drivers/pwm/pwm-meson.c

   1 /*
   2  * This file is provided under a dual BSD/GPLv2 license.  When using or
   3  * redistributing this file, you may do so under either license.
   4  *
   5  * GPL LICENSE SUMMARY
   6  *
   7  * Copyright (c) 2016 BayLibre, SAS.
   8  * Author: Neil Armstrong <narmstrong@baylibre.com>
   9  * Copyright (C) 2014 Amlogic, Inc.
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of version 2 of the GNU General Public License as
  13  * published by the Free Software Foundation.
  14  *
  15  * This program is distributed in the hope that it will be useful, but
  16  * WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  22  * The full GNU General Public License is included in this distribution
  23  * in the file called COPYING.
  24  *
  25  * BSD LICENSE
  26  *
  27  * Copyright (c) 2016 BayLibre, SAS.
  28  * Author: Neil Armstrong <narmstrong@baylibre.com>
  29  * Copyright (C) 2014 Amlogic, Inc.
  30  *
  31  * Redistribution and use in source and binary forms, with or without
  32  * modification, are permitted provided that the following conditions
  33  * are met:
  34  *
  35  *   * Redistributions of source code must retain the above copyright
  36  *     notice, this list of conditions and the following disclaimer.
  37  *   * Redistributions in binary form must reproduce the above copyright
  38  *     notice, this list of conditions and the following disclaimer in
  39  *     the documentation and/or other materials provided with the
  40  *     distribution.
  41  *   * Neither the name of Intel Corporation nor the names of its
  42  *     contributors may be used to endorse or promote products derived
  43  *     from this software without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  46  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  47  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  48  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  49  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  50  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  51  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  52  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  53  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  54  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  55  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  56  */
  57
  58 #include <linux/clk.h>
  59 #include <linux/clk-provider.h>
  60 #include <linux/err.h>
  61 #include <linux/io.h>
  62 #include <linux/kernel.h>
  63 #include <linux/module.h>
  64 #include <linux/of.h>
  65 #include <linux/of_device.h>
  66 #include <linux/platform_device.h>
  67 #include <linux/pwm.h>
  68 #include <linux/slab.h>
  69 #include <linux/spinlock.h>
  70
  71 #define REG_PWM_A               0x0
  72 #define REG_PWM_B               0x4
  73 #define PWM_HIGH_SHIFT          16
  74
  75 #define REG_MISC_AB             0x8
  76 #define MISC_B_CLK_EN           BIT(23)
  77 #define MISC_A_CLK_EN           BIT(15)
  78 #define MISC_CLK_DIV_MASK       0x7f
  79 #define MISC_B_CLK_DIV_SHIFT    16
  80 #define MISC_A_CLK_DIV_SHIFT    8
  81 #define MISC_B_CLK_SEL_SHIFT    6
  82 #define MISC_A_CLK_SEL_SHIFT    4
  83 #define MISC_CLK_SEL_WIDTH      2
  84 #define MISC_B_EN               BIT(1)
  85 #define MISC_A_EN               BIT(0)
  86
  87 static const unsigned int mux_reg_shifts[] = {
  88         MISC_A_CLK_SEL_SHIFT,
  89         MISC_B_CLK_SEL_SHIFT
  90 };
  91
  92 struct meson_pwm_channel {
  93         unsigned int hi;
  94         unsigned int lo;
  95         u8 pre_div;
  96
  97         struct pwm_state state;
  98
  99         struct clk *clk_parent;
 100         struct clk_mux mux;
 101         struct clk *clk;
 102 };
 103
 104 struct meson_pwm_data {
 105         const char * const *parent_names;
 106         unsigned int num_parents;
 107 };
 108
 109 struct meson_pwm {
 110         struct pwm_chip chip;
 111         const struct meson_pwm_data *data;
 112         void __iomem *base;
 113         u8 inverter_mask;
 114         spinlock_t lock;
 115 };
 116
 117 static inline struct meson_pwm *to_meson_pwm(struct pwm_chip *chip)
 118 {
 119         return container_of(chip, struct meson_pwm, chip);
 120 }
 121
 122 static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 123 {
 124         struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
 125         struct device *dev = chip->dev;
 126         int err;
 127
 128         if (!channel)
 129                 return -ENODEV;
 130
 131         if (channel->clk_parent) {
 132                 err = clk_set_parent(channel->clk, channel->clk_parent);
 133                 if (err < 0) {
 134                         dev_err(dev, "failed to set parent %s for %s: %d\n",
 135                                 __clk_get_name(channel->clk_parent),
 136                                 __clk_get_name(channel->clk), err);
 137                                 return err;
 138                 }
 139         }
 140
 141         err = clk_prepare_enable(channel->clk);
 142         if (err < 0) {
 143                 dev_err(dev, "failed to enable clock %s: %d\n",
 144                         __clk_get_name(channel->clk), err);
 145                 return err;
 146         }
 147
 148         chip->ops->get_state(chip, pwm, &channel->state);
 149
 150         return 0;
 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,
 162                           struct meson_pwm_channel *channel, unsigned int id,
 163                           unsigned int duty, unsigned int period)
 164 {
 165         unsigned int pre_div, cnt, duty_cnt;
 166         unsigned long fin_freq = -1;
 167         u64 fin_ps;
 168
 169         if (~(meson->inverter_mask >> id) & 0x1)
 170                 duty = period - duty;
 171
 172         if (period == channel->state.period &&
 173             duty == channel->state.duty_cycle)
 174                 return 0;
 175
 176         fin_freq = clk_get_rate(channel->clk);
 177         if (fin_freq == 0) {
 178                 dev_err(meson->chip.dev, "invalid source clock frequency\n");
 179                 return -EINVAL;
 180         }
 181
 182         dev_dbg(meson->chip.dev, "fin_freq: %lu Hz\n", fin_freq);
 183         fin_ps = (u64)NSEC_PER_SEC * 1000;
 184         do_div(fin_ps, fin_freq);
 185
 186         /* Calc pre_div with the period */
 187         for (pre_div = 0; pre_div < MISC_CLK_DIV_MASK; pre_div++) {
 188                 cnt = DIV_ROUND_CLOSEST_ULL((u64)period * 1000,
 189                                             fin_ps * (pre_div + 1));
 190                 dev_dbg(meson->chip.dev, "fin_ps=%llu pre_div=%u cnt=%u\n",
 191                         fin_ps, pre_div, cnt);
 192                 if (cnt <= 0xffff)
 193                         break;
 194         }
 195
 196         if (pre_div == MISC_CLK_DIV_MASK) {
 197                 dev_err(meson->chip.dev, "unable to get period pre_div\n");
 198                 return -EINVAL;
 199         }
 200
 201         dev_dbg(meson->chip.dev, "period=%u pre_div=%u cnt=%u\n", period,
 202                 pre_div, cnt);
 203
 204         if (duty == period) {
 205                 channel->pre_div = pre_div;
 206                 channel->hi = cnt;
 207                 channel->lo = 0;
 208         } else if (duty == 0) {
 209                 channel->pre_div = pre_div;
 210                 channel->hi = 0;
 211                 channel->lo = cnt;
 212         } else {
 213                 /* Then check is we can have the duty with the same pre_div */
 214                 duty_cnt = DIV_ROUND_CLOSEST_ULL((u64)duty * 1000,
 215                                                  fin_ps * (pre_div + 1));
 216                 if (duty_cnt > 0xffff) {
 217                         dev_err(meson->chip.dev, "unable to get duty cycle\n");
 218                         return -EINVAL;
 219                 }
 220
 221                 dev_dbg(meson->chip.dev, "duty=%u pre_div=%u duty_cnt=%u\n",
 222                         duty, pre_div, duty_cnt);
 223
 224                 channel->pre_div = pre_div;
 225                 channel->hi = duty_cnt;
 226                 channel->lo = cnt - duty_cnt;
 227         }
 228
 229         return 0;
 230 }
 231
 232 static void meson_pwm_enable(struct meson_pwm *meson,
 233                              struct meson_pwm_channel *channel,
 234                              unsigned int id)
 235 {
 236         u32 value, clk_shift, clk_enable, enable;
 237         unsigned int offset;
 238
 239         switch (id) {
 240         case 0:
 241                 clk_shift = MISC_A_CLK_DIV_SHIFT;
 242                 clk_enable = MISC_A_CLK_EN;
 243                 enable = MISC_A_EN;
 244                 offset = REG_PWM_A;
 245                 break;
 246
 247         case 1:
 248                 clk_shift = MISC_B_CLK_DIV_SHIFT;
 249                 clk_enable = MISC_B_CLK_EN;
 250                 enable = MISC_B_EN;
 251                 offset = REG_PWM_B;
 252                 break;
 253
 254         default:
 255                 return;
 256         }
 257
 258         value = readl(meson->base + REG_MISC_AB);
 259         value &= ~(MISC_CLK_DIV_MASK << clk_shift);
 260         value |= channel->pre_div << clk_shift;
 261         value |= clk_enable;
 262         writel(value, meson->base + REG_MISC_AB);
 263
 264         value = (channel->hi << PWM_HIGH_SHIFT) | channel->lo;
 265         writel(value, meson->base + offset);
 266
 267         value = readl(meson->base + REG_MISC_AB);
 268         value |= enable;
 269         writel(value, meson->base + REG_MISC_AB);
 270 }
 271
 272 static void meson_pwm_disable(struct meson_pwm *meson, unsigned int id)
 273 {
 274         u32 value, enable;
 275
 276         switch (id) {
 277         case 0:
 278                 enable = MISC_A_EN;
 279                 break;
 280
 281         case 1:
 282                 enable = MISC_B_EN;
 283                 break;
 284
 285         default:
 286                 return;
 287         }
 288
 289         value = readl(meson->base + REG_MISC_AB);
 290         value &= ~enable;
 291         writel(value, meson->base + REG_MISC_AB);
 292 }
 293
 294 static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 295                            struct pwm_state *state)
 296 {
 297         struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
 298         struct meson_pwm *meson = to_meson_pwm(chip);
 299         unsigned long flags;
 300         int err = 0;
 301
 302         if (!state)
 303                 return -EINVAL;
 304
 305         spin_lock_irqsave(&meson->lock, flags);
 306
 307         if (!state->enabled) {
 308                 meson_pwm_disable(meson, pwm->hwpwm);
 309                 channel->state.enabled = false;
 310
 311                 goto unlock;
 312         }
 313
 314         if (state->period != channel->state.period ||
 315             state->duty_cycle != channel->state.duty_cycle ||
 316             state->polarity != channel->state.polarity) {
 317                 if (channel->state.enabled) {
 318                         meson_pwm_disable(meson, pwm->hwpwm);
 319                         channel->state.enabled = false;
 320                 }
 321
 322                 if (state->polarity != channel->state.polarity) {
 323                         if (state->polarity == PWM_POLARITY_NORMAL)
 324                                 meson->inverter_mask |= BIT(pwm->hwpwm);
 325                         else
 326                                 meson->inverter_mask &= ~BIT(pwm->hwpwm);
 327                 }
 328
 329                 err = meson_pwm_calc(meson, channel, pwm->hwpwm,
 330                                      state->duty_cycle, state->period);
 331                 if (err < 0)
 332                         goto unlock;
 333
 334                 channel->state.polarity = state->polarity;
 335                 channel->state.period = state->period;
 336                 channel->state.duty_cycle = state->duty_cycle;
 337         }
 338
 339         if (state->enabled && !channel->state.enabled) {
 340                 meson_pwm_enable(meson, channel, pwm->hwpwm);
 341                 channel->state.enabled = true;
 342         }
 343
 344 unlock:
 345         spin_unlock_irqrestore(&meson->lock, flags);
 346         return err;
 347 }
 348
 349 static void meson_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 350                                 struct pwm_state *state)
 351 {
 352         struct meson_pwm *meson = to_meson_pwm(chip);
 353         u32 value, mask;
 354
 355         if (!state)
 356                 return;
 357
 358         switch (pwm->hwpwm) {
 359         case 0:
 360                 mask = MISC_A_EN;
 361                 break;
 362
 363         case 1:
 364                 mask = MISC_B_EN;
 365                 break;
 366
 367         default:
 368                 return;
 369         }
 370
 371         value = readl(meson->base + REG_MISC_AB);
 372         state->enabled = (value & mask) != 0;
 373 }
 374
 375 static const struct pwm_ops meson_pwm_ops = {
 376         .request = meson_pwm_request,
 377         .free = meson_pwm_free,
 378         .apply = meson_pwm_apply,
 379         .get_state = meson_pwm_get_state,
 380         .owner = THIS_MODULE,
 381 };
 382
 383 static const char * const pwm_meson8b_parent_names[] = {
 384         "xtal", "vid_pll", "fclk_div4", "fclk_div3"
 385 };
 386
 387 static const struct meson_pwm_data pwm_meson8b_data = {
 388         .parent_names = pwm_meson8b_parent_names,
 389         .num_parents = ARRAY_SIZE(pwm_meson8b_parent_names),
 390 };
 391
 392 static const char * const pwm_gxbb_parent_names[] = {
 393         "xtal", "hdmi_pll", "fclk_div4", "fclk_div3"
 394 };
 395
 396 static const struct meson_pwm_data pwm_gxbb_data = {
 397         .parent_names = pwm_gxbb_parent_names,
 398         .num_parents = ARRAY_SIZE(pwm_gxbb_parent_names),
 399 };
 400
 401 /*
 402  * Only the 2 first inputs of the GXBB AO PWMs are valid
 403  * The last 2 are grounded
 404  */
 405 static const char * const pwm_gxbb_ao_parent_names[] = {
 406         "xtal", "clk81"
 407 };
 408
 409 static const struct meson_pwm_data pwm_gxbb_ao_data = {
 410         .parent_names = pwm_gxbb_ao_parent_names,
 411         .num_parents = ARRAY_SIZE(pwm_gxbb_ao_parent_names),
 412 };
 413
 414 static const struct of_device_id meson_pwm_matches[] = {
 415         {
 416                 .compatible = "amlogic,meson8b-pwm",
 417                 .data = &pwm_meson8b_data
 418         },
 419         {
 420                 .compatible = "amlogic,meson-gxbb-pwm",
 421                 .data = &pwm_gxbb_data
 422         },
 423         {
 424                 .compatible = "amlogic,meson-gxbb-ao-pwm",
 425                 .data = &pwm_gxbb_ao_data
 426         },
 427         {},
 428 };
 429 MODULE_DEVICE_TABLE(of, meson_pwm_matches);
 430
 431 static int meson_pwm_init_channels(struct meson_pwm *meson,
 432                                    struct meson_pwm_channel *channels)
 433 {
 434         struct device *dev = meson->chip.dev;
 435         struct clk_init_data init;
 436         unsigned int i;
 437         char name[255];
 438         int err;
 439
 440         for (i = 0; i < meson->chip.npwm; i++) {
 441                 struct meson_pwm_channel *channel = &channels[i];
 442
 443                 snprintf(name, sizeof(name), "%s#mux%u", dev_name(dev), i);
 444
 445                 init.name = name;
 446                 init.ops = &clk_mux_ops;
 447                 init.flags = CLK_IS_BASIC;
 448                 init.parent_names = meson->data->parent_names;
 449                 init.num_parents = meson->data->num_parents;
 450
 451                 channel->mux.reg = meson->base + REG_MISC_AB;
 452                 channel->mux.shift = mux_reg_shifts[i];
 453                 channel->mux.mask = BIT(MISC_CLK_SEL_WIDTH) - 1;
 454                 channel->mux.flags = 0;
 455                 channel->mux.lock = &meson->lock;
 456                 channel->mux.table = NULL;
 457                 channel->mux.hw.init = &init;
 458
 459                 channel->clk = devm_clk_register(dev, &channel->mux.hw);
 460                 if (IS_ERR(channel->clk)) {
 461                         err = PTR_ERR(channel->clk);
 462                         dev_err(dev, "failed to register %s: %d\n", name, err);
 463                         return err;
 464                 }
 465
 466                 snprintf(name, sizeof(name), "clkin%u", i);
 467
 468                 channel->clk_parent = devm_clk_get(dev, name);
 469                 if (IS_ERR(channel->clk_parent)) {
 470                         err = PTR_ERR(channel->clk_parent);
 471                         if (err == -EPROBE_DEFER)
 472                                 return err;
 473
 474                         channel->clk_parent = NULL;
 475                 }
 476         }
 477
 478         return 0;
 479 }
 480
 481 static void meson_pwm_add_channels(struct meson_pwm *meson,
 482                                    struct meson_pwm_channel *channels)
 483 {
 484         unsigned int i;
 485
 486         for (i = 0; i < meson->chip.npwm; i++)
 487                 pwm_set_chip_data(&meson->chip.pwms[i], &channels[i]);
 488 }
 489
 490 static int meson_pwm_probe(struct platform_device *pdev)
 491 {
 492         struct meson_pwm_channel *channels;
 493         struct meson_pwm *meson;
 494         struct resource *regs;
 495         int err;
 496
 497         meson = devm_kzalloc(&pdev->dev, sizeof(*meson), GFP_KERNEL);
 498         if (!meson)
 499                 return -ENOMEM;
 500
 501         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 502         meson->base = devm_ioremap_resource(&pdev->dev, regs);
 503         if (IS_ERR(meson->base))
 504                 return PTR_ERR(meson->base);
 505
 506         spin_lock_init(&meson->lock);
 507         meson->chip.dev = &pdev->dev;
 508         meson->chip.ops = &meson_pwm_ops;
 509         meson->chip.base = -1;
 510         meson->chip.npwm = 2;
 511         meson->chip.of_xlate = of_pwm_xlate_with_flags;
 512         meson->chip.of_pwm_n_cells = 3;
 513
 514         meson->data = of_device_get_match_data(&pdev->dev);
 515         meson->inverter_mask = BIT(meson->chip.npwm) - 1;
 516
 517         channels = devm_kcalloc(&pdev->dev, meson->chip.npwm, sizeof(*meson),
 518                                 GFP_KERNEL);
 519         if (!channels)
 520                 return -ENOMEM;
 521
 522         err = meson_pwm_init_channels(meson, channels);
 523         if (err < 0)
 524                 return err;
 525
 526         err = pwmchip_add(&meson->chip);
 527         if (err < 0) {
 528                 dev_err(&pdev->dev, "failed to register PWM chip: %d\n", err);
 529                 return err;
 530         }
 531
 532         meson_pwm_add_channels(meson, channels);
 533
 534         platform_set_drvdata(pdev, meson);
 535
 536         return 0;
 537 }
 538
 539 static int meson_pwm_remove(struct platform_device *pdev)
 540 {
 541         struct meson_pwm *meson = platform_get_drvdata(pdev);
 542
 543         return pwmchip_remove(&meson->chip);
 544 }
 545
 546 static struct platform_driver meson_pwm_driver = {
 547         .driver = {
 548                 .name = "meson-pwm",
 549                 .of_match_table = meson_pwm_matches,
 550         },
 551         .probe = meson_pwm_probe,
 552         .remove = meson_pwm_remove,
 553 };
 554 module_platform_driver(meson_pwm_driver);
 555
 556 MODULE_DESCRIPTION("Amlogic Meson PWM Generator driver");
 557 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
 558 MODULE_LICENSE("Dual BSD/GPL");