arch/arm/plat-s3c/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/log2.h>
  18 #include <linux/clk.h>
  19 #include <linux/err.h>
  20 #include <linux/io.h>
  21
  22 #include <mach/hardware.h>
  23 #include <mach/map.h>
  24 #include <asm/irq.h>
  25
  26 #include <plat/clock.h>
  27 #include <plat/cpu.h>
  28
  29 #include <plat/regs-timer.h>
  30 #include <mach/pwm-clock.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 struct clk clk_timer_scaler[];
  77
  78 static unsigned long clk_pwm_scaler_get_rate(struct clk *clk)
  79 {
  80         unsigned long tcfg0 = __raw_readl(S3C2410_TCFG0);
  81
  82         if (clk == &clk_timer_scaler[1]) {
  83                 tcfg0 &= S3C2410_TCFG_PRESCALER1_MASK;
  84                 tcfg0 >>= S3C2410_TCFG_PRESCALER1_SHIFT;
  85         } else {
  86                 tcfg0 &= S3C2410_TCFG_PRESCALER0_MASK;
  87         }
  88
  89         return clk_get_rate(clk->parent) / (tcfg0 + 1);
  90 }
  91
  92 static unsigned long clk_pwm_scaler_round_rate(struct clk *clk,
  93                                                unsigned long rate)
  94 {
  95         unsigned long parent_rate = clk_get_rate(clk->parent);
  96         unsigned long divisor = parent_rate / rate;
  97
  98         if (divisor > 256)
  99                 divisor = 256;
 100         else if (divisor < 2)
 101                 divisor = 2;
 102
 103         return parent_rate / divisor;
 104 }
 105
 106 static int clk_pwm_scaler_set_rate(struct clk *clk, unsigned long rate)
 107 {
 108         unsigned long round = clk_pwm_scaler_round_rate(clk, rate);
 109         unsigned long tcfg0;
 110         unsigned long divisor;
 111         unsigned long flags;
 112
 113         divisor = clk_get_rate(clk->parent) / round;
 114         divisor--;
 115
 116         local_irq_save(flags);
 117         tcfg0 = __raw_readl(S3C2410_TCFG0);
 118
 119         if (clk == &clk_timer_scaler[1]) {
 120                 tcfg0 &= ~S3C2410_TCFG_PRESCALER1_MASK;
 121                 tcfg0 |= divisor << S3C2410_TCFG_PRESCALER1_SHIFT;
 122         } else {
 123                 tcfg0 &= ~S3C2410_TCFG_PRESCALER0_MASK;
 124                 tcfg0 |= divisor;
 125         }
 126
 127         __raw_writel(tcfg0, S3C2410_TCFG0);
 128         local_irq_restore(flags);
 129
 130         return 0;
 131 }
 132
 133 static struct clk clk_timer_scaler[] = {
 134         [0]     = {
 135                 .name           = "pwm-scaler0",
 136                 .id             = -1,
 137                 .get_rate       = clk_pwm_scaler_get_rate,
 138                 .set_rate       = clk_pwm_scaler_set_rate,
 139                 .round_rate     = clk_pwm_scaler_round_rate,
 140         },
 141         [1]     = {
 142                 .name           = "pwm-scaler1",
 143                 .id             = -1,
 144                 .get_rate       = clk_pwm_scaler_get_rate,
 145                 .set_rate       = clk_pwm_scaler_set_rate,
 146                 .round_rate     = clk_pwm_scaler_round_rate,
 147         },
 148 };
 149
 150 static struct clk clk_timer_tclk[] = {
 151         [0]     = {
 152                 .name           = "pwm-tclk0",
 153                 .id             = -1,
 154         },
 155         [1]     = {
 156                 .name           = "pwm-tclk1",
 157                 .id             = -1,
 158         },
 159 };
 160
 161 struct pwm_tdiv_clk {
 162         struct clk      clk;
 163         unsigned int    divisor;
 164 };
 165
 166 static inline struct pwm_tdiv_clk *to_tdiv(struct clk *clk)
 167 {
 168         return container_of(clk, struct pwm_tdiv_clk, clk);
 169 }
 170
 171 static unsigned long clk_pwm_tdiv_get_rate(struct clk *clk)
 172 {
 173         unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
 174         unsigned int divisor;
 175
 176         tcfg1 >>= S3C2410_TCFG1_SHIFT(clk->id);
 177         tcfg1 &= S3C2410_TCFG1_MUX_MASK;
 178
 179         if (pwm_cfg_src_is_tclk(tcfg1))
 180                 divisor = to_tdiv(clk)->divisor;
 181         else
 182                 divisor = tcfg_to_divisor(tcfg1);
 183
 184         return clk_get_rate(clk->parent) / divisor;
 185 }
 186
 187 static unsigned long clk_pwm_tdiv_round_rate(struct clk *clk,
 188                                              unsigned long rate)
 189 {
 190         unsigned long parent_rate;
 191         unsigned long divisor;
 192
 193         parent_rate = clk_get_rate(clk->parent);
 194         divisor = parent_rate / rate;
 195
 196         if (divisor <= 1 && pwm_tdiv_has_div1())
 197                 divisor = 1;
 198         else if (divisor <= 2)
 199                 divisor = 2;
 200         else if (divisor <= 4)
 201                 divisor = 4;
 202         else if (divisor <= 8)
 203                 divisor = 8;
 204         else
 205                 divisor = 16;
 206
 207         return parent_rate / divisor;
 208 }
 209
 210 static unsigned long clk_pwm_tdiv_bits(struct pwm_tdiv_clk *divclk)
 211 {
 212         return pwm_tdiv_div_bits(divclk->divisor);
 213 }
 214
 215 static void clk_pwm_tdiv_update(struct pwm_tdiv_clk *divclk)
 216 {
 217         unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
 218         unsigned long bits = clk_pwm_tdiv_bits(divclk);
 219         unsigned long flags;
 220         unsigned long shift =  S3C2410_TCFG1_SHIFT(divclk->clk.id);
 221
 222         local_irq_save(flags);
 223
 224         tcfg1 = __raw_readl(S3C2410_TCFG1);
 225         tcfg1 &= ~(S3C2410_TCFG1_MUX_MASK << shift);
 226         tcfg1 |= bits << shift;
 227         __raw_writel(tcfg1, S3C2410_TCFG1);
 228
 229         local_irq_restore(flags);
 230 }
 231
 232 static int clk_pwm_tdiv_set_rate(struct clk *clk, unsigned long rate)
 233 {
 234         struct pwm_tdiv_clk *divclk = to_tdiv(clk);
 235         unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
 236         unsigned long parent_rate = clk_get_rate(clk->parent);
 237         unsigned long divisor;
 238
 239         tcfg1 >>= S3C2410_TCFG1_SHIFT(clk->id);
 240         tcfg1 &= S3C2410_TCFG1_MUX_MASK;
 241
 242         rate = clk_round_rate(clk, rate);
 243         divisor = parent_rate / rate;
 244
 245         if (divisor > 16)
 246                 return -EINVAL;
 247
 248         divclk->divisor = divisor;
 249
 250         /* Update the current MUX settings if we are currently
 251          * selected as the clock source for this clock. */
 252
 253         if (!pwm_cfg_src_is_tclk(tcfg1))
 254                 clk_pwm_tdiv_update(divclk);
 255
 256         return 0;
 257 }
 258
 259 static struct pwm_tdiv_clk clk_timer_tdiv[] = {
 260         [0]     = {
 261                 .clk    = {
 262                         .name           = "pwm-tdiv",
 263                         .parent         = &clk_timer_scaler[0],
 264                         .get_rate       = clk_pwm_tdiv_get_rate,
 265                         .set_rate       = clk_pwm_tdiv_set_rate,
 266                         .round_rate     = clk_pwm_tdiv_round_rate,
 267                 },
 268         },
 269         [1]     = {
 270                 .clk    = {
 271                         .name           = "pwm-tdiv",
 272                         .parent         = &clk_timer_scaler[0],
 273                         .get_rate       = clk_pwm_tdiv_get_rate,
 274                         .set_rate       = clk_pwm_tdiv_set_rate,
 275                         .round_rate     = clk_pwm_tdiv_round_rate,
 276                 }
 277         },
 278         [2]     = {
 279                 .clk    = {
 280                         .name           = "pwm-tdiv",
 281                         .parent         = &clk_timer_scaler[1],
 282                         .get_rate       = clk_pwm_tdiv_get_rate,
 283                         .set_rate       = clk_pwm_tdiv_set_rate,
 284                         .round_rate     = clk_pwm_tdiv_round_rate,
 285                 },
 286         },
 287         [3]     = {
 288                 .clk    = {
 289                         .name           = "pwm-tdiv",
 290                         .parent         = &clk_timer_scaler[1],
 291                         .get_rate       = clk_pwm_tdiv_get_rate,
 292                         .set_rate       = clk_pwm_tdiv_set_rate,
 293                         .round_rate     = clk_pwm_tdiv_round_rate,
 294                 },
 295         },
 296         [4]     = {
 297                 .clk    = {
 298                         .name           = "pwm-tdiv",
 299                         .parent         = &clk_timer_scaler[1],
 300                         .get_rate       = clk_pwm_tdiv_get_rate,
 301                         .set_rate       = clk_pwm_tdiv_set_rate,
 302                         .round_rate     = clk_pwm_tdiv_round_rate,
 303                 },
 304         },
 305 };
 306
 307 static int __init clk_pwm_tdiv_register(unsigned int id)
 308 {
 309         struct pwm_tdiv_clk *divclk = &clk_timer_tdiv[id];
 310         unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
 311
 312         tcfg1 >>= S3C2410_TCFG1_SHIFT(id);
 313         tcfg1 &= S3C2410_TCFG1_MUX_MASK;
 314
 315         divclk->clk.id = id;
 316         divclk->divisor = tcfg_to_divisor(tcfg1);
 317
 318         return s3c24xx_register_clock(&divclk->clk);
 319 }
 320
 321 static inline struct clk *s3c24xx_pwmclk_tclk(unsigned int id)
 322 {
 323         return (id >= 2) ? &clk_timer_tclk[1] : &clk_timer_tclk[0];
 324 }
 325
 326 static inline struct clk *s3c24xx_pwmclk_tdiv(unsigned int id)
 327 {
 328         return &clk_timer_tdiv[id].clk;
 329 }
 330
 331 static int clk_pwm_tin_set_parent(struct clk *clk, struct clk *parent)
 332 {
 333         unsigned int id = clk->id;
 334         unsigned long tcfg1;
 335         unsigned long flags;
 336         unsigned long bits;
 337         unsigned long shift = S3C2410_TCFG1_SHIFT(id);
 338
 339         if (parent == s3c24xx_pwmclk_tclk(id))
 340                 bits = S3C_TCFG1_MUX_TCLK << shift;
 341         else if (parent == s3c24xx_pwmclk_tdiv(id))
 342                 bits = clk_pwm_tdiv_bits(to_tdiv(parent)) << shift;
 343         else
 344                 return -EINVAL;
 345
 346         clk->parent = parent;
 347
 348         local_irq_save(flags);
 349
 350         tcfg1 = __raw_readl(S3C2410_TCFG1);
 351         tcfg1 &= ~(S3C2410_TCFG1_MUX_MASK << shift);
 352         __raw_writel(tcfg1 | bits, S3C2410_TCFG1);
 353
 354         local_irq_restore(flags);
 355
 356         return 0;
 357 }
 358
 359 static struct clk clk_tin[] = {
 360         [0]     = {
 361                 .name           = "pwm-tin",
 362                 .id             = 0,
 363                 .set_parent     = clk_pwm_tin_set_parent,
 364         },
 365         [1]     = {
 366                 .name           = "pwm-tin",
 367                 .id             = 1,
 368                 .set_parent     = clk_pwm_tin_set_parent,
 369         },
 370         [2]     = {
 371                 .name           = "pwm-tin",
 372                 .id             = 2,
 373                 .set_parent     = clk_pwm_tin_set_parent,
 374         },
 375         [3]     = {
 376                 .name           = "pwm-tin",
 377                 .id             = 3,
 378                 .set_parent     = clk_pwm_tin_set_parent,
 379         },
 380         [4]     = {
 381                 .name           = "pwm-tin",
 382                 .id             = 4,
 383                 .set_parent     = clk_pwm_tin_set_parent,
 384         },
 385 };
 386
 387 static __init int clk_pwm_tin_register(struct clk *pwm)
 388 {
 389         unsigned long tcfg1 = __raw_readl(S3C2410_TCFG1);
 390         unsigned int id = pwm->id;
 391
 392         struct clk *parent;
 393         int ret;
 394
 395         ret = s3c24xx_register_clock(pwm);
 396         if (ret < 0)
 397                 return ret;
 398
 399         tcfg1 >>= S3C2410_TCFG1_SHIFT(id);
 400         tcfg1 &= S3C2410_TCFG1_MUX_MASK;
 401
 402         if (pwm_cfg_src_is_tclk(tcfg1))
 403                 parent = s3c24xx_pwmclk_tclk(id);
 404         else
 405                 parent = s3c24xx_pwmclk_tdiv(id);
 406
 407         return clk_set_parent(pwm, parent);
 408 }
 409
 410 /**
 411  * s3c_pwmclk_init() - initialise pwm clocks
 412  *
 413  * Initialise and register the clocks which provide the inputs for the
 414  * pwm timer blocks.
 415  *
 416  * Note, this call is required by the time core, so must be called after
 417  * the base clocks are added and before any of the initcalls are run.
 418  */
 419 __init void s3c_pwmclk_init(void)
 420 {
 421         struct clk *clk_timers;
 422         unsigned int clk;
 423         int ret;
 424
 425         clk_timers = clk_get(NULL, "timers");
 426         if (IS_ERR(clk_timers)) {
 427                 printk(KERN_ERR "%s: no parent clock\n", __func__);
 428                 return;
 429         }
 430
 431         for (clk = 0; clk < ARRAY_SIZE(clk_timer_scaler); clk++) {
 432                 clk_timer_scaler[clk].parent = clk_timers;
 433                 ret = s3c24xx_register_clock(&clk_timer_scaler[clk]);
 434                 if (ret < 0) {
 435                         printk(KERN_ERR "error adding pwm scaler%d clock\n", clk);
 436                         return;
 437                 }
 438         }
 439
 440         for (clk = 0; clk < ARRAY_SIZE(clk_timer_tclk); clk++) {
 441                 ret = s3c24xx_register_clock(&clk_timer_tclk[clk]);
 442                 if (ret < 0) {
 443                         printk(KERN_ERR "error adding pww tclk%d\n", clk);
 444                         return;
 445                 }
 446         }
 447
 448         for (clk = 0; clk < ARRAY_SIZE(clk_timer_tdiv); clk++) {
 449                 ret = clk_pwm_tdiv_register(clk);
 450                 if (ret < 0) {
 451                         printk(KERN_ERR "error adding pwm%d tdiv clock\n", clk);
 452                         return;
 453                 }
 454         }
 455
 456         for (clk = 0; clk < ARRAY_SIZE(clk_tin); clk++) {
 457                 ret = clk_pwm_tin_register(&clk_tin[clk]);
 458                 if (ret < 0) {
 459                         printk(KERN_ERR "error adding pwm%d tin clock\n", clk);
 460                         return;
 461                 }
 462         }
 463 }