Peter Korsgaard | b5ead1c | 2009-07-01 17:47:07 +0200 | [diff] [blame] | 1 | /* arch/arm/plat-s3c/pwm.c |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 2 | * |
| 3 | * Copyright (c) 2007 Ben Dooks |
| 4 | * Copyright (c) 2008 Simtec Electronics |
| 5 | * Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org> |
| 6 | * |
Peter Korsgaard | b5ead1c | 2009-07-01 17:47:07 +0200 | [diff] [blame] | 7 | * S3C series PWM device core |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 8 | * |
| 9 | * This program is free software; you can redistribute it and/or modify |
| 10 | * it under the terms of the GNU General Public License as published by |
| 11 | * the Free Software Foundation; either version 2 of the License. |
| 12 | */ |
| 13 | |
Kukjin Kim | a69e4c2 | 2011-11-17 01:14:38 +0900 | [diff] [blame] | 14 | #include <linux/export.h> |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 15 | #include <linux/kernel.h> |
| 16 | #include <linux/platform_device.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 17 | #include <linux/slab.h> |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 18 | #include <linux/err.h> |
| 19 | #include <linux/clk.h> |
| 20 | #include <linux/io.h> |
| 21 | #include <linux/pwm.h> |
| 22 | |
Peter Korsgaard | b5ead1c | 2009-07-01 17:47:07 +0200 | [diff] [blame] | 23 | #include <mach/map.h> |
Russell King | 80b02c1 | 2009-01-08 10:01:47 +0000 | [diff] [blame] | 24 | |
Ben Dooks | a2b7ba9 | 2008-10-07 22:26:09 +0100 | [diff] [blame] | 25 | #include <plat/regs-timer.h> |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 26 | |
| 27 | struct pwm_device { |
| 28 | struct list_head list; |
| 29 | struct platform_device *pdev; |
| 30 | |
| 31 | struct clk *clk_div; |
| 32 | struct clk *clk; |
| 33 | const char *label; |
| 34 | |
| 35 | unsigned int period_ns; |
| 36 | unsigned int duty_ns; |
| 37 | |
| 38 | unsigned char tcon_base; |
| 39 | unsigned char running; |
| 40 | unsigned char use_count; |
| 41 | unsigned char pwm_id; |
| 42 | }; |
| 43 | |
Ben Dooks | 66592ee | 2008-08-26 22:54:06 +0100 | [diff] [blame] | 44 | #define pwm_dbg(_pwm, msg...) dev_dbg(&(_pwm)->pdev->dev, msg) |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 45 | |
| 46 | static struct clk *clk_scaler[2]; |
| 47 | |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 48 | static inline int pwm_is_tdiv(struct pwm_device *pwm) |
| 49 | { |
| 50 | return clk_get_parent(pwm->clk) == pwm->clk_div; |
| 51 | } |
| 52 | |
| 53 | static DEFINE_MUTEX(pwm_lock); |
| 54 | static LIST_HEAD(pwm_list); |
| 55 | |
| 56 | struct pwm_device *pwm_request(int pwm_id, const char *label) |
| 57 | { |
| 58 | struct pwm_device *pwm; |
| 59 | int found = 0; |
| 60 | |
| 61 | mutex_lock(&pwm_lock); |
| 62 | |
| 63 | list_for_each_entry(pwm, &pwm_list, list) { |
| 64 | if (pwm->pwm_id == pwm_id) { |
| 65 | found = 1; |
| 66 | break; |
| 67 | } |
| 68 | } |
| 69 | |
| 70 | if (found) { |
| 71 | if (pwm->use_count == 0) { |
| 72 | pwm->use_count = 1; |
| 73 | pwm->label = label; |
| 74 | } else |
| 75 | pwm = ERR_PTR(-EBUSY); |
| 76 | } else |
| 77 | pwm = ERR_PTR(-ENOENT); |
| 78 | |
| 79 | mutex_unlock(&pwm_lock); |
| 80 | return pwm; |
| 81 | } |
| 82 | |
| 83 | EXPORT_SYMBOL(pwm_request); |
| 84 | |
| 85 | |
| 86 | void pwm_free(struct pwm_device *pwm) |
| 87 | { |
| 88 | mutex_lock(&pwm_lock); |
| 89 | |
| 90 | if (pwm->use_count) { |
| 91 | pwm->use_count--; |
| 92 | pwm->label = NULL; |
| 93 | } else |
| 94 | printk(KERN_ERR "PWM%d device already freed\n", pwm->pwm_id); |
| 95 | |
| 96 | mutex_unlock(&pwm_lock); |
| 97 | } |
| 98 | |
| 99 | EXPORT_SYMBOL(pwm_free); |
| 100 | |
| 101 | #define pwm_tcon_start(pwm) (1 << (pwm->tcon_base + 0)) |
| 102 | #define pwm_tcon_invert(pwm) (1 << (pwm->tcon_base + 2)) |
| 103 | #define pwm_tcon_autoreload(pwm) (1 << (pwm->tcon_base + 3)) |
| 104 | #define pwm_tcon_manulupdate(pwm) (1 << (pwm->tcon_base + 1)) |
| 105 | |
| 106 | int pwm_enable(struct pwm_device *pwm) |
| 107 | { |
| 108 | unsigned long flags; |
| 109 | unsigned long tcon; |
| 110 | |
| 111 | local_irq_save(flags); |
| 112 | |
| 113 | tcon = __raw_readl(S3C2410_TCON); |
| 114 | tcon |= pwm_tcon_start(pwm); |
| 115 | __raw_writel(tcon, S3C2410_TCON); |
| 116 | |
| 117 | local_irq_restore(flags); |
| 118 | |
| 119 | pwm->running = 1; |
| 120 | return 0; |
| 121 | } |
| 122 | |
| 123 | EXPORT_SYMBOL(pwm_enable); |
| 124 | |
| 125 | void pwm_disable(struct pwm_device *pwm) |
| 126 | { |
| 127 | unsigned long flags; |
| 128 | unsigned long tcon; |
| 129 | |
| 130 | local_irq_save(flags); |
| 131 | |
| 132 | tcon = __raw_readl(S3C2410_TCON); |
| 133 | tcon &= ~pwm_tcon_start(pwm); |
| 134 | __raw_writel(tcon, S3C2410_TCON); |
| 135 | |
| 136 | local_irq_restore(flags); |
| 137 | |
| 138 | pwm->running = 0; |
| 139 | } |
| 140 | |
| 141 | EXPORT_SYMBOL(pwm_disable); |
| 142 | |
Ben Dooks | 1038959 | 2008-08-26 22:54:05 +0100 | [diff] [blame] | 143 | static unsigned long pwm_calc_tin(struct pwm_device *pwm, unsigned long freq) |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 144 | { |
| 145 | unsigned long tin_parent_rate; |
| 146 | unsigned int div; |
| 147 | |
| 148 | tin_parent_rate = clk_get_rate(clk_get_parent(pwm->clk_div)); |
| 149 | pwm_dbg(pwm, "tin parent at %lu\n", tin_parent_rate); |
| 150 | |
| 151 | for (div = 2; div <= 16; div *= 2) { |
| 152 | if ((tin_parent_rate / (div << 16)) < freq) |
| 153 | return tin_parent_rate / div; |
| 154 | } |
| 155 | |
| 156 | return tin_parent_rate / 16; |
| 157 | } |
| 158 | |
| 159 | #define NS_IN_HZ (1000000000UL) |
| 160 | |
| 161 | int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) |
| 162 | { |
| 163 | unsigned long tin_rate; |
| 164 | unsigned long tin_ns; |
| 165 | unsigned long period; |
| 166 | unsigned long flags; |
| 167 | unsigned long tcon; |
| 168 | unsigned long tcnt; |
| 169 | long tcmp; |
| 170 | |
| 171 | /* We currently avoid using 64bit arithmetic by using the |
| 172 | * fact that anything faster than 1Hz is easily representable |
| 173 | * by 32bits. */ |
| 174 | |
| 175 | if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ) |
| 176 | return -ERANGE; |
| 177 | |
| 178 | if (duty_ns > period_ns) |
| 179 | return -EINVAL; |
| 180 | |
| 181 | if (period_ns == pwm->period_ns && |
| 182 | duty_ns == pwm->duty_ns) |
| 183 | return 0; |
| 184 | |
| 185 | /* The TCMP and TCNT can be read without a lock, they're not |
| 186 | * shared between the timers. */ |
| 187 | |
| 188 | tcmp = __raw_readl(S3C2410_TCMPB(pwm->pwm_id)); |
| 189 | tcnt = __raw_readl(S3C2410_TCNTB(pwm->pwm_id)); |
| 190 | |
| 191 | period = NS_IN_HZ / period_ns; |
| 192 | |
| 193 | pwm_dbg(pwm, "duty_ns=%d, period_ns=%d (%lu)\n", |
| 194 | duty_ns, period_ns, period); |
| 195 | |
| 196 | /* Check to see if we are changing the clock rate of the PWM */ |
| 197 | |
| 198 | if (pwm->period_ns != period_ns) { |
| 199 | if (pwm_is_tdiv(pwm)) { |
| 200 | tin_rate = pwm_calc_tin(pwm, period); |
| 201 | clk_set_rate(pwm->clk_div, tin_rate); |
| 202 | } else |
| 203 | tin_rate = clk_get_rate(pwm->clk); |
| 204 | |
| 205 | pwm->period_ns = period_ns; |
| 206 | |
| 207 | pwm_dbg(pwm, "tin_rate=%lu\n", tin_rate); |
| 208 | |
| 209 | tin_ns = NS_IN_HZ / tin_rate; |
| 210 | tcnt = period_ns / tin_ns; |
| 211 | } else |
| 212 | tin_ns = NS_IN_HZ / clk_get_rate(pwm->clk); |
| 213 | |
| 214 | /* Note, counters count down */ |
| 215 | |
| 216 | tcmp = duty_ns / tin_ns; |
| 217 | tcmp = tcnt - tcmp; |
Peter Korsgaard | 165f5f6 | 2009-07-01 17:47:08 +0200 | [diff] [blame] | 218 | /* the pwm hw only checks the compare register after a decrement, |
| 219 | so the pin never toggles if tcmp = tcnt */ |
| 220 | if (tcmp == tcnt) |
| 221 | tcmp--; |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 222 | |
| 223 | pwm_dbg(pwm, "tin_ns=%lu, tcmp=%ld/%lu\n", tin_ns, tcmp, tcnt); |
| 224 | |
| 225 | if (tcmp < 0) |
| 226 | tcmp = 0; |
| 227 | |
| 228 | /* Update the PWM register block. */ |
| 229 | |
| 230 | local_irq_save(flags); |
| 231 | |
| 232 | __raw_writel(tcmp, S3C2410_TCMPB(pwm->pwm_id)); |
| 233 | __raw_writel(tcnt, S3C2410_TCNTB(pwm->pwm_id)); |
| 234 | |
| 235 | tcon = __raw_readl(S3C2410_TCON); |
| 236 | tcon |= pwm_tcon_manulupdate(pwm); |
| 237 | tcon |= pwm_tcon_autoreload(pwm); |
| 238 | __raw_writel(tcon, S3C2410_TCON); |
| 239 | |
| 240 | tcon &= ~pwm_tcon_manulupdate(pwm); |
| 241 | __raw_writel(tcon, S3C2410_TCON); |
| 242 | |
| 243 | local_irq_restore(flags); |
| 244 | |
| 245 | return 0; |
| 246 | } |
| 247 | |
| 248 | EXPORT_SYMBOL(pwm_config); |
| 249 | |
| 250 | static int pwm_register(struct pwm_device *pwm) |
| 251 | { |
| 252 | pwm->duty_ns = -1; |
| 253 | pwm->period_ns = -1; |
| 254 | |
| 255 | mutex_lock(&pwm_lock); |
| 256 | list_add_tail(&pwm->list, &pwm_list); |
| 257 | mutex_unlock(&pwm_lock); |
| 258 | |
| 259 | return 0; |
| 260 | } |
| 261 | |
| 262 | static int s3c_pwm_probe(struct platform_device *pdev) |
| 263 | { |
| 264 | struct device *dev = &pdev->dev; |
| 265 | struct pwm_device *pwm; |
| 266 | unsigned long flags; |
| 267 | unsigned long tcon; |
| 268 | unsigned int id = pdev->id; |
| 269 | int ret; |
| 270 | |
| 271 | if (id == 4) { |
| 272 | dev_err(dev, "TIMER4 is currently not supported\n"); |
| 273 | return -ENXIO; |
| 274 | } |
| 275 | |
| 276 | pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); |
| 277 | if (pwm == NULL) { |
| 278 | dev_err(dev, "failed to allocate pwm_device\n"); |
| 279 | return -ENOMEM; |
| 280 | } |
| 281 | |
| 282 | pwm->pdev = pdev; |
| 283 | pwm->pwm_id = id; |
| 284 | |
| 285 | /* calculate base of control bits in TCON */ |
| 286 | pwm->tcon_base = id == 0 ? 0 : (id * 4) + 4; |
| 287 | |
| 288 | pwm->clk = clk_get(dev, "pwm-tin"); |
| 289 | if (IS_ERR(pwm->clk)) { |
| 290 | dev_err(dev, "failed to get pwm tin clk\n"); |
| 291 | ret = PTR_ERR(pwm->clk); |
| 292 | goto err_alloc; |
| 293 | } |
| 294 | |
| 295 | pwm->clk_div = clk_get(dev, "pwm-tdiv"); |
| 296 | if (IS_ERR(pwm->clk_div)) { |
| 297 | dev_err(dev, "failed to get pwm tdiv clk\n"); |
| 298 | ret = PTR_ERR(pwm->clk_div); |
| 299 | goto err_clk_tin; |
| 300 | } |
| 301 | |
Joonyoung Shim | d8633c1 | 2011-11-04 10:39:34 +0900 | [diff] [blame] | 302 | clk_enable(pwm->clk); |
| 303 | clk_enable(pwm->clk_div); |
| 304 | |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 305 | local_irq_save(flags); |
| 306 | |
| 307 | tcon = __raw_readl(S3C2410_TCON); |
| 308 | tcon |= pwm_tcon_invert(pwm); |
| 309 | __raw_writel(tcon, S3C2410_TCON); |
| 310 | |
| 311 | local_irq_restore(flags); |
| 312 | |
| 313 | |
| 314 | ret = pwm_register(pwm); |
| 315 | if (ret) { |
| 316 | dev_err(dev, "failed to register pwm\n"); |
| 317 | goto err_clk_tdiv; |
| 318 | } |
| 319 | |
| 320 | pwm_dbg(pwm, "config bits %02x\n", |
| 321 | (__raw_readl(S3C2410_TCON) >> pwm->tcon_base) & 0x0f); |
| 322 | |
| 323 | dev_info(dev, "tin at %lu, tdiv at %lu, tin=%sclk, base %d\n", |
| 324 | clk_get_rate(pwm->clk), |
| 325 | clk_get_rate(pwm->clk_div), |
| 326 | pwm_is_tdiv(pwm) ? "div" : "ext", pwm->tcon_base); |
| 327 | |
| 328 | platform_set_drvdata(pdev, pwm); |
| 329 | return 0; |
| 330 | |
| 331 | err_clk_tdiv: |
Joonyoung Shim | d8633c1 | 2011-11-04 10:39:34 +0900 | [diff] [blame] | 332 | clk_disable(pwm->clk_div); |
| 333 | clk_disable(pwm->clk); |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 334 | clk_put(pwm->clk_div); |
| 335 | |
| 336 | err_clk_tin: |
| 337 | clk_put(pwm->clk); |
| 338 | |
| 339 | err_alloc: |
| 340 | kfree(pwm); |
| 341 | return ret; |
| 342 | } |
| 343 | |
Uwe Kleine-König | 93b0d8c | 2009-11-24 22:07:11 +0100 | [diff] [blame] | 344 | static int __devexit s3c_pwm_remove(struct platform_device *pdev) |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 345 | { |
| 346 | struct pwm_device *pwm = platform_get_drvdata(pdev); |
| 347 | |
Joonyoung Shim | d8633c1 | 2011-11-04 10:39:34 +0900 | [diff] [blame] | 348 | clk_disable(pwm->clk_div); |
| 349 | clk_disable(pwm->clk); |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 350 | clk_put(pwm->clk_div); |
| 351 | clk_put(pwm->clk); |
| 352 | kfree(pwm); |
| 353 | |
| 354 | return 0; |
| 355 | } |
| 356 | |
Vasily Khoruzhick | e79032a | 2010-03-15 16:27:08 +0200 | [diff] [blame] | 357 | #ifdef CONFIG_PM |
| 358 | static int s3c_pwm_suspend(struct platform_device *pdev, pm_message_t state) |
| 359 | { |
| 360 | struct pwm_device *pwm = platform_get_drvdata(pdev); |
| 361 | |
| 362 | /* No one preserve these values during suspend so reset them |
| 363 | * Otherwise driver leaves PWM unconfigured if same values |
| 364 | * passed to pwm_config |
| 365 | */ |
| 366 | pwm->period_ns = 0; |
| 367 | pwm->duty_ns = 0; |
| 368 | |
| 369 | return 0; |
| 370 | } |
| 371 | |
| 372 | static int s3c_pwm_resume(struct platform_device *pdev) |
| 373 | { |
| 374 | struct pwm_device *pwm = platform_get_drvdata(pdev); |
| 375 | unsigned long tcon; |
| 376 | |
| 377 | /* Restore invertion */ |
| 378 | tcon = __raw_readl(S3C2410_TCON); |
| 379 | tcon |= pwm_tcon_invert(pwm); |
| 380 | __raw_writel(tcon, S3C2410_TCON); |
| 381 | |
| 382 | return 0; |
| 383 | } |
| 384 | |
| 385 | #else |
| 386 | #define s3c_pwm_suspend NULL |
| 387 | #define s3c_pwm_resume NULL |
| 388 | #endif |
| 389 | |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 390 | static struct platform_driver s3c_pwm_driver = { |
| 391 | .driver = { |
| 392 | .name = "s3c24xx-pwm", |
| 393 | .owner = THIS_MODULE, |
| 394 | }, |
| 395 | .probe = s3c_pwm_probe, |
| 396 | .remove = __devexit_p(s3c_pwm_remove), |
Vasily Khoruzhick | e79032a | 2010-03-15 16:27:08 +0200 | [diff] [blame] | 397 | .suspend = s3c_pwm_suspend, |
| 398 | .resume = s3c_pwm_resume, |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 399 | }; |
| 400 | |
| 401 | static int __init pwm_init(void) |
| 402 | { |
| 403 | int ret; |
| 404 | |
| 405 | clk_scaler[0] = clk_get(NULL, "pwm-scaler0"); |
| 406 | clk_scaler[1] = clk_get(NULL, "pwm-scaler1"); |
| 407 | |
| 408 | if (IS_ERR(clk_scaler[0]) || IS_ERR(clk_scaler[1])) { |
| 409 | printk(KERN_ERR "%s: failed to get scaler clocks\n", __func__); |
| 410 | return -EINVAL; |
| 411 | } |
| 412 | |
| 413 | ret = platform_driver_register(&s3c_pwm_driver); |
| 414 | if (ret) |
| 415 | printk(KERN_ERR "%s: failed to add pwm driver\n", __func__); |
| 416 | |
| 417 | return ret; |
| 418 | } |
| 419 | |
| 420 | arch_initcall(pwm_init); |