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 __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR)); 253 254 if (index == 0) 255 __raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RA)); 256 else 257 __raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RB)); 258 259 __raw_writel(tcbpwm->period, regs + ATMEL_TC_REG(group, RC)); 260 261 /* Use software trigger to apply the new setting */ 262 __raw_writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG, 263 regs + ATMEL_TC_REG(group, CCR)); 264 spin_unlock(&tcbpwmc->lock); 265 return 0; 266 } 267 268 static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 269 int duty_ns, int period_ns) 270 { 271 struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip); 272 struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm); 273 unsigned group = pwm->hwpwm / 2; 274 unsigned index = pwm->hwpwm % 2; 275 struct atmel_tcb_pwm_device *atcbpwm = NULL; 276 struct atmel_tc *tc = tcbpwmc->tc; 277 int i; 278 int slowclk = 0; 279 unsigned period; 280 unsigned duty; 281 unsigned rate = clk_get_rate(tc->clk[group]); 282 unsigned long long min; 283 unsigned long long max; 284 285 /* 286 * Find best clk divisor: 287 * the smallest divisor which can fulfill the period_ns requirements. 288 */ 289 for (i = 0; i < 5; ++i) { 290 if (atmel_tc_divisors[i] == 0) { 291 slowclk = i; 292 continue; 293 } 294 min = div_u64((u64)NSEC_PER_SEC * atmel_tc_divisors[i], rate); 295 max = min << tc->tcb_config->counter_width; 296 if (max >= period_ns) 297 break; 298 } 299 300 /* 301 * If none of the divisor are small enough to represent period_ns 302 * take slow clock (32KHz). 303 */ 304 if (i == 5) { 305 i = slowclk; 306 rate = 32768; 307 min = div_u64(NSEC_PER_SEC, rate); 308 max = min << 16; 309 310 /* If period is too big return ERANGE error */ 311 if (max < period_ns) 312 return -ERANGE; 313 } 314 315 duty = div_u64(duty_ns, min); 316 period = div_u64(period_ns, min); 317 318 if (index == 0) 319 atcbpwm = tcbpwmc->pwms[pwm->hwpwm + 1]; 320 else 321 atcbpwm = tcbpwmc->pwms[pwm->hwpwm - 1]; 322 323 /* 324 * PWM devices provided by TCB driver are grouped by 2: 325 * - group 0: PWM 0 & 1 326 * - group 1: PWM 2 & 3 327 * - group 2: PWM 4 & 5 328 * 329 * PWM devices in a given group must be configured with the 330 * same period_ns. 331 * 332 * We're checking the period value of the second PWM device 333 * in this group before applying the new config. 334 */ 335 if ((atcbpwm && atcbpwm->duty > 0 && 336 atcbpwm->duty != atcbpwm->period) && 337 (atcbpwm->div != i || atcbpwm->period != period)) { 338 dev_err(chip->dev, 339 "failed to configure period_ns: PWM group already configured with a different value\n"); 340 return -EINVAL; 341 } 342 343 tcbpwm->period = period; 344 tcbpwm->div = i; 345 tcbpwm->duty = duty; 346 347 /* If the PWM is enabled, call enable to apply the new conf */ 348 if (test_bit(PWMF_ENABLED, &pwm->flags)) 349 atmel_tcb_pwm_enable(chip, pwm); 350 351 return 0; 352 } 353 354 static const struct pwm_ops atmel_tcb_pwm_ops = { 355 .request = atmel_tcb_pwm_request, 356 .free = atmel_tcb_pwm_free, 357 .config = atmel_tcb_pwm_config, 358 .set_polarity = atmel_tcb_pwm_set_polarity, 359 .enable = atmel_tcb_pwm_enable, 360 .disable = atmel_tcb_pwm_disable, 361 .owner = THIS_MODULE, 362 }; 363 364 static int atmel_tcb_pwm_probe(struct platform_device *pdev) 365 { 366 struct atmel_tcb_pwm_chip *tcbpwm; 367 struct device_node *np = pdev->dev.of_node; 368 struct atmel_tc *tc; 369 int err; 370 int tcblock; 371 372 err = of_property_read_u32(np, "tc-block", &tcblock); 373 if (err < 0) { 374 dev_err(&pdev->dev, 375 "failed to get Timer Counter Block number from device tree (error: %d)\n", 376 err); 377 return err; 378 } 379 380 tc = atmel_tc_alloc(tcblock, "tcb-pwm"); 381 if (tc == NULL) { 382 dev_err(&pdev->dev, "failed to allocate Timer Counter Block\n"); 383 return -ENOMEM; 384 } 385 386 tcbpwm = devm_kzalloc(&pdev->dev, sizeof(*tcbpwm), GFP_KERNEL); 387 if (tcbpwm == NULL) { 388 atmel_tc_free(tc); 389 dev_err(&pdev->dev, "failed to allocate memory\n"); 390 return -ENOMEM; 391 } 392 393 tcbpwm->chip.dev = &pdev->dev; 394 tcbpwm->chip.ops = &atmel_tcb_pwm_ops; 395 tcbpwm->chip.of_xlate = of_pwm_xlate_with_flags; 396 tcbpwm->chip.of_pwm_n_cells = 3; 397 tcbpwm->chip.base = -1; 398 tcbpwm->chip.npwm = NPWM; 399 tcbpwm->tc = tc; 400 401 spin_lock_init(&tcbpwm->lock); 402 403 err = pwmchip_add(&tcbpwm->chip); 404 if (err < 0) { 405 atmel_tc_free(tc); 406 return err; 407 } 408 409 platform_set_drvdata(pdev, tcbpwm); 410 411 return 0; 412 } 413 414 static int atmel_tcb_pwm_remove(struct platform_device *pdev) 415 { 416 struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev); 417 int err; 418 419 err = pwmchip_remove(&tcbpwm->chip); 420 if (err < 0) 421 return err; 422 423 atmel_tc_free(tcbpwm->tc); 424 425 return 0; 426 } 427 428 static const struct of_device_id atmel_tcb_pwm_dt_ids[] = { 429 { .compatible = "atmel,tcb-pwm", }, 430 { /* sentinel */ } 431 }; 432 MODULE_DEVICE_TABLE(of, atmel_tcb_pwm_dt_ids); 433 434 static struct platform_driver atmel_tcb_pwm_driver = { 435 .driver = { 436 .name = "atmel-tcb-pwm", 437 .owner = THIS_MODULE, 438 .of_match_table = atmel_tcb_pwm_dt_ids, 439 }, 440 .probe = atmel_tcb_pwm_probe, 441 .remove = atmel_tcb_pwm_remove, 442 }; 443 module_platform_driver(atmel_tcb_pwm_driver); 444 445 MODULE_AUTHOR("Boris BREZILLON <b.brezillon@overkiz.com>"); 446 MODULE_DESCRIPTION("Atmel Timer Counter Pulse Width Modulation Driver"); 447 MODULE_LICENSE("GPL v2"); 448