drivers/input/touchscreen/himax_hx83112b.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for Himax hx83112b touchscreens
   4  *
   5  * Copyright (C) 2022 Job Noorman <job@noorman.info>
   6  *
   7  * HX83100A support
   8  * Copyright (C) 2024 Felix Kaechele <felix@kaechele.ca>
   9  *
  10  * This code is based on "Himax Android Driver Sample Code for QCT platform":
  11  *
  12  * Copyright (C) 2017 Himax Corporation.
  13  */
  14
  15 #include <linux/delay.h>
  16 #include <linux/err.h>
  17 #include <linux/gpio/consumer.h>
  18 #include <linux/i2c.h>
  19 #include <linux/input.h>
  20 #include <linux/input/mt.h>
  21 #include <linux/input/touchscreen.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/kernel.h>
  24 #include <linux/regmap.h>
  25
  26 #define HIMAX_MAX_POINTS                10
  27
  28 #define HIMAX_AHB_ADDR_BYTE_0                   0x00
  29 #define HIMAX_AHB_ADDR_RDATA_BYTE_0             0x08
  30 #define HIMAX_AHB_ADDR_ACCESS_DIRECTION         0x0c
  31 #define HIMAX_AHB_ADDR_INCR4                    0x0d
  32 #define HIMAX_AHB_ADDR_CONTI                    0x13
  33 #define HIMAX_AHB_ADDR_EVENT_STACK              0x30
  34
  35 #define HIMAX_AHB_CMD_ACCESS_DIRECTION_READ     0x00
  36 #define HIMAX_AHB_CMD_INCR4                     0x10
  37 #define HIMAX_AHB_CMD_CONTI                     0x31
  38
  39 #define HIMAX_REG_ADDR_ICID                     0x900000d0
  40
  41 #define HX83100A_REG_FW_EVENT_STACK             0x90060000
  42
  43 #define HIMAX_INVALID_COORD             0xffff
  44
  45 struct himax_event_point {
  46         __be16 x;
  47         __be16 y;
  48 } __packed;
  49
  50 struct himax_event {
  51         struct himax_event_point points[HIMAX_MAX_POINTS];
  52         u8 majors[HIMAX_MAX_POINTS];
  53         u8 pad0[2];
  54         u8 num_points;
  55         u8 pad1[2];
  56         u8 checksum_fix;
  57 } __packed;
  58
  59 static_assert(sizeof(struct himax_event) == 56);
  60
  61 struct himax_ts_data;
  62 struct himax_chip {
  63         u32 id;
  64         int (*check_id)(struct himax_ts_data *ts);
  65         int (*read_events)(struct himax_ts_data *ts, struct himax_event *event,
  66                            size_t length);
  67 };
  68
  69 struct himax_ts_data {
  70         const struct himax_chip *chip;
  71         struct gpio_desc *gpiod_rst;
  72         struct input_dev *input_dev;
  73         struct i2c_client *client;
  74         struct regmap *regmap;
  75         struct touchscreen_properties props;
  76 };
  77
  78 static const struct regmap_config himax_regmap_config = {
  79         .reg_bits = 8,
  80         .val_bits = 32,
  81         .val_format_endian = REGMAP_ENDIAN_LITTLE,
  82 };
  83
  84 static int himax_bus_enable_burst(struct himax_ts_data *ts)
  85 {
  86         int error;
  87
  88         error = regmap_write(ts->regmap, HIMAX_AHB_ADDR_CONTI,
  89                              HIMAX_AHB_CMD_CONTI);
  90         if (error)
  91                 return error;
  92
  93         error = regmap_write(ts->regmap, HIMAX_AHB_ADDR_INCR4,
  94                              HIMAX_AHB_CMD_INCR4);
  95         if (error)
  96                 return error;
  97
  98         return 0;
  99 }
 100
 101 static int himax_bus_read(struct himax_ts_data *ts, u32 address, void *dst,
 102                           size_t length)
 103 {
 104         int error;
 105
 106         if (length > 4) {
 107                 error = himax_bus_enable_burst(ts);
 108                 if (error)
 109                         return error;
 110         }
 111
 112         error = regmap_write(ts->regmap, HIMAX_AHB_ADDR_BYTE_0, address);
 113         if (error)
 114                 return error;
 115
 116         error = regmap_write(ts->regmap, HIMAX_AHB_ADDR_ACCESS_DIRECTION,
 117                              HIMAX_AHB_CMD_ACCESS_DIRECTION_READ);
 118         if (error)
 119                 return error;
 120
 121         if (length > 4)
 122                 error = regmap_noinc_read(ts->regmap, HIMAX_AHB_ADDR_RDATA_BYTE_0,
 123                                           dst, length);
 124         else
 125                 error = regmap_read(ts->regmap, HIMAX_AHB_ADDR_RDATA_BYTE_0,
 126                                     dst);
 127         if (error)
 128                 return error;
 129
 130         return 0;
 131 }
 132
 133 static void himax_reset(struct himax_ts_data *ts)
 134 {
 135         gpiod_set_value_cansleep(ts->gpiod_rst, 1);
 136
 137         /* Delay copied from downstream driver */
 138         msleep(20);
 139         gpiod_set_value_cansleep(ts->gpiod_rst, 0);
 140
 141         /*
 142          * The downstream driver doesn't contain this delay but is seems safer
 143          * to include it. The range is just a guess that seems to work well.
 144          */
 145         usleep_range(1000, 1100);
 146 }
 147
 148 static int himax_read_product_id(struct himax_ts_data *ts, u32 *product_id)
 149 {
 150         int error;
 151
 152         error = himax_bus_read(ts, HIMAX_REG_ADDR_ICID, product_id,
 153                                sizeof(*product_id));
 154         if (error)
 155                 return error;
 156
 157         *product_id >>= 8;
 158         return 0;
 159 }
 160
 161 static int himax_check_product_id(struct himax_ts_data *ts)
 162 {
 163         int error;
 164         u32 product_id;
 165
 166         error = himax_read_product_id(ts, &product_id);
 167         if (error)
 168                 return error;
 169
 170         dev_dbg(&ts->client->dev, "Product id: %x\n", product_id);
 171
 172         if (product_id == ts->chip->id)
 173                 return 0;
 174
 175         dev_err(&ts->client->dev, "Unknown product id: %x\n",
 176                 product_id);
 177         return -EINVAL;
 178 }
 179
 180 static int himax_input_register(struct himax_ts_data *ts)
 181 {
 182         int error;
 183
 184         ts->input_dev = devm_input_allocate_device(&ts->client->dev);
 185         if (!ts->input_dev) {
 186                 dev_err(&ts->client->dev, "Failed to allocate input device\n");
 187                 return -ENOMEM;
 188         }
 189
 190         ts->input_dev->name = "Himax Touchscreen";
 191
 192         input_set_capability(ts->input_dev, EV_ABS, ABS_MT_POSITION_X);
 193         input_set_capability(ts->input_dev, EV_ABS, ABS_MT_POSITION_Y);
 194         input_set_abs_params(ts->input_dev, ABS_MT_WIDTH_MAJOR, 0, 200, 0, 0);
 195         input_set_abs_params(ts->input_dev, ABS_MT_TOUCH_MAJOR, 0, 200, 0, 0);
 196
 197         touchscreen_parse_properties(ts->input_dev, true, &ts->props);
 198
 199         error = input_mt_init_slots(ts->input_dev, HIMAX_MAX_POINTS,
 200                                     INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
 201         if (error) {
 202                 dev_err(&ts->client->dev,
 203                         "Failed to initialize MT slots: %d\n", error);
 204                 return error;
 205         }
 206
 207         error = input_register_device(ts->input_dev);
 208         if (error) {
 209                 dev_err(&ts->client->dev,
 210                         "Failed to register input device: %d\n", error);
 211                 return error;
 212         }
 213
 214         return 0;
 215 }
 216
 217 static u8 himax_event_get_num_points(const struct himax_event *event)
 218 {
 219         if (event->num_points == 0xff)
 220                 return 0;
 221         else
 222                 return event->num_points & 0x0f;
 223 }
 224
 225 static bool himax_process_event_point(struct himax_ts_data *ts,
 226                                       const struct himax_event *event,
 227                                       int point_index)
 228 {
 229         const struct himax_event_point *point = &event->points[point_index];
 230         u16 x = be16_to_cpu(point->x);
 231         u16 y = be16_to_cpu(point->y);
 232         u8 w = event->majors[point_index];
 233
 234         if (x == HIMAX_INVALID_COORD || y == HIMAX_INVALID_COORD)
 235                 return false;
 236
 237         input_mt_slot(ts->input_dev, point_index);
 238         input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER, true);
 239         touchscreen_report_pos(ts->input_dev, &ts->props, x, y, true);
 240         input_report_abs(ts->input_dev, ABS_MT_TOUCH_MAJOR, w);
 241         input_report_abs(ts->input_dev, ABS_MT_WIDTH_MAJOR, w);
 242         return true;
 243 }
 244
 245 static void himax_process_event(struct himax_ts_data *ts,
 246                                 const struct himax_event *event)
 247 {
 248         int i;
 249         int num_points_left = himax_event_get_num_points(event);
 250
 251         for (i = 0; i < HIMAX_MAX_POINTS && num_points_left > 0; i++) {
 252                 if (himax_process_event_point(ts, event, i))
 253                         num_points_left--;
 254         }
 255
 256         input_mt_sync_frame(ts->input_dev);
 257         input_sync(ts->input_dev);
 258 }
 259
 260 static bool himax_verify_checksum(struct himax_ts_data *ts,
 261                                   const struct himax_event *event)
 262 {
 263         u8 *data = (u8 *)event;
 264         int i;
 265         u16 checksum = 0;
 266
 267         for (i = 0; i < sizeof(*event); i++)
 268                 checksum += data[i];
 269
 270         if ((checksum & 0x00ff) != 0) {
 271                 dev_err(&ts->client->dev, "Wrong event checksum: %04x\n",
 272                         checksum);
 273                 return false;
 274         }
 275
 276         return true;
 277 }
 278
 279 static int himax_read_events(struct himax_ts_data *ts,
 280                              struct himax_event *event, size_t length)
 281 {
 282         return regmap_raw_read(ts->regmap, HIMAX_AHB_ADDR_EVENT_STACK, event,
 283                                length);
 284 }
 285
 286 static int hx83100a_read_events(struct himax_ts_data *ts,
 287                                 struct himax_event *event, size_t length)
 288 {
 289         return himax_bus_read(ts, HX83100A_REG_FW_EVENT_STACK, event, length);
 290 };
 291
 292 static int himax_handle_input(struct himax_ts_data *ts)
 293 {
 294         int error;
 295         struct himax_event event;
 296
 297         error = ts->chip->read_events(ts, &event, sizeof(event));
 298         if (error) {
 299                 dev_err(&ts->client->dev, "Failed to read input event: %d\n",
 300                         error);
 301                 return error;
 302         }
 303
 304         /*
 305          * Only process the current event when it has a valid checksum but
 306          * don't consider it a fatal error when it doesn't.
 307          */
 308         if (himax_verify_checksum(ts, &event))
 309                 himax_process_event(ts, &event);
 310
 311         return 0;
 312 }
 313
 314 static irqreturn_t himax_irq_handler(int irq, void *dev_id)
 315 {
 316         int error;
 317         struct himax_ts_data *ts = dev_id;
 318
 319         error = himax_handle_input(ts);
 320         if (error)
 321                 return IRQ_NONE;
 322
 323         return IRQ_HANDLED;
 324 }
 325
 326 static int himax_probe(struct i2c_client *client)
 327 {
 328         int error;
 329         struct device *dev = &client->dev;
 330         struct himax_ts_data *ts;
 331
 332         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 333                 dev_err(dev, "I2C check functionality failed\n");
 334                 return -ENXIO;
 335         }
 336
 337         ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
 338         if (!ts)
 339                 return -ENOMEM;
 340
 341         i2c_set_clientdata(client, ts);
 342         ts->client = client;
 343         ts->chip = i2c_get_match_data(client);
 344
 345         ts->regmap = devm_regmap_init_i2c(client, &himax_regmap_config);
 346         error = PTR_ERR_OR_ZERO(ts->regmap);
 347         if (error) {
 348                 dev_err(dev, "Failed to initialize regmap: %d\n", error);
 349                 return error;
 350         }
 351
 352         ts->gpiod_rst = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
 353         error = PTR_ERR_OR_ZERO(ts->gpiod_rst);
 354         if (error) {
 355                 dev_err(dev, "Failed to get reset GPIO: %d\n", error);
 356                 return error;
 357         }
 358
 359         himax_reset(ts);
 360
 361         if (ts->chip->check_id) {
 362                 error = himax_check_product_id(ts);
 363                 if (error)
 364                         return error;
 365         }
 366
 367         error = himax_input_register(ts);
 368         if (error)
 369                 return error;
 370
 371         error = devm_request_threaded_irq(dev, client->irq, NULL,
 372                                           himax_irq_handler, IRQF_ONESHOT,
 373                                           client->name, ts);
 374         if (error)
 375                 return error;
 376
 377         return 0;
 378 }
 379
 380 static int himax_suspend(struct device *dev)
 381 {
 382         struct himax_ts_data *ts = dev_get_drvdata(dev);
 383
 384         disable_irq(ts->client->irq);
 385         return 0;
 386 }
 387
 388 static int himax_resume(struct device *dev)
 389 {
 390         struct himax_ts_data *ts = dev_get_drvdata(dev);
 391
 392         enable_irq(ts->client->irq);
 393         return 0;
 394 }
 395
 396 static DEFINE_SIMPLE_DEV_PM_OPS(himax_pm_ops, himax_suspend, himax_resume);
 397
 398 static const struct himax_chip hx83100a_chip = {
 399         .read_events = hx83100a_read_events,
 400 };
 401
 402 static const struct himax_chip hx83112b_chip = {
 403         .id = 0x83112b,
 404         .check_id = himax_check_product_id,
 405         .read_events = himax_read_events,
 406 };
 407
 408 static const struct i2c_device_id himax_ts_id[] = {
 409         { "hx83100a", (kernel_ulong_t)&hx83100a_chip },
 410         { "hx83112b", (kernel_ulong_t)&hx83112b_chip },
 411         { /* sentinel */ }
 412 };
 413 MODULE_DEVICE_TABLE(i2c, himax_ts_id);
 414
 415 #ifdef CONFIG_OF
 416 static const struct of_device_id himax_of_match[] = {
 417         { .compatible = "himax,hx83100a", .data = &hx83100a_chip },
 418         { .compatible = "himax,hx83112b", .data = &hx83112b_chip },
 419         { /* sentinel */ }
 420 };
 421 MODULE_DEVICE_TABLE(of, himax_of_match);
 422 #endif
 423
 424 static struct i2c_driver himax_ts_driver = {
 425         .probe = himax_probe,
 426         .id_table = himax_ts_id,
 427         .driver = {
 428                 .name = "Himax-hx83112b-TS",
 429                 .of_match_table = of_match_ptr(himax_of_match),
 430                 .pm = pm_sleep_ptr(&himax_pm_ops),
 431         },
 432 };
 433 module_i2c_driver(himax_ts_driver);
 434
 435 MODULE_AUTHOR("Job Noorman <job@noorman.info>");
 436 MODULE_DESCRIPTION("Himax hx83112b touchscreen driver");
 437 MODULE_LICENSE("GPL");