1 /* 2 * R-Mobile TPU PWM driver 3 * 4 * Copyright (C) 2012 Renesas Solutions Corp. 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 */ 15 16 #include <linux/clk.h> 17 #include <linux/err.h> 18 #include <linux/io.h> 19 #include <linux/init.h> 20 #include <linux/ioport.h> 21 #include <linux/module.h> 22 #include <linux/mutex.h> 23 #include <linux/of.h> 24 #include <linux/platform_device.h> 25 #include <linux/pm_runtime.h> 26 #include <linux/pwm.h> 27 #include <linux/slab.h> 28 #include <linux/spinlock.h> 29 30 #define TPU_CHANNEL_MAX 4 31 32 #define TPU_TSTR 0x00 /* Timer start register (shared) */ 33 34 #define TPU_TCRn 0x00 /* Timer control register */ 35 #define TPU_TCR_CCLR_NONE (0 << 5) 36 #define TPU_TCR_CCLR_TGRA (1 << 5) 37 #define TPU_TCR_CCLR_TGRB (2 << 5) 38 #define TPU_TCR_CCLR_TGRC (5 << 5) 39 #define TPU_TCR_CCLR_TGRD (6 << 5) 40 #define TPU_TCR_CKEG_RISING (0 << 3) 41 #define TPU_TCR_CKEG_FALLING (1 << 3) 42 #define TPU_TCR_CKEG_BOTH (2 << 3) 43 #define TPU_TMDRn 0x04 /* Timer mode register */ 44 #define TPU_TMDR_BFWT (1 << 6) 45 #define TPU_TMDR_BFB (1 << 5) 46 #define TPU_TMDR_BFA (1 << 4) 47 #define TPU_TMDR_MD_NORMAL (0 << 0) 48 #define TPU_TMDR_MD_PWM (2 << 0) 49 #define TPU_TIORn 0x08 /* Timer I/O control register */ 50 #define TPU_TIOR_IOA_0 (0 << 0) 51 #define TPU_TIOR_IOA_0_CLR (1 << 0) 52 #define TPU_TIOR_IOA_0_SET (2 << 0) 53 #define TPU_TIOR_IOA_0_TOGGLE (3 << 0) 54 #define TPU_TIOR_IOA_1 (4 << 0) 55 #define TPU_TIOR_IOA_1_CLR (5 << 0) 56 #define TPU_TIOR_IOA_1_SET (6 << 0) 57 #define TPU_TIOR_IOA_1_TOGGLE (7 << 0) 58 #define TPU_TIERn 0x0c /* Timer interrupt enable register */ 59 #define TPU_TSRn 0x10 /* Timer status register */ 60 #define TPU_TCNTn 0x14 /* Timer counter */ 61 #define TPU_TGRAn 0x18 /* Timer general register A */ 62 #define TPU_TGRBn 0x1c /* Timer general register B */ 63 #define TPU_TGRCn 0x20 /* Timer general register C */ 64 #define TPU_TGRDn 0x24 /* Timer general register D */ 65 66 #define TPU_CHANNEL_OFFSET 0x10 67 #define TPU_CHANNEL_SIZE 0x40 68 69 enum tpu_pin_state { 70 TPU_PIN_INACTIVE, /* Pin is driven inactive */ 71 TPU_PIN_PWM, /* Pin is driven by PWM */ 72 TPU_PIN_ACTIVE, /* Pin is driven active */ 73 }; 74 75 struct tpu_device; 76 77 struct tpu_pwm_device { 78 bool timer_on; /* Whether the timer is running */ 79 80 struct tpu_device *tpu; 81 unsigned int channel; /* Channel number in the TPU */ 82 83 enum pwm_polarity polarity; 84 unsigned int prescaler; 85 u16 period; 86 u16 duty; 87 }; 88 89 struct tpu_device { 90 struct platform_device *pdev; 91 struct pwm_chip chip; 92 spinlock_t lock; 93 94 void __iomem *base; 95 struct clk *clk; 96 }; 97 98 #define to_tpu_device(c) container_of(c, struct tpu_device, chip) 99 100 static void tpu_pwm_write(struct tpu_pwm_device *pwm, int reg_nr, u16 value) 101 { 102 void __iomem *base = pwm->tpu->base + TPU_CHANNEL_OFFSET 103 + pwm->channel * TPU_CHANNEL_SIZE; 104 105 iowrite16(value, base + reg_nr); 106 } 107 108 static void tpu_pwm_set_pin(struct tpu_pwm_device *pwm, 109 enum tpu_pin_state state) 110 { 111 static const char * const states[] = { "inactive", "PWM", "active" }; 112 113 dev_dbg(&pwm->tpu->pdev->dev, "%u: configuring pin as %s\n", 114 pwm->channel, states[state]); 115 116 switch (state) { 117 case TPU_PIN_INACTIVE: 118 tpu_pwm_write(pwm, TPU_TIORn, 119 pwm->polarity == PWM_POLARITY_INVERSED ? 120 TPU_TIOR_IOA_1 : TPU_TIOR_IOA_0); 121 break; 122 case TPU_PIN_PWM: 123 tpu_pwm_write(pwm, TPU_TIORn, 124 pwm->polarity == PWM_POLARITY_INVERSED ? 125 TPU_TIOR_IOA_0_SET : TPU_TIOR_IOA_1_CLR); 126 break; 127 case TPU_PIN_ACTIVE: 128 tpu_pwm_write(pwm, TPU_TIORn, 129 pwm->polarity == PWM_POLARITY_INVERSED ? 130 TPU_TIOR_IOA_0 : TPU_TIOR_IOA_1); 131 break; 132 } 133 } 134 135 static void tpu_pwm_start_stop(struct tpu_pwm_device *pwm, int start) 136 { 137 unsigned long flags; 138 u16 value; 139 140 spin_lock_irqsave(&pwm->tpu->lock, flags); 141 value = ioread16(pwm->tpu->base + TPU_TSTR); 142 143 if (start) 144 value |= 1 << pwm->channel; 145 else 146 value &= ~(1 << pwm->channel); 147 148 iowrite16(value, pwm->tpu->base + TPU_TSTR); 149 spin_unlock_irqrestore(&pwm->tpu->lock, flags); 150 } 151 152 static int tpu_pwm_timer_start(struct tpu_pwm_device *pwm) 153 { 154 int ret; 155 156 if (!pwm->timer_on) { 157 /* Wake up device and enable clock. */ 158 pm_runtime_get_sync(&pwm->tpu->pdev->dev); 159 ret = clk_prepare_enable(pwm->tpu->clk); 160 if (ret) { 161 dev_err(&pwm->tpu->pdev->dev, "cannot enable clock\n"); 162 return ret; 163 } 164 pwm->timer_on = true; 165 } 166 167 /* 168 * Make sure the channel is stopped, as we need to reconfigure it 169 * completely. First drive the pin to the inactive state to avoid 170 * glitches. 171 */ 172 tpu_pwm_set_pin(pwm, TPU_PIN_INACTIVE); 173 tpu_pwm_start_stop(pwm, false); 174 175 /* 176 * - Clear TCNT on TGRB match 177 * - Count on rising edge 178 * - Set prescaler 179 * - Output 0 until TGRA, output 1 until TGRB (active low polarity) 180 * - Output 1 until TGRA, output 0 until TGRB (active high polarity 181 * - PWM mode 182 */ 183 tpu_pwm_write(pwm, TPU_TCRn, TPU_TCR_CCLR_TGRB | TPU_TCR_CKEG_RISING | 184 pwm->prescaler); 185 tpu_pwm_write(pwm, TPU_TMDRn, TPU_TMDR_MD_PWM); 186 tpu_pwm_set_pin(pwm, TPU_PIN_PWM); 187 tpu_pwm_write(pwm, TPU_TGRAn, pwm->duty); 188 tpu_pwm_write(pwm, TPU_TGRBn, pwm->period); 189 190 dev_dbg(&pwm->tpu->pdev->dev, "%u: TGRA 0x%04x TGRB 0x%04x\n", 191 pwm->channel, pwm->duty, pwm->period); 192 193 /* Start the channel. */ 194 tpu_pwm_start_stop(pwm, true); 195 196 return 0; 197 } 198 199 static void tpu_pwm_timer_stop(struct tpu_pwm_device *pwm) 200 { 201 if (!pwm->timer_on) 202 return; 203 204 /* Disable channel. */ 205 tpu_pwm_start_stop(pwm, false); 206 207 /* Stop clock and mark device as idle. */ 208 clk_disable_unprepare(pwm->tpu->clk); 209 pm_runtime_put(&pwm->tpu->pdev->dev); 210 211 pwm->timer_on = false; 212 } 213 214 /* ----------------------------------------------------------------------------- 215 * PWM API 216 */ 217 218 static int tpu_pwm_request(struct pwm_chip *chip, struct pwm_device *_pwm) 219 { 220 struct tpu_device *tpu = to_tpu_device(chip); 221 struct tpu_pwm_device *pwm; 222 223 if (_pwm->hwpwm >= TPU_CHANNEL_MAX) 224 return -EINVAL; 225 226 pwm = kzalloc(sizeof(*pwm), GFP_KERNEL); 227 if (pwm == NULL) 228 return -ENOMEM; 229 230 pwm->tpu = tpu; 231 pwm->channel = _pwm->hwpwm; 232 pwm->polarity = PWM_POLARITY_NORMAL; 233 pwm->prescaler = 0; 234 pwm->period = 0; 235 pwm->duty = 0; 236 237 pwm->timer_on = false; 238 239 pwm_set_chip_data(_pwm, pwm); 240 241 return 0; 242 } 243 244 static void tpu_pwm_free(struct pwm_chip *chip, struct pwm_device *_pwm) 245 { 246 struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm); 247 248 tpu_pwm_timer_stop(pwm); 249 kfree(pwm); 250 } 251 252 static int tpu_pwm_config(struct pwm_chip *chip, struct pwm_device *_pwm, 253 int duty_ns, int period_ns) 254 { 255 static const unsigned int prescalers[] = { 1, 4, 16, 64 }; 256 struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm); 257 struct tpu_device *tpu = to_tpu_device(chip); 258 unsigned int prescaler; 259 bool duty_only = false; 260 u32 clk_rate; 261 u32 period; 262 u32 duty; 263 int ret; 264 265 /* 266 * Pick a prescaler to avoid overflowing the counter. 267 * TODO: Pick the highest acceptable prescaler. 268 */ 269 clk_rate = clk_get_rate(tpu->clk); 270 271 for (prescaler = 0; prescaler < ARRAY_SIZE(prescalers); ++prescaler) { 272 period = clk_rate / prescalers[prescaler] 273 / (NSEC_PER_SEC / period_ns); 274 if (period <= 0xffff) 275 break; 276 } 277 278 if (prescaler == ARRAY_SIZE(prescalers) || period == 0) { 279 dev_err(&tpu->pdev->dev, "clock rate mismatch\n"); 280 return -ENOTSUPP; 281 } 282 283 if (duty_ns) { 284 duty = clk_rate / prescalers[prescaler] 285 / (NSEC_PER_SEC / duty_ns); 286 if (duty > period) 287 return -EINVAL; 288 } else { 289 duty = 0; 290 } 291 292 dev_dbg(&tpu->pdev->dev, 293 "rate %u, prescaler %u, period %u, duty %u\n", 294 clk_rate, prescalers[prescaler], period, duty); 295 296 if (pwm->prescaler == prescaler && pwm->period == period) 297 duty_only = true; 298 299 pwm->prescaler = prescaler; 300 pwm->period = period; 301 pwm->duty = duty; 302 303 /* If the channel is disabled we're done. */ 304 if (!pwm_is_enabled(_pwm)) 305 return 0; 306 307 if (duty_only && pwm->timer_on) { 308 /* 309 * If only the duty cycle changed and the timer is already 310 * running, there's no need to reconfigure it completely, Just 311 * modify the duty cycle. 312 */ 313 tpu_pwm_write(pwm, TPU_TGRAn, pwm->duty); 314 dev_dbg(&tpu->pdev->dev, "%u: TGRA 0x%04x\n", pwm->channel, 315 pwm->duty); 316 } else { 317 /* Otherwise perform a full reconfiguration. */ 318 ret = tpu_pwm_timer_start(pwm); 319 if (ret < 0) 320 return ret; 321 } 322 323 if (duty == 0 || duty == period) { 324 /* 325 * To avoid running the timer when not strictly required, handle 326 * 0% and 100% duty cycles as fixed levels and stop the timer. 327 */ 328 tpu_pwm_set_pin(pwm, duty ? TPU_PIN_ACTIVE : TPU_PIN_INACTIVE); 329 tpu_pwm_timer_stop(pwm); 330 } 331 332 return 0; 333 } 334 335 static int tpu_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *_pwm, 336 enum pwm_polarity polarity) 337 { 338 struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm); 339 340 pwm->polarity = polarity; 341 342 return 0; 343 } 344 345 static int tpu_pwm_enable(struct pwm_chip *chip, struct pwm_device *_pwm) 346 { 347 struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm); 348 int ret; 349 350 ret = tpu_pwm_timer_start(pwm); 351 if (ret < 0) 352 return ret; 353 354 /* 355 * To avoid running the timer when not strictly required, handle 0% and 356 * 100% duty cycles as fixed levels and stop the timer. 357 */ 358 if (pwm->duty == 0 || pwm->duty == pwm->period) { 359 tpu_pwm_set_pin(pwm, pwm->duty ? 360 TPU_PIN_ACTIVE : TPU_PIN_INACTIVE); 361 tpu_pwm_timer_stop(pwm); 362 } 363 364 return 0; 365 } 366 367 static void tpu_pwm_disable(struct pwm_chip *chip, struct pwm_device *_pwm) 368 { 369 struct tpu_pwm_device *pwm = pwm_get_chip_data(_pwm); 370 371 /* The timer must be running to modify the pin output configuration. */ 372 tpu_pwm_timer_start(pwm); 373 tpu_pwm_set_pin(pwm, TPU_PIN_INACTIVE); 374 tpu_pwm_timer_stop(pwm); 375 } 376 377 static const struct pwm_ops tpu_pwm_ops = { 378 .request = tpu_pwm_request, 379 .free = tpu_pwm_free, 380 .config = tpu_pwm_config, 381 .set_polarity = tpu_pwm_set_polarity, 382 .enable = tpu_pwm_enable, 383 .disable = tpu_pwm_disable, 384 .owner = THIS_MODULE, 385 }; 386 387 /* ----------------------------------------------------------------------------- 388 * Probe and remove 389 */ 390 391 static int tpu_probe(struct platform_device *pdev) 392 { 393 struct tpu_device *tpu; 394 struct resource *res; 395 int ret; 396 397 tpu = devm_kzalloc(&pdev->dev, sizeof(*tpu), GFP_KERNEL); 398 if (tpu == NULL) 399 return -ENOMEM; 400 401 spin_lock_init(&tpu->lock); 402 tpu->pdev = pdev; 403 404 /* Map memory, get clock and pin control. */ 405 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 406 tpu->base = devm_ioremap_resource(&pdev->dev, res); 407 if (IS_ERR(tpu->base)) 408 return PTR_ERR(tpu->base); 409 410 tpu->clk = devm_clk_get(&pdev->dev, NULL); 411 if (IS_ERR(tpu->clk)) { 412 dev_err(&pdev->dev, "cannot get clock\n"); 413 return PTR_ERR(tpu->clk); 414 } 415 416 /* Initialize and register the device. */ 417 platform_set_drvdata(pdev, tpu); 418 419 tpu->chip.dev = &pdev->dev; 420 tpu->chip.ops = &tpu_pwm_ops; 421 tpu->chip.of_xlate = of_pwm_xlate_with_flags; 422 tpu->chip.of_pwm_n_cells = 3; 423 tpu->chip.base = -1; 424 tpu->chip.npwm = TPU_CHANNEL_MAX; 425 426 ret = pwmchip_add(&tpu->chip); 427 if (ret < 0) { 428 dev_err(&pdev->dev, "failed to register PWM chip\n"); 429 return ret; 430 } 431 432 dev_info(&pdev->dev, "TPU PWM %d registered\n", tpu->pdev->id); 433 434 pm_runtime_enable(&pdev->dev); 435 436 return 0; 437 } 438 439 static int tpu_remove(struct platform_device *pdev) 440 { 441 struct tpu_device *tpu = platform_get_drvdata(pdev); 442 int ret; 443 444 ret = pwmchip_remove(&tpu->chip); 445 if (ret) 446 return ret; 447 448 pm_runtime_disable(&pdev->dev); 449 450 return 0; 451 } 452 453 #ifdef CONFIG_OF 454 static const struct of_device_id tpu_of_table[] = { 455 { .compatible = "renesas,tpu-r8a73a4", }, 456 { .compatible = "renesas,tpu-r8a7740", }, 457 { .compatible = "renesas,tpu-r8a7790", }, 458 { .compatible = "renesas,tpu", }, 459 { }, 460 }; 461 462 MODULE_DEVICE_TABLE(of, tpu_of_table); 463 #endif 464 465 static struct platform_driver tpu_driver = { 466 .probe = tpu_probe, 467 .remove = tpu_remove, 468 .driver = { 469 .name = "renesas-tpu-pwm", 470 .of_match_table = of_match_ptr(tpu_of_table), 471 } 472 }; 473 474 module_platform_driver(tpu_driver); 475 476 MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>"); 477 MODULE_DESCRIPTION("Renesas TPU PWM Driver"); 478 MODULE_LICENSE("GPL v2"); 479 MODULE_ALIAS("platform:renesas-tpu-pwm"); 480