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/iio/iio.h>
  12 #include <linux/iio/types.h>
  13 #include <linux/mfd/stm32-timers.h>
  14 #include <linux/module.h>
  15 #include <linux/platform_device.h>
  16
  17 #define TIM_CCMR_CCXS   (BIT(8) | BIT(0))
  18 #define TIM_CCMR_MASK   (TIM_CCMR_CC1S | TIM_CCMR_CC2S | \
  19                          TIM_CCMR_IC1F | TIM_CCMR_IC2F)
  20 #define TIM_CCER_MASK   (TIM_CCER_CC1P | TIM_CCER_CC1NP | \
  21                          TIM_CCER_CC2P | TIM_CCER_CC2NP)
  22
  23 struct stm32_timer_cnt {
  24         struct counter_device counter;
  25         struct regmap *regmap;
  26         struct clk *clk;
  27         u32 ceiling;
  28 };
  29
  30 /**
  31  * enum stm32_count_function - enumerates stm32 timer counter encoder modes
  32  * @STM32_COUNT_SLAVE_MODE_DISABLED: counts on internal clock when CEN=1
  33  * @STM32_COUNT_ENCODER_MODE_1: counts TI1FP1 edges, depending on TI2FP2 level
  34  * @STM32_COUNT_ENCODER_MODE_2: counts TI2FP2 edges, depending on TI1FP1 level
  35  * @STM32_COUNT_ENCODER_MODE_3: counts on both TI1FP1 and TI2FP2 edges
  36  */
  37 enum stm32_count_function {
  38         STM32_COUNT_SLAVE_MODE_DISABLED = -1,
  39         STM32_COUNT_ENCODER_MODE_1,
  40         STM32_COUNT_ENCODER_MODE_2,
  41         STM32_COUNT_ENCODER_MODE_3,
  42 };
  43
  44 static enum counter_count_function stm32_count_functions[] = {
  45         [STM32_COUNT_ENCODER_MODE_1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
  46         [STM32_COUNT_ENCODER_MODE_2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
  47         [STM32_COUNT_ENCODER_MODE_3] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
  48 };
  49
  50 static int stm32_count_read(struct counter_device *counter,
  51                             struct counter_count *count, unsigned long *val)
  52 {
  53         struct stm32_timer_cnt *const priv = counter->priv;
  54         u32 cnt;
  55
  56         regmap_read(priv->regmap, TIM_CNT, &cnt);
  57         *val = cnt;
  58
  59         return 0;
  60 }
  61
  62 static int stm32_count_write(struct counter_device *counter,
  63                              struct counter_count *count,
  64                              const unsigned long val)
  65 {
  66         struct stm32_timer_cnt *const priv = counter->priv;
  67
  68         if (val > priv->ceiling)
  69                 return -EINVAL;
  70
  71         return regmap_write(priv->regmap, TIM_CNT, val);
  72 }
  73
  74 static int stm32_count_function_get(struct counter_device *counter,
  75                                     struct counter_count *count,
  76                                     size_t *function)
  77 {
  78         struct stm32_timer_cnt *const priv = counter->priv;
  79         u32 smcr;
  80
  81         regmap_read(priv->regmap, TIM_SMCR, &smcr);
  82
  83         switch (smcr & TIM_SMCR_SMS) {
  84         case 1:
  85                 *function = STM32_COUNT_ENCODER_MODE_1;
  86                 return 0;
  87         case 2:
  88                 *function = STM32_COUNT_ENCODER_MODE_2;
  89                 return 0;
  90         case 3:
  91                 *function = STM32_COUNT_ENCODER_MODE_3;
  92                 return 0;
  93         }
  94
  95         return -EINVAL;
  96 }
  97
  98 static int stm32_count_function_set(struct counter_device *counter,
  99                                     struct counter_count *count,
 100                                     size_t function)
 101 {
 102         struct stm32_timer_cnt *const priv = counter->priv;
 103         u32 cr1, sms;
 104
 105         switch (function) {
 106         case STM32_COUNT_ENCODER_MODE_1:
 107                 sms = 1;
 108                 break;
 109         case STM32_COUNT_ENCODER_MODE_2:
 110                 sms = 2;
 111                 break;
 112         case STM32_COUNT_ENCODER_MODE_3:
 113                 sms = 3;
 114                 break;
 115         default:
 116                 sms = 0;
 117                 break;
 118         }
 119
 120         /* Store enable status */
 121         regmap_read(priv->regmap, TIM_CR1, &cr1);
 122
 123         regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
 124
 125         /* TIMx_ARR register shouldn't be buffered (ARPE=0) */
 126         regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
 127         regmap_write(priv->regmap, TIM_ARR, priv->ceiling);
 128
 129         regmap_update_bits(priv->regmap, TIM_SMCR, TIM_SMCR_SMS, sms);
 130
 131         /* Make sure that registers are updated */
 132         regmap_update_bits(priv->regmap, TIM_EGR, TIM_EGR_UG, TIM_EGR_UG);
 133
 134         /* Restore the enable status */
 135         regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, cr1);
 136
 137         return 0;
 138 }
 139
 140 static ssize_t stm32_count_direction_read(struct counter_device *counter,
 141                                       struct counter_count *count,
 142                                       void *private, char *buf)
 143 {
 144         struct stm32_timer_cnt *const priv = counter->priv;
 145         const char *direction;
 146         u32 cr1;
 147
 148         regmap_read(priv->regmap, TIM_CR1, &cr1);
 149         direction = (cr1 & TIM_CR1_DIR) ? "backward" : "forward";
 150
 151         return scnprintf(buf, PAGE_SIZE, "%s\n", direction);
 152 }
 153
 154 static ssize_t stm32_count_ceiling_read(struct counter_device *counter,
 155                                         struct counter_count *count,
 156                                         void *private, char *buf)
 157 {
 158         struct stm32_timer_cnt *const priv = counter->priv;
 159         u32 arr;
 160
 161         regmap_read(priv->regmap, TIM_ARR, &arr);
 162
 163         return snprintf(buf, PAGE_SIZE, "%u\n", arr);
 164 }
 165
 166 static ssize_t stm32_count_ceiling_write(struct counter_device *counter,
 167                                          struct counter_count *count,
 168                                          void *private,
 169                                          const char *buf, size_t len)
 170 {
 171         struct stm32_timer_cnt *const priv = counter->priv;
 172         unsigned int ceiling;
 173         int ret;
 174
 175         ret = kstrtouint(buf, 0, &ceiling);
 176         if (ret)
 177                 return ret;
 178
 179         /* TIMx_ARR register shouldn't be buffered (ARPE=0) */
 180         regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
 181         regmap_write(priv->regmap, TIM_ARR, ceiling);
 182
 183         priv->ceiling = ceiling;
 184         return len;
 185 }
 186
 187 static ssize_t stm32_count_enable_read(struct counter_device *counter,
 188                                        struct counter_count *count,
 189                                        void *private, char *buf)
 190 {
 191         struct stm32_timer_cnt *const priv = counter->priv;
 192         u32 cr1;
 193
 194         regmap_read(priv->regmap, TIM_CR1, &cr1);
 195
 196         return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)(cr1 & TIM_CR1_CEN));
 197 }
 198
 199 static ssize_t stm32_count_enable_write(struct counter_device *counter,
 200                                         struct counter_count *count,
 201                                         void *private,
 202                                         const char *buf, size_t len)
 203 {
 204         struct stm32_timer_cnt *const priv = counter->priv;
 205         int err;
 206         u32 cr1;
 207         bool enable;
 208
 209         err = kstrtobool(buf, &enable);
 210         if (err)
 211                 return err;
 212
 213         if (enable) {
 214                 regmap_read(priv->regmap, TIM_CR1, &cr1);
 215                 if (!(cr1 & TIM_CR1_CEN))
 216                         clk_enable(priv->clk);
 217
 218                 regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN,
 219                                    TIM_CR1_CEN);
 220         } else {
 221                 regmap_read(priv->regmap, TIM_CR1, &cr1);
 222                 regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_CEN, 0);
 223                 if (cr1 & TIM_CR1_CEN)
 224                         clk_disable(priv->clk);
 225         }
 226
 227         return len;
 228 }
 229
 230 static const struct counter_count_ext stm32_count_ext[] = {
 231         {
 232                 .name = "direction",
 233                 .read = stm32_count_direction_read,
 234         },
 235         {
 236                 .name = "enable",
 237                 .read = stm32_count_enable_read,
 238                 .write = stm32_count_enable_write
 239         },
 240         {
 241                 .name = "ceiling",
 242                 .read = stm32_count_ceiling_read,
 243                 .write = stm32_count_ceiling_write
 244         },
 245 };
 246
 247 enum stm32_synapse_action {
 248         STM32_SYNAPSE_ACTION_NONE,
 249         STM32_SYNAPSE_ACTION_BOTH_EDGES
 250 };
 251
 252 static enum counter_synapse_action stm32_synapse_actions[] = {
 253         [STM32_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
 254         [STM32_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES
 255 };
 256
 257 static int stm32_action_get(struct counter_device *counter,
 258                             struct counter_count *count,
 259                             struct counter_synapse *synapse,
 260                             size_t *action)
 261 {
 262         size_t function;
 263         int err;
 264
 265         /* Default action mode (e.g. STM32_COUNT_SLAVE_MODE_DISABLED) */
 266         *action = STM32_SYNAPSE_ACTION_NONE;
 267
 268         err = stm32_count_function_get(counter, count, &function);
 269         if (err)
 270                 return 0;
 271
 272         switch (function) {
 273         case STM32_COUNT_ENCODER_MODE_1:
 274                 /* counts up/down on TI1FP1 edge depending on TI2FP2 level */
 275                 if (synapse->signal->id == count->synapses[0].signal->id)
 276                         *action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
 277                 break;
 278         case STM32_COUNT_ENCODER_MODE_2:
 279                 /* counts up/down on TI2FP2 edge depending on TI1FP1 level */
 280                 if (synapse->signal->id == count->synapses[1].signal->id)
 281                         *action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
 282                 break;
 283         case STM32_COUNT_ENCODER_MODE_3:
 284                 /* counts up/down on both TI1FP1 and TI2FP2 edges */
 285                 *action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
 286                 break;
 287         }
 288
 289         return 0;
 290 }
 291
 292 static const struct counter_ops stm32_timer_cnt_ops = {
 293         .count_read = stm32_count_read,
 294         .count_write = stm32_count_write,
 295         .function_get = stm32_count_function_get,
 296         .function_set = stm32_count_function_set,
 297         .action_get = stm32_action_get,
 298 };
 299
 300 static struct counter_signal stm32_signals[] = {
 301         {
 302                 .id = 0,
 303                 .name = "Channel 1 Quadrature A"
 304         },
 305         {
 306                 .id = 1,
 307                 .name = "Channel 1 Quadrature B"
 308         }
 309 };
 310
 311 static struct counter_synapse stm32_count_synapses[] = {
 312         {
 313                 .actions_list = stm32_synapse_actions,
 314                 .num_actions = ARRAY_SIZE(stm32_synapse_actions),
 315                 .signal = &stm32_signals[0]
 316         },
 317         {
 318                 .actions_list = stm32_synapse_actions,
 319                 .num_actions = ARRAY_SIZE(stm32_synapse_actions),
 320                 .signal = &stm32_signals[1]
 321         }
 322 };
 323
 324 static struct counter_count stm32_counts = {
 325         .id = 0,
 326         .name = "Channel 1 Count",
 327         .functions_list = stm32_count_functions,
 328         .num_functions = ARRAY_SIZE(stm32_count_functions),
 329         .synapses = stm32_count_synapses,
 330         .num_synapses = ARRAY_SIZE(stm32_count_synapses),
 331         .ext = stm32_count_ext,
 332         .num_ext = ARRAY_SIZE(stm32_count_ext)
 333 };
 334
 335 static int stm32_timer_cnt_probe(struct platform_device *pdev)
 336 {
 337         struct stm32_timers *ddata = dev_get_drvdata(pdev->dev.parent);
 338         struct device *dev = &pdev->dev;
 339         struct stm32_timer_cnt *priv;
 340
 341         if (IS_ERR_OR_NULL(ddata))
 342                 return -EINVAL;
 343
 344         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 345         if (!priv)
 346                 return -ENOMEM;
 347
 348         priv->regmap = ddata->regmap;
 349         priv->clk = ddata->clk;
 350         priv->ceiling = ddata->max_arr;
 351
 352         priv->counter.name = dev_name(dev);
 353         priv->counter.parent = dev;
 354         priv->counter.ops = &stm32_timer_cnt_ops;
 355         priv->counter.counts = &stm32_counts;
 356         priv->counter.num_counts = 1;
 357         priv->counter.signals = stm32_signals;
 358         priv->counter.num_signals = ARRAY_SIZE(stm32_signals);
 359         priv->counter.priv = priv;
 360
 361         /* Register Counter device */
 362         return devm_counter_register(dev, &priv->counter);
 363 }
 364
 365 static const struct of_device_id stm32_timer_cnt_of_match[] = {
 366         { .compatible = "st,stm32-timer-counter", },
 367         {},
 368 };
 369 MODULE_DEVICE_TABLE(of, stm32_timer_cnt_of_match);
 370
 371 static struct platform_driver stm32_timer_cnt_driver = {
 372         .probe = stm32_timer_cnt_probe,
 373         .driver = {
 374                 .name = "stm32-timer-counter",
 375                 .of_match_table = stm32_timer_cnt_of_match,
 376         },
 377 };
 378 module_platform_driver(stm32_timer_cnt_driver);
 379
 380 MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@st.com>");
 381 MODULE_ALIAS("platform:stm32-timer-counter");
 382 MODULE_DESCRIPTION("STMicroelectronics STM32 TIMER counter driver");
 383 MODULE_LICENSE("GPL v2");