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/of_device.h> 41 #include <linux/platform_device.h> 42 #include <linux/pwm.h> 43 #include <linux/slab.h> 44 #include <linux/spinlock.h> 45 46 #define REG_PWM_A 0x0 47 #define REG_PWM_B 0x4 48 #define PWM_LOW_MASK GENMASK(15, 0) 49 #define PWM_HIGH_MASK GENMASK(31, 16) 50 51 #define REG_MISC_AB 0x8 52 #define MISC_B_CLK_EN BIT(23) 53 #define MISC_A_CLK_EN BIT(15) 54 #define MISC_CLK_DIV_MASK 0x7f 55 #define MISC_B_CLK_DIV_SHIFT 16 56 #define MISC_A_CLK_DIV_SHIFT 8 57 #define MISC_B_CLK_SEL_SHIFT 6 58 #define MISC_A_CLK_SEL_SHIFT 4 59 #define MISC_CLK_SEL_MASK 0x3 60 #define MISC_B_EN BIT(1) 61 #define MISC_A_EN BIT(0) 62 63 #define MESON_NUM_PWMS 2 64 65 static struct meson_pwm_channel_data { 66 u8 reg_offset; 67 u8 clk_sel_shift; 68 u8 clk_div_shift; 69 u32 clk_en_mask; 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_mask = MISC_A_CLK_EN, 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_mask = MISC_B_CLK_EN, 84 .pwm_en_mask = MISC_B_EN, 85 } 86 }; 87 88 struct meson_pwm_channel { 89 unsigned int hi; 90 unsigned int lo; 91 u8 pre_div; 92 93 struct clk *clk_parent; 94 struct clk_mux mux; 95 struct clk *clk; 96 }; 97 98 struct meson_pwm_data { 99 const char * const *parent_names; 100 unsigned int num_parents; 101 }; 102 103 struct meson_pwm { 104 struct pwm_chip chip; 105 const struct meson_pwm_data *data; 106 struct meson_pwm_channel channels[MESON_NUM_PWMS]; 107 void __iomem *base; 108 /* 109 * Protects register (write) access to the REG_MISC_AB register 110 * that is shared between the two PWMs. 111 */ 112 spinlock_t lock; 113 }; 114 115 static inline struct meson_pwm *to_meson_pwm(struct pwm_chip *chip) 116 { 117 return container_of(chip, struct meson_pwm, chip); 118 } 119 120 static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) 121 { 122 struct meson_pwm *meson = to_meson_pwm(chip); 123 struct meson_pwm_channel *channel; 124 struct device *dev = chip->dev; 125 int err; 126 127 channel = pwm_get_chip_data(pwm); 128 if (channel) 129 return 0; 130 131 channel = &meson->channels[pwm->hwpwm]; 132 133 if (channel->clk_parent) { 134 err = clk_set_parent(channel->clk, channel->clk_parent); 135 if (err < 0) { 136 dev_err(dev, "failed to set parent %s for %s: %d\n", 137 __clk_get_name(channel->clk_parent), 138 __clk_get_name(channel->clk), err); 139 return err; 140 } 141 } 142 143 err = clk_prepare_enable(channel->clk); 144 if (err < 0) { 145 dev_err(dev, "failed to enable clock %s: %d\n", 146 __clk_get_name(channel->clk), err); 147 return err; 148 } 149 150 return pwm_set_chip_data(pwm, channel); 151 } 152 153 static void meson_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) 154 { 155 struct meson_pwm_channel *channel = pwm_get_chip_data(pwm); 156 157 if (channel) 158 clk_disable_unprepare(channel->clk); 159 } 160 161 static int meson_pwm_calc(struct meson_pwm *meson, struct pwm_device *pwm, 162 const struct pwm_state *state) 163 { 164 struct meson_pwm_channel *channel = pwm_get_chip_data(pwm); 165 unsigned int duty, period, pre_div, cnt, duty_cnt; 166 unsigned long fin_freq; 167 168 duty = state->duty_cycle; 169 period = state->period; 170 171 if (state->polarity == PWM_POLARITY_INVERSED) 172 duty = period - duty; 173 174 fin_freq = clk_get_rate(channel->clk); 175 if (fin_freq == 0) { 176 dev_err(meson->chip.dev, "invalid source clock frequency\n"); 177 return -EINVAL; 178 } 179 180 dev_dbg(meson->chip.dev, "fin_freq: %lu Hz\n", fin_freq); 181 182 pre_div = div64_u64(fin_freq * (u64)period, NSEC_PER_SEC * 0xffffLL); 183 if (pre_div > MISC_CLK_DIV_MASK) { 184 dev_err(meson->chip.dev, "unable to get period pre_div\n"); 185 return -EINVAL; 186 } 187 188 cnt = div64_u64(fin_freq * (u64)period, NSEC_PER_SEC * (pre_div + 1)); 189 if (cnt > 0xffff) { 190 dev_err(meson->chip.dev, "unable to get period cnt\n"); 191 return -EINVAL; 192 } 193 194 dev_dbg(meson->chip.dev, "period=%u pre_div=%u cnt=%u\n", period, 195 pre_div, cnt); 196 197 if (duty == period) { 198 channel->pre_div = pre_div; 199 channel->hi = cnt; 200 channel->lo = 0; 201 } else if (duty == 0) { 202 channel->pre_div = pre_div; 203 channel->hi = 0; 204 channel->lo = cnt; 205 } else { 206 /* Then check is we can have the duty with the same pre_div */ 207 duty_cnt = div64_u64(fin_freq * (u64)duty, 208 NSEC_PER_SEC * (pre_div + 1)); 209 if (duty_cnt > 0xffff) { 210 dev_err(meson->chip.dev, "unable to get duty cycle\n"); 211 return -EINVAL; 212 } 213 214 dev_dbg(meson->chip.dev, "duty=%u pre_div=%u duty_cnt=%u\n", 215 duty, pre_div, duty_cnt); 216 217 channel->pre_div = pre_div; 218 channel->hi = duty_cnt; 219 channel->lo = cnt - duty_cnt; 220 } 221 222 return 0; 223 } 224 225 static void meson_pwm_enable(struct meson_pwm *meson, struct pwm_device *pwm) 226 { 227 struct meson_pwm_channel *channel = pwm_get_chip_data(pwm); 228 struct meson_pwm_channel_data *channel_data; 229 unsigned long flags; 230 u32 value; 231 232 channel_data = &meson_pwm_per_channel_data[pwm->hwpwm]; 233 234 spin_lock_irqsave(&meson->lock, flags); 235 236 value = readl(meson->base + REG_MISC_AB); 237 value &= ~(MISC_CLK_DIV_MASK << channel_data->clk_div_shift); 238 value |= channel->pre_div << channel_data->clk_div_shift; 239 value |= channel_data->clk_en_mask; 240 writel(value, meson->base + REG_MISC_AB); 241 242 value = FIELD_PREP(PWM_HIGH_MASK, channel->hi) | 243 FIELD_PREP(PWM_LOW_MASK, channel->lo); 244 writel(value, meson->base + channel_data->reg_offset); 245 246 value = readl(meson->base + REG_MISC_AB); 247 value |= channel_data->pwm_en_mask; 248 writel(value, meson->base + REG_MISC_AB); 249 250 spin_unlock_irqrestore(&meson->lock, flags); 251 } 252 253 static void meson_pwm_disable(struct meson_pwm *meson, struct pwm_device *pwm) 254 { 255 unsigned long flags; 256 u32 value; 257 258 spin_lock_irqsave(&meson->lock, flags); 259 260 value = readl(meson->base + REG_MISC_AB); 261 value &= ~meson_pwm_per_channel_data[pwm->hwpwm].pwm_en_mask; 262 writel(value, meson->base + REG_MISC_AB); 263 264 spin_unlock_irqrestore(&meson->lock, flags); 265 } 266 267 static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, 268 const struct pwm_state *state) 269 { 270 struct meson_pwm_channel *channel = pwm_get_chip_data(pwm); 271 struct meson_pwm *meson = to_meson_pwm(chip); 272 int err = 0; 273 274 if (!state) 275 return -EINVAL; 276 277 if (!state->enabled) { 278 if (state->polarity == PWM_POLARITY_INVERSED) { 279 /* 280 * This IP block revision doesn't have an "always high" 281 * setting which we can use for "inverted disabled". 282 * Instead we achieve this using the same settings 283 * that we use a pre_div of 0 (to get the shortest 284 * possible duration for one "count") and 285 * "period == duty_cycle". This results in a signal 286 * which is LOW for one "count", while being HIGH for 287 * the rest of the (so the signal is HIGH for slightly 288 * less than 100% of the period, but this is the best 289 * we can achieve). 290 */ 291 channel->pre_div = 0; 292 channel->hi = ~0; 293 channel->lo = 0; 294 295 meson_pwm_enable(meson, pwm); 296 } else { 297 meson_pwm_disable(meson, pwm); 298 } 299 } else { 300 err = meson_pwm_calc(meson, pwm, state); 301 if (err < 0) 302 return err; 303 304 meson_pwm_enable(meson, pwm); 305 } 306 307 return 0; 308 } 309 310 static unsigned int meson_pwm_cnt_to_ns(struct pwm_chip *chip, 311 struct pwm_device *pwm, u32 cnt) 312 { 313 struct meson_pwm *meson = to_meson_pwm(chip); 314 struct meson_pwm_channel *channel; 315 unsigned long fin_freq; 316 u32 fin_ns; 317 318 /* to_meson_pwm() can only be used after .get_state() is called */ 319 channel = &meson->channels[pwm->hwpwm]; 320 321 fin_freq = clk_get_rate(channel->clk); 322 if (fin_freq == 0) 323 return 0; 324 325 fin_ns = div_u64(NSEC_PER_SEC, fin_freq); 326 327 return cnt * fin_ns * (channel->pre_div + 1); 328 } 329 330 static void meson_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, 331 struct pwm_state *state) 332 { 333 struct meson_pwm *meson = to_meson_pwm(chip); 334 struct meson_pwm_channel_data *channel_data; 335 struct meson_pwm_channel *channel; 336 u32 value, tmp; 337 338 if (!state) 339 return; 340 341 channel = &meson->channels[pwm->hwpwm]; 342 channel_data = &meson_pwm_per_channel_data[pwm->hwpwm]; 343 344 value = readl(meson->base + REG_MISC_AB); 345 346 tmp = channel_data->pwm_en_mask | channel_data->clk_en_mask; 347 state->enabled = (value & tmp) == tmp; 348 349 tmp = value >> channel_data->clk_div_shift; 350 channel->pre_div = FIELD_GET(MISC_CLK_DIV_MASK, tmp); 351 352 value = readl(meson->base + channel_data->reg_offset); 353 354 channel->lo = FIELD_GET(PWM_LOW_MASK, value); 355 channel->hi = FIELD_GET(PWM_HIGH_MASK, value); 356 357 if (channel->lo == 0) { 358 state->period = meson_pwm_cnt_to_ns(chip, pwm, channel->hi); 359 state->duty_cycle = state->period; 360 } else if (channel->lo >= channel->hi) { 361 state->period = meson_pwm_cnt_to_ns(chip, pwm, 362 channel->lo + channel->hi); 363 state->duty_cycle = meson_pwm_cnt_to_ns(chip, pwm, 364 channel->hi); 365 } else { 366 state->period = 0; 367 state->duty_cycle = 0; 368 } 369 } 370 371 static const struct pwm_ops meson_pwm_ops = { 372 .request = meson_pwm_request, 373 .free = meson_pwm_free, 374 .apply = meson_pwm_apply, 375 .get_state = meson_pwm_get_state, 376 .owner = THIS_MODULE, 377 }; 378 379 static const char * const pwm_meson8b_parent_names[] = { 380 "xtal", "vid_pll", "fclk_div4", "fclk_div3" 381 }; 382 383 static const struct meson_pwm_data pwm_meson8b_data = { 384 .parent_names = pwm_meson8b_parent_names, 385 .num_parents = ARRAY_SIZE(pwm_meson8b_parent_names), 386 }; 387 388 static const char * const pwm_gxbb_parent_names[] = { 389 "xtal", "hdmi_pll", "fclk_div4", "fclk_div3" 390 }; 391 392 static const struct meson_pwm_data pwm_gxbb_data = { 393 .parent_names = pwm_gxbb_parent_names, 394 .num_parents = ARRAY_SIZE(pwm_gxbb_parent_names), 395 }; 396 397 /* 398 * Only the 2 first inputs of the GXBB AO PWMs are valid 399 * The last 2 are grounded 400 */ 401 static const char * const pwm_gxbb_ao_parent_names[] = { 402 "xtal", "clk81" 403 }; 404 405 static const struct meson_pwm_data pwm_gxbb_ao_data = { 406 .parent_names = pwm_gxbb_ao_parent_names, 407 .num_parents = ARRAY_SIZE(pwm_gxbb_ao_parent_names), 408 }; 409 410 static const char * const pwm_axg_ee_parent_names[] = { 411 "xtal", "fclk_div5", "fclk_div4", "fclk_div3" 412 }; 413 414 static const struct meson_pwm_data pwm_axg_ee_data = { 415 .parent_names = pwm_axg_ee_parent_names, 416 .num_parents = ARRAY_SIZE(pwm_axg_ee_parent_names), 417 }; 418 419 static const char * const pwm_axg_ao_parent_names[] = { 420 "aoclk81", "xtal", "fclk_div4", "fclk_div5" 421 }; 422 423 static const struct meson_pwm_data pwm_axg_ao_data = { 424 .parent_names = pwm_axg_ao_parent_names, 425 .num_parents = ARRAY_SIZE(pwm_axg_ao_parent_names), 426 }; 427 428 static const char * const pwm_g12a_ao_ab_parent_names[] = { 429 "xtal", "aoclk81", "fclk_div4", "fclk_div5" 430 }; 431 432 static const struct meson_pwm_data pwm_g12a_ao_ab_data = { 433 .parent_names = pwm_g12a_ao_ab_parent_names, 434 .num_parents = ARRAY_SIZE(pwm_g12a_ao_ab_parent_names), 435 }; 436 437 static const char * const pwm_g12a_ao_cd_parent_names[] = { 438 "xtal", "aoclk81", 439 }; 440 441 static const struct meson_pwm_data pwm_g12a_ao_cd_data = { 442 .parent_names = pwm_g12a_ao_cd_parent_names, 443 .num_parents = ARRAY_SIZE(pwm_g12a_ao_cd_parent_names), 444 }; 445 446 static const char * const pwm_g12a_ee_parent_names[] = { 447 "xtal", "hdmi_pll", "fclk_div4", "fclk_div3" 448 }; 449 450 static const struct meson_pwm_data pwm_g12a_ee_data = { 451 .parent_names = pwm_g12a_ee_parent_names, 452 .num_parents = ARRAY_SIZE(pwm_g12a_ee_parent_names), 453 }; 454 455 static const struct of_device_id meson_pwm_matches[] = { 456 { 457 .compatible = "amlogic,meson8b-pwm", 458 .data = &pwm_meson8b_data 459 }, 460 { 461 .compatible = "amlogic,meson-gxbb-pwm", 462 .data = &pwm_gxbb_data 463 }, 464 { 465 .compatible = "amlogic,meson-gxbb-ao-pwm", 466 .data = &pwm_gxbb_ao_data 467 }, 468 { 469 .compatible = "amlogic,meson-axg-ee-pwm", 470 .data = &pwm_axg_ee_data 471 }, 472 { 473 .compatible = "amlogic,meson-axg-ao-pwm", 474 .data = &pwm_axg_ao_data 475 }, 476 { 477 .compatible = "amlogic,meson-g12a-ee-pwm", 478 .data = &pwm_g12a_ee_data 479 }, 480 { 481 .compatible = "amlogic,meson-g12a-ao-pwm-ab", 482 .data = &pwm_g12a_ao_ab_data 483 }, 484 { 485 .compatible = "amlogic,meson-g12a-ao-pwm-cd", 486 .data = &pwm_g12a_ao_cd_data 487 }, 488 {}, 489 }; 490 MODULE_DEVICE_TABLE(of, meson_pwm_matches); 491 492 static int meson_pwm_init_channels(struct meson_pwm *meson) 493 { 494 struct device *dev = meson->chip.dev; 495 struct clk_init_data init; 496 unsigned int i; 497 char name[255]; 498 int err; 499 500 for (i = 0; i < meson->chip.npwm; i++) { 501 struct meson_pwm_channel *channel = &meson->channels[i]; 502 503 snprintf(name, sizeof(name), "%s#mux%u", dev_name(dev), i); 504 505 init.name = name; 506 init.ops = &clk_mux_ops; 507 init.flags = 0; 508 init.parent_names = meson->data->parent_names; 509 init.num_parents = meson->data->num_parents; 510 511 channel->mux.reg = meson->base + REG_MISC_AB; 512 channel->mux.shift = 513 meson_pwm_per_channel_data[i].clk_sel_shift; 514 channel->mux.mask = MISC_CLK_SEL_MASK; 515 channel->mux.flags = 0; 516 channel->mux.lock = &meson->lock; 517 channel->mux.table = NULL; 518 channel->mux.hw.init = &init; 519 520 channel->clk = devm_clk_register(dev, &channel->mux.hw); 521 if (IS_ERR(channel->clk)) { 522 err = PTR_ERR(channel->clk); 523 dev_err(dev, "failed to register %s: %d\n", name, err); 524 return err; 525 } 526 527 snprintf(name, sizeof(name), "clkin%u", i); 528 529 channel->clk_parent = devm_clk_get_optional(dev, name); 530 if (IS_ERR(channel->clk_parent)) 531 return PTR_ERR(channel->clk_parent); 532 } 533 534 return 0; 535 } 536 537 static int meson_pwm_probe(struct platform_device *pdev) 538 { 539 struct meson_pwm *meson; 540 int err; 541 542 meson = devm_kzalloc(&pdev->dev, sizeof(*meson), GFP_KERNEL); 543 if (!meson) 544 return -ENOMEM; 545 546 meson->base = devm_platform_ioremap_resource(pdev, 0); 547 if (IS_ERR(meson->base)) 548 return PTR_ERR(meson->base); 549 550 spin_lock_init(&meson->lock); 551 meson->chip.dev = &pdev->dev; 552 meson->chip.ops = &meson_pwm_ops; 553 meson->chip.npwm = MESON_NUM_PWMS; 554 555 meson->data = of_device_get_match_data(&pdev->dev); 556 557 err = meson_pwm_init_channels(meson); 558 if (err < 0) 559 return err; 560 561 err = devm_pwmchip_add(&pdev->dev, &meson->chip); 562 if (err < 0) { 563 dev_err(&pdev->dev, "failed to register PWM chip: %d\n", err); 564 return err; 565 } 566 567 return 0; 568 } 569 570 static struct platform_driver meson_pwm_driver = { 571 .driver = { 572 .name = "meson-pwm", 573 .of_match_table = meson_pwm_matches, 574 }, 575 .probe = meson_pwm_probe, 576 }; 577 module_platform_driver(meson_pwm_driver); 578 579 MODULE_DESCRIPTION("Amlogic Meson PWM Generator driver"); 580 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); 581 MODULE_LICENSE("Dual BSD/GPL"); 582