arch/arm/plat-s3c24xx/pwm-clock.c

   1 /* linux/arch/arm/plat-s3c24xx/pwm-clock.c
   2  *
   3  * Copyright (c) 2007 Simtec Electronics
   4  * Copyright (c) 2007, 2008 Ben Dooks
   5  *      Ben Dooks <ben-linux@fluff.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.
  10 */
  11
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/list.h>
  16 #include <linux/errno.h>
  17 #include <linux/clk.h>
  18 #include <linux/err.h>
  19 #include <linux/io.h>
  20
  21 #include <mach/hardware.h>
  22 #include <asm/irq.h>
  23
  24 #include <mach/regs-clock.h>
  25 #include <mach/regs-gpio.h>
  26
  27 #include <plat/clock.h>
  28 #include <plat/cpu.h>
  29
  30 #include <plat/regs-timer.h>
  31
  32 /* Each of the timers 0 through 5 go through the following
  33  * clock tree, with the inputs depending on the timers.
  34  *
  35  * pclk ---- [ prescaler 0 ] -+---> timer 0
  36  *                            +---> timer 1
  37  *
  38  * pclk ---- [ prescaler 1 ] -+---> timer 2
  39  *                            +---> timer 3
  40  *                            \---> timer 4
  41  *
  42  * Which are fed into the timers as so:
  43  *
  44  * prescaled 0 ---- [ div 2,4,8,16 ] ---\
  45  *                                     [mux] -> timer 0
  46  * tclk 0 ------------------------------/
  47  *
  48  * prescaled 0 ---- [ div 2,4,8,16 ] ---\
  49  *                                     [mux] -> timer 1
  50  * tclk 0 ------------------------------/
  51  *
  52  *
  53  * prescaled 1 ---- [ div 2,4,8,16 ] ---\
  54  *                                     [mux] -> timer 2
  55  * tclk 1 ------------------------------/
  56  *
  57  * prescaled 1 ---- [ div 2,4,8,16 ] ---\
  58  *                                     [mux] -> timer 3
  59  * tclk 1 ------------------------------/
  60  *
  61  * prescaled 1 ---- [ div 2,4,8, 16 ] --\
  62  *                                     [mux] -> timer 4
  63  * tclk 1 ------------------------------/
  64  *
  65  * Since the mux and the divider are tied together in the
  66  * same register space, it is impossible to set the parent
  67  * and the rate at the same time. To avoid this, we add an
  68  * intermediate 'prescaled-and-divided' clock to select
  69  * as the parent for the timer input clock called tdiv.
  70  *
  71  * prescaled clk --> pwm-tdiv ---\
  72  *                             [ mux ] --> timer X
  73  * tclk -------------------------/
  74 */
  75
  76 static unsigned long clk_pwm_scaler_getrate(struct clk *clk)
  77 {
  78         unsigned long tcfg0 = __raw_readl(S3C2410_TCFG0);
  79
  80         if (clk->id == 1) {
  81                 tcfg0 &= S3C2410_TCFG_PRESCALER1_MASK;
  82                 tcfg0 >>= S3C2410_TCFG_PRESCALER1_SHIFT;
  83         } else {
  84                 tcfg0 &= S3C2410_TCFG_PRESCALER0_MASK;
  85         }
  86
  87         return clk_get_rate(clk->parent) / (tcfg0 + 1);
  88 }
  89
  90 /* TODO - add set rate calls. */
  91
  92 static struct clk clk_timer_scaler[] = {
  93         [0]     = {
  94                 .name           = "pwm-scaler0",
  95                 .id             = -1,
  96                 .get_rate       = clk_pwm_scaler_getrate,
  97         },
  98         [1]     = {
  99                 .name           = "pwm-scaler1",
 100                 .id             = -1,
 101                 .get_rate       = clk_pwm_scaler_getrate,
 102         },
 103 };
 104
 105 static struct clk clk_timer_tclk[] = {
 106         [0]     = {
 107                 .name           = "pwm-tclk0",
 108                 .id             = -1,
 109         },
 110         [1]     = {
 111                 .name           = "pwm-tclk1",
 112                 .id             = -1,
 113         },
 114 };
 115
 116 struct pwm_tdiv_clk {
 117         struct clk      clk;
 118         unsigned int    divisor;
 119 };
 120
 121 static inline struct pwm_tdiv_clk *to_tdiv(struct clk *clk)
 122 {
 123         return container_of(clk, struct pwm_tdiv_clk, clk);
 124 }
 125
 126 static inline unsigned long tcfg_to_divisor(unsigned long tcfg1)
 127 {
 128         return 1 << (1 + tcfg1);
 129 }
 130
 131 static unsigned long clk_pwm_tdiv_get_rate(struct clk *clk)
 132 {
 133         unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
 134         unsigned int divisor;
 135
 136         tcfg1 >>= S3C2410_TCFG1_SHIFT(clk->id);
 137         tcfg1 &= S3C2410_TCFG1_MUX_MASK;
 138
 139         if (tcfg1 == S3C2410_TCFG1_MUX_TCLK)
 140                 divisor = to_tdiv(clk)->divisor;
 141         else
 142                 divisor = tcfg_to_divisor(tcfg1);
 143
 144         return clk_get_rate(clk->parent) / divisor;
 145 }
 146
 147 static unsigned long clk_pwm_tdiv_round_rate(struct clk *clk,
 148                                              unsigned long rate)
 149 {
 150         unsigned long parent_rate;
 151         unsigned long divisor;
 152
 153         parent_rate = clk_get_rate(clk->parent);
 154         divisor = parent_rate / rate;
 155
 156         if (divisor <= 2)
 157                 divisor = 2;
 158         else if (divisor <= 4)
 159                 divisor = 4;
 160         else if (divisor <= 8)
 161                 divisor = 8;
 162         else
 163                 divisor = 16;
 164
 165         return parent_rate / divisor;
 166 }
 167
 168 static unsigned long clk_pwm_tdiv_bits(struct pwm_tdiv_clk *divclk)
 169 {
 170         unsigned long bits;
 171
 172         switch (divclk->divisor) {
 173         case 2:
 174                 bits = S3C2410_TCFG1_MUX_DIV2;
 175                 break;
 176         case 4:
 177                 bits = S3C2410_TCFG1_MUX_DIV4;
 178                 break;
 179         case 8:
 180                 bits = S3C2410_TCFG1_MUX_DIV8;
 181                 break;
 182         case 16:
 183         default:
 184                 bits = S3C2410_TCFG1_MUX_DIV16;
 185                 break;
 186         }
 187
 188         return bits;
 189 }
 190
 191 static void clk_pwm_tdiv_update(struct pwm_tdiv_clk *divclk)
 192 {
 193         unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
 194         unsigned long bits = clk_pwm_tdiv_bits(divclk);
 195         unsigned long flags;
 196         unsigned long shift =  S3C2410_TCFG1_SHIFT(divclk->clk.id);
 197
 198         local_irq_save(flags);
 199
 200         tcfg1 = __raw_readl(S3C2410_TCFG1);
 201         tcfg1 &= ~(S3C2410_TCFG1_MUX_MASK << shift);
 202         tcfg1 |= bits << shift;
 203         __raw_writel(tcfg1, S3C2410_TCFG1);
 204
 205         local_irq_restore(flags);
 206 }
 207
 208 static int clk_pwm_tdiv_set_rate(struct clk *clk, unsigned long rate)
 209 {
 210         struct pwm_tdiv_clk *divclk = to_tdiv(clk);
 211         unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
 212         unsigned long parent_rate = clk_get_rate(clk->parent);
 213         unsigned long divisor;
 214
 215         tcfg1 >>= S3C2410_TCFG1_SHIFT(clk->id);
 216         tcfg1 &= S3C2410_TCFG1_MUX_MASK;
 217
 218         rate = clk_round_rate(clk, rate);
 219         divisor = parent_rate / rate;
 220
 221         if (divisor > 16)
 222                 return -EINVAL;
 223
 224         divclk->divisor = divisor;
 225
 226         /* Update the current MUX settings if we are currently
 227          * selected as the clock source for this clock. */
 228
 229         if (tcfg1 != S3C2410_TCFG1_MUX_TCLK)
 230                 clk_pwm_tdiv_update(divclk);
 231
 232         return 0;
 233 }
 234
 235 static struct pwm_tdiv_clk clk_timer_tdiv[] = {
 236         [0]     = {
 237                 .clk    = {
 238                         .name           = "pwm-tdiv",
 239                         .parent         = &clk_timer_scaler[0],
 240                         .get_rate       = clk_pwm_tdiv_get_rate,
 241                         .set_rate       = clk_pwm_tdiv_set_rate,
 242                         .round_rate     = clk_pwm_tdiv_round_rate,
 243                 },
 244         },
 245         [1]     = {
 246                 .clk    = {
 247                         .name           = "pwm-tdiv",
 248                         .parent         = &clk_timer_scaler[0],
 249                         .get_rate       = clk_pwm_tdiv_get_rate,
 250                         .set_rate       = clk_pwm_tdiv_set_rate,
 251                         .round_rate     = clk_pwm_tdiv_round_rate,
 252                 }
 253         },
 254         [2]     = {
 255                 .clk    = {
 256                         .name           = "pwm-tdiv",
 257                         .parent         = &clk_timer_scaler[1],
 258                         .get_rate       = clk_pwm_tdiv_get_rate,
 259                         .set_rate       = clk_pwm_tdiv_set_rate,
 260                         .round_rate     = clk_pwm_tdiv_round_rate,
 261                 },
 262         },
 263         [3]     = {
 264                 .clk    = {
 265                         .name           = "pwm-tdiv",
 266                         .parent         = &clk_timer_scaler[1],
 267                         .get_rate       = clk_pwm_tdiv_get_rate,
 268                         .set_rate       = clk_pwm_tdiv_set_rate,
 269                         .round_rate     = clk_pwm_tdiv_round_rate,
 270                 },
 271         },
 272         [4]     = {
 273                 .clk    = {
 274                         .name           = "pwm-tdiv",
 275                         .parent         = &clk_timer_scaler[1],
 276                         .get_rate       = clk_pwm_tdiv_get_rate,
 277                         .set_rate       = clk_pwm_tdiv_set_rate,
 278                         .round_rate     = clk_pwm_tdiv_round_rate,
 279                 },
 280         },
 281 };
 282
 283 static int __init clk_pwm_tdiv_register(unsigned int id)
 284 {
 285         struct pwm_tdiv_clk *divclk = &clk_timer_tdiv[id];
 286         unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
 287
 288         tcfg1 >>= S3C2410_TCFG1_SHIFT(id);
 289         tcfg1 &= S3C2410_TCFG1_MUX_MASK;
 290
 291         divclk->clk.id = id;
 292         divclk->divisor = tcfg_to_divisor(tcfg1);
 293
 294         return s3c24xx_register_clock(&divclk->clk);
 295 }
 296
 297 static inline struct clk *s3c24xx_pwmclk_tclk(unsigned int id)
 298 {
 299         return (id >= 2) ? &clk_timer_tclk[1] : &clk_timer_tclk[0];
 300 }
 301
 302 static inline struct clk *s3c24xx_pwmclk_tdiv(unsigned int id)
 303 {
 304         return &clk_timer_tdiv[id].clk;
 305 }
 306
 307 static int clk_pwm_tin_set_parent(struct clk *clk, struct clk *parent)
 308 {
 309         unsigned int id = clk->id;
 310         unsigned long tcfg1;
 311         unsigned long flags;
 312         unsigned long bits;
 313         unsigned long shift = S3C2410_TCFG1_SHIFT(id);
 314
 315         if (parent == s3c24xx_pwmclk_tclk(id))
 316                 bits = S3C2410_TCFG1_MUX_TCLK << shift;
 317         else if (parent == s3c24xx_pwmclk_tdiv(id))
 318                 bits = clk_pwm_tdiv_bits(to_tdiv(clk)) << shift;
 319         else
 320                 return -EINVAL;
 321
 322         clk->parent = parent;
 323
 324         local_irq_save(flags);
 325
 326         tcfg1 = __raw_readl(S3C2410_TCFG1);
 327         tcfg1 &= ~(S3C2410_TCFG1_MUX_MASK << shift);
 328         __raw_writel(tcfg1 | bits, S3C2410_TCFG1);
 329
 330         local_irq_restore(flags);
 331
 332         return 0;
 333 }
 334
 335 static struct clk clk_tin[] = {
 336         [0]     = {
 337                 .name           = "pwm-tin",
 338                 .id             = 0,
 339                 .set_parent     = clk_pwm_tin_set_parent,
 340         },
 341         [1]     = {
 342                 .name           = "pwm-tin",
 343                 .id             = 1,
 344                 .set_parent     = clk_pwm_tin_set_parent,
 345         },
 346         [2]     = {
 347                 .name           = "pwm-tin",
 348                 .id             = 2,
 349                 .set_parent     = clk_pwm_tin_set_parent,
 350         },
 351         [3]     = {
 352                 .name           = "pwm-tin",
 353                 .id             = 3,
 354                 .set_parent     = clk_pwm_tin_set_parent,
 355         },
 356         [4]     = {
 357                 .name           = "pwm-tin",
 358                 .id             = 4,
 359                 .set_parent     = clk_pwm_tin_set_parent,
 360         },
 361 };
 362
 363 static __init int clk_pwm_tin_register(struct clk *pwm)
 364 {
 365         unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
 366         unsigned int id = pwm->id;
 367
 368         struct clk *parent;
 369         int ret;
 370
 371         ret = s3c24xx_register_clock(pwm);
 372         if (ret < 0)
 373                 return ret;
 374
 375         tcfg1 >>= S3C2410_TCFG1_SHIFT(id);
 376         tcfg1 &= S3C2410_TCFG1_MUX_MASK;
 377
 378         if (tcfg1 == S3C2410_TCFG1_MUX_TCLK)
 379                 parent = s3c24xx_pwmclk_tclk(id);
 380         else
 381                 parent = s3c24xx_pwmclk_tdiv(id);
 382
 383         return clk_set_parent(pwm, parent);
 384 }
 385
 386 static __init int s3c24xx_pwmclk_init(void)
 387 {
 388         struct clk *clk_timers;
 389         unsigned int clk;
 390         int ret;
 391
 392         clk_timers = clk_get(NULL, "timers");
 393         if (IS_ERR(clk_timers)) {
 394                 printk(KERN_ERR "%s: no parent clock\n", __func__);
 395                 return -EINVAL;
 396         }
 397
 398         for (clk = 0; clk < ARRAY_SIZE(clk_timer_scaler); clk++) {
 399                 clk_timer_scaler[clk].parent = clk_timers;
 400                 ret = s3c24xx_register_clock(&clk_timer_scaler[clk]);
 401                 if (ret < 0) {
 402                         printk(KERN_ERR "error adding pwm scaler%d clock\n", clk);
 403                         goto err;
 404                 }
 405         }
 406
 407         for (clk = 0; clk < ARRAY_SIZE(clk_timer_tclk); clk++) {
 408                 ret = s3c24xx_register_clock(&clk_timer_tclk[clk]);
 409                 if (ret < 0) {
 410                         printk(KERN_ERR "error adding pww tclk%d\n", clk);
 411                         goto err;
 412                 }
 413         }
 414
 415         for (clk = 0; clk < ARRAY_SIZE(clk_timer_tdiv); clk++) {
 416                 ret = clk_pwm_tdiv_register(clk);
 417                 if (ret < 0) {
 418                         printk(KERN_ERR "error adding pwm%d tdiv clock\n", clk);
 419                         goto err;
 420                 }
 421         }
 422
 423         for (clk = 0; clk < ARRAY_SIZE(clk_tin); clk++) {
 424                 ret = clk_pwm_tin_register(&clk_tin[clk]);
 425                 if (ret < 0) {
 426                         printk(KERN_ERR "error adding pwm%d tin clock\n", clk);
 427                         goto err;
 428                 }
 429         }
 430
 431         return 0;
 432
 433  err:
 434         return ret;
 435 }
 436
 437 arch_initcall(s3c24xx_pwmclk_init);