1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Rohm BU21029 touchscreen controller driver 4 * 5 * Copyright (C) 2015-2018 Bosch Sicherheitssysteme GmbH 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 12 #include <linux/delay.h> 13 #include <linux/gpio/consumer.h> 14 #include <linux/i2c.h> 15 #include <linux/input.h> 16 #include <linux/input/touchscreen.h> 17 #include <linux/interrupt.h> 18 #include <linux/irq.h> 19 #include <linux/module.h> 20 #include <linux/regulator/consumer.h> 21 #include <linux/timer.h> 22 23 /* 24 * HW_ID1 Register (PAGE=0, ADDR=0x0E, Reset value=0x02, Read only) 25 * +--------+--------+--------+--------+--------+--------+--------+--------+ 26 * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | 27 * +--------+--------+--------+--------+--------+--------+--------+--------+ 28 * | HW_IDH | 29 * +--------+--------+--------+--------+--------+--------+--------+--------+ 30 * HW_ID2 Register (PAGE=0, ADDR=0x0F, Reset value=0x29, Read only) 31 * +--------+--------+--------+--------+--------+--------+--------+--------+ 32 * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | 33 * +--------+--------+--------+--------+--------+--------+--------+--------+ 34 * | HW_IDL | 35 * +--------+--------+--------+--------+--------+--------+--------+--------+ 36 * HW_IDH: high 8bits of IC's ID 37 * HW_IDL: low 8bits of IC's ID 38 */ 39 #define BU21029_HWID_REG (0x0E << 3) 40 #define SUPPORTED_HWID 0x0229 41 42 /* 43 * CFR0 Register (PAGE=0, ADDR=0x00, Reset value=0x20) 44 * +--------+--------+--------+--------+--------+--------+--------+--------+ 45 * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | 46 * +--------+--------+--------+--------+--------+--------+--------+--------+ 47 * | 0 | 0 | CALIB | INTRM | 0 | 0 | 0 | 0 | 48 * +--------+--------+--------+--------+--------+--------+--------+--------+ 49 * CALIB: 0 = not to use calibration result (*) 50 * 1 = use calibration result 51 * INTRM: 0 = INT output depend on "pen down" (*) 52 * 1 = INT output always "0" 53 */ 54 #define BU21029_CFR0_REG (0x00 << 3) 55 #define CFR0_VALUE 0x00 56 57 /* 58 * CFR1 Register (PAGE=0, ADDR=0x01, Reset value=0xA6) 59 * +--------+--------+--------+--------+--------+--------+--------+--------+ 60 * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | 61 * +--------+--------+--------+--------+--------+--------+--------+--------+ 62 * | MAV | AVE[2:0] | 0 | SMPL[2:0] | 63 * +--------+--------+--------+--------+--------+--------+--------+--------+ 64 * MAV: 0 = median average filter off 65 * 1 = median average filter on (*) 66 * AVE: AVE+1 = number of average samples for MAV, 67 * if AVE>SMPL, then AVE=SMPL (=3) 68 * SMPL: SMPL+1 = number of conversion samples for MAV (=7) 69 */ 70 #define BU21029_CFR1_REG (0x01 << 3) 71 #define CFR1_VALUE 0xA6 72 73 /* 74 * CFR2 Register (PAGE=0, ADDR=0x02, Reset value=0x04) 75 * +--------+--------+--------+--------+--------+--------+--------+--------+ 76 * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | 77 * +--------+--------+--------+--------+--------+--------+--------+--------+ 78 * | INTVL_TIME[3:0] | TIME_ST_ADC[3:0] | 79 * +--------+--------+--------+--------+--------+--------+--------+--------+ 80 * INTVL_TIME: waiting time between completion of conversion 81 * and start of next conversion, only usable in 82 * autoscan mode (=20.480ms) 83 * TIME_ST_ADC: waiting time between application of voltage 84 * to panel and start of A/D conversion (=100us) 85 */ 86 #define BU21029_CFR2_REG (0x02 << 3) 87 #define CFR2_VALUE 0xC9 88 89 /* 90 * CFR3 Register (PAGE=0, ADDR=0x0B, Reset value=0x72) 91 * +--------+--------+--------+--------+--------+--------+--------+--------+ 92 * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | 93 * +--------+--------+--------+--------+--------+--------+--------+--------+ 94 * | RM8 | STRETCH| PU90K | DUAL | PIDAC_OFS[3:0] | 95 * +--------+--------+--------+--------+--------+--------+--------+--------+ 96 * RM8: 0 = coordinate resolution is 12bit (*) 97 * 1 = coordinate resolution is 8bit 98 * STRETCH: 0 = SCL_STRETCH function off 99 * 1 = SCL_STRETCH function on (*) 100 * PU90K: 0 = internal pull-up resistance for touch detection is ~50kohms (*) 101 * 1 = internal pull-up resistance for touch detection is ~90kohms 102 * DUAL: 0 = dual touch detection off (*) 103 * 1 = dual touch detection on 104 * PIDAC_OFS: dual touch detection circuit adjustment, it is not necessary 105 * to change this from initial value 106 */ 107 #define BU21029_CFR3_REG (0x0B << 3) 108 #define CFR3_VALUE 0x42 109 110 /* 111 * LDO Register (PAGE=0, ADDR=0x0C, Reset value=0x00) 112 * +--------+--------+--------+--------+--------+--------+--------+--------+ 113 * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | 114 * +--------+--------+--------+--------+--------+--------+--------+--------+ 115 * | 0 | PVDD[2:0] | 0 | AVDD[2:0] | 116 * +--------+--------+--------+--------+--------+--------+--------+--------+ 117 * PVDD: output voltage of panel output regulator (=2.000V) 118 * AVDD: output voltage of analog circuit regulator (=2.000V) 119 */ 120 #define BU21029_LDO_REG (0x0C << 3) 121 #define LDO_VALUE 0x77 122 123 /* 124 * Serial Interface Command Byte 1 (CID=1) 125 * +--------+--------+--------+--------+--------+--------+--------+--------+ 126 * | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | 127 * +--------+--------+--------+--------+--------+--------+--------+--------+ 128 * | 1 | CF | CMSK | PDM | STP | 129 * +--------+--------+--------+--------+--------+--------+--------+--------+ 130 * CF: conversion function, see table 3 in datasheet p6 (=0000, automatic scan) 131 * CMSK: 0 = executes convert function (*) 132 * 1 = reads the convert result 133 * PDM: 0 = power down after convert function stops (*) 134 * 1 = keep power on after convert function stops 135 * STP: 1 = abort current conversion and power down, set to "0" automatically 136 */ 137 #define BU21029_AUTOSCAN 0x80 138 139 /* 140 * The timeout value needs to be larger than INTVL_TIME + tConv4 (sample and 141 * conversion time), where tConv4 is calculated by formula: 142 * tPON + tDLY1 + (tTIME_ST_ADC + (tADC * tSMPL) * 2 + tDLY2) * 3 143 * see figure 8 in datasheet p15 for details of each field. 144 */ 145 #define PEN_UP_TIMEOUT_MS 50 146 147 #define STOP_DELAY_MIN_US 50 148 #define STOP_DELAY_MAX_US 1000 149 #define START_DELAY_MS 2 150 #define BUF_LEN 8 151 #define SCALE_12BIT (1 << 12) 152 #define MAX_12BIT ((1 << 12) - 1) 153 #define DRIVER_NAME "bu21029" 154 155 struct bu21029_ts_data { 156 struct i2c_client *client; 157 struct input_dev *in_dev; 158 struct timer_list timer; 159 struct regulator *vdd; 160 struct gpio_desc *reset_gpios; 161 u32 x_plate_ohms; 162 struct touchscreen_properties prop; 163 }; 164 165 static void bu21029_touch_report(struct bu21029_ts_data *bu21029, const u8 *buf) 166 { 167 u16 x, y, z1, z2; 168 u32 rz; 169 s32 max_pressure = input_abs_get_max(bu21029->in_dev, ABS_PRESSURE); 170 171 /* 172 * compose upper 8 and lower 4 bits into a 12bit value: 173 * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 174 * | ByteH | ByteL | 175 * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 176 * |b07|b06|b05|b04|b03|b02|b01|b00|b07|b06|b05|b04|b03|b02|b01|b00| 177 * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 178 * |v11|v10|v09|v08|v07|v06|v05|v04|v03|v02|v01|v00| 0 | 0 | 0 | 0 | 179 * +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ 180 */ 181 x = (buf[0] << 4) | (buf[1] >> 4); 182 y = (buf[2] << 4) | (buf[3] >> 4); 183 z1 = (buf[4] << 4) | (buf[5] >> 4); 184 z2 = (buf[6] << 4) | (buf[7] >> 4); 185 186 if (z1 && z2) { 187 /* 188 * calculate Rz (pressure resistance value) by equation: 189 * Rz = Rx * (x/Q) * ((z2/z1) - 1), where 190 * Rx is x-plate resistance, 191 * Q is the touch screen resolution (8bit = 256, 12bit = 4096) 192 * x, z1, z2 are the measured positions. 193 */ 194 rz = z2 - z1; 195 rz *= x; 196 rz *= bu21029->x_plate_ohms; 197 rz /= z1; 198 rz = DIV_ROUND_CLOSEST(rz, SCALE_12BIT); 199 if (rz <= max_pressure) { 200 touchscreen_report_pos(bu21029->in_dev, &bu21029->prop, 201 x, y, false); 202 input_report_abs(bu21029->in_dev, ABS_PRESSURE, 203 max_pressure - rz); 204 input_report_key(bu21029->in_dev, BTN_TOUCH, 1); 205 input_sync(bu21029->in_dev); 206 } 207 } 208 } 209 210 static void bu21029_touch_release(struct timer_list *t) 211 { 212 struct bu21029_ts_data *bu21029 = from_timer(bu21029, t, timer); 213 214 input_report_abs(bu21029->in_dev, ABS_PRESSURE, 0); 215 input_report_key(bu21029->in_dev, BTN_TOUCH, 0); 216 input_sync(bu21029->in_dev); 217 } 218 219 static irqreturn_t bu21029_touch_soft_irq(int irq, void *data) 220 { 221 struct bu21029_ts_data *bu21029 = data; 222 u8 buf[BUF_LEN]; 223 int error; 224 225 /* 226 * Read touch data and deassert interrupt (will assert again after 227 * INTVL_TIME + tConv4 for continuous touch) 228 */ 229 error = i2c_smbus_read_i2c_block_data(bu21029->client, BU21029_AUTOSCAN, 230 sizeof(buf), buf); 231 if (error < 0) 232 goto out; 233 234 bu21029_touch_report(bu21029, buf); 235 236 /* reset timer for pen up detection */ 237 mod_timer(&bu21029->timer, 238 jiffies + msecs_to_jiffies(PEN_UP_TIMEOUT_MS)); 239 240 out: 241 return IRQ_HANDLED; 242 } 243 244 static void bu21029_put_chip_in_reset(struct bu21029_ts_data *bu21029) 245 { 246 if (bu21029->reset_gpios) { 247 gpiod_set_value_cansleep(bu21029->reset_gpios, 1); 248 usleep_range(STOP_DELAY_MIN_US, STOP_DELAY_MAX_US); 249 } 250 } 251 252 static int bu21029_start_chip(struct input_dev *dev) 253 { 254 struct bu21029_ts_data *bu21029 = input_get_drvdata(dev); 255 struct i2c_client *i2c = bu21029->client; 256 struct { 257 u8 reg; 258 u8 value; 259 } init_table[] = { 260 {BU21029_CFR0_REG, CFR0_VALUE}, 261 {BU21029_CFR1_REG, CFR1_VALUE}, 262 {BU21029_CFR2_REG, CFR2_VALUE}, 263 {BU21029_CFR3_REG, CFR3_VALUE}, 264 {BU21029_LDO_REG, LDO_VALUE} 265 }; 266 int error, i; 267 __be16 hwid; 268 269 error = regulator_enable(bu21029->vdd); 270 if (error) { 271 dev_err(&i2c->dev, "failed to power up chip: %d", error); 272 return error; 273 } 274 275 /* take chip out of reset */ 276 if (bu21029->reset_gpios) { 277 gpiod_set_value_cansleep(bu21029->reset_gpios, 0); 278 msleep(START_DELAY_MS); 279 } 280 281 error = i2c_smbus_read_i2c_block_data(i2c, BU21029_HWID_REG, 282 sizeof(hwid), (u8 *)&hwid); 283 if (error < 0) { 284 dev_err(&i2c->dev, "failed to read HW ID\n"); 285 goto err_out; 286 } 287 288 if (be16_to_cpu(hwid) != SUPPORTED_HWID) { 289 dev_err(&i2c->dev, 290 "unsupported HW ID 0x%x\n", be16_to_cpu(hwid)); 291 error = -ENODEV; 292 goto err_out; 293 } 294 295 for (i = 0; i < ARRAY_SIZE(init_table); ++i) { 296 error = i2c_smbus_write_byte_data(i2c, 297 init_table[i].reg, 298 init_table[i].value); 299 if (error < 0) { 300 dev_err(&i2c->dev, 301 "failed to write %#02x to register %#02x: %d\n", 302 init_table[i].value, init_table[i].reg, 303 error); 304 goto err_out; 305 } 306 } 307 308 error = i2c_smbus_write_byte(i2c, BU21029_AUTOSCAN); 309 if (error < 0) { 310 dev_err(&i2c->dev, "failed to start autoscan\n"); 311 goto err_out; 312 } 313 314 enable_irq(bu21029->client->irq); 315 return 0; 316 317 err_out: 318 bu21029_put_chip_in_reset(bu21029); 319 regulator_disable(bu21029->vdd); 320 return error; 321 } 322 323 static void bu21029_stop_chip(struct input_dev *dev) 324 { 325 struct bu21029_ts_data *bu21029 = input_get_drvdata(dev); 326 327 disable_irq(bu21029->client->irq); 328 del_timer_sync(&bu21029->timer); 329 330 bu21029_put_chip_in_reset(bu21029); 331 regulator_disable(bu21029->vdd); 332 } 333 334 static int bu21029_probe(struct i2c_client *client) 335 { 336 struct device *dev = &client->dev; 337 struct bu21029_ts_data *bu21029; 338 struct input_dev *in_dev; 339 int error; 340 341 if (!i2c_check_functionality(client->adapter, 342 I2C_FUNC_SMBUS_WRITE_BYTE | 343 I2C_FUNC_SMBUS_WRITE_BYTE_DATA | 344 I2C_FUNC_SMBUS_READ_I2C_BLOCK)) { 345 dev_err(dev, "i2c functionality support is not sufficient\n"); 346 return -EIO; 347 } 348 349 bu21029 = devm_kzalloc(dev, sizeof(*bu21029), GFP_KERNEL); 350 if (!bu21029) 351 return -ENOMEM; 352 353 error = device_property_read_u32(dev, "rohm,x-plate-ohms", &bu21029->x_plate_ohms); 354 if (error) { 355 dev_err(dev, "invalid 'x-plate-ohms' supplied: %d\n", error); 356 return error; 357 } 358 359 bu21029->vdd = devm_regulator_get(dev, "vdd"); 360 if (IS_ERR(bu21029->vdd)) 361 return dev_err_probe(dev, PTR_ERR(bu21029->vdd), 362 "failed to acquire 'vdd' supply\n"); 363 364 bu21029->reset_gpios = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); 365 if (IS_ERR(bu21029->reset_gpios)) 366 return dev_err_probe(dev, PTR_ERR(bu21029->reset_gpios), 367 "failed to acquire 'reset' gpio\n"); 368 369 in_dev = devm_input_allocate_device(dev); 370 if (!in_dev) { 371 dev_err(dev, "unable to allocate input device\n"); 372 return -ENOMEM; 373 } 374 375 bu21029->client = client; 376 bu21029->in_dev = in_dev; 377 timer_setup(&bu21029->timer, bu21029_touch_release, 0); 378 379 in_dev->name = DRIVER_NAME; 380 in_dev->id.bustype = BUS_I2C; 381 in_dev->open = bu21029_start_chip; 382 in_dev->close = bu21029_stop_chip; 383 384 input_set_capability(in_dev, EV_KEY, BTN_TOUCH); 385 input_set_abs_params(in_dev, ABS_X, 0, MAX_12BIT, 0, 0); 386 input_set_abs_params(in_dev, ABS_Y, 0, MAX_12BIT, 0, 0); 387 input_set_abs_params(in_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0); 388 touchscreen_parse_properties(in_dev, false, &bu21029->prop); 389 390 input_set_drvdata(in_dev, bu21029); 391 392 error = devm_request_threaded_irq(dev, client->irq, NULL, 393 bu21029_touch_soft_irq, 394 IRQF_ONESHOT | IRQF_NO_AUTOEN, 395 DRIVER_NAME, bu21029); 396 if (error) { 397 dev_err(dev, "unable to request touch irq: %d\n", error); 398 return error; 399 } 400 401 error = input_register_device(in_dev); 402 if (error) { 403 dev_err(dev, "unable to register input device: %d\n", error); 404 return error; 405 } 406 407 i2c_set_clientdata(client, bu21029); 408 409 return 0; 410 } 411 412 static int bu21029_suspend(struct device *dev) 413 { 414 struct i2c_client *i2c = to_i2c_client(dev); 415 struct bu21029_ts_data *bu21029 = i2c_get_clientdata(i2c); 416 417 if (!device_may_wakeup(dev)) { 418 mutex_lock(&bu21029->in_dev->mutex); 419 if (input_device_enabled(bu21029->in_dev)) 420 bu21029_stop_chip(bu21029->in_dev); 421 mutex_unlock(&bu21029->in_dev->mutex); 422 } 423 424 return 0; 425 } 426 427 static int bu21029_resume(struct device *dev) 428 { 429 struct i2c_client *i2c = to_i2c_client(dev); 430 struct bu21029_ts_data *bu21029 = i2c_get_clientdata(i2c); 431 432 if (!device_may_wakeup(dev)) { 433 mutex_lock(&bu21029->in_dev->mutex); 434 if (input_device_enabled(bu21029->in_dev)) 435 bu21029_start_chip(bu21029->in_dev); 436 mutex_unlock(&bu21029->in_dev->mutex); 437 } 438 439 return 0; 440 } 441 static DEFINE_SIMPLE_DEV_PM_OPS(bu21029_pm_ops, bu21029_suspend, bu21029_resume); 442 443 static const struct i2c_device_id bu21029_ids[] = { 444 { DRIVER_NAME, 0 }, 445 { /* sentinel */ } 446 }; 447 MODULE_DEVICE_TABLE(i2c, bu21029_ids); 448 449 #ifdef CONFIG_OF 450 static const struct of_device_id bu21029_of_ids[] = { 451 { .compatible = "rohm,bu21029" }, 452 { /* sentinel */ } 453 }; 454 MODULE_DEVICE_TABLE(of, bu21029_of_ids); 455 #endif 456 457 static struct i2c_driver bu21029_driver = { 458 .driver = { 459 .name = DRIVER_NAME, 460 .of_match_table = of_match_ptr(bu21029_of_ids), 461 .pm = pm_sleep_ptr(&bu21029_pm_ops), 462 }, 463 .id_table = bu21029_ids, 464 .probe = bu21029_probe, 465 }; 466 module_i2c_driver(bu21029_driver); 467 468 MODULE_AUTHOR("Zhu Yi <yi.zhu5@cn.bosch.com>"); 469 MODULE_DESCRIPTION("Rohm BU21029 touchscreen controller driver"); 470 MODULE_LICENSE("GPL v2"); 471