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_pwm_chip { 41 struct pwm_chip chip; 42 spinlock_t lock; 43 struct atmel_tc *tc; 44 struct atmel_tcb_pwm_device *pwms[NPWM]; 45 }; 46 47 static inline struct atmel_tcb_pwm_chip *to_tcb_chip(struct pwm_chip *chip) 48 { 49 return container_of(chip, struct atmel_tcb_pwm_chip, chip); 50 } 51 52 static int atmel_tcb_pwm_set_polarity(struct pwm_chip *chip, 53 struct pwm_device *pwm, 54 enum pwm_polarity polarity) 55 { 56 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); 57 58 tcbpwm->polarity = polarity; 59 60 return 0; 61 } 62 63 static int atmel_tcb_pwm_request(struct pwm_chip *chip, 64 struct pwm_device *pwm) 65 { 66 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); 67 struct atmel_tcb_pwm_device *tcbpwm; 68 struct atmel_tc *tc = tcbpwmc->tc; 69 void __iomem *regs = tc->regs; 70 unsigned group = pwm->hwpwm / 2; 71 unsigned index = pwm->hwpwm % 2; 72 unsigned cmr; 73 int ret; 74 75 tcbpwm = devm_kzalloc(chip->dev, sizeof(*tcbpwm), GFP_KERNEL); 76 if (!tcbpwm) 77 return -ENOMEM; 78 79 ret = clk_prepare_enable(tc->clk[group]); 80 if (ret) { 81 devm_kfree(chip->dev, tcbpwm); 82 return ret; 83 } 84 85 pwm_set_chip_data(pwm, tcbpwm); 86 tcbpwm->polarity = PWM_POLARITY_NORMAL; 87 tcbpwm->duty = 0; 88 tcbpwm->period = 0; 89 tcbpwm->div = 0; 90 91 spin_lock(&tcbpwmc->lock); 92 cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR)); 93 /* 94 * Get init config from Timer Counter registers if 95 * Timer Counter is already configured as a PWM generator. 96 */ 97 if (cmr & ATMEL_TC_WAVE) { 98 if (index == 0) 99 tcbpwm->duty = 100 __raw_readl(regs + ATMEL_TC_REG(group, RA)); 101 else 102 tcbpwm->duty = 103 __raw_readl(regs + ATMEL_TC_REG(group, RB)); 104 105 tcbpwm->div = cmr & ATMEL_TC_TCCLKS; 106 tcbpwm->period = __raw_readl(regs + ATMEL_TC_REG(group, RC)); 107 cmr &= (ATMEL_TC_TCCLKS | ATMEL_TC_ACMR_MASK | 108 ATMEL_TC_BCMR_MASK); 109 } else 110 cmr = 0; 111 112 cmr |= ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO | ATMEL_TC_EEVT_XC0; 113 __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR)); 114 spin_unlock(&tcbpwmc->lock); 115 116 tcbpwmc->pwms[pwm->hwpwm] = tcbpwm; 117 118 return 0; 119 } 120 121 static void atmel_tcb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) 122 { 123 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); 124 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); 125 struct atmel_tc *tc = tcbpwmc->tc; 126 127 clk_disable_unprepare(tc->clk[pwm->hwpwm / 2]); 128 tcbpwmc->pwms[pwm->hwpwm] = NULL; 129 devm_kfree(chip->dev, tcbpwm); 130 } 131 132 static void atmel_tcb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 133 { 134 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); 135 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); 136 struct atmel_tc *tc = tcbpwmc->tc; 137 void __iomem *regs = tc->regs; 138 unsigned group = pwm->hwpwm / 2; 139 unsigned index = pwm->hwpwm % 2; 140 unsigned cmr; 141 enum pwm_polarity polarity = tcbpwm->polarity; 142 143 /* 144 * If duty is 0 the timer will be stopped and we have to 145 * configure the output correctly on software trigger: 146 * - set output to high if PWM_POLARITY_INVERSED 147 * - set output to low if PWM_POLARITY_NORMAL 148 * 149 * This is why we're reverting polarity in this case. 150 */ 151 if (tcbpwm->duty == 0) 152 polarity = !polarity; 153 154 spin_lock(&tcbpwmc->lock); 155 cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR)); 156 157 /* flush old setting and set the new one */ 158 if (index == 0) { 159 cmr &= ~ATMEL_TC_ACMR_MASK; 160 if (polarity == PWM_POLARITY_INVERSED) 161 cmr |= ATMEL_TC_ASWTRG_CLEAR; 162 else 163 cmr |= ATMEL_TC_ASWTRG_SET; 164 } else { 165 cmr &= ~ATMEL_TC_BCMR_MASK; 166 if (polarity == PWM_POLARITY_INVERSED) 167 cmr |= ATMEL_TC_BSWTRG_CLEAR; 168 else 169 cmr |= ATMEL_TC_BSWTRG_SET; 170 } 171 172 __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR)); 173 174 /* 175 * Use software trigger to apply the new setting. 176 * If both PWM devices in this group are disabled we stop the clock. 177 */ 178 if (!(cmr & (ATMEL_TC_ACPC | ATMEL_TC_BCPC))) 179 __raw_writel(ATMEL_TC_SWTRG | ATMEL_TC_CLKDIS, 180 regs + ATMEL_TC_REG(group, CCR)); 181 else 182 __raw_writel(ATMEL_TC_SWTRG, regs + 183 ATMEL_TC_REG(group, CCR)); 184 185 spin_unlock(&tcbpwmc->lock); 186 } 187 188 static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 189 { 190 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); 191 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); 192 struct atmel_tc *tc = tcbpwmc->tc; 193 void __iomem *regs = tc->regs; 194 unsigned group = pwm->hwpwm / 2; 195 unsigned index = pwm->hwpwm % 2; 196 u32 cmr; 197 enum pwm_polarity polarity = tcbpwm->polarity; 198 199 /* 200 * If duty is 0 the timer will be stopped and we have to 201 * configure the output correctly on software trigger: 202 * - set output to high if PWM_POLARITY_INVERSED 203 * - set output to low if PWM_POLARITY_NORMAL 204 * 205 * This is why we're reverting polarity in this case. 206 */ 207 if (tcbpwm->duty == 0) 208 polarity = !polarity; 209 210 spin_lock(&tcbpwmc->lock); 211 cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR)); 212 213 /* flush old setting and set the new one */ 214 cmr &= ~ATMEL_TC_TCCLKS; 215 216 if (index == 0) { 217 cmr &= ~ATMEL_TC_ACMR_MASK; 218 219 /* Set CMR flags according to given polarity */ 220 if (polarity == PWM_POLARITY_INVERSED) 221 cmr |= ATMEL_TC_ASWTRG_CLEAR; 222 else 223 cmr |= ATMEL_TC_ASWTRG_SET; 224 } else { 225 cmr &= ~ATMEL_TC_BCMR_MASK; 226 if (polarity == PWM_POLARITY_INVERSED) 227 cmr |= ATMEL_TC_BSWTRG_CLEAR; 228 else 229 cmr |= ATMEL_TC_BSWTRG_SET; 230 } 231 232 /* 233 * If duty is 0 or equal to period there's no need to register 234 * a specific action on RA/RB and RC compare. 235 * The output will be configured on software trigger and keep 236 * this config till next config call. 237 */ 238 if (tcbpwm->duty != tcbpwm->period && tcbpwm->duty > 0) { 239 if (index == 0) { 240 if (polarity == PWM_POLARITY_INVERSED) 241 cmr |= ATMEL_TC_ACPA_SET | ATMEL_TC_ACPC_CLEAR; 242 else 243 cmr |= ATMEL_TC_ACPA_CLEAR | ATMEL_TC_ACPC_SET; 244 } else { 245 if (polarity == PWM_POLARITY_INVERSED) 246 cmr |= ATMEL_TC_BCPB_SET | ATMEL_TC_BCPC_CLEAR; 247 else 248 cmr |= ATMEL_TC_BCPB_CLEAR | ATMEL_TC_BCPC_SET; 249 } 250 } 251 252 cmr |= (tcbpwm->div & ATMEL_TC_TCCLKS); 253 254 __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR)); 255 256 if (index == 0) 257 __raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RA)); 258 else 259 __raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RB)); 260 261 __raw_writel(tcbpwm->period, regs + ATMEL_TC_REG(group, RC)); 262 263 /* Use software trigger to apply the new setting */ 264 __raw_writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG, 265 regs + ATMEL_TC_REG(group, CCR)); 266 spin_unlock(&tcbpwmc->lock); 267 return 0; 268 } 269 270 static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 271 int duty_ns, int period_ns) 272 { 273 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); 274 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); 275 unsigned group = pwm->hwpwm / 2; 276 unsigned index = pwm->hwpwm % 2; 277 struct atmel_tcb_pwm_device *atcbpwm = NULL; 278 struct atmel_tc *tc = tcbpwmc->tc; 279 int i; 280 int slowclk = 0; 281 unsigned period; 282 unsigned duty; 283 unsigned rate = clk_get_rate(tc->clk[group]); 284 unsigned long long min; 285 unsigned long long max; 286 287 /* 288 * Find best clk divisor: 289 * the smallest divisor which can fulfill the period_ns requirements. 290 */ 291 for (i = 0; i < 5; ++i) { 292 if (atmel_tc_divisors[i] == 0) { 293 slowclk = i; 294 continue; 295 } 296 min = div_u64((u64)NSEC_PER_SEC * atmel_tc_divisors[i], rate); 297 max = min << tc->tcb_config->counter_width; 298 if (max >= period_ns) 299 break; 300 } 301 302 /* 303 * If none of the divisor are small enough to represent period_ns 304 * take slow clock (32KHz). 305 */ 306 if (i == 5) { 307 i = slowclk; 308 rate = 32768; 309 min = div_u64(NSEC_PER_SEC, rate); 310 max = min << tc->tcb_config->counter_width; 311 312 /* If period is too big return ERANGE error */ 313 if (max < period_ns) 314 return -ERANGE; 315 } 316 317 duty = div_u64(duty_ns, min); 318 period = div_u64(period_ns, min); 319 320 if (index == 0) 321 atcbpwm = tcbpwmc->pwms[pwm->hwpwm + 1]; 322 else 323 atcbpwm = tcbpwmc->pwms[pwm->hwpwm - 1]; 324 325 /* 326 * PWM devices provided by TCB driver are grouped by 2: 327 * - group 0: PWM 0 & 1 328 * - group 1: PWM 2 & 3 329 * - group 2: PWM 4 & 5 330 * 331 * PWM devices in a given group must be configured with the 332 * same period_ns. 333 * 334 * We're checking the period value of the second PWM device 335 * in this group before applying the new config. 336 */ 337 if ((atcbpwm && atcbpwm->duty > 0 && 338 atcbpwm->duty != atcbpwm->period) && 339 (atcbpwm->div != i || atcbpwm->period != period)) { 340 dev_err(chip->dev, 341 "failed to configure period_ns: PWM group already configured with a different value\n"); 342 return -EINVAL; 343 } 344 345 tcbpwm->period = period; 346 tcbpwm->div = i; 347 tcbpwm->duty = duty; 348 349 /* If the PWM is enabled, call enable to apply the new conf */ 350 if (pwm_is_enabled(pwm)) 351 atmel_tcb_pwm_enable(chip, pwm); 352 353 return 0; 354 } 355 356 static const struct pwm_ops atmel_tcb_pwm_ops = { 357 .request = atmel_tcb_pwm_request, 358 .free = atmel_tcb_pwm_free, 359 .config = atmel_tcb_pwm_config, 360 .set_polarity = atmel_tcb_pwm_set_polarity, 361 .enable = atmel_tcb_pwm_enable, 362 .disable = atmel_tcb_pwm_disable, 363 .owner = THIS_MODULE, 364 }; 365 366 static int atmel_tcb_pwm_probe(struct platform_device *pdev) 367 { 368 struct atmel_tcb_pwm_chip *tcbpwm; 369 struct device_node *np = pdev->dev.of_node; 370 struct atmel_tc *tc; 371 int err; 372 int tcblock; 373 374 err = of_property_read_u32(np, "tc-block", &tcblock); 375 if (err < 0) { 376 dev_err(&pdev->dev, 377 "failed to get Timer Counter Block number from device tree (error: %d)\n", 378 err); 379 return err; 380 } 381 382 tc = atmel_tc_alloc(tcblock); 383 if (tc == NULL) { 384 dev_err(&pdev->dev, "failed to allocate Timer Counter Block\n"); 385 return -ENOMEM; 386 } 387 388 tcbpwm = devm_kzalloc(&pdev->dev, sizeof(*tcbpwm), GFP_KERNEL); 389 if (tcbpwm == NULL) { 390 atmel_tc_free(tc); 391 dev_err(&pdev->dev, "failed to allocate memory\n"); 392 return -ENOMEM; 393 } 394 395 tcbpwm->chip.dev = &pdev->dev; 396 tcbpwm->chip.ops = &atmel_tcb_pwm_ops; 397 tcbpwm->chip.of_xlate = of_pwm_xlate_with_flags; 398 tcbpwm->chip.of_pwm_n_cells = 3; 399 tcbpwm->chip.base = -1; 400 tcbpwm->chip.npwm = NPWM; 401 tcbpwm->tc = tc; 402 403 spin_lock_init(&tcbpwm->lock); 404 405 err = pwmchip_add(&tcbpwm->chip); 406 if (err < 0) { 407 atmel_tc_free(tc); 408 return err; 409 } 410 411 platform_set_drvdata(pdev, tcbpwm); 412 413 return 0; 414 } 415 416 static int atmel_tcb_pwm_remove(struct platform_device *pdev) 417 { 418 struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev); 419 int err; 420 421 err = pwmchip_remove(&tcbpwm->chip); 422 if (err < 0) 423 return err; 424 425 atmel_tc_free(tcbpwm->tc); 426 427 return 0; 428 } 429 430 static const struct of_device_id atmel_tcb_pwm_dt_ids[] = { 431 { .compatible = "atmel,tcb-pwm", }, 432 { /* sentinel */ } 433 }; 434 MODULE_DEVICE_TABLE(of, atmel_tcb_pwm_dt_ids); 435 436 static struct platform_driver atmel_tcb_pwm_driver = { 437 .driver = { 438 .name = "atmel-tcb-pwm", 439 .of_match_table = atmel_tcb_pwm_dt_ids, 440 }, 441 .probe = atmel_tcb_pwm_probe, 442 .remove = atmel_tcb_pwm_remove, 443 }; 444 module_platform_driver(atmel_tcb_pwm_driver); 445 446 MODULE_AUTHOR("Boris BREZILLON <b.brezillon@overkiz.com>"); 447 MODULE_DESCRIPTION("Atmel Timer Counter Pulse Width Modulation Driver"); 448 MODULE_LICENSE("GPL v2"); 449