1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * EHRPWM PWM driver 4 * 5 * Copyright (C) 2012 Texas Instruments, Inc. - https://www.ti.com/ 6 */ 7 8 #include <linux/module.h> 9 #include <linux/platform_device.h> 10 #include <linux/pwm.h> 11 #include <linux/io.h> 12 #include <linux/err.h> 13 #include <linux/clk.h> 14 #include <linux/pm_runtime.h> 15 #include <linux/of_device.h> 16 17 /* EHRPWM registers and bits definitions */ 18 19 /* Time base module registers */ 20 #define TBCTL 0x00 21 #define TBPRD 0x0A 22 23 #define TBCTL_PRDLD_MASK BIT(3) 24 #define TBCTL_PRDLD_SHDW 0 25 #define TBCTL_PRDLD_IMDT BIT(3) 26 #define TBCTL_CLKDIV_MASK (BIT(12) | BIT(11) | BIT(10) | BIT(9) | \ 27 BIT(8) | BIT(7)) 28 #define TBCTL_CTRMODE_MASK (BIT(1) | BIT(0)) 29 #define TBCTL_CTRMODE_UP 0 30 #define TBCTL_CTRMODE_DOWN BIT(0) 31 #define TBCTL_CTRMODE_UPDOWN BIT(1) 32 #define TBCTL_CTRMODE_FREEZE (BIT(1) | BIT(0)) 33 34 #define TBCTL_HSPCLKDIV_SHIFT 7 35 #define TBCTL_CLKDIV_SHIFT 10 36 37 #define CLKDIV_MAX 7 38 #define HSPCLKDIV_MAX 7 39 #define PERIOD_MAX 0xFFFF 40 41 /* compare module registers */ 42 #define CMPA 0x12 43 #define CMPB 0x14 44 45 /* Action qualifier module registers */ 46 #define AQCTLA 0x16 47 #define AQCTLB 0x18 48 #define AQSFRC 0x1A 49 #define AQCSFRC 0x1C 50 51 #define AQCTL_CBU_MASK (BIT(9) | BIT(8)) 52 #define AQCTL_CBU_FRCLOW BIT(8) 53 #define AQCTL_CBU_FRCHIGH BIT(9) 54 #define AQCTL_CBU_FRCTOGGLE (BIT(9) | BIT(8)) 55 #define AQCTL_CAU_MASK (BIT(5) | BIT(4)) 56 #define AQCTL_CAU_FRCLOW BIT(4) 57 #define AQCTL_CAU_FRCHIGH BIT(5) 58 #define AQCTL_CAU_FRCTOGGLE (BIT(5) | BIT(4)) 59 #define AQCTL_PRD_MASK (BIT(3) | BIT(2)) 60 #define AQCTL_PRD_FRCLOW BIT(2) 61 #define AQCTL_PRD_FRCHIGH BIT(3) 62 #define AQCTL_PRD_FRCTOGGLE (BIT(3) | BIT(2)) 63 #define AQCTL_ZRO_MASK (BIT(1) | BIT(0)) 64 #define AQCTL_ZRO_FRCLOW BIT(0) 65 #define AQCTL_ZRO_FRCHIGH BIT(1) 66 #define AQCTL_ZRO_FRCTOGGLE (BIT(1) | BIT(0)) 67 68 #define AQCTL_CHANA_POLNORMAL (AQCTL_CAU_FRCLOW | AQCTL_PRD_FRCHIGH | \ 69 AQCTL_ZRO_FRCHIGH) 70 #define AQCTL_CHANA_POLINVERSED (AQCTL_CAU_FRCHIGH | AQCTL_PRD_FRCLOW | \ 71 AQCTL_ZRO_FRCLOW) 72 #define AQCTL_CHANB_POLNORMAL (AQCTL_CBU_FRCLOW | AQCTL_PRD_FRCHIGH | \ 73 AQCTL_ZRO_FRCHIGH) 74 #define AQCTL_CHANB_POLINVERSED (AQCTL_CBU_FRCHIGH | AQCTL_PRD_FRCLOW | \ 75 AQCTL_ZRO_FRCLOW) 76 77 #define AQSFRC_RLDCSF_MASK (BIT(7) | BIT(6)) 78 #define AQSFRC_RLDCSF_ZRO 0 79 #define AQSFRC_RLDCSF_PRD BIT(6) 80 #define AQSFRC_RLDCSF_ZROPRD BIT(7) 81 #define AQSFRC_RLDCSF_IMDT (BIT(7) | BIT(6)) 82 83 #define AQCSFRC_CSFB_MASK (BIT(3) | BIT(2)) 84 #define AQCSFRC_CSFB_FRCDIS 0 85 #define AQCSFRC_CSFB_FRCLOW BIT(2) 86 #define AQCSFRC_CSFB_FRCHIGH BIT(3) 87 #define AQCSFRC_CSFB_DISSWFRC (BIT(3) | BIT(2)) 88 #define AQCSFRC_CSFA_MASK (BIT(1) | BIT(0)) 89 #define AQCSFRC_CSFA_FRCDIS 0 90 #define AQCSFRC_CSFA_FRCLOW BIT(0) 91 #define AQCSFRC_CSFA_FRCHIGH BIT(1) 92 #define AQCSFRC_CSFA_DISSWFRC (BIT(1) | BIT(0)) 93 94 #define NUM_PWM_CHANNEL 2 /* EHRPWM channels */ 95 96 struct ehrpwm_context { 97 u16 tbctl; 98 u16 tbprd; 99 u16 cmpa; 100 u16 cmpb; 101 u16 aqctla; 102 u16 aqctlb; 103 u16 aqsfrc; 104 u16 aqcsfrc; 105 }; 106 107 struct ehrpwm_pwm_chip { 108 struct pwm_chip chip; 109 unsigned long clk_rate; 110 void __iomem *mmio_base; 111 unsigned long period_cycles[NUM_PWM_CHANNEL]; 112 enum pwm_polarity polarity[NUM_PWM_CHANNEL]; 113 struct clk *tbclk; 114 struct ehrpwm_context ctx; 115 }; 116 117 static inline struct ehrpwm_pwm_chip *to_ehrpwm_pwm_chip(struct pwm_chip *chip) 118 { 119 return container_of(chip, struct ehrpwm_pwm_chip, chip); 120 } 121 122 static inline u16 ehrpwm_read(void __iomem *base, unsigned int offset) 123 { 124 return readw(base + offset); 125 } 126 127 static inline void ehrpwm_write(void __iomem *base, unsigned int offset, 128 u16 value) 129 { 130 writew(value, base + offset); 131 } 132 133 static void ehrpwm_modify(void __iomem *base, unsigned int offset, u16 mask, 134 u16 value) 135 { 136 unsigned short val; 137 138 val = readw(base + offset); 139 val &= ~mask; 140 val |= value & mask; 141 writew(val, base + offset); 142 } 143 144 /** 145 * set_prescale_div - Set up the prescaler divider function 146 * @rqst_prescaler: prescaler value min 147 * @prescale_div: prescaler value set 148 * @tb_clk_div: Time Base Control prescaler bits 149 */ 150 static int set_prescale_div(unsigned long rqst_prescaler, u16 *prescale_div, 151 u16 *tb_clk_div) 152 { 153 unsigned int clkdiv, hspclkdiv; 154 155 for (clkdiv = 0; clkdiv <= CLKDIV_MAX; clkdiv++) { 156 for (hspclkdiv = 0; hspclkdiv <= HSPCLKDIV_MAX; hspclkdiv++) { 157 /* 158 * calculations for prescaler value : 159 * prescale_div = HSPCLKDIVIDER * CLKDIVIDER. 160 * HSPCLKDIVIDER = 2 ** hspclkdiv 161 * CLKDIVIDER = (1), if clkdiv == 0 *OR* 162 * (2 * clkdiv), if clkdiv != 0 163 * 164 * Configure prescale_div value such that period 165 * register value is less than 65535. 166 */ 167 168 *prescale_div = (1 << clkdiv) * 169 (hspclkdiv ? (hspclkdiv * 2) : 1); 170 if (*prescale_div > rqst_prescaler) { 171 *tb_clk_div = (clkdiv << TBCTL_CLKDIV_SHIFT) | 172 (hspclkdiv << TBCTL_HSPCLKDIV_SHIFT); 173 return 0; 174 } 175 } 176 } 177 178 return 1; 179 } 180 181 static void configure_polarity(struct ehrpwm_pwm_chip *pc, int chan) 182 { 183 u16 aqctl_val, aqctl_mask; 184 unsigned int aqctl_reg; 185 186 /* 187 * Configure PWM output to HIGH/LOW level on counter 188 * reaches compare register value and LOW/HIGH level 189 * on counter value reaches period register value and 190 * zero value on counter 191 */ 192 if (chan == 1) { 193 aqctl_reg = AQCTLB; 194 aqctl_mask = AQCTL_CBU_MASK; 195 196 if (pc->polarity[chan] == PWM_POLARITY_INVERSED) 197 aqctl_val = AQCTL_CHANB_POLINVERSED; 198 else 199 aqctl_val = AQCTL_CHANB_POLNORMAL; 200 } else { 201 aqctl_reg = AQCTLA; 202 aqctl_mask = AQCTL_CAU_MASK; 203 204 if (pc->polarity[chan] == PWM_POLARITY_INVERSED) 205 aqctl_val = AQCTL_CHANA_POLINVERSED; 206 else 207 aqctl_val = AQCTL_CHANA_POLNORMAL; 208 } 209 210 aqctl_mask |= AQCTL_PRD_MASK | AQCTL_ZRO_MASK; 211 ehrpwm_modify(pc->mmio_base, aqctl_reg, aqctl_mask, aqctl_val); 212 } 213 214 /* 215 * period_ns = 10^9 * (ps_divval * period_cycles) / PWM_CLK_RATE 216 * duty_ns = 10^9 * (ps_divval * duty_cycles) / PWM_CLK_RATE 217 */ 218 static int ehrpwm_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, 219 int duty_ns, int period_ns) 220 { 221 struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip); 222 u32 period_cycles, duty_cycles; 223 u16 ps_divval, tb_divval; 224 unsigned int i, cmp_reg; 225 unsigned long long c; 226 227 if (period_ns > NSEC_PER_SEC) 228 return -ERANGE; 229 230 c = pc->clk_rate; 231 c = c * period_ns; 232 do_div(c, NSEC_PER_SEC); 233 period_cycles = (unsigned long)c; 234 235 if (period_cycles < 1) { 236 period_cycles = 1; 237 duty_cycles = 1; 238 } else { 239 c = pc->clk_rate; 240 c = c * duty_ns; 241 do_div(c, NSEC_PER_SEC); 242 duty_cycles = (unsigned long)c; 243 } 244 245 /* 246 * Period values should be same for multiple PWM channels as IP uses 247 * same period register for multiple channels. 248 */ 249 for (i = 0; i < NUM_PWM_CHANNEL; i++) { 250 if (pc->period_cycles[i] && 251 (pc->period_cycles[i] != period_cycles)) { 252 /* 253 * Allow channel to reconfigure period if no other 254 * channels being configured. 255 */ 256 if (i == pwm->hwpwm) 257 continue; 258 259 dev_err(chip->dev, 260 "period value conflicts with channel %u\n", 261 i); 262 return -EINVAL; 263 } 264 } 265 266 pc->period_cycles[pwm->hwpwm] = period_cycles; 267 268 /* Configure clock prescaler to support Low frequency PWM wave */ 269 if (set_prescale_div(period_cycles/PERIOD_MAX, &ps_divval, 270 &tb_divval)) { 271 dev_err(chip->dev, "Unsupported values\n"); 272 return -EINVAL; 273 } 274 275 pm_runtime_get_sync(chip->dev); 276 277 /* Update clock prescaler values */ 278 ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CLKDIV_MASK, tb_divval); 279 280 /* Update period & duty cycle with presacler division */ 281 period_cycles = period_cycles / ps_divval; 282 duty_cycles = duty_cycles / ps_divval; 283 284 /* Configure shadow loading on Period register */ 285 ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_PRDLD_MASK, TBCTL_PRDLD_SHDW); 286 287 ehrpwm_write(pc->mmio_base, TBPRD, period_cycles); 288 289 /* Configure ehrpwm counter for up-count mode */ 290 ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CTRMODE_MASK, 291 TBCTL_CTRMODE_UP); 292 293 if (pwm->hwpwm == 1) 294 /* Channel 1 configured with compare B register */ 295 cmp_reg = CMPB; 296 else 297 /* Channel 0 configured with compare A register */ 298 cmp_reg = CMPA; 299 300 ehrpwm_write(pc->mmio_base, cmp_reg, duty_cycles); 301 302 pm_runtime_put_sync(chip->dev); 303 304 return 0; 305 } 306 307 static int ehrpwm_pwm_set_polarity(struct pwm_chip *chip, 308 struct pwm_device *pwm, 309 enum pwm_polarity polarity) 310 { 311 struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip); 312 313 /* Configuration of polarity in hardware delayed, do at enable */ 314 pc->polarity[pwm->hwpwm] = polarity; 315 316 return 0; 317 } 318 319 static int ehrpwm_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 320 { 321 struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip); 322 u16 aqcsfrc_val, aqcsfrc_mask; 323 int ret; 324 325 /* Leave clock enabled on enabling PWM */ 326 pm_runtime_get_sync(chip->dev); 327 328 /* Disabling Action Qualifier on PWM output */ 329 if (pwm->hwpwm) { 330 aqcsfrc_val = AQCSFRC_CSFB_FRCDIS; 331 aqcsfrc_mask = AQCSFRC_CSFB_MASK; 332 } else { 333 aqcsfrc_val = AQCSFRC_CSFA_FRCDIS; 334 aqcsfrc_mask = AQCSFRC_CSFA_MASK; 335 } 336 337 /* Changes to shadow mode */ 338 ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK, 339 AQSFRC_RLDCSF_ZRO); 340 341 ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val); 342 343 /* Channels polarity can be configured from action qualifier module */ 344 configure_polarity(pc, pwm->hwpwm); 345 346 /* Enable TBCLK */ 347 ret = clk_enable(pc->tbclk); 348 if (ret) { 349 dev_err(chip->dev, "Failed to enable TBCLK for %s: %d\n", 350 dev_name(pc->chip.dev), ret); 351 return ret; 352 } 353 354 return 0; 355 } 356 357 static void ehrpwm_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) 358 { 359 struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip); 360 u16 aqcsfrc_val, aqcsfrc_mask; 361 362 /* Action Qualifier puts PWM output low forcefully */ 363 if (pwm->hwpwm) { 364 aqcsfrc_val = AQCSFRC_CSFB_FRCLOW; 365 aqcsfrc_mask = AQCSFRC_CSFB_MASK; 366 } else { 367 aqcsfrc_val = AQCSFRC_CSFA_FRCLOW; 368 aqcsfrc_mask = AQCSFRC_CSFA_MASK; 369 } 370 371 /* Update shadow register first before modifying active register */ 372 ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK, 373 AQSFRC_RLDCSF_ZRO); 374 ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val); 375 /* 376 * Changes to immediate action on Action Qualifier. This puts 377 * Action Qualifier control on PWM output from next TBCLK 378 */ 379 ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK, 380 AQSFRC_RLDCSF_IMDT); 381 382 ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val); 383 384 /* Disabling TBCLK on PWM disable */ 385 clk_disable(pc->tbclk); 386 387 /* Disable clock on PWM disable */ 388 pm_runtime_put_sync(chip->dev); 389 } 390 391 static void ehrpwm_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) 392 { 393 struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip); 394 395 if (pwm_is_enabled(pwm)) { 396 dev_warn(chip->dev, "Removing PWM device without disabling\n"); 397 pm_runtime_put_sync(chip->dev); 398 } 399 400 /* set period value to zero on free */ 401 pc->period_cycles[pwm->hwpwm] = 0; 402 } 403 404 static const struct pwm_ops ehrpwm_pwm_ops = { 405 .free = ehrpwm_pwm_free, 406 .config = ehrpwm_pwm_config, 407 .set_polarity = ehrpwm_pwm_set_polarity, 408 .enable = ehrpwm_pwm_enable, 409 .disable = ehrpwm_pwm_disable, 410 .owner = THIS_MODULE, 411 }; 412 413 static const struct of_device_id ehrpwm_of_match[] = { 414 { .compatible = "ti,am3352-ehrpwm" }, 415 { .compatible = "ti,am33xx-ehrpwm" }, 416 {}, 417 }; 418 MODULE_DEVICE_TABLE(of, ehrpwm_of_match); 419 420 static int ehrpwm_pwm_probe(struct platform_device *pdev) 421 { 422 struct device_node *np = pdev->dev.of_node; 423 struct ehrpwm_pwm_chip *pc; 424 struct clk *clk; 425 int ret; 426 427 pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL); 428 if (!pc) 429 return -ENOMEM; 430 431 clk = devm_clk_get(&pdev->dev, "fck"); 432 if (IS_ERR(clk)) { 433 if (of_device_is_compatible(np, "ti,am33xx-ecap")) { 434 dev_warn(&pdev->dev, "Binding is obsolete.\n"); 435 clk = devm_clk_get(pdev->dev.parent, "fck"); 436 } 437 } 438 439 if (IS_ERR(clk)) 440 return dev_err_probe(&pdev->dev, PTR_ERR(clk), "Failed to get fck\n"); 441 442 pc->clk_rate = clk_get_rate(clk); 443 if (!pc->clk_rate) { 444 dev_err(&pdev->dev, "failed to get clock rate\n"); 445 return -EINVAL; 446 } 447 448 pc->chip.dev = &pdev->dev; 449 pc->chip.ops = &ehrpwm_pwm_ops; 450 pc->chip.npwm = NUM_PWM_CHANNEL; 451 452 pc->mmio_base = devm_platform_ioremap_resource(pdev, 0); 453 if (IS_ERR(pc->mmio_base)) 454 return PTR_ERR(pc->mmio_base); 455 456 /* Acquire tbclk for Time Base EHRPWM submodule */ 457 pc->tbclk = devm_clk_get(&pdev->dev, "tbclk"); 458 if (IS_ERR(pc->tbclk)) 459 return dev_err_probe(&pdev->dev, PTR_ERR(pc->tbclk), "Failed to get tbclk\n"); 460 461 ret = clk_prepare(pc->tbclk); 462 if (ret < 0) { 463 dev_err(&pdev->dev, "clk_prepare() failed: %d\n", ret); 464 return ret; 465 } 466 467 ret = pwmchip_add(&pc->chip); 468 if (ret < 0) { 469 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); 470 goto err_clk_unprepare; 471 } 472 473 platform_set_drvdata(pdev, pc); 474 pm_runtime_enable(&pdev->dev); 475 476 return 0; 477 478 err_clk_unprepare: 479 clk_unprepare(pc->tbclk); 480 481 return ret; 482 } 483 484 static int ehrpwm_pwm_remove(struct platform_device *pdev) 485 { 486 struct ehrpwm_pwm_chip *pc = platform_get_drvdata(pdev); 487 488 pwmchip_remove(&pc->chip); 489 490 clk_unprepare(pc->tbclk); 491 492 pm_runtime_disable(&pdev->dev); 493 494 return 0; 495 } 496 497 #ifdef CONFIG_PM_SLEEP 498 static void ehrpwm_pwm_save_context(struct ehrpwm_pwm_chip *pc) 499 { 500 pm_runtime_get_sync(pc->chip.dev); 501 502 pc->ctx.tbctl = ehrpwm_read(pc->mmio_base, TBCTL); 503 pc->ctx.tbprd = ehrpwm_read(pc->mmio_base, TBPRD); 504 pc->ctx.cmpa = ehrpwm_read(pc->mmio_base, CMPA); 505 pc->ctx.cmpb = ehrpwm_read(pc->mmio_base, CMPB); 506 pc->ctx.aqctla = ehrpwm_read(pc->mmio_base, AQCTLA); 507 pc->ctx.aqctlb = ehrpwm_read(pc->mmio_base, AQCTLB); 508 pc->ctx.aqsfrc = ehrpwm_read(pc->mmio_base, AQSFRC); 509 pc->ctx.aqcsfrc = ehrpwm_read(pc->mmio_base, AQCSFRC); 510 511 pm_runtime_put_sync(pc->chip.dev); 512 } 513 514 static void ehrpwm_pwm_restore_context(struct ehrpwm_pwm_chip *pc) 515 { 516 ehrpwm_write(pc->mmio_base, TBPRD, pc->ctx.tbprd); 517 ehrpwm_write(pc->mmio_base, CMPA, pc->ctx.cmpa); 518 ehrpwm_write(pc->mmio_base, CMPB, pc->ctx.cmpb); 519 ehrpwm_write(pc->mmio_base, AQCTLA, pc->ctx.aqctla); 520 ehrpwm_write(pc->mmio_base, AQCTLB, pc->ctx.aqctlb); 521 ehrpwm_write(pc->mmio_base, AQSFRC, pc->ctx.aqsfrc); 522 ehrpwm_write(pc->mmio_base, AQCSFRC, pc->ctx.aqcsfrc); 523 ehrpwm_write(pc->mmio_base, TBCTL, pc->ctx.tbctl); 524 } 525 526 static int ehrpwm_pwm_suspend(struct device *dev) 527 { 528 struct ehrpwm_pwm_chip *pc = dev_get_drvdata(dev); 529 unsigned int i; 530 531 ehrpwm_pwm_save_context(pc); 532 533 for (i = 0; i < pc->chip.npwm; i++) { 534 struct pwm_device *pwm = &pc->chip.pwms[i]; 535 536 if (!pwm_is_enabled(pwm)) 537 continue; 538 539 /* Disable explicitly if PWM is running */ 540 pm_runtime_put_sync(dev); 541 } 542 543 return 0; 544 } 545 546 static int ehrpwm_pwm_resume(struct device *dev) 547 { 548 struct ehrpwm_pwm_chip *pc = dev_get_drvdata(dev); 549 unsigned int i; 550 551 for (i = 0; i < pc->chip.npwm; i++) { 552 struct pwm_device *pwm = &pc->chip.pwms[i]; 553 554 if (!pwm_is_enabled(pwm)) 555 continue; 556 557 /* Enable explicitly if PWM was running */ 558 pm_runtime_get_sync(dev); 559 } 560 561 ehrpwm_pwm_restore_context(pc); 562 563 return 0; 564 } 565 #endif 566 567 static SIMPLE_DEV_PM_OPS(ehrpwm_pwm_pm_ops, ehrpwm_pwm_suspend, 568 ehrpwm_pwm_resume); 569 570 static struct platform_driver ehrpwm_pwm_driver = { 571 .driver = { 572 .name = "ehrpwm", 573 .of_match_table = ehrpwm_of_match, 574 .pm = &ehrpwm_pwm_pm_ops, 575 }, 576 .probe = ehrpwm_pwm_probe, 577 .remove = ehrpwm_pwm_remove, 578 }; 579 module_platform_driver(ehrpwm_pwm_driver); 580 581 MODULE_DESCRIPTION("EHRPWM PWM driver"); 582 MODULE_AUTHOR("Texas Instruments"); 583 MODULE_LICENSE("GPL"); 584