1 /* 2 * Copyright (C) Overkiz SAS 2012 3 * 4 * Author: Boris BREZILLON <b.brezillon@overkiz.com> 5 * License terms: GNU General Public License (GPL) version 2 6 */ 7 8 #include <linux/module.h> 9 #include <linux/init.h> 10 #include <linux/clocksource.h> 11 #include <linux/clockchips.h> 12 #include <linux/interrupt.h> 13 #include <linux/irq.h> 14 15 #include <linux/clk.h> 16 #include <linux/err.h> 17 #include <linux/ioport.h> 18 #include <linux/io.h> 19 #include <linux/platform_device.h> 20 #include <linux/atmel_tc.h> 21 #include <linux/pwm.h> 22 #include <linux/of_device.h> 23 #include <linux/slab.h> 24 25 #define NPWM 6 26 27 #define ATMEL_TC_ACMR_MASK (ATMEL_TC_ACPA | ATMEL_TC_ACPC | \ 28 ATMEL_TC_AEEVT | ATMEL_TC_ASWTRG) 29 30 #define ATMEL_TC_BCMR_MASK (ATMEL_TC_BCPB | ATMEL_TC_BCPC | \ 31 ATMEL_TC_BEEVT | ATMEL_TC_BSWTRG) 32 33 struct atmel_tcb_pwm_device { 34 enum pwm_polarity polarity; /* PWM polarity */ 35 unsigned div; /* PWM clock divider */ 36 unsigned duty; /* PWM duty expressed in clk cycles */ 37 unsigned period; /* PWM period expressed in clk cycles */ 38 }; 39 40 struct atmel_tcb_channel { 41 u32 enabled; 42 u32 cmr; 43 u32 ra; 44 u32 rb; 45 u32 rc; 46 }; 47 48 struct atmel_tcb_pwm_chip { 49 struct pwm_chip chip; 50 spinlock_t lock; 51 struct atmel_tc *tc; 52 struct atmel_tcb_pwm_device *pwms[NPWM]; 53 struct atmel_tcb_channel bkup[NPWM / 2]; 54 }; 55 56 static inline struct atmel_tcb_pwm_chip *to_tcb_chip(struct pwm_chip *chip) 57 { 58 return container_of(chip, struct atmel_tcb_pwm_chip, chip); 59 } 60 61 static int atmel_tcb_pwm_set_polarity(struct pwm_chip *chip, 62 struct pwm_device *pwm, 63 enum pwm_polarity polarity) 64 { 65 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); 66 67 tcbpwm->polarity = polarity; 68 69 return 0; 70 } 71 72 static int atmel_tcb_pwm_request(struct pwm_chip *chip, 73 struct pwm_device *pwm) 74 { 75 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); 76 struct atmel_tcb_pwm_device *tcbpwm; 77 struct atmel_tc *tc = tcbpwmc->tc; 78 void __iomem *regs = tc->regs; 79 unsigned group = pwm->hwpwm / 2; 80 unsigned index = pwm->hwpwm % 2; 81 unsigned cmr; 82 int ret; 83 84 tcbpwm = devm_kzalloc(chip->dev, sizeof(*tcbpwm), GFP_KERNEL); 85 if (!tcbpwm) 86 return -ENOMEM; 87 88 ret = clk_prepare_enable(tc->clk[group]); 89 if (ret) { 90 devm_kfree(chip->dev, tcbpwm); 91 return ret; 92 } 93 94 pwm_set_chip_data(pwm, tcbpwm); 95 tcbpwm->polarity = PWM_POLARITY_NORMAL; 96 tcbpwm->duty = 0; 97 tcbpwm->period = 0; 98 tcbpwm->div = 0; 99 100 spin_lock(&tcbpwmc->lock); 101 cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR)); 102 /* 103 * Get init config from Timer Counter registers if 104 * Timer Counter is already configured as a PWM generator. 105 */ 106 if (cmr & ATMEL_TC_WAVE) { 107 if (index == 0) 108 tcbpwm->duty = 109 __raw_readl(regs + ATMEL_TC_REG(group, RA)); 110 else 111 tcbpwm->duty = 112 __raw_readl(regs + ATMEL_TC_REG(group, RB)); 113 114 tcbpwm->div = cmr & ATMEL_TC_TCCLKS; 115 tcbpwm->period = __raw_readl(regs + ATMEL_TC_REG(group, RC)); 116 cmr &= (ATMEL_TC_TCCLKS | ATMEL_TC_ACMR_MASK | 117 ATMEL_TC_BCMR_MASK); 118 } else 119 cmr = 0; 120 121 cmr |= ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO | ATMEL_TC_EEVT_XC0; 122 __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR)); 123 spin_unlock(&tcbpwmc->lock); 124 125 tcbpwmc->pwms[pwm->hwpwm] = tcbpwm; 126 127 return 0; 128 } 129 130 static void atmel_tcb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) 131 { 132 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); 133 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); 134 struct atmel_tc *tc = tcbpwmc->tc; 135 136 clk_disable_unprepare(tc->clk[pwm->hwpwm / 2]); 137 tcbpwmc->pwms[pwm->hwpwm] = NULL; 138 devm_kfree(chip->dev, tcbpwm); 139 } 140 141 static void atmel_tcb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 142 { 143 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); 144 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); 145 struct atmel_tc *tc = tcbpwmc->tc; 146 void __iomem *regs = tc->regs; 147 unsigned group = pwm->hwpwm / 2; 148 unsigned index = pwm->hwpwm % 2; 149 unsigned cmr; 150 enum pwm_polarity polarity = tcbpwm->polarity; 151 152 /* 153 * If duty is 0 the timer will be stopped and we have to 154 * configure the output correctly on software trigger: 155 * - set output to high if PWM_POLARITY_INVERSED 156 * - set output to low if PWM_POLARITY_NORMAL 157 * 158 * This is why we're reverting polarity in this case. 159 */ 160 if (tcbpwm->duty == 0) 161 polarity = !polarity; 162 163 spin_lock(&tcbpwmc->lock); 164 cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR)); 165 166 /* flush old setting and set the new one */ 167 if (index == 0) { 168 cmr &= ~ATMEL_TC_ACMR_MASK; 169 if (polarity == PWM_POLARITY_INVERSED) 170 cmr |= ATMEL_TC_ASWTRG_CLEAR; 171 else 172 cmr |= ATMEL_TC_ASWTRG_SET; 173 } else { 174 cmr &= ~ATMEL_TC_BCMR_MASK; 175 if (polarity == PWM_POLARITY_INVERSED) 176 cmr |= ATMEL_TC_BSWTRG_CLEAR; 177 else 178 cmr |= ATMEL_TC_BSWTRG_SET; 179 } 180 181 __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR)); 182 183 /* 184 * Use software trigger to apply the new setting. 185 * If both PWM devices in this group are disabled we stop the clock. 186 */ 187 if (!(cmr & (ATMEL_TC_ACPC | ATMEL_TC_BCPC))) { 188 __raw_writel(ATMEL_TC_SWTRG | ATMEL_TC_CLKDIS, 189 regs + ATMEL_TC_REG(group, CCR)); 190 tcbpwmc->bkup[group].enabled = 1; 191 } else { 192 __raw_writel(ATMEL_TC_SWTRG, regs + 193 ATMEL_TC_REG(group, CCR)); 194 tcbpwmc->bkup[group].enabled = 0; 195 } 196 197 spin_unlock(&tcbpwmc->lock); 198 } 199 200 static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 201 { 202 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); 203 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); 204 struct atmel_tc *tc = tcbpwmc->tc; 205 void __iomem *regs = tc->regs; 206 unsigned group = pwm->hwpwm / 2; 207 unsigned index = pwm->hwpwm % 2; 208 u32 cmr; 209 enum pwm_polarity polarity = tcbpwm->polarity; 210 211 /* 212 * If duty is 0 the timer will be stopped and we have to 213 * configure the output correctly on software trigger: 214 * - set output to high if PWM_POLARITY_INVERSED 215 * - set output to low if PWM_POLARITY_NORMAL 216 * 217 * This is why we're reverting polarity in this case. 218 */ 219 if (tcbpwm->duty == 0) 220 polarity = !polarity; 221 222 spin_lock(&tcbpwmc->lock); 223 cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR)); 224 225 /* flush old setting and set the new one */ 226 cmr &= ~ATMEL_TC_TCCLKS; 227 228 if (index == 0) { 229 cmr &= ~ATMEL_TC_ACMR_MASK; 230 231 /* Set CMR flags according to given polarity */ 232 if (polarity == PWM_POLARITY_INVERSED) 233 cmr |= ATMEL_TC_ASWTRG_CLEAR; 234 else 235 cmr |= ATMEL_TC_ASWTRG_SET; 236 } else { 237 cmr &= ~ATMEL_TC_BCMR_MASK; 238 if (polarity == PWM_POLARITY_INVERSED) 239 cmr |= ATMEL_TC_BSWTRG_CLEAR; 240 else 241 cmr |= ATMEL_TC_BSWTRG_SET; 242 } 243 244 /* 245 * If duty is 0 or equal to period there's no need to register 246 * a specific action on RA/RB and RC compare. 247 * The output will be configured on software trigger and keep 248 * this config till next config call. 249 */ 250 if (tcbpwm->duty != tcbpwm->period && tcbpwm->duty > 0) { 251 if (index == 0) { 252 if (polarity == PWM_POLARITY_INVERSED) 253 cmr |= ATMEL_TC_ACPA_SET | ATMEL_TC_ACPC_CLEAR; 254 else 255 cmr |= ATMEL_TC_ACPA_CLEAR | ATMEL_TC_ACPC_SET; 256 } else { 257 if (polarity == PWM_POLARITY_INVERSED) 258 cmr |= ATMEL_TC_BCPB_SET | ATMEL_TC_BCPC_CLEAR; 259 else 260 cmr |= ATMEL_TC_BCPB_CLEAR | ATMEL_TC_BCPC_SET; 261 } 262 } 263 264 cmr |= (tcbpwm->div & ATMEL_TC_TCCLKS); 265 266 __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR)); 267 268 if (index == 0) 269 __raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RA)); 270 else 271 __raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RB)); 272 273 __raw_writel(tcbpwm->period, regs + ATMEL_TC_REG(group, RC)); 274 275 /* Use software trigger to apply the new setting */ 276 __raw_writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG, 277 regs + ATMEL_TC_REG(group, CCR)); 278 tcbpwmc->bkup[group].enabled = 1; 279 spin_unlock(&tcbpwmc->lock); 280 return 0; 281 } 282 283 static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 284 int duty_ns, int period_ns) 285 { 286 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); 287 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); 288 unsigned group = pwm->hwpwm / 2; 289 unsigned index = pwm->hwpwm % 2; 290 struct atmel_tcb_pwm_device *atcbpwm = NULL; 291 struct atmel_tc *tc = tcbpwmc->tc; 292 int i; 293 int slowclk = 0; 294 unsigned period; 295 unsigned duty; 296 unsigned rate = clk_get_rate(tc->clk[group]); 297 unsigned long long min; 298 unsigned long long max; 299 300 /* 301 * Find best clk divisor: 302 * the smallest divisor which can fulfill the period_ns requirements. 303 */ 304 for (i = 0; i < 5; ++i) { 305 if (atmel_tc_divisors[i] == 0) { 306 slowclk = i; 307 continue; 308 } 309 min = div_u64((u64)NSEC_PER_SEC * atmel_tc_divisors[i], rate); 310 max = min << tc->tcb_config->counter_width; 311 if (max >= period_ns) 312 break; 313 } 314 315 /* 316 * If none of the divisor are small enough to represent period_ns 317 * take slow clock (32KHz). 318 */ 319 if (i == 5) { 320 i = slowclk; 321 rate = clk_get_rate(tc->slow_clk); 322 min = div_u64(NSEC_PER_SEC, rate); 323 max = min << tc->tcb_config->counter_width; 324 325 /* If period is too big return ERANGE error */ 326 if (max < period_ns) 327 return -ERANGE; 328 } 329 330 duty = div_u64(duty_ns, min); 331 period = div_u64(period_ns, min); 332 333 if (index == 0) 334 atcbpwm = tcbpwmc->pwms[pwm->hwpwm + 1]; 335 else 336 atcbpwm = tcbpwmc->pwms[pwm->hwpwm - 1]; 337 338 /* 339 * PWM devices provided by TCB driver are grouped by 2: 340 * - group 0: PWM 0 & 1 341 * - group 1: PWM 2 & 3 342 * - group 2: PWM 4 & 5 343 * 344 * PWM devices in a given group must be configured with the 345 * same period_ns. 346 * 347 * We're checking the period value of the second PWM device 348 * in this group before applying the new config. 349 */ 350 if ((atcbpwm && atcbpwm->duty > 0 && 351 atcbpwm->duty != atcbpwm->period) && 352 (atcbpwm->div != i || atcbpwm->period != period)) { 353 dev_err(chip->dev, 354 "failed to configure period_ns: PWM group already configured with a different value\n"); 355 return -EINVAL; 356 } 357 358 tcbpwm->period = period; 359 tcbpwm->div = i; 360 tcbpwm->duty = duty; 361 362 /* If the PWM is enabled, call enable to apply the new conf */ 363 if (pwm_is_enabled(pwm)) 364 atmel_tcb_pwm_enable(chip, pwm); 365 366 return 0; 367 } 368 369 static const struct pwm_ops atmel_tcb_pwm_ops = { 370 .request = atmel_tcb_pwm_request, 371 .free = atmel_tcb_pwm_free, 372 .config = atmel_tcb_pwm_config, 373 .set_polarity = atmel_tcb_pwm_set_polarity, 374 .enable = atmel_tcb_pwm_enable, 375 .disable = atmel_tcb_pwm_disable, 376 .owner = THIS_MODULE, 377 }; 378 379 static int atmel_tcb_pwm_probe(struct platform_device *pdev) 380 { 381 struct atmel_tcb_pwm_chip *tcbpwm; 382 struct device_node *np = pdev->dev.of_node; 383 struct atmel_tc *tc; 384 int err; 385 int tcblock; 386 387 err = of_property_read_u32(np, "tc-block", &tcblock); 388 if (err < 0) { 389 dev_err(&pdev->dev, 390 "failed to get Timer Counter Block number from device tree (error: %d)\n", 391 err); 392 return err; 393 } 394 395 tc = atmel_tc_alloc(tcblock); 396 if (tc == NULL) { 397 dev_err(&pdev->dev, "failed to allocate Timer Counter Block\n"); 398 return -ENOMEM; 399 } 400 401 tcbpwm = devm_kzalloc(&pdev->dev, sizeof(*tcbpwm), GFP_KERNEL); 402 if (tcbpwm == NULL) { 403 err = -ENOMEM; 404 goto err_free_tc; 405 } 406 407 tcbpwm->chip.dev = &pdev->dev; 408 tcbpwm->chip.ops = &atmel_tcb_pwm_ops; 409 tcbpwm->chip.of_xlate = of_pwm_xlate_with_flags; 410 tcbpwm->chip.of_pwm_n_cells = 3; 411 tcbpwm->chip.base = -1; 412 tcbpwm->chip.npwm = NPWM; 413 tcbpwm->tc = tc; 414 415 err = clk_prepare_enable(tc->slow_clk); 416 if (err) 417 goto err_free_tc; 418 419 spin_lock_init(&tcbpwm->lock); 420 421 err = pwmchip_add(&tcbpwm->chip); 422 if (err < 0) 423 goto err_disable_clk; 424 425 platform_set_drvdata(pdev, tcbpwm); 426 427 return 0; 428 429 err_disable_clk: 430 clk_disable_unprepare(tcbpwm->tc->slow_clk); 431 432 err_free_tc: 433 atmel_tc_free(tc); 434 435 return err; 436 } 437 438 static int atmel_tcb_pwm_remove(struct platform_device *pdev) 439 { 440 struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev); 441 int err; 442 443 clk_disable_unprepare(tcbpwm->tc->slow_clk); 444 445 err = pwmchip_remove(&tcbpwm->chip); 446 if (err < 0) 447 return err; 448 449 atmel_tc_free(tcbpwm->tc); 450 451 return 0; 452 } 453 454 static const struct of_device_id atmel_tcb_pwm_dt_ids[] = { 455 { .compatible = "atmel,tcb-pwm", }, 456 { /* sentinel */ } 457 }; 458 MODULE_DEVICE_TABLE(of, atmel_tcb_pwm_dt_ids); 459 460 #ifdef CONFIG_PM_SLEEP 461 static int atmel_tcb_pwm_suspend(struct device *dev) 462 { 463 struct atmel_tcb_pwm_chip *tcbpwm = dev_get_drvdata(dev); 464 void __iomem *base = tcbpwm->tc->regs; 465 int i; 466 467 for (i = 0; i < (NPWM / 2); i++) { 468 struct atmel_tcb_channel *chan = &tcbpwm->bkup[i]; 469 470 chan->cmr = readl(base + ATMEL_TC_REG(i, CMR)); 471 chan->ra = readl(base + ATMEL_TC_REG(i, RA)); 472 chan->rb = readl(base + ATMEL_TC_REG(i, RB)); 473 chan->rc = readl(base + ATMEL_TC_REG(i, RC)); 474 } 475 return 0; 476 } 477 478 static int atmel_tcb_pwm_resume(struct device *dev) 479 { 480 struct atmel_tcb_pwm_chip *tcbpwm = dev_get_drvdata(dev); 481 void __iomem *base = tcbpwm->tc->regs; 482 int i; 483 484 for (i = 0; i < (NPWM / 2); i++) { 485 struct atmel_tcb_channel *chan = &tcbpwm->bkup[i]; 486 487 writel(chan->cmr, base + ATMEL_TC_REG(i, CMR)); 488 writel(chan->ra, base + ATMEL_TC_REG(i, RA)); 489 writel(chan->rb, base + ATMEL_TC_REG(i, RB)); 490 writel(chan->rc, base + ATMEL_TC_REG(i, RC)); 491 if (chan->enabled) { 492 writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG, 493 base + ATMEL_TC_REG(i, CCR)); 494 } 495 } 496 return 0; 497 } 498 #endif 499 500 static SIMPLE_DEV_PM_OPS(atmel_tcb_pwm_pm_ops, atmel_tcb_pwm_suspend, 501 atmel_tcb_pwm_resume); 502 503 static struct platform_driver atmel_tcb_pwm_driver = { 504 .driver = { 505 .name = "atmel-tcb-pwm", 506 .of_match_table = atmel_tcb_pwm_dt_ids, 507 .pm = &atmel_tcb_pwm_pm_ops, 508 }, 509 .probe = atmel_tcb_pwm_probe, 510 .remove = atmel_tcb_pwm_remove, 511 }; 512 module_platform_driver(atmel_tcb_pwm_driver); 513 514 MODULE_AUTHOR("Boris BREZILLON <b.brezillon@overkiz.com>"); 515 MODULE_DESCRIPTION("Atmel Timer Counter Pulse Width Modulation Driver"); 516 MODULE_LICENSE("GPL v2"); 517