drivers/counter/stm32-timer-cnt.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * STM32 Timer Encoder and Counter driver
   4  *
   5  * Copyright (C) STMicroelectronics 2018
   6  *
   7  * Author: Benjamin Gaignard <benjamin.gaignard@st.com>
   8  *
   9  */
  10 #include <linux/counter.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/mfd/stm32-timers.h>
  13 #include <linux/mod_devicetable.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/pinctrl/consumer.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/types.h>
  19
  20 #define TIM_CCMR_CCXS   (BIT(8) | BIT(0))
  21 #define TIM_CCMR_MASK   (TIM_CCMR_CC1S | TIM_CCMR_CC2S | \
  22                          TIM_CCMR_IC1F | TIM_CCMR_IC2F)
  23 #define TIM_CCER_MASK   (TIM_CCER_CC1P | TIM_CCER_CC1NP | \
  24                          TIM_CCER_CC2P | TIM_CCER_CC2NP)
  25
  26 #define STM32_CH1_SIG           0
  27 #define STM32_CH2_SIG           1
  28 #define STM32_CLOCK_SIG         2
  29 #define STM32_CH3_SIG           3
  30 #define STM32_CH4_SIG           4
  31
  32 struct stm32_timer_regs {
  33         u32 cr1;
  34         u32 cnt;
  35         u32 smcr;
  36         u32 arr;
  37 };
  38
  39 struct stm32_timer_cnt {
  40         struct regmap *regmap;
  41         struct clk *clk;
  42         u32 max_arr;
  43         bool enabled;
  44         struct stm32_timer_regs bak;
  45         bool has_encoder;
  46         unsigned int nchannels;
  47         unsigned int nr_irqs;
  48         spinlock_t lock; /* protects nb_ovf */
  49         u64 nb_ovf;
  50 };
  51
  52 static const enum counter_function stm32_count_functions[] = {
  53         COUNTER_FUNCTION_INCREASE,
  54         COUNTER_FUNCTION_QUADRATURE_X2_A,
  55         COUNTER_FUNCTION_QUADRATURE_X2_B,
  56         COUNTER_FUNCTION_QUADRATURE_X4,
  57 };
  58
  59 static int stm32_count_read(struct counter_device *counter,
  60                             struct counter_count *count, u64 *val)
  61 {
  62         struct stm32_timer_cnt *const priv = counter_priv(counter);
  63         u32 cnt;
  64
  65         regmap_read(priv->regmap, TIM_CNT, &cnt);
  66         *val = cnt;
  67
  68         return 0;
  69 }
  70
  71 static int stm32_count_write(struct counter_device *counter,
  72                              struct counter_count *count, const u64 val)
  73 {
  74         struct stm32_timer_cnt *const priv = counter_priv(counter);
  75         u32 ceiling;
  76
  77         regmap_read(priv->regmap, TIM_ARR, &ceiling);
  78         if (val > ceiling)
  79                 return -EINVAL;
  80
  81         return regmap_write(priv->regmap, TIM_CNT, val);
  82 }
  83
  84 static int stm32_count_function_read(struct counter_device *counter,
  85                                      struct counter_count *count,
  86                                      enum counter_function *function)
  87 {
  88         struct stm32_timer_cnt *const priv = counter_priv(counter);
  89         u32 smcr;
  90
  91         regmap_read(priv->regmap, TIM_SMCR, &smcr);
  92
  93         switch (smcr & TIM_SMCR_SMS) {
  94         case TIM_SMCR_SMS_SLAVE_MODE_DISABLED:
  95                 *function = COUNTER_FUNCTION_INCREASE;
  96                 return 0;
  97         case TIM_SMCR_SMS_ENCODER_MODE_1:
  98                 *function = COUNTER_FUNCTION_QUADRATURE_X2_A;
  99                 return 0;
 100         case TIM_SMCR_SMS_ENCODER_MODE_2:
 101                 *function = COUNTER_FUNCTION_QUADRATURE_X2_B;
 102                 return 0;
 103         case TIM_SMCR_SMS_ENCODER_MODE_3:
 104                 *function = COUNTER_FUNCTION_QUADRATURE_X4;
 105                 return 0;
 106         default:
 107                 return -EINVAL;
 108         }
 109 }
 110
 111 static int stm32_count_function_write(struct counter_device *counter,
 112                                       struct counter_count *count,
 113                                       enum counter_function function)
 114 {
 115         struct stm32_timer_cnt *const priv = counter_priv(counter);
 116         u32 cr1, sms;
 117
 118         switch (function) {
 119         case COUNTER_FUNCTION_INCREASE:
 120                 sms = TIM_SMCR_SMS_SLAVE_MODE_DISABLED;
 121                 break;
 122         case COUNTER_FUNCTION_QUADRATURE_X2_A:
 123                 if (!priv->has_encoder)
 124                         return -EOPNOTSUPP;
 125                 sms = TIM_SMCR_SMS_ENCODER_MODE_1;
 126                 break;
 127         case COUNTER_FUNCTION_QUADRATURE_X2_B:
 128                 if (!priv->has_encoder)
 129                         return -EOPNOTSUPP;
 130                 sms = TIM_SMCR_SMS_ENCODER_MODE_2;
 131                 break;
 132         case COUNTER_FUNCTION_QUADRATURE_X4:
 133                 if (!priv->has_encoder)
 134                         return -EOPNOTSUPP;
 135                 sms = TIM_SMCR_SMS_ENCODER_MODE_3;
 136                 break;
 137         default:
 138                 return -EINVAL;
 139         }
 140
 141         /* Store enable status */
 142         regmap_read(priv->regmap, TIM_CR1, &cr1);
 143
 144         regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
 145
 146         regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, sms);
 147
 148         /* Make sure that registers are updated */
 149         regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
 150
 151         /* Restore the enable status */
 152         regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, cr1);
 153
 154         return 0;
 155 }
 156
 157 static int stm32_count_direction_read(struct counter_device *counter,
 158                                       struct counter_count *count,
 159                                       enum counter_count_direction *direction)
 160 {
 161         struct stm32_timer_cnt *const priv = counter_priv(counter);
 162         u32 cr1;
 163
 164         regmap_read(priv->regmap, TIM_CR1, &cr1);
 165         *direction = (cr1 & TIM_CR1_DIR) ? COUNTER_COUNT_DIRECTION_BACKWARD :
 166                 COUNTER_COUNT_DIRECTION_FORWARD;
 167
 168         return 0;
 169 }
 170
 171 static int stm32_count_ceiling_read(struct counter_device *counter,
 172                                     struct counter_count *count, u64 *ceiling)
 173 {
 174         struct stm32_timer_cnt *const priv = counter_priv(counter);
 175         u32 arr;
 176
 177         regmap_read(priv->regmap, TIM_ARR, &arr);
 178
 179         *ceiling = arr;
 180
 181         return 0;
 182 }
 183
 184 static int stm32_count_ceiling_write(struct counter_device *counter,
 185                                      struct counter_count *count, u64 ceiling)
 186 {
 187         struct stm32_timer_cnt *const priv = counter_priv(counter);
 188
 189         if (ceiling > priv->max_arr)
 190                 return -ERANGE;
 191
 192         /* TIMx_ARR register shouldn't be buffered (ARPE=0) */
 193         regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
 194         regmap_write(priv->regmap, TIM_ARR, ceiling);
 195
 196         return 0;
 197 }
 198
 199 static int stm32_count_enable_read(struct counter_device *counter,
 200                                    struct counter_count *count, u8 *enable)
 201 {
 202         struct stm32_timer_cnt *const priv = counter_priv(counter);
 203         u32 cr1;
 204
 205         regmap_read(priv->regmap, TIM_CR1, &cr1);
 206
 207         *enable = cr1 & TIM_CR1_CEN;
 208
 209         return 0;
 210 }
 211
 212 static int stm32_count_enable_write(struct counter_device *counter,
 213                                     struct counter_count *count, u8 enable)
 214 {
 215         struct stm32_timer_cnt *const priv = counter_priv(counter);
 216         u32 cr1;
 217
 218         if (enable) {
 219                 regmap_read(priv->regmap, TIM_CR1, &cr1);
 220                 if (!(cr1 & TIM_CR1_CEN))
 221                         clk_enable(priv->clk);
 222
 223                 regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN,
 224                                    TIM_CR1_CEN);
 225         } else {
 226                 regmap_read(priv->regmap, TIM_CR1, &cr1);
 227                 regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
 228                 if (cr1 & TIM_CR1_CEN)
 229                         clk_disable(priv->clk);
 230         }
 231
 232         /* Keep enabled state to properly handle low power states */
 233         priv->enabled = enable;
 234
 235         return 0;
 236 }
 237
 238 static int stm32_count_prescaler_read(struct counter_device *counter,
 239                                       struct counter_count *count, u64 *prescaler)
 240 {
 241         struct stm32_timer_cnt *const priv = counter_priv(counter);
 242         u32 psc;
 243
 244         regmap_read(priv->regmap, TIM_PSC, &psc);
 245
 246         *prescaler = psc + 1;
 247
 248         return 0;
 249 }
 250
 251 static int stm32_count_prescaler_write(struct counter_device *counter,
 252                                        struct counter_count *count, u64 prescaler)
 253 {
 254         struct stm32_timer_cnt *const priv = counter_priv(counter);
 255         u32 psc;
 256
 257         if (!prescaler || prescaler > MAX_TIM_PSC + 1)
 258                 return -ERANGE;
 259
 260         psc = prescaler - 1;
 261
 262         return regmap_write(priv->regmap, TIM_PSC, psc);
 263 }
 264
 265 static int stm32_count_cap_read(struct counter_device *counter,
 266                                 struct counter_count *count,
 267                                 size_t ch, u64 *cap)
 268 {
 269         struct stm32_timer_cnt *const priv = counter_priv(counter);
 270         u32 ccrx;
 271
 272         if (ch >= priv->nchannels)
 273                 return -EOPNOTSUPP;
 274
 275         switch (ch) {
 276         case 0:
 277                 regmap_read(priv->regmap, TIM_CCR1, &ccrx);
 278                 break;
 279         case 1:
 280                 regmap_read(priv->regmap, TIM_CCR2, &ccrx);
 281                 break;
 282         case 2:
 283                 regmap_read(priv->regmap, TIM_CCR3, &ccrx);
 284                 break;
 285         case 3:
 286                 regmap_read(priv->regmap, TIM_CCR4, &ccrx);
 287                 break;
 288         default:
 289                 return -EINVAL;
 290         }
 291
 292         dev_dbg(counter->parent, "CCR%zu: 0x%08x\n", ch + 1, ccrx);
 293
 294         *cap = ccrx;
 295
 296         return 0;
 297 }
 298
 299 static int stm32_count_nb_ovf_read(struct counter_device *counter,
 300                                    struct counter_count *count, u64 *val)
 301 {
 302         struct stm32_timer_cnt *const priv = counter_priv(counter);
 303         unsigned long irqflags;
 304
 305         spin_lock_irqsave(&priv->lock, irqflags);
 306         *val = priv->nb_ovf;
 307         spin_unlock_irqrestore(&priv->lock, irqflags);
 308
 309         return 0;
 310 }
 311
 312 static int stm32_count_nb_ovf_write(struct counter_device *counter,
 313                                     struct counter_count *count, u64 val)
 314 {
 315         struct stm32_timer_cnt *const priv = counter_priv(counter);
 316         unsigned long irqflags;
 317
 318         spin_lock_irqsave(&priv->lock, irqflags);
 319         priv->nb_ovf = val;
 320         spin_unlock_irqrestore(&priv->lock, irqflags);
 321
 322         return 0;
 323 }
 324
 325 static DEFINE_COUNTER_ARRAY_CAPTURE(stm32_count_cap_array, 4);
 326
 327 static struct counter_comp stm32_count_ext[] = {
 328         COUNTER_COMP_DIRECTION(stm32_count_direction_read),
 329         COUNTER_COMP_ENABLE(stm32_count_enable_read, stm32_count_enable_write),
 330         COUNTER_COMP_CEILING(stm32_count_ceiling_read,
 331                              stm32_count_ceiling_write),
 332         COUNTER_COMP_COUNT_U64("prescaler", stm32_count_prescaler_read,
 333                                stm32_count_prescaler_write),
 334         COUNTER_COMP_ARRAY_CAPTURE(stm32_count_cap_read, NULL, stm32_count_cap_array),
 335         COUNTER_COMP_COUNT_U64("num_overflows", stm32_count_nb_ovf_read, stm32_count_nb_ovf_write),
 336 };
 337
 338 static const enum counter_synapse_action stm32_clock_synapse_actions[] = {
 339         COUNTER_SYNAPSE_ACTION_RISING_EDGE,
 340 };
 341
 342 static const enum counter_synapse_action stm32_synapse_actions[] = {
 343         COUNTER_SYNAPSE_ACTION_NONE,
 344         COUNTER_SYNAPSE_ACTION_BOTH_EDGES
 345 };
 346
 347 static int stm32_action_read(struct counter_device *counter,
 348                              struct counter_count *count,
 349                              struct counter_synapse *synapse,
 350                              enum counter_synapse_action *action)
 351 {
 352         enum counter_function function;
 353         int err;
 354
 355         err = stm32_count_function_read(counter, count, &function);
 356         if (err)
 357                 return err;
 358
 359         switch (function) {
 360         case COUNTER_FUNCTION_INCREASE:
 361                 /* counts on internal clock when CEN=1 */
 362                 if (synapse->signal->id == STM32_CLOCK_SIG)
 363                         *action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
 364                 else
 365                         *action = COUNTER_SYNAPSE_ACTION_NONE;
 366                 return 0;
 367         case COUNTER_FUNCTION_QUADRATURE_X2_A:
 368                 /* counts up/down on TI1FP1 edge depending on TI2FP2 level */
 369                 if (synapse->signal->id == STM32_CH1_SIG)
 370                         *action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 371                 else
 372                         *action = COUNTER_SYNAPSE_ACTION_NONE;
 373                 return 0;
 374         case COUNTER_FUNCTION_QUADRATURE_X2_B:
 375                 /* counts up/down on TI2FP2 edge depending on TI1FP1 level */
 376                 if (synapse->signal->id == STM32_CH2_SIG)
 377                         *action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 378                 else
 379                         *action = COUNTER_SYNAPSE_ACTION_NONE;
 380                 return 0;
 381         case COUNTER_FUNCTION_QUADRATURE_X4:
 382                 /* counts up/down on both TI1FP1 and TI2FP2 edges */
 383                 if (synapse->signal->id == STM32_CH1_SIG || synapse->signal->id == STM32_CH2_SIG)
 384                         *action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 385                 else
 386                         *action = COUNTER_SYNAPSE_ACTION_NONE;
 387                 return 0;
 388         default:
 389                 return -EINVAL;
 390         }
 391 }
 392
 393 struct stm32_count_cc_regs {
 394         u32 ccmr_reg;
 395         u32 ccmr_mask;
 396         u32 ccmr_bits;
 397         u32 ccer_bits;
 398 };
 399
 400 static const struct stm32_count_cc_regs stm32_cc[] = {
 401         { TIM_CCMR1, TIM_CCMR_CC1S, TIM_CCMR_CC1S_TI1,
 402                 TIM_CCER_CC1E | TIM_CCER_CC1P | TIM_CCER_CC1NP },
 403         { TIM_CCMR1, TIM_CCMR_CC2S, TIM_CCMR_CC2S_TI2,
 404                 TIM_CCER_CC2E | TIM_CCER_CC2P | TIM_CCER_CC2NP },
 405         { TIM_CCMR2, TIM_CCMR_CC3S, TIM_CCMR_CC3S_TI3,
 406                 TIM_CCER_CC3E | TIM_CCER_CC3P | TIM_CCER_CC3NP },
 407         { TIM_CCMR2, TIM_CCMR_CC4S, TIM_CCMR_CC4S_TI4,
 408                 TIM_CCER_CC4E | TIM_CCER_CC4P | TIM_CCER_CC4NP },
 409 };
 410
 411 static int stm32_count_capture_configure(struct counter_device *counter, unsigned int ch,
 412                                          bool enable)
 413 {
 414         struct stm32_timer_cnt *const priv = counter_priv(counter);
 415         const struct stm32_count_cc_regs *cc;
 416         u32 ccmr, ccer;
 417
 418         if (ch >= ARRAY_SIZE(stm32_cc) || ch >= priv->nchannels) {
 419                 dev_err(counter->parent, "invalid ch: %d\n", ch);
 420                 return -EINVAL;
 421         }
 422
 423         cc = &stm32_cc[ch];
 424
 425         /*
 426          * configure channel in input capture mode, map channel 1 on TI1, channel2 on TI2...
 427          * Select both edges / non-inverted to trigger a capture.
 428          */
 429         if (enable) {
 430                 /* first clear possibly latched capture flag upon enabling */
 431                 if (!regmap_test_bits(priv->regmap, TIM_CCER, cc->ccer_bits))
 432                         regmap_write(priv->regmap, TIM_SR, ~TIM_SR_CC_IF(ch));
 433                 regmap_update_bits(priv->regmap, cc->ccmr_reg, cc->ccmr_mask,
 434                                    cc->ccmr_bits);
 435                 regmap_set_bits(priv->regmap, TIM_CCER, cc->ccer_bits);
 436         } else {
 437                 regmap_clear_bits(priv->regmap, TIM_CCER, cc->ccer_bits);
 438                 regmap_clear_bits(priv->regmap, cc->ccmr_reg, cc->ccmr_mask);
 439         }
 440
 441         regmap_read(priv->regmap, cc->ccmr_reg, &ccmr);
 442         regmap_read(priv->regmap, TIM_CCER, &ccer);
 443         dev_dbg(counter->parent, "%s(%s) ch%d 0x%08x 0x%08x\n", __func__, enable ? "ena" : "dis",
 444                 ch, ccmr, ccer);
 445
 446         return 0;
 447 }
 448
 449 static int stm32_count_events_configure(struct counter_device *counter)
 450 {
 451         struct stm32_timer_cnt *const priv = counter_priv(counter);
 452         struct counter_event_node *event_node;
 453         u32 dier = 0;
 454         int i, ret;
 455
 456         list_for_each_entry(event_node, &counter->events_list, l) {
 457                 switch (event_node->event) {
 458                 case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
 459                         /* first clear possibly latched UIF before enabling */
 460                         if (!regmap_test_bits(priv->regmap, TIM_DIER, TIM_DIER_UIE))
 461                                 regmap_write(priv->regmap, TIM_SR, (u32)~TIM_SR_UIF);
 462                         dier |= TIM_DIER_UIE;
 463                         break;
 464                 case COUNTER_EVENT_CAPTURE:
 465                         ret = stm32_count_capture_configure(counter, event_node->channel, true);
 466                         if (ret)
 467                                 return ret;
 468                         dier |= TIM_DIER_CCxIE(event_node->channel + 1);
 469                         break;
 470                 default:
 471                         /* should never reach this path */
 472                         return -EINVAL;
 473                 }
 474         }
 475
 476         /* Enable / disable all events at once, from events_list, so write all DIER bits */
 477         regmap_write(priv->regmap, TIM_DIER, dier);
 478
 479         /* check for disabled capture events */
 480         for (i = 0 ; i < priv->nchannels; i++) {
 481                 if (!(dier & TIM_DIER_CCxIE(i + 1))) {
 482                         ret = stm32_count_capture_configure(counter, i, false);
 483                         if (ret)
 484                                 return ret;
 485                 }
 486         }
 487
 488         return 0;
 489 }
 490
 491 static int stm32_count_watch_validate(struct counter_device *counter,
 492                                       const struct counter_watch *watch)
 493 {
 494         struct stm32_timer_cnt *const priv = counter_priv(counter);
 495
 496         /* Interrupts are optional */
 497         if (!priv->nr_irqs)
 498                 return -EOPNOTSUPP;
 499
 500         switch (watch->event) {
 501         case COUNTER_EVENT_CAPTURE:
 502                 if (watch->channel >= priv->nchannels) {
 503                         dev_err(counter->parent, "Invalid channel %d\n", watch->channel);
 504                         return -EINVAL;
 505                 }
 506                 return 0;
 507         case COUNTER_EVENT_OVERFLOW_UNDERFLOW:
 508                 return 0;
 509         default:
 510                 return -EINVAL;
 511         }
 512 }
 513
 514 static const struct counter_ops stm32_timer_cnt_ops = {
 515         .count_read = stm32_count_read,
 516         .count_write = stm32_count_write,
 517         .function_read = stm32_count_function_read,
 518         .function_write = stm32_count_function_write,
 519         .action_read = stm32_action_read,
 520         .events_configure = stm32_count_events_configure,
 521         .watch_validate = stm32_count_watch_validate,
 522 };
 523
 524 static int stm32_count_clk_get_freq(struct counter_device *counter,
 525                                     struct counter_signal *signal, u64 *freq)
 526 {
 527         struct stm32_timer_cnt *const priv = counter_priv(counter);
 528
 529         *freq = clk_get_rate(priv->clk);
 530
 531         return 0;
 532 }
 533
 534 static struct counter_comp stm32_count_clock_ext[] = {
 535         COUNTER_COMP_FREQUENCY(stm32_count_clk_get_freq),
 536 };
 537
 538 static struct counter_signal stm32_signals[] = {
 539         /*
 540          * Need to declare all the signals as a static array, and keep the signals order here,
 541          * even if they're unused or unexisting on some timer instances. It's an abstraction,
 542          * e.g. high level view of the counter features.
 543          *
 544          * Userspace programs may rely on signal0 to be "Channel 1", signal1 to be "Channel 2",
 545          * and so on. When a signal is unexisting, the COUNTER_SYNAPSE_ACTION_NONE can be used,
 546          * to indicate that a signal doesn't affect the counter.
 547          */
 548         {
 549                 .id = STM32_CH1_SIG,
 550                 .name = "Channel 1"
 551         },
 552         {
 553                 .id = STM32_CH2_SIG,
 554                 .name = "Channel 2"
 555         },
 556         {
 557                 .id = STM32_CLOCK_SIG,
 558                 .name = "Clock",
 559                 .ext = stm32_count_clock_ext,
 560                 .num_ext = ARRAY_SIZE(stm32_count_clock_ext),
 561         },
 562         {
 563                 .id = STM32_CH3_SIG,
 564                 .name = "Channel 3"
 565         },
 566         {
 567                 .id = STM32_CH4_SIG,
 568                 .name = "Channel 4"
 569         },
 570 };
 571
 572 static struct counter_synapse stm32_count_synapses[] = {
 573         {
 574                 .actions_list = stm32_synapse_actions,
 575                 .num_actions = ARRAY_SIZE(stm32_synapse_actions),
 576                 .signal = &stm32_signals[STM32_CH1_SIG]
 577         },
 578         {
 579                 .actions_list = stm32_synapse_actions,
 580                 .num_actions = ARRAY_SIZE(stm32_synapse_actions),
 581                 .signal = &stm32_signals[STM32_CH2_SIG]
 582         },
 583         {
 584                 .actions_list = stm32_clock_synapse_actions,
 585                 .num_actions = ARRAY_SIZE(stm32_clock_synapse_actions),
 586                 .signal = &stm32_signals[STM32_CLOCK_SIG]
 587         },
 588         {
 589                 .actions_list = stm32_synapse_actions,
 590                 .num_actions = ARRAY_SIZE(stm32_synapse_actions),
 591                 .signal = &stm32_signals[STM32_CH3_SIG]
 592         },
 593         {
 594                 .actions_list = stm32_synapse_actions,
 595                 .num_actions = ARRAY_SIZE(stm32_synapse_actions),
 596                 .signal = &stm32_signals[STM32_CH4_SIG]
 597         },
 598 };
 599
 600 static struct counter_count stm32_counts = {
 601         .id = 0,
 602         .name = "STM32 Timer Counter",
 603         .functions_list = stm32_count_functions,
 604         .num_functions = ARRAY_SIZE(stm32_count_functions),
 605         .synapses = stm32_count_synapses,
 606         .num_synapses = ARRAY_SIZE(stm32_count_synapses),
 607         .ext = stm32_count_ext,
 608         .num_ext = ARRAY_SIZE(stm32_count_ext)
 609 };
 610
 611 static irqreturn_t stm32_timer_cnt_isr(int irq, void *ptr)
 612 {
 613         struct counter_device *counter = ptr;
 614         struct stm32_timer_cnt *const priv = counter_priv(counter);
 615         u32 clr = GENMASK(31, 0); /* SR flags can be cleared by writing 0 (wr 1 has no effect) */
 616         u32 sr, dier;
 617         int i;
 618
 619         regmap_read(priv->regmap, TIM_SR, &sr);
 620         regmap_read(priv->regmap, TIM_DIER, &dier);
 621         /*
 622          * Some status bits in SR don't match with the enable bits in DIER. Only take care of
 623          * the possibly enabled bits in DIER (that matches in between SR and DIER).
 624          */
 625         dier &= (TIM_DIER_UIE | TIM_DIER_CC1IE | TIM_DIER_CC2IE | TIM_DIER_CC3IE | TIM_DIER_CC4IE);
 626         sr &= dier;
 627
 628         if (sr & TIM_SR_UIF) {
 629                 spin_lock(&priv->lock);
 630                 priv->nb_ovf++;
 631                 spin_unlock(&priv->lock);
 632                 counter_push_event(counter, COUNTER_EVENT_OVERFLOW_UNDERFLOW, 0);
 633                 dev_dbg(counter->parent, "COUNTER_EVENT_OVERFLOW_UNDERFLOW\n");
 634                 /* SR flags can be cleared by writing 0, only clear relevant flag */
 635                 clr &= ~TIM_SR_UIF;
 636         }
 637
 638         /* Check capture events */
 639         for (i = 0 ; i < priv->nchannels; i++) {
 640                 if (sr & TIM_SR_CC_IF(i)) {
 641                         counter_push_event(counter, COUNTER_EVENT_CAPTURE, i);
 642                         clr &= ~TIM_SR_CC_IF(i);
 643                         dev_dbg(counter->parent, "COUNTER_EVENT_CAPTURE, %d\n", i);
 644                 }
 645         }
 646
 647         regmap_write(priv->regmap, TIM_SR, clr);
 648
 649         return IRQ_HANDLED;
 650 };
 651
 652 static void stm32_timer_cnt_detect_channels(struct device *dev,
 653                                             struct stm32_timer_cnt *priv)
 654 {
 655         u32 ccer, ccer_backup;
 656
 657         regmap_read(priv->regmap, TIM_CCER, &ccer_backup);
 658         regmap_set_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE);
 659         regmap_read(priv->regmap, TIM_CCER, &ccer);
 660         regmap_write(priv->regmap, TIM_CCER, ccer_backup);
 661         priv->nchannels = hweight32(ccer & TIM_CCER_CCXE);
 662
 663         dev_dbg(dev, "has %d cc channels\n", priv->nchannels);
 664 }
 665
 666 /* encoder supported on TIM1 TIM2 TIM3 TIM4 TIM5 TIM8 */
 667 #define STM32_TIM_ENCODER_SUPPORTED     (BIT(0) | BIT(1) | BIT(2) | BIT(3) | BIT(4) | BIT(7))
 668
 669 static const char * const stm32_timer_trigger_compat[] = {
 670         "st,stm32-timer-trigger",
 671         "st,stm32h7-timer-trigger",
 672 };
 673
 674 static int stm32_timer_cnt_probe_encoder(struct device *dev,
 675                                          struct stm32_timer_cnt *priv)
 676 {
 677         struct device *parent = dev->parent;
 678         struct device_node *tnode = NULL, *pnode = parent->of_node;
 679         int i, ret;
 680         u32 idx;
 681
 682         /*
 683          * Need to retrieve the trigger node index from DT, to be able
 684          * to determine if the counter supports encoder mode. It also
 685          * enforce backward compatibility, and allow to support other
 686          * counter modes in this driver (when the timer doesn't support
 687          * encoder).
 688          */
 689         for (i = 0; i < ARRAY_SIZE(stm32_timer_trigger_compat) && !tnode; i++)
 690                 tnode = of_get_compatible_child(pnode, stm32_timer_trigger_compat[i]);
 691         if (!tnode) {
 692                 dev_err(dev, "Can't find trigger node\n");
 693                 return -ENODATA;
 694         }
 695
 696         ret = of_property_read_u32(tnode, "reg", &idx);
 697         if (ret) {
 698                 dev_err(dev, "Can't get index (%d)\n", ret);
 699                 return ret;
 700         }
 701
 702         priv->has_encoder = !!(STM32_TIM_ENCODER_SUPPORTED & BIT(idx));
 703
 704         dev_dbg(dev, "encoder support: %s\n", priv->has_encoder ? "yes" : "no");
 705
 706         return 0;
 707 }
 708
 709 static int stm32_timer_cnt_probe(struct platform_device *pdev)
 710 {
 711         struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
 712         struct device *dev = &pdev->dev;
 713         struct stm32_timer_cnt *priv;
 714         struct counter_device *counter;
 715         int i, ret;
 716
 717         if (IS_ERR_OR_NULL(ddata))
 718                 return -EINVAL;
 719
 720         counter = devm_counter_alloc(dev, sizeof(*priv));
 721         if (!counter)
 722                 return -ENOMEM;
 723
 724         priv = counter_priv(counter);
 725
 726         priv->regmap = ddata->regmap;
 727         priv->clk = ddata->clk;
 728         priv->max_arr = ddata->max_arr;
 729         priv->nr_irqs = ddata->nr_irqs;
 730
 731         ret = stm32_timer_cnt_probe_encoder(dev, priv);
 732         if (ret)
 733                 return ret;
 734
 735         stm32_timer_cnt_detect_channels(dev, priv);
 736
 737         counter->name = dev_name(dev);
 738         counter->parent = dev;
 739         counter->ops = &stm32_timer_cnt_ops;
 740         counter->counts = &stm32_counts;
 741         counter->num_counts = 1;
 742         counter->signals = stm32_signals;
 743         counter->num_signals = ARRAY_SIZE(stm32_signals);
 744
 745         spin_lock_init(&priv->lock);
 746
 747         platform_set_drvdata(pdev, priv);
 748
 749         /* STM32 Timers can have either 1 global, or 4 dedicated interrupts (optional) */
 750         if (priv->nr_irqs == 1) {
 751                 /* All events reported through the global interrupt */
 752                 ret = devm_request_irq(&pdev->dev, ddata->irq[0], stm32_timer_cnt_isr,
 753                                        0, dev_name(dev), counter);
 754                 if (ret) {
 755                         dev_err(dev, "Failed to request irq %d (err %d)\n",
 756                                 ddata->irq[0], ret);
 757                         return ret;
 758                 }
 759         } else {
 760                 for (i = 0; i < priv->nr_irqs; i++) {
 761                         /*
 762                          * Only take care of update IRQ for overflow events, and cc for
 763                          * capture events.
 764                          */
 765                         if (i != STM32_TIMERS_IRQ_UP && i != STM32_TIMERS_IRQ_CC)
 766                                 continue;
 767
 768                         ret = devm_request_irq(&pdev->dev, ddata->irq[i], stm32_timer_cnt_isr,
 769                                                0, dev_name(dev), counter);
 770                         if (ret) {
 771                                 dev_err(dev, "Failed to request irq %d (err %d)\n",
 772                                         ddata->irq[i], ret);
 773                                 return ret;
 774                         }
 775                 }
 776         }
 777
 778         /* Reset input selector to its default input */
 779         regmap_write(priv->regmap, TIM_TISEL, 0x0);
 780
 781         /* Register Counter device */
 782         ret = devm_counter_add(dev, counter);
 783         if (ret < 0)
 784                 dev_err_probe(dev, ret, "Failed to add counter\n");
 785
 786         return ret;
 787 }
 788
 789 static int __maybe_unused stm32_timer_cnt_suspend(struct device *dev)
 790 {
 791         struct stm32_timer_cnt *priv = dev_get_drvdata(dev);
 792
 793         /* Only take care of enabled counter: don't disturb other MFD child */
 794         if (priv->enabled) {
 795                 /* Backup registers that may get lost in low power mode */
 796                 regmap_read(priv->regmap, TIM_SMCR, &priv->bak.smcr);
 797                 regmap_read(priv->regmap, TIM_ARR, &priv->bak.arr);
 798                 regmap_read(priv->regmap, TIM_CNT, &priv->bak.cnt);
 799                 regmap_read(priv->regmap, TIM_CR1, &priv->bak.cr1);
 800
 801                 /* Disable the counter */
 802                 regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
 803                 clk_disable(priv->clk);
 804         }
 805
 806         return pinctrl_pm_select_sleep_state(dev);
 807 }
 808
 809 static int __maybe_unused stm32_timer_cnt_resume(struct device *dev)
 810 {
 811         struct stm32_timer_cnt *priv = dev_get_drvdata(dev);
 812         int ret;
 813
 814         ret = pinctrl_pm_select_default_state(dev);
 815         if (ret)
 816                 return ret;
 817
 818         if (priv->enabled) {
 819                 clk_enable(priv->clk);
 820
 821                 /* Restore registers that may have been lost */
 822                 regmap_write(priv->regmap, TIM_SMCR, priv->bak.smcr);
 823                 regmap_write(priv->regmap, TIM_ARR, priv->bak.arr);
 824                 regmap_write(priv->regmap, TIM_CNT, priv->bak.cnt);
 825
 826                 /* Also re-enables the counter */
 827                 regmap_write(priv->regmap, TIM_CR1, priv->bak.cr1);
 828         }
 829
 830         return 0;
 831 }
 832
 833 static SIMPLE_DEV_PM_OPS(stm32_timer_cnt_pm_ops, stm32_timer_cnt_suspend,
 834                          stm32_timer_cnt_resume);
 835
 836 static const struct of_device_id stm32_timer_cnt_of_match[] = {
 837         { .compatible = "st,stm32-timer-counter", },
 838         {},
 839 };
 840 MODULE_DEVICE_TABLE(of, stm32_timer_cnt_of_match);
 841
 842 static struct platform_driver stm32_timer_cnt_driver = {
 843         .probe = stm32_timer_cnt_probe,
 844         .driver = {
 845                 .name = "stm32-timer-counter",
 846                 .of_match_table = stm32_timer_cnt_of_match,
 847                 .pm = &stm32_timer_cnt_pm_ops,
 848         },
 849 };
 850 module_platform_driver(stm32_timer_cnt_driver);
 851
 852 MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");
 853 MODULE_ALIAS("platform:stm32-timer-counter");
 854 MODULE_DESCRIPTION("STMicroelectronics STM32 TIMER counter driver");
 855 MODULE_LICENSE("GPL v2");
 856 MODULE_IMPORT_NS(COUNTER);