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         /*
 115          * Protects register (write) access to the REG_MISC_AB register
 116          * that is shared between the two PWMs.
 117          */
 118         spinlock_t lock;
 119 };
 120
 121 static inline struct meson_pwm *to_meson_pwm(struct pwm_chip *chip)
 122 {
 123         return container_of(chip, struct meson_pwm, chip);
 124 }
 125
 126 static int meson_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
 127 {
 128         struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
 129         struct device *dev = chip->dev;
 130         int err;
 131
 132         if (!channel)
 133                 return -ENODEV;
 134
 135         if (channel->clk_parent) {
 136                 err = clk_set_parent(channel->clk, channel->clk_parent);
 137                 if (err < 0) {
 138                         dev_err(dev, "failed to set parent %s for %s: %d\n",
 139                                 __clk_get_name(channel->clk_parent),
 140                                 __clk_get_name(channel->clk), err);
 141                                 return err;
 142                 }
 143         }
 144
 145         err = clk_prepare_enable(channel->clk);
 146         if (err < 0) {
 147                 dev_err(dev, "failed to enable clock %s: %d\n",
 148                         __clk_get_name(channel->clk), err);
 149                 return err;
 150         }
 151
 152         chip->ops->get_state(chip, pwm, &channel->state);
 153
 154         return 0;
 155 }
 156
 157 static void meson_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
 158 {
 159         struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
 160
 161         if (channel)
 162                 clk_disable_unprepare(channel->clk);
 163 }
 164
 165 static int meson_pwm_calc(struct meson_pwm *meson,
 166                           struct meson_pwm_channel *channel, unsigned int id,
 167                           unsigned int duty, unsigned int period)
 168 {
 169         unsigned int pre_div, cnt, duty_cnt;
 170         unsigned long fin_freq = -1;
 171         u64 fin_ps;
 172
 173         if (~(meson->inverter_mask >> id) & 0x1)
 174                 duty = period - duty;
 175
 176         if (period == channel->state.period &&
 177             duty == channel->state.duty_cycle)
 178                 return 0;
 179
 180         fin_freq = clk_get_rate(channel->clk);
 181         if (fin_freq == 0) {
 182                 dev_err(meson->chip.dev, "invalid source clock frequency\n");
 183                 return -EINVAL;
 184         }
 185
 186         dev_dbg(meson->chip.dev, "fin_freq: %lu Hz\n", fin_freq);
 187         fin_ps = (u64)NSEC_PER_SEC * 1000;
 188         do_div(fin_ps, fin_freq);
 189
 190         /* Calc pre_div with the period */
 191         for (pre_div = 0; pre_div <= MISC_CLK_DIV_MASK; pre_div++) {
 192                 cnt = DIV_ROUND_CLOSEST_ULL((u64)period * 1000,
 193                                             fin_ps * (pre_div + 1));
 194                 dev_dbg(meson->chip.dev, "fin_ps=%llu pre_div=%u cnt=%u\n",
 195                         fin_ps, pre_div, cnt);
 196                 if (cnt <= 0xffff)
 197                         break;
 198         }
 199
 200         if (pre_div > MISC_CLK_DIV_MASK) {
 201                 dev_err(meson->chip.dev, "unable to get period pre_div\n");
 202                 return -EINVAL;
 203         }
 204
 205         dev_dbg(meson->chip.dev, "period=%u pre_div=%u cnt=%u\n", period,
 206                 pre_div, cnt);
 207
 208         if (duty == period) {
 209                 channel->pre_div = pre_div;
 210                 channel->hi = cnt;
 211                 channel->lo = 0;
 212         } else if (duty == 0) {
 213                 channel->pre_div = pre_div;
 214                 channel->hi = 0;
 215                 channel->lo = cnt;
 216         } else {
 217                 /* Then check is we can have the duty with the same pre_div */
 218                 duty_cnt = DIV_ROUND_CLOSEST_ULL((u64)duty * 1000,
 219                                                  fin_ps * (pre_div + 1));
 220                 if (duty_cnt > 0xffff) {
 221                         dev_err(meson->chip.dev, "unable to get duty cycle\n");
 222                         return -EINVAL;
 223                 }
 224
 225                 dev_dbg(meson->chip.dev, "duty=%u pre_div=%u duty_cnt=%u\n",
 226                         duty, pre_div, duty_cnt);
 227
 228                 channel->pre_div = pre_div;
 229                 channel->hi = duty_cnt;
 230                 channel->lo = cnt - duty_cnt;
 231         }
 232
 233         return 0;
 234 }
 235
 236 static void meson_pwm_enable(struct meson_pwm *meson,
 237                              struct meson_pwm_channel *channel,
 238                              unsigned int id)
 239 {
 240         u32 value, clk_shift, clk_enable, enable;
 241         unsigned int offset;
 242         unsigned long flags;
 243
 244         switch (id) {
 245         case 0:
 246                 clk_shift = MISC_A_CLK_DIV_SHIFT;
 247                 clk_enable = MISC_A_CLK_EN;
 248                 enable = MISC_A_EN;
 249                 offset = REG_PWM_A;
 250                 break;
 251
 252         case 1:
 253                 clk_shift = MISC_B_CLK_DIV_SHIFT;
 254                 clk_enable = MISC_B_CLK_EN;
 255                 enable = MISC_B_EN;
 256                 offset = REG_PWM_B;
 257                 break;
 258
 259         default:
 260                 return;
 261         }
 262
 263         spin_lock_irqsave(&meson->lock, flags);
 264
 265         value = readl(meson->base + REG_MISC_AB);
 266         value &= ~(MISC_CLK_DIV_MASK << clk_shift);
 267         value |= channel->pre_div << clk_shift;
 268         value |= clk_enable;
 269         writel(value, meson->base + REG_MISC_AB);
 270
 271         value = (channel->hi << PWM_HIGH_SHIFT) | channel->lo;
 272         writel(value, meson->base + offset);
 273
 274         value = readl(meson->base + REG_MISC_AB);
 275         value |= enable;
 276         writel(value, meson->base + REG_MISC_AB);
 277
 278         spin_unlock_irqrestore(&meson->lock, flags);
 279 }
 280
 281 static void meson_pwm_disable(struct meson_pwm *meson, unsigned int id)
 282 {
 283         u32 value, enable;
 284         unsigned long flags;
 285
 286         switch (id) {
 287         case 0:
 288                 enable = MISC_A_EN;
 289                 break;
 290
 291         case 1:
 292                 enable = MISC_B_EN;
 293                 break;
 294
 295         default:
 296                 return;
 297         }
 298
 299         spin_lock_irqsave(&meson->lock, flags);
 300
 301         value = readl(meson->base + REG_MISC_AB);
 302         value &= ~enable;
 303         writel(value, meson->base + REG_MISC_AB);
 304
 305         spin_unlock_irqrestore(&meson->lock, flags);
 306 }
 307
 308 static int meson_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 309                            struct pwm_state *state)
 310 {
 311         struct meson_pwm_channel *channel = pwm_get_chip_data(pwm);
 312         struct meson_pwm *meson = to_meson_pwm(chip);
 313         int err = 0;
 314
 315         if (!state)
 316                 return -EINVAL;
 317
 318         if (!state->enabled) {
 319                 meson_pwm_disable(meson, pwm->hwpwm);
 320                 channel->state.enabled = false;
 321
 322                 return 0;
 323         }
 324
 325         if (state->period != channel->state.period ||
 326             state->duty_cycle != channel->state.duty_cycle ||
 327             state->polarity != channel->state.polarity) {
 328                 if (state->polarity != channel->state.polarity) {
 329                         if (state->polarity == PWM_POLARITY_NORMAL)
 330                                 meson->inverter_mask |= BIT(pwm->hwpwm);
 331                         else
 332                                 meson->inverter_mask &= ~BIT(pwm->hwpwm);
 333                 }
 334
 335                 err = meson_pwm_calc(meson, channel, pwm->hwpwm,
 336                                      state->duty_cycle, state->period);
 337                 if (err < 0)
 338                         return err;
 339
 340                 channel->state.polarity = state->polarity;
 341                 channel->state.period = state->period;
 342                 channel->state.duty_cycle = state->duty_cycle;
 343         }
 344
 345         if (state->enabled && !channel->state.enabled) {
 346                 meson_pwm_enable(meson, channel, pwm->hwpwm);
 347                 channel->state.enabled = true;
 348         }
 349
 350         return 0;
 351 }
 352
 353 static void meson_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 354                                 struct pwm_state *state)
 355 {
 356         struct meson_pwm *meson = to_meson_pwm(chip);
 357         u32 value, mask;
 358
 359         if (!state)
 360                 return;
 361
 362         switch (pwm->hwpwm) {
 363         case 0:
 364                 mask = MISC_A_EN;
 365                 break;
 366
 367         case 1:
 368                 mask = MISC_B_EN;
 369                 break;
 370
 371         default:
 372                 return;
 373         }
 374
 375         value = readl(meson->base + REG_MISC_AB);
 376         state->enabled = (value & mask) != 0;
 377 }
 378
 379 static const struct pwm_ops meson_pwm_ops = {
 380         .request = meson_pwm_request,
 381         .free = meson_pwm_free,
 382         .apply = meson_pwm_apply,
 383         .get_state = meson_pwm_get_state,
 384         .owner = THIS_MODULE,
 385 };
 386
 387 static const char * const pwm_meson8b_parent_names[] = {
 388         "xtal", "vid_pll", "fclk_div4", "fclk_div3"
 389 };
 390
 391 static const struct meson_pwm_data pwm_meson8b_data = {
 392         .parent_names = pwm_meson8b_parent_names,
 393         .num_parents = ARRAY_SIZE(pwm_meson8b_parent_names),
 394 };
 395
 396 static const char * const pwm_gxbb_parent_names[] = {
 397         "xtal", "hdmi_pll", "fclk_div4", "fclk_div3"
 398 };
 399
 400 static const struct meson_pwm_data pwm_gxbb_data = {
 401         .parent_names = pwm_gxbb_parent_names,
 402         .num_parents = ARRAY_SIZE(pwm_gxbb_parent_names),
 403 };
 404
 405 /*
 406  * Only the 2 first inputs of the GXBB AO PWMs are valid
 407  * The last 2 are grounded
 408  */
 409 static const char * const pwm_gxbb_ao_parent_names[] = {
 410         "xtal", "clk81"
 411 };
 412
 413 static const struct meson_pwm_data pwm_gxbb_ao_data = {
 414         .parent_names = pwm_gxbb_ao_parent_names,
 415         .num_parents = ARRAY_SIZE(pwm_gxbb_ao_parent_names),
 416 };
 417
 418 static const struct of_device_id meson_pwm_matches[] = {
 419         {
 420                 .compatible = "amlogic,meson8b-pwm",
 421                 .data = &pwm_meson8b_data
 422         },
 423         {
 424                 .compatible = "amlogic,meson-gxbb-pwm",
 425                 .data = &pwm_gxbb_data
 426         },
 427         {
 428                 .compatible = "amlogic,meson-gxbb-ao-pwm",
 429                 .data = &pwm_gxbb_ao_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                                    struct meson_pwm_channel *channels)
 437 {
 438         struct device *dev = meson->chip.dev;
 439         struct clk_init_data init;
 440         unsigned int i;
 441         char name[255];
 442         int err;
 443
 444         for (i = 0; i < meson->chip.npwm; i++) {
 445                 struct meson_pwm_channel *channel = &channels[i];
 446
 447                 snprintf(name, sizeof(name), "%s#mux%u", dev_name(dev), i);
 448
 449                 init.name = name;
 450                 init.ops = &clk_mux_ops;
 451                 init.flags = CLK_IS_BASIC;
 452                 init.parent_names = meson->data->parent_names;
 453                 init.num_parents = meson->data->num_parents;
 454
 455                 channel->mux.reg = meson->base + REG_MISC_AB;
 456                 channel->mux.shift = mux_reg_shifts[i];
 457                 channel->mux.mask = BIT(MISC_CLK_SEL_WIDTH) - 1;
 458                 channel->mux.flags = 0;
 459                 channel->mux.lock = &meson->lock;
 460                 channel->mux.table = NULL;
 461                 channel->mux.hw.init = &init;
 462
 463                 channel->clk = devm_clk_register(dev, &channel->mux.hw);
 464                 if (IS_ERR(channel->clk)) {
 465                         err = PTR_ERR(channel->clk);
 466                         dev_err(dev, "failed to register %s: %d\n", name, err);
 467                         return err;
 468                 }
 469
 470                 snprintf(name, sizeof(name), "clkin%u", i);
 471
 472                 channel->clk_parent = devm_clk_get(dev, name);
 473                 if (IS_ERR(channel->clk_parent)) {
 474                         err = PTR_ERR(channel->clk_parent);
 475                         if (err == -EPROBE_DEFER)
 476                                 return err;
 477
 478                         channel->clk_parent = NULL;
 479                 }
 480         }
 481
 482         return 0;
 483 }
 484
 485 static void meson_pwm_add_channels(struct meson_pwm *meson,
 486                                    struct meson_pwm_channel *channels)
 487 {
 488         unsigned int i;
 489
 490         for (i = 0; i < meson->chip.npwm; i++)
 491                 pwm_set_chip_data(&meson->chip.pwms[i], &channels[i]);
 492 }
 493
 494 static int meson_pwm_probe(struct platform_device *pdev)
 495 {
 496         struct meson_pwm_channel *channels;
 497         struct meson_pwm *meson;
 498         struct resource *regs;
 499         int err;
 500
 501         meson = devm_kzalloc(&pdev->dev, sizeof(*meson), GFP_KERNEL);
 502         if (!meson)
 503                 return -ENOMEM;
 504
 505         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 506         meson->base = devm_ioremap_resource(&pdev->dev, regs);
 507         if (IS_ERR(meson->base))
 508                 return PTR_ERR(meson->base);
 509
 510         spin_lock_init(&meson->lock);
 511         meson->chip.dev = &pdev->dev;
 512         meson->chip.ops = &meson_pwm_ops;
 513         meson->chip.base = -1;
 514         meson->chip.npwm = 2;
 515         meson->chip.of_xlate = of_pwm_xlate_with_flags;
 516         meson->chip.of_pwm_n_cells = 3;
 517
 518         meson->data = of_device_get_match_data(&pdev->dev);
 519         meson->inverter_mask = BIT(meson->chip.npwm) - 1;
 520
 521         channels = devm_kcalloc(&pdev->dev, meson->chip.npwm, sizeof(*meson),
 522                                 GFP_KERNEL);
 523         if (!channels)
 524                 return -ENOMEM;
 525
 526         err = meson_pwm_init_channels(meson, channels);
 527         if (err < 0)
 528                 return err;
 529
 530         err = pwmchip_add(&meson->chip);
 531         if (err < 0) {
 532                 dev_err(&pdev->dev, "failed to register PWM chip: %d\n", err);
 533                 return err;
 534         }
 535
 536         meson_pwm_add_channels(meson, channels);
 537
 538         platform_set_drvdata(pdev, meson);
 539
 540         return 0;
 541 }
 542
 543 static int meson_pwm_remove(struct platform_device *pdev)
 544 {
 545         struct meson_pwm *meson = platform_get_drvdata(pdev);
 546
 547         return pwmchip_remove(&meson->chip);
 548 }
 549
 550 static struct platform_driver meson_pwm_driver = {
 551         .driver = {
 552                 .name = "meson-pwm",
 553                 .of_match_table = meson_pwm_matches,
 554         },
 555         .probe = meson_pwm_probe,
 556         .remove = meson_pwm_remove,
 557 };
 558 module_platform_driver(meson_pwm_driver);
 559
 560 MODULE_DESCRIPTION("Amlogic Meson PWM Generator driver");
 561 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
 562 MODULE_LICENSE("Dual BSD/GPL");