1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause 2 /* 3 * PWM controller driver for Amlogic Meson SoCs. 4 * 5 * This PWM is only a set of Gates, Dividers and Counters: 6 * PWM output is achieved by calculating a clock that permits calculating 7 * two periods (low and high). The counter then has to be set to switch after 8 * N cycles for the first half period. 9 * The hardware has no "polarity" setting. This driver reverses the period 10 * cycles (the low length is inverted with the high length) for 11 * PWM_POLARITY_INVERSED. This means that .get_state cannot read the polarity 12 * from the hardware. 13 * Setting the duty cycle will disable and re-enable the PWM output. 14 * Disabling the PWM stops the output immediately (without waiting for the 15 * current period to complete first). 16 * 17 * The public S912 (GXM) datasheet contains some documentation for this PWM 18 * controller starting on page 543: 19 * https://dl.khadas.com/Hardware/VIM2/Datasheet/S912_Datasheet_V0.220170314publicversion-Wesion.pdf 20 * An updated version of this IP block is found in S922X (G12B) SoCs. The 21 * datasheet contains the description for this IP block revision starting at 22 * page 1084: 23 * https://dn.odroid.com/S922X/ODROID-N2/Datasheet/S922X_Public_Datasheet_V0.2.pdf 24 * 25 * Copyright (c) 2016 BayLibre, SAS. 26 * Author: Neil Armstrong <narmstrong@baylibre.com> 27 * Copyright (C) 2014 Amlogic, Inc. 28 */ 29 30 #include <linux/bitfield.h> 31 #include <linux/bits.h> 32 #include <linux/clk.h> 33 #include <linux/clk-provider.h> 34 #include <linux/err.h> 35 #include <linux/io.h> 36 #include <linux/kernel.h> 37 #include <linux/math64.h> 38 #include <linux/module.h> 39 #include <linux/of.h> 40 #include <linux/platform_device.h> 41 #include <linux/pwm.h> 42 #include <linux/slab.h> 43 #include <linux/spinlock.h> 44 45 #define REG_PWM_A 0x0 46 #define REG_PWM_B 0x4 47 #define PWM_LOW_MASK GENMASK(15, 0) 48 #define PWM_HIGH_MASK GENMASK(31, 16) 49 50 #define REG_MISC_AB 0x8 51 #define MISC_B_CLK_EN_SHIFT 23 52 #define MISC_A_CLK_EN_SHIFT 15 53 #define MISC_CLK_DIV_WIDTH 7 54 #define MISC_B_CLK_DIV_SHIFT 16 55 #define MISC_A_CLK_DIV_SHIFT 8 56 #define MISC_B_CLK_SEL_SHIFT 6 57 #define MISC_A_CLK_SEL_SHIFT 4 58 #define MISC_CLK_SEL_MASK 0x3 59 #define MISC_B_EN BIT(1) 60 #define MISC_A_EN BIT(0) 61 62 #define MESON_NUM_PWMS 2 63 #define MESON_MAX_MUX_PARENTS 4 64 65 static struct meson_pwm_channel_data { 66 u8 reg_offset; 67 u8 clk_sel_shift; 68 u8 clk_div_shift; 69 u8 clk_en_shift; 70 u32 pwm_en_mask; 71 } meson_pwm_per_channel_data[MESON_NUM_PWMS] = { 72 { 73 .reg_offset = REG_PWM_A, 74 .clk_sel_shift = MISC_A_CLK_SEL_SHIFT, 75 .clk_div_shift = MISC_A_CLK_DIV_SHIFT, 76 .clk_en_shift = MISC_A_CLK_EN_SHIFT, 77 .pwm_en_mask = MISC_A_EN, 78 }, 79 { 80 .reg_offset = REG_PWM_B, 81 .clk_sel_shift = MISC_B_CLK_SEL_SHIFT, 82 .clk_div_shift = MISC_B_CLK_DIV_SHIFT, 83 .clk_en_shift = MISC_B_CLK_EN_SHIFT, 84 .pwm_en_mask = MISC_B_EN, 85 } 86 }; 87 88 struct meson_pwm_channel { 89 unsigned long rate; 90 unsigned int hi; 91 unsigned int lo; 92 93 struct clk_mux mux; 94 struct clk_divider div; 95 struct clk_gate gate; 96 struct clk *clk; 97 }; 98 99 struct meson_pwm_data { 100 const char * const *parent_names; 101 unsigned int num_parents; 102 }; 103 104 struct meson_pwm { 105 struct pwm_chip chip; 106 const struct meson_pwm_data *data; 107 struct meson_pwm_channel channels[MESON_NUM_PWMS]; 108 void __iomem *base; 109 /* 110 * Protects register (write) access to the REG_MISC_AB register 111 * that is shared between the two PWMs. 112 */ 113 spinlock_t lock; 114 }; 115 116 static inline struct meson_pwm *to_meson_pwm(struct pwm_chip *chip) 117 { 118 return container_of(chip, struct meson_pwm, chip); 119 } 120 121 static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) 122 { 123 struct meson_pwm *meson = to_meson_pwm(chip); 124 struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm]; 125 struct device *dev = chip->dev; 126 int err; 127 128 err = clk_prepare_enable(channel->clk); 129 if (err < 0) { 130 dev_err(dev, "failed to enable clock %s: %d\n", 131 __clk_get_name(channel->clk), err); 132 return err; 133 } 134 135 return 0; 136 } 137 138 static void meson_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) 139 { 140 struct meson_pwm *meson = to_meson_pwm(chip); 141 struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm]; 142 143 clk_disable_unprepare(channel->clk); 144 } 145 146 static int meson_pwm_calc(struct meson_pwm *meson, struct pwm_device *pwm, 147 const struct pwm_state *state) 148 { 149 struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm]; 150 unsigned int cnt, duty_cnt; 151 unsigned long fin_freq; 152 u64 duty, period, freq; 153 154 duty = state->duty_cycle; 155 period = state->period; 156 157 /* 158 * Note this is wrong. The result is an output wave that isn't really 159 * inverted and so is wrongly identified by .get_state as normal. 160 * Fixing this needs some care however as some machines might rely on 161 * this. 162 */ 163 if (state->polarity == PWM_POLARITY_INVERSED) 164 duty = period - duty; 165 166 freq = div64_u64(NSEC_PER_SEC * 0xffffULL, period); 167 if (freq > ULONG_MAX) 168 freq = ULONG_MAX; 169 170 fin_freq = clk_round_rate(channel->clk, freq); 171 if (fin_freq == 0) { 172 dev_err(meson->chip.dev, "invalid source clock frequency\n"); 173 return -EINVAL; 174 } 175 176 dev_dbg(meson->chip.dev, "fin_freq: %lu Hz\n", fin_freq); 177 178 cnt = div_u64(fin_freq * period, NSEC_PER_SEC); 179 if (cnt > 0xffff) { 180 dev_err(meson->chip.dev, "unable to get period cnt\n"); 181 return -EINVAL; 182 } 183 184 dev_dbg(meson->chip.dev, "period=%llu cnt=%u\n", period, cnt); 185 186 if (duty == period) { 187 channel->hi = cnt; 188 channel->lo = 0; 189 } else if (duty == 0) { 190 channel->hi = 0; 191 channel->lo = cnt; 192 } else { 193 duty_cnt = div_u64(fin_freq * duty, NSEC_PER_SEC); 194 195 dev_dbg(meson->chip.dev, "duty=%llu duty_cnt=%u\n", duty, duty_cnt); 196 197 channel->hi = duty_cnt; 198 channel->lo = cnt - duty_cnt; 199 } 200 201 channel->rate = fin_freq; 202 203 return 0; 204 } 205 206 static void meson_pwm_enable(struct meson_pwm *meson, struct pwm_device *pwm) 207 { 208 struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm]; 209 struct meson_pwm_channel_data *channel_data; 210 unsigned long flags; 211 u32 value; 212 int err; 213 214 channel_data = &meson_pwm_per_channel_data[pwm->hwpwm]; 215 216 err = clk_set_rate(channel->clk, channel->rate); 217 if (err) 218 dev_err(meson->chip.dev, "setting clock rate failed\n"); 219 220 spin_lock_irqsave(&meson->lock, flags); 221 222 value = FIELD_PREP(PWM_HIGH_MASK, channel->hi) | 223 FIELD_PREP(PWM_LOW_MASK, channel->lo); 224 writel(value, meson->base + channel_data->reg_offset); 225 226 value = readl(meson->base + REG_MISC_AB); 227 value |= channel_data->pwm_en_mask; 228 writel(value, meson->base + REG_MISC_AB); 229 230 spin_unlock_irqrestore(&meson->lock, flags); 231 } 232 233 static void meson_pwm_disable(struct meson_pwm *meson, struct pwm_device *pwm) 234 { 235 unsigned long flags; 236 u32 value; 237 238 spin_lock_irqsave(&meson->lock, flags); 239 240 value = readl(meson->base + REG_MISC_AB); 241 value &= ~meson_pwm_per_channel_data[pwm->hwpwm].pwm_en_mask; 242 writel(value, meson->base + REG_MISC_AB); 243 244 spin_unlock_irqrestore(&meson->lock, flags); 245 } 246 247 static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, 248 const struct pwm_state *state) 249 { 250 struct meson_pwm *meson = to_meson_pwm(chip); 251 struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm]; 252 int err = 0; 253 254 if (!state->enabled) { 255 if (state->polarity == PWM_POLARITY_INVERSED) { 256 /* 257 * This IP block revision doesn't have an "always high" 258 * setting which we can use for "inverted disabled". 259 * Instead we achieve this by setting mux parent with 260 * highest rate and minimum divider value, resulting 261 * in the shortest possible duration for one "count" 262 * and "period == duty_cycle". This results in a signal 263 * which is LOW for one "count", while being HIGH for 264 * the rest of the (so the signal is HIGH for slightly 265 * less than 100% of the period, but this is the best 266 * we can achieve). 267 */ 268 channel->rate = ULONG_MAX; 269 channel->hi = ~0; 270 channel->lo = 0; 271 272 meson_pwm_enable(meson, pwm); 273 } else { 274 meson_pwm_disable(meson, pwm); 275 } 276 } else { 277 err = meson_pwm_calc(meson, pwm, state); 278 if (err < 0) 279 return err; 280 281 meson_pwm_enable(meson, pwm); 282 } 283 284 return 0; 285 } 286 287 static u64 meson_pwm_cnt_to_ns(struct pwm_chip *chip, struct pwm_device *pwm, 288 u32 cnt) 289 { 290 struct meson_pwm *meson = to_meson_pwm(chip); 291 struct meson_pwm_channel *channel; 292 unsigned long fin_freq; 293 294 /* to_meson_pwm() can only be used after .get_state() is called */ 295 channel = &meson->channels[pwm->hwpwm]; 296 297 fin_freq = clk_get_rate(channel->clk); 298 if (fin_freq == 0) 299 return 0; 300 301 return div64_ul(NSEC_PER_SEC * (u64)cnt, fin_freq); 302 } 303 304 static int meson_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, 305 struct pwm_state *state) 306 { 307 struct meson_pwm *meson = to_meson_pwm(chip); 308 struct meson_pwm_channel_data *channel_data; 309 struct meson_pwm_channel *channel; 310 u32 value; 311 312 if (!state) 313 return 0; 314 315 channel = &meson->channels[pwm->hwpwm]; 316 channel_data = &meson_pwm_per_channel_data[pwm->hwpwm]; 317 318 value = readl(meson->base + REG_MISC_AB); 319 state->enabled = value & channel_data->pwm_en_mask; 320 321 value = readl(meson->base + channel_data->reg_offset); 322 channel->lo = FIELD_GET(PWM_LOW_MASK, value); 323 channel->hi = FIELD_GET(PWM_HIGH_MASK, value); 324 325 state->period = meson_pwm_cnt_to_ns(chip, pwm, channel->lo + channel->hi); 326 state->duty_cycle = meson_pwm_cnt_to_ns(chip, pwm, channel->hi); 327 328 state->polarity = PWM_POLARITY_NORMAL; 329 330 return 0; 331 } 332 333 static const struct pwm_ops meson_pwm_ops = { 334 .request = meson_pwm_request, 335 .free = meson_pwm_free, 336 .apply = meson_pwm_apply, 337 .get_state = meson_pwm_get_state, 338 }; 339 340 static const char * const pwm_meson8b_parent_names[] = { 341 "xtal", NULL, "fclk_div4", "fclk_div3" 342 }; 343 344 static const struct meson_pwm_data pwm_meson8b_data = { 345 .parent_names = pwm_meson8b_parent_names, 346 .num_parents = ARRAY_SIZE(pwm_meson8b_parent_names), 347 }; 348 349 /* 350 * Only the 2 first inputs of the GXBB AO PWMs are valid 351 * The last 2 are grounded 352 */ 353 static const char * const pwm_gxbb_ao_parent_names[] = { 354 "xtal", "clk81" 355 }; 356 357 static const struct meson_pwm_data pwm_gxbb_ao_data = { 358 .parent_names = pwm_gxbb_ao_parent_names, 359 .num_parents = ARRAY_SIZE(pwm_gxbb_ao_parent_names), 360 }; 361 362 static const char * const pwm_axg_ee_parent_names[] = { 363 "xtal", "fclk_div5", "fclk_div4", "fclk_div3" 364 }; 365 366 static const struct meson_pwm_data pwm_axg_ee_data = { 367 .parent_names = pwm_axg_ee_parent_names, 368 .num_parents = ARRAY_SIZE(pwm_axg_ee_parent_names), 369 }; 370 371 static const char * const pwm_axg_ao_parent_names[] = { 372 "xtal", "axg_ao_clk81", "fclk_div4", "fclk_div5" 373 }; 374 375 static const struct meson_pwm_data pwm_axg_ao_data = { 376 .parent_names = pwm_axg_ao_parent_names, 377 .num_parents = ARRAY_SIZE(pwm_axg_ao_parent_names), 378 }; 379 380 static const char * const pwm_g12a_ao_ab_parent_names[] = { 381 "xtal", "g12a_ao_clk81", "fclk_div4", "fclk_div5" 382 }; 383 384 static const struct meson_pwm_data pwm_g12a_ao_ab_data = { 385 .parent_names = pwm_g12a_ao_ab_parent_names, 386 .num_parents = ARRAY_SIZE(pwm_g12a_ao_ab_parent_names), 387 }; 388 389 static const char * const pwm_g12a_ao_cd_parent_names[] = { 390 "xtal", "g12a_ao_clk81", 391 }; 392 393 static const struct meson_pwm_data pwm_g12a_ao_cd_data = { 394 .parent_names = pwm_g12a_ao_cd_parent_names, 395 .num_parents = ARRAY_SIZE(pwm_g12a_ao_cd_parent_names), 396 }; 397 398 static const struct of_device_id meson_pwm_matches[] = { 399 { 400 .compatible = "amlogic,meson8b-pwm", 401 .data = &pwm_meson8b_data 402 }, 403 { 404 .compatible = "amlogic,meson-gxbb-pwm", 405 .data = &pwm_meson8b_data 406 }, 407 { 408 .compatible = "amlogic,meson-gxbb-ao-pwm", 409 .data = &pwm_gxbb_ao_data 410 }, 411 { 412 .compatible = "amlogic,meson-axg-ee-pwm", 413 .data = &pwm_axg_ee_data 414 }, 415 { 416 .compatible = "amlogic,meson-axg-ao-pwm", 417 .data = &pwm_axg_ao_data 418 }, 419 { 420 .compatible = "amlogic,meson-g12a-ee-pwm", 421 .data = &pwm_meson8b_data 422 }, 423 { 424 .compatible = "amlogic,meson-g12a-ao-pwm-ab", 425 .data = &pwm_g12a_ao_ab_data 426 }, 427 { 428 .compatible = "amlogic,meson-g12a-ao-pwm-cd", 429 .data = &pwm_g12a_ao_cd_data 430 }, 431 {}, 432 }; 433 MODULE_DEVICE_TABLE(of, meson_pwm_matches); 434 435 static int meson_pwm_init_channels(struct meson_pwm *meson) 436 { 437 struct clk_parent_data mux_parent_data[MESON_MAX_MUX_PARENTS] = {}; 438 struct device *dev = meson->chip.dev; 439 unsigned int i; 440 char name[255]; 441 int err; 442 443 for (i = 0; i < meson->data->num_parents; i++) { 444 mux_parent_data[i].index = -1; 445 mux_parent_data[i].name = meson->data->parent_names[i]; 446 } 447 448 for (i = 0; i < meson->chip.npwm; i++) { 449 struct meson_pwm_channel *channel = &meson->channels[i]; 450 struct clk_parent_data div_parent = {}, gate_parent = {}; 451 struct clk_init_data init = {}; 452 453 snprintf(name, sizeof(name), "%s#mux%u", dev_name(dev), i); 454 455 init.name = name; 456 init.ops = &clk_mux_ops; 457 init.flags = 0; 458 init.parent_data = mux_parent_data; 459 init.num_parents = meson->data->num_parents; 460 461 channel->mux.reg = meson->base + REG_MISC_AB; 462 channel->mux.shift = 463 meson_pwm_per_channel_data[i].clk_sel_shift; 464 channel->mux.mask = MISC_CLK_SEL_MASK; 465 channel->mux.flags = 0; 466 channel->mux.lock = &meson->lock; 467 channel->mux.table = NULL; 468 channel->mux.hw.init = &init; 469 470 err = devm_clk_hw_register(dev, &channel->mux.hw); 471 if (err) { 472 dev_err(dev, "failed to register %s: %d\n", name, err); 473 return err; 474 } 475 476 snprintf(name, sizeof(name), "%s#div%u", dev_name(dev), i); 477 478 init.name = name; 479 init.ops = &clk_divider_ops; 480 init.flags = CLK_SET_RATE_PARENT; 481 div_parent.index = -1; 482 div_parent.hw = &channel->mux.hw; 483 init.parent_data = &div_parent; 484 init.num_parents = 1; 485 486 channel->div.reg = meson->base + REG_MISC_AB; 487 channel->div.shift = meson_pwm_per_channel_data[i].clk_div_shift; 488 channel->div.width = MISC_CLK_DIV_WIDTH; 489 channel->div.hw.init = &init; 490 channel->div.flags = 0; 491 channel->div.lock = &meson->lock; 492 493 err = devm_clk_hw_register(dev, &channel->div.hw); 494 if (err) { 495 dev_err(dev, "failed to register %s: %d\n", name, err); 496 return err; 497 } 498 499 snprintf(name, sizeof(name), "%s#gate%u", dev_name(dev), i); 500 501 init.name = name; 502 init.ops = &clk_gate_ops; 503 init.flags = CLK_SET_RATE_PARENT | CLK_IGNORE_UNUSED; 504 gate_parent.index = -1; 505 gate_parent.hw = &channel->div.hw; 506 init.parent_data = &gate_parent; 507 init.num_parents = 1; 508 509 channel->gate.reg = meson->base + REG_MISC_AB; 510 channel->gate.bit_idx = meson_pwm_per_channel_data[i].clk_en_shift; 511 channel->gate.hw.init = &init; 512 channel->gate.flags = 0; 513 channel->gate.lock = &meson->lock; 514 515 err = devm_clk_hw_register(dev, &channel->gate.hw); 516 if (err) { 517 dev_err(dev, "failed to register %s: %d\n", name, err); 518 return err; 519 } 520 521 channel->clk = devm_clk_hw_get_clk(dev, &channel->gate.hw, NULL); 522 if (IS_ERR(channel->clk)) { 523 err = PTR_ERR(channel->clk); 524 dev_err(dev, "failed to register %s: %d\n", name, err); 525 return err; 526 } 527 } 528 529 return 0; 530 } 531 532 static int meson_pwm_probe(struct platform_device *pdev) 533 { 534 struct meson_pwm *meson; 535 int err; 536 537 meson = devm_kzalloc(&pdev->dev, sizeof(*meson), GFP_KERNEL); 538 if (!meson) 539 return -ENOMEM; 540 541 meson->base = devm_platform_ioremap_resource(pdev, 0); 542 if (IS_ERR(meson->base)) 543 return PTR_ERR(meson->base); 544 545 spin_lock_init(&meson->lock); 546 meson->chip.dev = &pdev->dev; 547 meson->chip.ops = &meson_pwm_ops; 548 meson->chip.npwm = MESON_NUM_PWMS; 549 550 meson->data = of_device_get_match_data(&pdev->dev); 551 552 err = meson_pwm_init_channels(meson); 553 if (err < 0) 554 return err; 555 556 err = devm_pwmchip_add(&pdev->dev, &meson->chip); 557 if (err < 0) { 558 dev_err(&pdev->dev, "failed to register PWM chip: %d\n", err); 559 return err; 560 } 561 562 return 0; 563 } 564 565 static struct platform_driver meson_pwm_driver = { 566 .driver = { 567 .name = "meson-pwm", 568 .of_match_table = meson_pwm_matches, 569 }, 570 .probe = meson_pwm_probe, 571 }; 572 module_platform_driver(meson_pwm_driver); 573 574 MODULE_DESCRIPTION("Amlogic Meson PWM Generator driver"); 575 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); 576 MODULE_LICENSE("Dual BSD/GPL"); 577