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_NUM_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[MESON_NUM_MUX_PARENTS]; 101 }; 102 103 struct meson_pwm { 104 const struct meson_pwm_data *data; 105 struct meson_pwm_channel channels[MESON_NUM_PWMS]; 106 void __iomem *base; 107 /* 108 * Protects register (write) access to the REG_MISC_AB register 109 * that is shared between the two PWMs. 110 */ 111 spinlock_t lock; 112 }; 113 114 static inline struct meson_pwm *to_meson_pwm(struct pwm_chip *chip) 115 { 116 return pwmchip_get_drvdata(chip); 117 } 118 119 static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) 120 { 121 struct meson_pwm *meson = to_meson_pwm(chip); 122 struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm]; 123 struct device *dev = pwmchip_parent(chip); 124 int err; 125 126 err = clk_prepare_enable(channel->clk); 127 if (err < 0) { 128 dev_err(dev, "failed to enable clock %s: %d\n", 129 __clk_get_name(channel->clk), err); 130 return err; 131 } 132 133 return 0; 134 } 135 136 static void meson_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) 137 { 138 struct meson_pwm *meson = to_meson_pwm(chip); 139 struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm]; 140 141 clk_disable_unprepare(channel->clk); 142 } 143 144 static int meson_pwm_calc(struct pwm_chip *chip, struct pwm_device *pwm, 145 const struct pwm_state *state) 146 { 147 struct meson_pwm *meson = to_meson_pwm(chip); 148 struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm]; 149 unsigned int cnt, duty_cnt; 150 unsigned long fin_freq; 151 u64 duty, period, freq; 152 153 duty = state->duty_cycle; 154 period = state->period; 155 156 /* 157 * Note this is wrong. The result is an output wave that isn't really 158 * inverted and so is wrongly identified by .get_state as normal. 159 * Fixing this needs some care however as some machines might rely on 160 * this. 161 */ 162 if (state->polarity == PWM_POLARITY_INVERSED) 163 duty = period - duty; 164 165 freq = div64_u64(NSEC_PER_SEC * 0xffffULL, period); 166 if (freq > ULONG_MAX) 167 freq = ULONG_MAX; 168 169 fin_freq = clk_round_rate(channel->clk, freq); 170 if (fin_freq == 0) { 171 dev_err(pwmchip_parent(chip), "invalid source clock frequency\n"); 172 return -EINVAL; 173 } 174 175 dev_dbg(pwmchip_parent(chip), "fin_freq: %lu Hz\n", fin_freq); 176 177 cnt = div_u64(fin_freq * period, NSEC_PER_SEC); 178 if (cnt > 0xffff) { 179 dev_err(pwmchip_parent(chip), "unable to get period cnt\n"); 180 return -EINVAL; 181 } 182 183 dev_dbg(pwmchip_parent(chip), "period=%llu cnt=%u\n", period, cnt); 184 185 if (duty == period) { 186 channel->hi = cnt; 187 channel->lo = 0; 188 } else if (duty == 0) { 189 channel->hi = 0; 190 channel->lo = cnt; 191 } else { 192 duty_cnt = div_u64(fin_freq * duty, NSEC_PER_SEC); 193 194 dev_dbg(pwmchip_parent(chip), "duty=%llu duty_cnt=%u\n", duty, duty_cnt); 195 196 channel->hi = duty_cnt; 197 channel->lo = cnt - duty_cnt; 198 } 199 200 channel->rate = fin_freq; 201 202 return 0; 203 } 204 205 static void meson_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) 206 { 207 struct meson_pwm *meson = to_meson_pwm(chip); 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(pwmchip_parent(chip), "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 pwm_chip *chip, struct pwm_device *pwm) 234 { 235 struct meson_pwm *meson = to_meson_pwm(chip); 236 unsigned long flags; 237 u32 value; 238 239 spin_lock_irqsave(&meson->lock, flags); 240 241 value = readl(meson->base + REG_MISC_AB); 242 value &= ~meson_pwm_per_channel_data[pwm->hwpwm].pwm_en_mask; 243 writel(value, meson->base + REG_MISC_AB); 244 245 spin_unlock_irqrestore(&meson->lock, flags); 246 } 247 248 static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, 249 const struct pwm_state *state) 250 { 251 struct meson_pwm *meson = to_meson_pwm(chip); 252 struct meson_pwm_channel *channel = &meson->channels[pwm->hwpwm]; 253 int err = 0; 254 255 if (!state->enabled) { 256 if (state->polarity == PWM_POLARITY_INVERSED) { 257 /* 258 * This IP block revision doesn't have an "always high" 259 * setting which we can use for "inverted disabled". 260 * Instead we achieve this by setting mux parent with 261 * highest rate and minimum divider value, resulting 262 * in the shortest possible duration for one "count" 263 * and "period == duty_cycle". This results in a signal 264 * which is LOW for one "count", while being HIGH for 265 * the rest of the (so the signal is HIGH for slightly 266 * less than 100% of the period, but this is the best 267 * we can achieve). 268 */ 269 channel->rate = ULONG_MAX; 270 channel->hi = ~0; 271 channel->lo = 0; 272 273 meson_pwm_enable(chip, pwm); 274 } else { 275 meson_pwm_disable(chip, pwm); 276 } 277 } else { 278 err = meson_pwm_calc(chip, pwm, state); 279 if (err < 0) 280 return err; 281 282 meson_pwm_enable(chip, pwm); 283 } 284 285 return 0; 286 } 287 288 static u64 meson_pwm_cnt_to_ns(struct pwm_chip *chip, struct pwm_device *pwm, 289 u32 cnt) 290 { 291 struct meson_pwm *meson = to_meson_pwm(chip); 292 struct meson_pwm_channel *channel; 293 unsigned long fin_freq; 294 295 /* to_meson_pwm() can only be used after .get_state() is called */ 296 channel = &meson->channels[pwm->hwpwm]; 297 298 fin_freq = clk_get_rate(channel->clk); 299 if (fin_freq == 0) 300 return 0; 301 302 return div64_ul(NSEC_PER_SEC * (u64)cnt, fin_freq); 303 } 304 305 static int meson_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, 306 struct pwm_state *state) 307 { 308 struct meson_pwm *meson = to_meson_pwm(chip); 309 struct meson_pwm_channel_data *channel_data; 310 struct meson_pwm_channel *channel; 311 u32 value; 312 313 if (!state) 314 return 0; 315 316 channel = &meson->channels[pwm->hwpwm]; 317 channel_data = &meson_pwm_per_channel_data[pwm->hwpwm]; 318 319 value = readl(meson->base + REG_MISC_AB); 320 state->enabled = value & channel_data->pwm_en_mask; 321 322 value = readl(meson->base + channel_data->reg_offset); 323 channel->lo = FIELD_GET(PWM_LOW_MASK, value); 324 channel->hi = FIELD_GET(PWM_HIGH_MASK, value); 325 326 state->period = meson_pwm_cnt_to_ns(chip, pwm, channel->lo + channel->hi); 327 state->duty_cycle = meson_pwm_cnt_to_ns(chip, pwm, channel->hi); 328 329 state->polarity = PWM_POLARITY_NORMAL; 330 331 return 0; 332 } 333 334 static const struct pwm_ops meson_pwm_ops = { 335 .request = meson_pwm_request, 336 .free = meson_pwm_free, 337 .apply = meson_pwm_apply, 338 .get_state = meson_pwm_get_state, 339 }; 340 341 static const struct meson_pwm_data pwm_meson8b_data = { 342 .parent_names = { "xtal", NULL, "fclk_div4", "fclk_div3" }, 343 }; 344 345 /* 346 * Only the 2 first inputs of the GXBB AO PWMs are valid 347 * The last 2 are grounded 348 */ 349 static const struct meson_pwm_data pwm_gxbb_ao_data = { 350 .parent_names = { "xtal", "clk81", NULL, NULL }, 351 }; 352 353 static const struct meson_pwm_data pwm_axg_ee_data = { 354 .parent_names = { "xtal", "fclk_div5", "fclk_div4", "fclk_div3" }, 355 }; 356 357 static const struct meson_pwm_data pwm_axg_ao_data = { 358 .parent_names = { "xtal", "axg_ao_clk81", "fclk_div4", "fclk_div5" }, 359 }; 360 361 static const struct meson_pwm_data pwm_g12a_ao_ab_data = { 362 .parent_names = { "xtal", "g12a_ao_clk81", "fclk_div4", "fclk_div5" }, 363 }; 364 365 static const struct meson_pwm_data pwm_g12a_ao_cd_data = { 366 .parent_names = { "xtal", "g12a_ao_clk81", NULL, NULL }, 367 }; 368 369 static const struct of_device_id meson_pwm_matches[] = { 370 { 371 .compatible = "amlogic,meson8b-pwm", 372 .data = &pwm_meson8b_data 373 }, 374 { 375 .compatible = "amlogic,meson-gxbb-pwm", 376 .data = &pwm_meson8b_data 377 }, 378 { 379 .compatible = "amlogic,meson-gxbb-ao-pwm", 380 .data = &pwm_gxbb_ao_data 381 }, 382 { 383 .compatible = "amlogic,meson-axg-ee-pwm", 384 .data = &pwm_axg_ee_data 385 }, 386 { 387 .compatible = "amlogic,meson-axg-ao-pwm", 388 .data = &pwm_axg_ao_data 389 }, 390 { 391 .compatible = "amlogic,meson-g12a-ee-pwm", 392 .data = &pwm_meson8b_data 393 }, 394 { 395 .compatible = "amlogic,meson-g12a-ao-pwm-ab", 396 .data = &pwm_g12a_ao_ab_data 397 }, 398 { 399 .compatible = "amlogic,meson-g12a-ao-pwm-cd", 400 .data = &pwm_g12a_ao_cd_data 401 }, 402 {}, 403 }; 404 MODULE_DEVICE_TABLE(of, meson_pwm_matches); 405 406 static int meson_pwm_init_channels(struct pwm_chip *chip) 407 { 408 struct meson_pwm *meson = to_meson_pwm(chip); 409 struct clk_parent_data mux_parent_data[MESON_NUM_MUX_PARENTS] = {}; 410 struct device *dev = pwmchip_parent(chip); 411 unsigned int i; 412 char name[255]; 413 int err; 414 415 for (i = 0; i < MESON_NUM_MUX_PARENTS; i++) { 416 mux_parent_data[i].index = -1; 417 mux_parent_data[i].name = meson->data->parent_names[i]; 418 } 419 420 for (i = 0; i < chip->npwm; i++) { 421 struct meson_pwm_channel *channel = &meson->channels[i]; 422 struct clk_parent_data div_parent = {}, gate_parent = {}; 423 struct clk_init_data init = {}; 424 425 snprintf(name, sizeof(name), "%s#mux%u", dev_name(dev), i); 426 427 init.name = name; 428 init.ops = &clk_mux_ops; 429 init.flags = 0; 430 init.parent_data = mux_parent_data; 431 init.num_parents = MESON_NUM_MUX_PARENTS; 432 433 channel->mux.reg = meson->base + REG_MISC_AB; 434 channel->mux.shift = 435 meson_pwm_per_channel_data[i].clk_sel_shift; 436 channel->mux.mask = MISC_CLK_SEL_MASK; 437 channel->mux.flags = 0; 438 channel->mux.lock = &meson->lock; 439 channel->mux.table = NULL; 440 channel->mux.hw.init = &init; 441 442 err = devm_clk_hw_register(dev, &channel->mux.hw); 443 if (err) 444 return dev_err_probe(dev, err, 445 "failed to register %s\n", name); 446 447 snprintf(name, sizeof(name), "%s#div%u", dev_name(dev), i); 448 449 init.name = name; 450 init.ops = &clk_divider_ops; 451 init.flags = CLK_SET_RATE_PARENT; 452 div_parent.index = -1; 453 div_parent.hw = &channel->mux.hw; 454 init.parent_data = &div_parent; 455 init.num_parents = 1; 456 457 channel->div.reg = meson->base + REG_MISC_AB; 458 channel->div.shift = meson_pwm_per_channel_data[i].clk_div_shift; 459 channel->div.width = MISC_CLK_DIV_WIDTH; 460 channel->div.hw.init = &init; 461 channel->div.flags = 0; 462 channel->div.lock = &meson->lock; 463 464 err = devm_clk_hw_register(dev, &channel->div.hw); 465 if (err) 466 return dev_err_probe(dev, err, 467 "failed to register %s\n", name); 468 469 snprintf(name, sizeof(name), "%s#gate%u", dev_name(dev), i); 470 471 init.name = name; 472 init.ops = &clk_gate_ops; 473 init.flags = CLK_SET_RATE_PARENT | CLK_IGNORE_UNUSED; 474 gate_parent.index = -1; 475 gate_parent.hw = &channel->div.hw; 476 init.parent_data = &gate_parent; 477 init.num_parents = 1; 478 479 channel->gate.reg = meson->base + REG_MISC_AB; 480 channel->gate.bit_idx = meson_pwm_per_channel_data[i].clk_en_shift; 481 channel->gate.hw.init = &init; 482 channel->gate.flags = 0; 483 channel->gate.lock = &meson->lock; 484 485 err = devm_clk_hw_register(dev, &channel->gate.hw); 486 if (err) 487 return dev_err_probe(dev, err, "failed to register %s\n", name); 488 489 channel->clk = devm_clk_hw_get_clk(dev, &channel->gate.hw, NULL); 490 if (IS_ERR(channel->clk)) 491 return dev_err_probe(dev, PTR_ERR(channel->clk), 492 "failed to register %s\n", name); 493 } 494 495 return 0; 496 } 497 498 static int meson_pwm_probe(struct platform_device *pdev) 499 { 500 struct pwm_chip *chip; 501 struct meson_pwm *meson; 502 int err; 503 504 chip = devm_pwmchip_alloc(&pdev->dev, MESON_NUM_PWMS, sizeof(*meson)); 505 if (IS_ERR(chip)) 506 return PTR_ERR(chip); 507 meson = to_meson_pwm(chip); 508 509 meson->base = devm_platform_ioremap_resource(pdev, 0); 510 if (IS_ERR(meson->base)) 511 return PTR_ERR(meson->base); 512 513 spin_lock_init(&meson->lock); 514 chip->ops = &meson_pwm_ops; 515 516 meson->data = of_device_get_match_data(&pdev->dev); 517 518 err = meson_pwm_init_channels(chip); 519 if (err < 0) 520 return err; 521 522 err = devm_pwmchip_add(&pdev->dev, chip); 523 if (err < 0) 524 return dev_err_probe(&pdev->dev, err, 525 "failed to register PWM chip\n"); 526 527 return 0; 528 } 529 530 static struct platform_driver meson_pwm_driver = { 531 .driver = { 532 .name = "meson-pwm", 533 .of_match_table = meson_pwm_matches, 534 }, 535 .probe = meson_pwm_probe, 536 }; 537 module_platform_driver(meson_pwm_driver); 538 539 MODULE_DESCRIPTION("Amlogic Meson PWM Generator driver"); 540 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); 541 MODULE_LICENSE("Dual BSD/GPL"); 542