drivers/counter/microchip-tcb-capture.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2020 Microchip
   4  *
   5  * Author: Kamel Bouhara <kamel.bouhara@bootlin.com>
   6  */
   7 #include <linux/clk.h>
   8 #include <linux/counter.h>
   9 #include <linux/mfd/syscon.h>
  10 #include <linux/module.h>
  11 #include <linux/mutex.h>
  12 #include <linux/of.h>
  13 #include <linux/of_device.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/regmap.h>
  16 #include <soc/at91/atmel_tcb.h>
  17
  18 #define ATMEL_TC_CMR_MASK       (ATMEL_TC_LDRA_RISING | ATMEL_TC_LDRB_FALLING | \
  19                                  ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_LDBDIS | \
  20                                  ATMEL_TC_LDBSTOP)
  21
  22 #define ATMEL_TC_QDEN                   BIT(8)
  23 #define ATMEL_TC_POSEN                  BIT(9)
  24
  25 struct mchp_tc_data {
  26         const struct atmel_tcb_config *tc_cfg;
  27         struct regmap *regmap;
  28         int qdec_mode;
  29         int num_channels;
  30         int channel[2];
  31         bool trig_inverted;
  32 };
  33
  34 static const enum counter_function mchp_tc_count_functions[] = {
  35         COUNTER_FUNCTION_INCREASE,
  36         COUNTER_FUNCTION_QUADRATURE_X4,
  37 };
  38
  39 static const enum counter_synapse_action mchp_tc_synapse_actions[] = {
  40         COUNTER_SYNAPSE_ACTION_NONE,
  41         COUNTER_SYNAPSE_ACTION_RISING_EDGE,
  42         COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
  43         COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
  44 };
  45
  46 static struct counter_signal mchp_tc_count_signals[] = {
  47         {
  48                 .id = 0,
  49                 .name = "Channel A",
  50         },
  51         {
  52                 .id = 1,
  53                 .name = "Channel B",
  54         }
  55 };
  56
  57 static struct counter_synapse mchp_tc_count_synapses[] = {
  58         {
  59                 .actions_list = mchp_tc_synapse_actions,
  60                 .num_actions = ARRAY_SIZE(mchp_tc_synapse_actions),
  61                 .signal = &mchp_tc_count_signals[0]
  62         },
  63         {
  64                 .actions_list = mchp_tc_synapse_actions,
  65                 .num_actions = ARRAY_SIZE(mchp_tc_synapse_actions),
  66                 .signal = &mchp_tc_count_signals[1]
  67         }
  68 };
  69
  70 static int mchp_tc_count_function_read(struct counter_device *counter,
  71                                        struct counter_count *count,
  72                                        enum counter_function *function)
  73 {
  74         struct mchp_tc_data *const priv = counter_priv(counter);
  75
  76         if (priv->qdec_mode)
  77                 *function = COUNTER_FUNCTION_QUADRATURE_X4;
  78         else
  79                 *function = COUNTER_FUNCTION_INCREASE;
  80
  81         return 0;
  82 }
  83
  84 static int mchp_tc_count_function_write(struct counter_device *counter,
  85                                         struct counter_count *count,
  86                                         enum counter_function function)
  87 {
  88         struct mchp_tc_data *const priv = counter_priv(counter);
  89         u32 bmr, cmr;
  90
  91         regmap_read(priv->regmap, ATMEL_TC_BMR, &bmr);
  92         regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), &cmr);
  93
  94         /* Set capture mode */
  95         cmr &= ~ATMEL_TC_WAVE;
  96
  97         switch (function) {
  98         case COUNTER_FUNCTION_INCREASE:
  99                 priv->qdec_mode = 0;
 100                 /* Set highest rate based on whether soc has gclk or not */
 101                 bmr &= ~(ATMEL_TC_QDEN | ATMEL_TC_POSEN);
 102                 if (priv->tc_cfg->has_gclk)
 103                         cmr |= ATMEL_TC_TIMER_CLOCK2;
 104                 else
 105                         cmr |= ATMEL_TC_TIMER_CLOCK1;
 106                 /* Setup the period capture mode */
 107                 cmr |=  ATMEL_TC_CMR_MASK;
 108                 cmr &= ~(ATMEL_TC_ABETRG | ATMEL_TC_XC0);
 109                 break;
 110         case COUNTER_FUNCTION_QUADRATURE_X4:
 111                 if (!priv->tc_cfg->has_qdec)
 112                         return -EINVAL;
 113                 /* In QDEC mode settings both channels 0 and 1 are required */
 114                 if (priv->num_channels < 2 || priv->channel[0] != 0 ||
 115                     priv->channel[1] != 1) {
 116                         pr_err("Invalid channels number or id for quadrature mode\n");
 117                         return -EINVAL;
 118                 }
 119                 priv->qdec_mode = 1;
 120                 bmr |= ATMEL_TC_QDEN | ATMEL_TC_POSEN;
 121                 cmr |= ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_ABETRG | ATMEL_TC_XC0;
 122                 break;
 123         default:
 124                 /* should never reach this path */
 125                 return -EINVAL;
 126         }
 127
 128         regmap_write(priv->regmap, ATMEL_TC_BMR, bmr);
 129         regmap_write(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), cmr);
 130
 131         /* Enable clock and trigger counter */
 132         regmap_write(priv->regmap, ATMEL_TC_REG(priv->channel[0], CCR),
 133                      ATMEL_TC_CLKEN | ATMEL_TC_SWTRG);
 134
 135         if (priv->qdec_mode) {
 136                 regmap_write(priv->regmap,
 137                              ATMEL_TC_REG(priv->channel[1], CMR), cmr);
 138                 regmap_write(priv->regmap,
 139                              ATMEL_TC_REG(priv->channel[1], CCR),
 140                              ATMEL_TC_CLKEN | ATMEL_TC_SWTRG);
 141         }
 142
 143         return 0;
 144 }
 145
 146 static int mchp_tc_count_signal_read(struct counter_device *counter,
 147                                      struct counter_signal *signal,
 148                                      enum counter_signal_level *lvl)
 149 {
 150         struct mchp_tc_data *const priv = counter_priv(counter);
 151         bool sigstatus;
 152         u32 sr;
 153
 154         regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], SR), &sr);
 155
 156         if (priv->trig_inverted)
 157                 sigstatus = (sr & ATMEL_TC_MTIOB);
 158         else
 159                 sigstatus = (sr & ATMEL_TC_MTIOA);
 160
 161         *lvl = sigstatus ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
 162
 163         return 0;
 164 }
 165
 166 static int mchp_tc_count_action_read(struct counter_device *counter,
 167                                      struct counter_count *count,
 168                                      struct counter_synapse *synapse,
 169                                      enum counter_synapse_action *action)
 170 {
 171         struct mchp_tc_data *const priv = counter_priv(counter);
 172         u32 cmr;
 173
 174         regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), &cmr);
 175
 176         switch (cmr & ATMEL_TC_ETRGEDG) {
 177         default:
 178                 *action = COUNTER_SYNAPSE_ACTION_NONE;
 179                 break;
 180         case ATMEL_TC_ETRGEDG_RISING:
 181                 *action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
 182                 break;
 183         case ATMEL_TC_ETRGEDG_FALLING:
 184                 *action = COUNTER_SYNAPSE_ACTION_FALLING_EDGE;
 185                 break;
 186         case ATMEL_TC_ETRGEDG_BOTH:
 187                 *action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
 188                 break;
 189         }
 190
 191         return 0;
 192 }
 193
 194 static int mchp_tc_count_action_write(struct counter_device *counter,
 195                                       struct counter_count *count,
 196                                       struct counter_synapse *synapse,
 197                                       enum counter_synapse_action action)
 198 {
 199         struct mchp_tc_data *const priv = counter_priv(counter);
 200         u32 edge = ATMEL_TC_ETRGEDG_NONE;
 201
 202         /* QDEC mode is rising edge only */
 203         if (priv->qdec_mode)
 204                 return -EINVAL;
 205
 206         switch (action) {
 207         case COUNTER_SYNAPSE_ACTION_NONE:
 208                 edge = ATMEL_TC_ETRGEDG_NONE;
 209                 break;
 210         case COUNTER_SYNAPSE_ACTION_RISING_EDGE:
 211                 edge = ATMEL_TC_ETRGEDG_RISING;
 212                 break;
 213         case COUNTER_SYNAPSE_ACTION_FALLING_EDGE:
 214                 edge = ATMEL_TC_ETRGEDG_FALLING;
 215                 break;
 216         case COUNTER_SYNAPSE_ACTION_BOTH_EDGES:
 217                 edge = ATMEL_TC_ETRGEDG_BOTH;
 218                 break;
 219         default:
 220                 /* should never reach this path */
 221                 return -EINVAL;
 222         }
 223
 224         return regmap_write_bits(priv->regmap,
 225                                 ATMEL_TC_REG(priv->channel[0], CMR),
 226                                 ATMEL_TC_ETRGEDG, edge);
 227 }
 228
 229 static int mchp_tc_count_read(struct counter_device *counter,
 230                               struct counter_count *count, u64 *val)
 231 {
 232         struct mchp_tc_data *const priv = counter_priv(counter);
 233         u32 cnt;
 234
 235         regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CV), &cnt);
 236         *val = cnt;
 237
 238         return 0;
 239 }
 240
 241 static struct counter_count mchp_tc_counts[] = {
 242         {
 243                 .id = 0,
 244                 .name = "Timer Counter",
 245                 .functions_list = mchp_tc_count_functions,
 246                 .num_functions = ARRAY_SIZE(mchp_tc_count_functions),
 247                 .synapses = mchp_tc_count_synapses,
 248                 .num_synapses = ARRAY_SIZE(mchp_tc_count_synapses),
 249         },
 250 };
 251
 252 static const struct counter_ops mchp_tc_ops = {
 253         .signal_read    = mchp_tc_count_signal_read,
 254         .count_read     = mchp_tc_count_read,
 255         .function_read  = mchp_tc_count_function_read,
 256         .function_write = mchp_tc_count_function_write,
 257         .action_read    = mchp_tc_count_action_read,
 258         .action_write   = mchp_tc_count_action_write
 259 };
 260
 261 static const struct atmel_tcb_config tcb_rm9200_config = {
 262                 .counter_width = 16,
 263 };
 264
 265 static const struct atmel_tcb_config tcb_sam9x5_config = {
 266                 .counter_width = 32,
 267 };
 268
 269 static const struct atmel_tcb_config tcb_sama5d2_config = {
 270                 .counter_width = 32,
 271                 .has_gclk = true,
 272                 .has_qdec = true,
 273 };
 274
 275 static const struct atmel_tcb_config tcb_sama5d3_config = {
 276                 .counter_width = 32,
 277                 .has_qdec = true,
 278 };
 279
 280 static const struct of_device_id atmel_tc_of_match[] = {
 281         { .compatible = "atmel,at91rm9200-tcb", .data = &tcb_rm9200_config, },
 282         { .compatible = "atmel,at91sam9x5-tcb", .data = &tcb_sam9x5_config, },
 283         { .compatible = "atmel,sama5d2-tcb", .data = &tcb_sama5d2_config, },
 284         { .compatible = "atmel,sama5d3-tcb", .data = &tcb_sama5d3_config, },
 285         { /* sentinel */ }
 286 };
 287
 288 static void mchp_tc_clk_remove(void *ptr)
 289 {
 290         clk_disable_unprepare((struct clk *)ptr);
 291 }
 292
 293 static int mchp_tc_probe(struct platform_device *pdev)
 294 {
 295         struct device_node *np = pdev->dev.of_node;
 296         const struct atmel_tcb_config *tcb_config;
 297         const struct of_device_id *match;
 298         struct counter_device *counter;
 299         struct mchp_tc_data *priv;
 300         char clk_name[7];
 301         struct regmap *regmap;
 302         struct clk *clk[3];
 303         int channel;
 304         int ret, i;
 305
 306         counter = devm_counter_alloc(&pdev->dev, sizeof(*priv));
 307         if (!counter)
 308                 return -ENOMEM;
 309         priv = counter_priv(counter);
 310
 311         match = of_match_node(atmel_tc_of_match, np->parent);
 312         tcb_config = match->data;
 313         if (!tcb_config) {
 314                 dev_err(&pdev->dev, "No matching parent node found\n");
 315                 return -ENODEV;
 316         }
 317
 318         regmap = syscon_node_to_regmap(np->parent);
 319         if (IS_ERR(regmap))
 320                 return PTR_ERR(regmap);
 321
 322         /* max. channels number is 2 when in QDEC mode */
 323         priv->num_channels = of_property_count_u32_elems(np, "reg");
 324         if (priv->num_channels < 0) {
 325                 dev_err(&pdev->dev, "Invalid or missing channel\n");
 326                 return -EINVAL;
 327         }
 328
 329         /* Register channels and initialize clocks */
 330         for (i = 0; i < priv->num_channels; i++) {
 331                 ret = of_property_read_u32_index(np, "reg", i, &channel);
 332                 if (ret < 0 || channel > 2)
 333                         return -ENODEV;
 334
 335                 priv->channel[i] = channel;
 336
 337                 snprintf(clk_name, sizeof(clk_name), "t%d_clk", channel);
 338
 339                 clk[i] = of_clk_get_by_name(np->parent, clk_name);
 340                 if (IS_ERR(clk[i])) {
 341                         /* Fallback to t0_clk */
 342                         clk[i] = of_clk_get_by_name(np->parent, "t0_clk");
 343                         if (IS_ERR(clk[i]))
 344                                 return PTR_ERR(clk[i]);
 345                 }
 346
 347                 ret = clk_prepare_enable(clk[i]);
 348                 if (ret)
 349                         return ret;
 350
 351                 ret = devm_add_action_or_reset(&pdev->dev,
 352                                                mchp_tc_clk_remove,
 353                                                clk[i]);
 354                 if (ret)
 355                         return ret;
 356
 357                 dev_dbg(&pdev->dev,
 358                         "Initialized capture mode on channel %d\n",
 359                         channel);
 360         }
 361
 362         priv->tc_cfg = tcb_config;
 363         priv->regmap = regmap;
 364         counter->name = dev_name(&pdev->dev);
 365         counter->parent = &pdev->dev;
 366         counter->ops = &mchp_tc_ops;
 367         counter->num_counts = ARRAY_SIZE(mchp_tc_counts);
 368         counter->counts = mchp_tc_counts;
 369         counter->num_signals = ARRAY_SIZE(mchp_tc_count_signals);
 370         counter->signals = mchp_tc_count_signals;
 371
 372         ret = devm_counter_add(&pdev->dev, counter);
 373         if (ret < 0)
 374                 return dev_err_probe(&pdev->dev, ret, "Failed to add counter\n");
 375
 376         return 0;
 377 }
 378
 379 static const struct of_device_id mchp_tc_dt_ids[] = {
 380         { .compatible = "microchip,tcb-capture", },
 381         { /* sentinel */ },
 382 };
 383 MODULE_DEVICE_TABLE(of, mchp_tc_dt_ids);
 384
 385 static struct platform_driver mchp_tc_driver = {
 386         .probe = mchp_tc_probe,
 387         .driver = {
 388                 .name = "microchip-tcb-capture",
 389                 .of_match_table = mchp_tc_dt_ids,
 390         },
 391 };
 392 module_platform_driver(mchp_tc_driver);
 393
 394 MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>");
 395 MODULE_DESCRIPTION("Microchip TCB Capture driver");
 396 MODULE_LICENSE("GPL v2");