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 | |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/kernel.h> |
| 16 | #include <linux/platform_device.h> |
| 17 | #include <linux/err.h> |
| 18 | #include <linux/clk.h> |
| 19 | #include <linux/io.h> |
| 20 | #include <linux/pwm.h> |
| 21 | |
Russell King | 80b02c1 | 2009-01-08 10:01:47 +0000 | [diff] [blame] | 22 | #include <mach/irqs.h> |
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/devs.h> |
| 26 | #include <plat/regs-timer.h> |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 27 | |
| 28 | struct pwm_device { |
| 29 | struct list_head list; |
| 30 | struct platform_device *pdev; |
| 31 | |
| 32 | struct clk *clk_div; |
| 33 | struct clk *clk; |
| 34 | const char *label; |
| 35 | |
| 36 | unsigned int period_ns; |
| 37 | unsigned int duty_ns; |
| 38 | |
| 39 | unsigned char tcon_base; |
| 40 | unsigned char running; |
| 41 | unsigned char use_count; |
| 42 | unsigned char pwm_id; |
| 43 | }; |
| 44 | |
Ben Dooks | 66592ee | 2008-08-26 22:54:06 +0100 | [diff] [blame] | 45 | #define pwm_dbg(_pwm, msg...) dev_dbg(&(_pwm)->pdev->dev, msg) |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 46 | |
| 47 | static struct clk *clk_scaler[2]; |
| 48 | |
| 49 | /* Standard setup for a timer block. */ |
| 50 | |
| 51 | #define TIMER_RESOURCE_SIZE (1) |
| 52 | |
| 53 | #define TIMER_RESOURCE(_tmr, _irq) \ |
| 54 | (struct resource [TIMER_RESOURCE_SIZE]) { \ |
| 55 | [0] = { \ |
| 56 | .start = _irq, \ |
| 57 | .end = _irq, \ |
| 58 | .flags = IORESOURCE_IRQ \ |
| 59 | } \ |
| 60 | } |
| 61 | |
Nelson Castillo | 55b404f | 2008-10-16 16:46:10 +0100 | [diff] [blame] | 62 | #define DEFINE_S3C_TIMER(_tmr_no, _irq) \ |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 63 | .name = "s3c24xx-pwm", \ |
| 64 | .id = _tmr_no, \ |
| 65 | .num_resources = TIMER_RESOURCE_SIZE, \ |
| 66 | .resource = TIMER_RESOURCE(_tmr_no, _irq), \ |
| 67 | |
| 68 | /* since we already have an static mapping for the timer, we do not |
| 69 | * bother setting any IO resource for the base. |
| 70 | */ |
| 71 | |
| 72 | struct platform_device s3c_device_timer[] = { |
Nelson Castillo | 55b404f | 2008-10-16 16:46:10 +0100 | [diff] [blame] | 73 | [0] = { DEFINE_S3C_TIMER(0, IRQ_TIMER0) }, |
| 74 | [1] = { DEFINE_S3C_TIMER(1, IRQ_TIMER1) }, |
| 75 | [2] = { DEFINE_S3C_TIMER(2, IRQ_TIMER2) }, |
| 76 | [3] = { DEFINE_S3C_TIMER(3, IRQ_TIMER3) }, |
| 77 | [4] = { DEFINE_S3C_TIMER(4, IRQ_TIMER4) }, |
Ben Dooks | 6fc601e | 2008-07-01 13:17:24 +0100 | [diff] [blame] | 78 | }; |
| 79 | |
| 80 | static inline int pwm_is_tdiv(struct pwm_device *pwm) |
| 81 | { |
| 82 | return clk_get_parent(pwm->clk) == pwm->clk_div; |
| 83 | } |
| 84 | |
| 85 | static DEFINE_MUTEX(pwm_lock); |
| 86 | static LIST_HEAD(pwm_list); |
| 87 | |
| 88 | struct pwm_device *pwm_request(int pwm_id, const char *label) |
| 89 | { |
| 90 | struct pwm_device *pwm; |
| 91 | int found = 0; |
| 92 | |
| 93 | mutex_lock(&pwm_lock); |
| 94 | |
| 95 | list_for_each_entry(pwm, &pwm_list, list) { |
| 96 | if (pwm->pwm_id == pwm_id) { |
| 97 | found = 1; |
| 98 | break; |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | if (found) { |
| 103 | if (pwm->use_count == 0) { |
| 104 | pwm->use_count = 1; |
| 105 | pwm->label = label; |
| 106 | } else |
| 107 | pwm = ERR_PTR(-EBUSY); |
| 108 | } else |
| 109 | pwm = ERR_PTR(-ENOENT); |
| 110 | |
| 111 | mutex_unlock(&pwm_lock); |
| 112 | return pwm; |
| 113 | } |
| 114 | |
| 115 | EXPORT_SYMBOL(pwm_request); |
| 116 | |
| 117 | |
| 118 | void pwm_free(struct pwm_device *pwm) |
| 119 | { |
| 120 | mutex_lock(&pwm_lock); |
| 121 | |
| 122 | if (pwm->use_count) { |
| 123 | pwm->use_count--; |
| 124 | pwm->label = NULL; |
| 125 | } else |
| 126 | printk(KERN_ERR "PWM%d device already freed\n", pwm->pwm_id); |
| 127 | |
| 128 | mutex_unlock(&pwm_lock); |
| 129 | } |
| 130 | |
| 131 | EXPORT_SYMBOL(pwm_free); |
| 132 | |
| 133 | #define pwm_tcon_start(pwm) (1 << (pwm->tcon_base + 0)) |
| 134 | #define pwm_tcon_invert(pwm) (1 << (pwm->tcon_base + 2)) |
| 135 | #define pwm_tcon_autoreload(pwm) (1 << (pwm->tcon_base + 3)) |
| 136 | #define pwm_tcon_manulupdate(pwm) (1 << (pwm->tcon_base + 1)) |
| 137 | |
| 138 | int pwm_enable(struct pwm_device *pwm) |
| 139 | { |
| 140 | unsigned long flags; |
| 141 | unsigned long tcon; |
| 142 | |
| 143 | local_irq_save(flags); |
| 144 | |
| 145 | tcon = __raw_readl(S3C2410_TCON); |
| 146 | tcon |= pwm_tcon_start(pwm); |
| 147 | __raw_writel(tcon, S3C2410_TCON); |
| 148 | |
| 149 | local_irq_restore(flags); |
| 150 | |
| 151 | pwm->running = 1; |
| 152 | return 0; |
| 153 | } |
| 154 | |
| 155 | EXPORT_SYMBOL(pwm_enable); |
| 156 | |
| 157 | void pwm_disable(struct pwm_device *pwm) |
| 158 | { |
| 159 | unsigned long flags; |
| 160 | unsigned long tcon; |
| 161 | |
| 162 | local_irq_save(flags); |
| 163 | |
| 164 | tcon = __raw_readl(S3C2410_TCON); |
| 165 | tcon &= ~pwm_tcon_start(pwm); |
| 166 | __raw_writel(tcon, S3C2410_TCON); |
| 167 | |
| 168 | local_irq_restore(flags); |
| 169 | |
| 170 | pwm->running = 0; |
| 171 | } |
| 172 | |
| 173 | EXPORT_SYMBOL(pwm_disable); |
| 174 | |
Ben Dooks | 1038959 | 2008-08-26 22:54:05 +0100 | [diff] [blame] | 175 | 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] | 176 | { |
| 177 | unsigned long tin_parent_rate; |
| 178 | unsigned int div; |
| 179 | |
| 180 | tin_parent_rate = clk_get_rate(clk_get_parent(pwm->clk_div)); |
| 181 | pwm_dbg(pwm, "tin parent at %lu\n", tin_parent_rate); |
| 182 | |
| 183 | for (div = 2; div <= 16; div *= 2) { |
| 184 | if ((tin_parent_rate / (div << 16)) < freq) |
| 185 | return tin_parent_rate / div; |
| 186 | } |
| 187 | |
| 188 | return tin_parent_rate / 16; |
| 189 | } |
| 190 | |
| 191 | #define NS_IN_HZ (1000000000UL) |
| 192 | |
| 193 | int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) |
| 194 | { |
| 195 | unsigned long tin_rate; |
| 196 | unsigned long tin_ns; |
| 197 | unsigned long period; |
| 198 | unsigned long flags; |
| 199 | unsigned long tcon; |
| 200 | unsigned long tcnt; |
| 201 | long tcmp; |
| 202 | |
| 203 | /* We currently avoid using 64bit arithmetic by using the |
| 204 | * fact that anything faster than 1Hz is easily representable |
| 205 | * by 32bits. */ |
| 206 | |
| 207 | if (period_ns > NS_IN_HZ || duty_ns > NS_IN_HZ) |
| 208 | return -ERANGE; |
| 209 | |
| 210 | if (duty_ns > period_ns) |
| 211 | return -EINVAL; |
| 212 | |
| 213 | if (period_ns == pwm->period_ns && |
| 214 | duty_ns == pwm->duty_ns) |
| 215 | return 0; |
| 216 | |
| 217 | /* The TCMP and TCNT can be read without a lock, they're not |
| 218 | * shared between the timers. */ |
| 219 | |
| 220 | tcmp = __raw_readl(S3C2410_TCMPB(pwm->pwm_id)); |
| 221 | tcnt = __raw_readl(S3C2410_TCNTB(pwm->pwm_id)); |
| 222 | |
| 223 | period = NS_IN_HZ / period_ns; |
| 224 | |
| 225 | pwm_dbg(pwm, "duty_ns=%d, period_ns=%d (%lu)\n", |
| 226 | duty_ns, period_ns, period); |
| 227 | |
| 228 | /* Check to see if we are changing the clock rate of the PWM */ |
| 229 | |
| 230 | if (pwm->period_ns != period_ns) { |
| 231 | if (pwm_is_tdiv(pwm)) { |
| 232 | tin_rate = pwm_calc_tin(pwm, period); |
| 233 | clk_set_rate(pwm->clk_div, tin_rate); |
| 234 | } else |
| 235 | tin_rate = clk_get_rate(pwm->clk); |
| 236 | |
| 237 | pwm->period_ns = period_ns; |
| 238 | |
| 239 | pwm_dbg(pwm, "tin_rate=%lu\n", tin_rate); |
| 240 | |
| 241 | tin_ns = NS_IN_HZ / tin_rate; |
| 242 | tcnt = period_ns / tin_ns; |
| 243 | } else |
| 244 | tin_ns = NS_IN_HZ / clk_get_rate(pwm->clk); |
| 245 | |
| 246 | /* Note, counters count down */ |
| 247 | |
| 248 | tcmp = duty_ns / tin_ns; |
| 249 | tcmp = tcnt - tcmp; |
| 250 | |
| 251 | pwm_dbg(pwm, "tin_ns=%lu, tcmp=%ld/%lu\n", tin_ns, tcmp, tcnt); |
| 252 | |
| 253 | if (tcmp < 0) |
| 254 | tcmp = 0; |
| 255 | |
| 256 | /* Update the PWM register block. */ |
| 257 | |
| 258 | local_irq_save(flags); |
| 259 | |
| 260 | __raw_writel(tcmp, S3C2410_TCMPB(pwm->pwm_id)); |
| 261 | __raw_writel(tcnt, S3C2410_TCNTB(pwm->pwm_id)); |
| 262 | |
| 263 | tcon = __raw_readl(S3C2410_TCON); |
| 264 | tcon |= pwm_tcon_manulupdate(pwm); |
| 265 | tcon |= pwm_tcon_autoreload(pwm); |
| 266 | __raw_writel(tcon, S3C2410_TCON); |
| 267 | |
| 268 | tcon &= ~pwm_tcon_manulupdate(pwm); |
| 269 | __raw_writel(tcon, S3C2410_TCON); |
| 270 | |
| 271 | local_irq_restore(flags); |
| 272 | |
| 273 | return 0; |
| 274 | } |
| 275 | |
| 276 | EXPORT_SYMBOL(pwm_config); |
| 277 | |
| 278 | static int pwm_register(struct pwm_device *pwm) |
| 279 | { |
| 280 | pwm->duty_ns = -1; |
| 281 | pwm->period_ns = -1; |
| 282 | |
| 283 | mutex_lock(&pwm_lock); |
| 284 | list_add_tail(&pwm->list, &pwm_list); |
| 285 | mutex_unlock(&pwm_lock); |
| 286 | |
| 287 | return 0; |
| 288 | } |
| 289 | |
| 290 | static int s3c_pwm_probe(struct platform_device *pdev) |
| 291 | { |
| 292 | struct device *dev = &pdev->dev; |
| 293 | struct pwm_device *pwm; |
| 294 | unsigned long flags; |
| 295 | unsigned long tcon; |
| 296 | unsigned int id = pdev->id; |
| 297 | int ret; |
| 298 | |
| 299 | if (id == 4) { |
| 300 | dev_err(dev, "TIMER4 is currently not supported\n"); |
| 301 | return -ENXIO; |
| 302 | } |
| 303 | |
| 304 | pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); |
| 305 | if (pwm == NULL) { |
| 306 | dev_err(dev, "failed to allocate pwm_device\n"); |
| 307 | return -ENOMEM; |
| 308 | } |
| 309 | |
| 310 | pwm->pdev = pdev; |
| 311 | pwm->pwm_id = id; |
| 312 | |
| 313 | /* calculate base of control bits in TCON */ |
| 314 | pwm->tcon_base = id == 0 ? 0 : (id * 4) + 4; |
| 315 | |
| 316 | pwm->clk = clk_get(dev, "pwm-tin"); |
| 317 | if (IS_ERR(pwm->clk)) { |
| 318 | dev_err(dev, "failed to get pwm tin clk\n"); |
| 319 | ret = PTR_ERR(pwm->clk); |
| 320 | goto err_alloc; |
| 321 | } |
| 322 | |
| 323 | pwm->clk_div = clk_get(dev, "pwm-tdiv"); |
| 324 | if (IS_ERR(pwm->clk_div)) { |
| 325 | dev_err(dev, "failed to get pwm tdiv clk\n"); |
| 326 | ret = PTR_ERR(pwm->clk_div); |
| 327 | goto err_clk_tin; |
| 328 | } |
| 329 | |
| 330 | local_irq_save(flags); |
| 331 | |
| 332 | tcon = __raw_readl(S3C2410_TCON); |
| 333 | tcon |= pwm_tcon_invert(pwm); |
| 334 | __raw_writel(tcon, S3C2410_TCON); |
| 335 | |
| 336 | local_irq_restore(flags); |
| 337 | |
| 338 | |
| 339 | ret = pwm_register(pwm); |
| 340 | if (ret) { |
| 341 | dev_err(dev, "failed to register pwm\n"); |
| 342 | goto err_clk_tdiv; |
| 343 | } |
| 344 | |
| 345 | pwm_dbg(pwm, "config bits %02x\n", |
| 346 | (__raw_readl(S3C2410_TCON) >> pwm->tcon_base) & 0x0f); |
| 347 | |
| 348 | dev_info(dev, "tin at %lu, tdiv at %lu, tin=%sclk, base %d\n", |
| 349 | clk_get_rate(pwm->clk), |
| 350 | clk_get_rate(pwm->clk_div), |
| 351 | pwm_is_tdiv(pwm) ? "div" : "ext", pwm->tcon_base); |
| 352 | |
| 353 | platform_set_drvdata(pdev, pwm); |
| 354 | return 0; |
| 355 | |
| 356 | err_clk_tdiv: |
| 357 | clk_put(pwm->clk_div); |
| 358 | |
| 359 | err_clk_tin: |
| 360 | clk_put(pwm->clk); |
| 361 | |
| 362 | err_alloc: |
| 363 | kfree(pwm); |
| 364 | return ret; |
| 365 | } |
| 366 | |
| 367 | static int s3c_pwm_remove(struct platform_device *pdev) |
| 368 | { |
| 369 | struct pwm_device *pwm = platform_get_drvdata(pdev); |
| 370 | |
| 371 | clk_put(pwm->clk_div); |
| 372 | clk_put(pwm->clk); |
| 373 | kfree(pwm); |
| 374 | |
| 375 | return 0; |
| 376 | } |
| 377 | |
| 378 | static struct platform_driver s3c_pwm_driver = { |
| 379 | .driver = { |
| 380 | .name = "s3c24xx-pwm", |
| 381 | .owner = THIS_MODULE, |
| 382 | }, |
| 383 | .probe = s3c_pwm_probe, |
| 384 | .remove = __devexit_p(s3c_pwm_remove), |
| 385 | }; |
| 386 | |
| 387 | static int __init pwm_init(void) |
| 388 | { |
| 389 | int ret; |
| 390 | |
| 391 | clk_scaler[0] = clk_get(NULL, "pwm-scaler0"); |
| 392 | clk_scaler[1] = clk_get(NULL, "pwm-scaler1"); |
| 393 | |
| 394 | if (IS_ERR(clk_scaler[0]) || IS_ERR(clk_scaler[1])) { |
| 395 | printk(KERN_ERR "%s: failed to get scaler clocks\n", __func__); |
| 396 | return -EINVAL; |
| 397 | } |
| 398 | |
| 399 | ret = platform_driver_register(&s3c_pwm_driver); |
| 400 | if (ret) |
| 401 | printk(KERN_ERR "%s: failed to add pwm driver\n", __func__); |
| 402 | |
| 403 | return ret; |
| 404 | } |
| 405 | |
| 406 | arch_initcall(pwm_init); |