEL : 0) |
 320                 (pdiv << EP93XX_SYSCON_CLKDIV_PDIV_SHIFT) | div;
 321         ep93xx_syscon_swlocked_write(val, clk->enable_reg);
 322         return 0;
 323 }
 324
 325 int clk_set_rate(struct clk *clk, unsigned long rate)
 326 {
 327         if (clk->set_rate)
 328                 return clk->set_rate(clk, rate);
 329
 330         return -EINVAL;
 331 }
 332 EXPORT_SYMBOL(clk_set_rate);
 333
 334
 335 static char fclk_divisors[] = { 1, 2, 4, 8, 16, 1, 1, 1 };
 336 static char hclk_divisors[] = { 1, 2, 4, 5, 6, 8, 16, 32 };
 337 static char pclk_divisors[] = { 1, 2, 4, 8 };
 338
 339 /*
 340  * PLL rate = 14.7456 MHz * (X1FBD + 1) * (X2FBD + 1) / (X2IPD + 1) / 2^PS
 341  */
 342 static unsigned long calc_pll_rate(u32 config_word)
 343 {
 344         unsigned long long rate;
 345         int i;
 346
 347         rate = EP93XX_EXT_CLK_RATE;
 348         rate *= ((config_word >> 11) & 0x1f) + 1;               /* X1FBD */
 349         rate *= ((config_word >> 5) & 0x3f) + 1;                /* X2FBD */
 350         do_div(rate, (config_word & 0x1f) + 1);                 /* X2IPD */
 351         for (i = 0; i < ((config_word >> 16) & 3); i++)         /* PS */
 352                 rate >>= 1;
 353
 354         return (unsigned long)rate;
 355 }
 356
 357 static void __init ep93xx_dma_clock_init(void)
 358 {
 359         clk_m2p0.rate = clk_h.rate;
 360         clk_m2p1.rate = clk_h.rate;
 361         clk_m2p2.rate = clk_h.rate;
 362         clk_m2p3.rate = clk_h.rate;
 363         clk_m2p4.rate = clk_h.rate;
 364         clk_m2p5.rate = clk_h.rate;
 365         clk_m2p6.rate = clk_h.rate;
 366         clk_m2p7.rate = clk_h.rate;
 367         clk_m2p8.rate = clk_h.rate;
 368         clk_m2p9.rate = clk_h.rate;
 369         clk_m2m0.rate = clk_h.rate;
 370         clk_m2m1.rate = clk_h.rate;
 371 }
 372
 373 static int __init ep93xx_clock_init(void)
 374 {
 375         u32 value;
 376         int i;
 377
 378         value = __raw_readl(EP93XX_SYSCON_CLOCK_SET1);
 379         if (!(value & 0x00800000)) {                    /* PLL1 bypassed?  */
 380                 clk_pll1.rate = EP93XX_EXT_CLK_RATE;
 381         } else {
 382                 clk_pll1.rate = calc_pll_rate(value);
 383         }
 384         clk_f.rate = clk_pll1.rate / fclk_divisors[(value >> 25) & 0x7];
 385         clk_h.rate = clk_pll1.rate / hclk_divisors[(value >> 20) & 0x7];
 386         clk_p.rate = clk_h.rate / pclk_divisors[(value >> 18) & 0x3];
 387         ep93xx_dma_clock_init();
 388
 389         value = __raw_readl(EP93XX_SYSCON_CLOCK_SET2);
 390         if (!(value & 0x00080000)) {                    /* PLL2 bypassed?  */
 391                 clk_pll2.rate = EP93XX_EXT_CLK_RATE;
 392         } else if (value & 0x00040000) {                /* PLL2 enabled?  */
 393                 clk_pll2.rate = calc_pll_rate(value);
 394         } else {
 395                 clk_pll2.rate = 0;
 396         }
 397         clk_usb_host.rate = clk_pll2.rate / (((value >> 28) & 0xf) + 1);
 398
 399         printk(KERN_INFO "ep93xx: PLL1 running at %ld MHz, PLL2 at %ld MHz\n",
 400                 clk_pll1.rate / 1000000, clk_pll2.rate / 1000000);
 401         printk(KERN_INFO "ep93xx: FCLK %ld MHz, HCLK %ld MHz, PCLK %ld MHz\n",
 402                 clk_f.rate / 1000000, clk_h.rate / 1000000,
 403                 clk_p.rate / 1000000);
 404
 405         for (i = 0; i < ARRAY_SIZE(clocks); i++)
 406                 clkdev_add(&clocks[i]);
 407         return 0;
 408 }
 409 arch_initcall(ep93xx_clock_init);