1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * (C) Copyright 2008 4 * Stefano Babic, DENX Software Engineering, sbabic@denx.de. 5 * 6 * This driver implements a lcd device for the ILITEK 922x display 7 * controller. The interface to the display is SPI and the display's 8 * memory is cyclically updated over the RGB interface. 9 */ 10 11 #include <linux/fb.h> 12 #include <linux/delay.h> 13 #include <linux/errno.h> 14 #include <linux/init.h> 15 #include <linux/kernel.h> 16 #include <linux/lcd.h> 17 #include <linux/module.h> 18 #include <linux/of.h> 19 #include <linux/slab.h> 20 #include <linux/spi/spi.h> 21 #include <linux/string.h> 22 23 /* Register offset, see manual section 8.2 */ 24 #define REG_START_OSCILLATION 0x00 25 #define REG_DRIVER_CODE_READ 0x00 26 #define REG_DRIVER_OUTPUT_CONTROL 0x01 27 #define REG_LCD_AC_DRIVEING_CONTROL 0x02 28 #define REG_ENTRY_MODE 0x03 29 #define REG_COMPARE_1 0x04 30 #define REG_COMPARE_2 0x05 31 #define REG_DISPLAY_CONTROL_1 0x07 32 #define REG_DISPLAY_CONTROL_2 0x08 33 #define REG_DISPLAY_CONTROL_3 0x09 34 #define REG_FRAME_CYCLE_CONTROL 0x0B 35 #define REG_EXT_INTF_CONTROL 0x0C 36 #define REG_POWER_CONTROL_1 0x10 37 #define REG_POWER_CONTROL_2 0x11 38 #define REG_POWER_CONTROL_3 0x12 39 #define REG_POWER_CONTROL_4 0x13 40 #define REG_RAM_ADDRESS_SET 0x21 41 #define REG_WRITE_DATA_TO_GRAM 0x22 42 #define REG_RAM_WRITE_MASK1 0x23 43 #define REG_RAM_WRITE_MASK2 0x24 44 #define REG_GAMMA_CONTROL_1 0x30 45 #define REG_GAMMA_CONTROL_2 0x31 46 #define REG_GAMMA_CONTROL_3 0x32 47 #define REG_GAMMA_CONTROL_4 0x33 48 #define REG_GAMMA_CONTROL_5 0x34 49 #define REG_GAMMA_CONTROL_6 0x35 50 #define REG_GAMMA_CONTROL_7 0x36 51 #define REG_GAMMA_CONTROL_8 0x37 52 #define REG_GAMMA_CONTROL_9 0x38 53 #define REG_GAMMA_CONTROL_10 0x39 54 #define REG_GATE_SCAN_CONTROL 0x40 55 #define REG_VERT_SCROLL_CONTROL 0x41 56 #define REG_FIRST_SCREEN_DRIVE_POS 0x42 57 #define REG_SECOND_SCREEN_DRIVE_POS 0x43 58 #define REG_RAM_ADDR_POS_H 0x44 59 #define REG_RAM_ADDR_POS_V 0x45 60 #define REG_OSCILLATOR_CONTROL 0x4F 61 #define REG_GPIO 0x60 62 #define REG_OTP_VCM_PROGRAMMING 0x61 63 #define REG_OTP_VCM_STATUS_ENABLE 0x62 64 #define REG_OTP_PROGRAMMING_ID_KEY 0x65 65 66 /* 67 * maximum frequency for register access 68 * (not for the GRAM access) 69 */ 70 #define ILITEK_MAX_FREQ_REG 4000000 71 72 /* 73 * Device ID as found in the datasheet (supports 9221 and 9222) 74 */ 75 #define ILITEK_DEVICE_ID 0x9220 76 #define ILITEK_DEVICE_ID_MASK 0xFFF0 77 78 /* Last two bits in the START BYTE */ 79 #define START_RS_INDEX 0 80 #define START_RS_REG 1 81 #define START_RW_WRITE 0 82 #define START_RW_READ 1 83 84 /** 85 * START_BYTE(id, rs, rw) 86 * 87 * Set the start byte according to the required operation. 88 * The start byte is defined as: 89 * ---------------------------------- 90 * | 0 | 1 | 1 | 1 | 0 | ID | RS | RW | 91 * ---------------------------------- 92 * @id: display's id as set by the manufacturer 93 * @rs: operation type bit, one of: 94 * - START_RS_INDEX set the index register 95 * - START_RS_REG write/read registers/GRAM 96 * @rw: read/write operation 97 * - START_RW_WRITE write 98 * - START_RW_READ read 99 */ 100 #define START_BYTE(id, rs, rw) \ 101 (0x70 | (((id) & 0x01) << 2) | (((rs) & 0x01) << 1) | ((rw) & 0x01)) 102 103 /** 104 * CHECK_FREQ_REG(spi_device s, spi_transfer x) - Check the frequency 105 * for the SPI transfer. According to the datasheet, the controller 106 * accept higher frequency for the GRAM transfer, but it requires 107 * lower frequency when the registers are read/written. 108 * The macro sets the frequency in the spi_transfer structure if 109 * the frequency exceeds the maximum value. 110 * @s: pointer to an SPI device 111 * @x: pointer to the read/write buffer pair 112 */ 113 #define CHECK_FREQ_REG(s, x) \ 114 do { \ 115 if (s->max_speed_hz > ILITEK_MAX_FREQ_REG) \ 116 ((struct spi_transfer *)x)->speed_hz = \ 117 ILITEK_MAX_FREQ_REG; \ 118 } while (0) 119 120 #define CMD_BUFSIZE 16 121 122 #define POWER_IS_ON(pwr) ((pwr) <= FB_BLANK_NORMAL) 123 124 #define set_tx_byte(b) (tx_invert ? ~(b) : b) 125 126 /* 127 * ili922x_id - id as set by manufacturer 128 */ 129 static int ili922x_id = 1; 130 module_param(ili922x_id, int, 0); 131 132 static int tx_invert; 133 module_param(tx_invert, int, 0); 134 135 /* 136 * driver's private structure 137 */ 138 struct ili922x { 139 struct spi_device *spi; 140 struct lcd_device *ld; 141 int power; 142 }; 143 144 /** 145 * ili922x_read_status - read status register from display 146 * @spi: spi device 147 * @rs: output value 148 */ 149 static int ili922x_read_status(struct spi_device *spi, u16 *rs) 150 { 151 struct spi_message msg; 152 struct spi_transfer xfer; 153 unsigned char tbuf[CMD_BUFSIZE]; 154 unsigned char rbuf[CMD_BUFSIZE]; 155 int ret, i; 156 157 memset(&xfer, 0, sizeof(struct spi_transfer)); 158 spi_message_init(&msg); 159 xfer.tx_buf = tbuf; 160 xfer.rx_buf = rbuf; 161 xfer.cs_change = 1; 162 CHECK_FREQ_REG(spi, &xfer); 163 164 tbuf[0] = set_tx_byte(START_BYTE(ili922x_id, START_RS_INDEX, 165 START_RW_READ)); 166 /* 167 * we need 4-byte xfer here due to invalid dummy byte 168 * received after start byte 169 */ 170 for (i = 1; i < 4; i++) 171 tbuf[i] = set_tx_byte(0); /* dummy */ 172 173 xfer.bits_per_word = 8; 174 xfer.len = 4; 175 spi_message_add_tail(&xfer, &msg); 176 ret = spi_sync(spi, &msg); 177 if (ret < 0) { 178 dev_dbg(&spi->dev, "Error sending SPI message 0x%x", ret); 179 return ret; 180 } 181 182 *rs = (rbuf[2] << 8) + rbuf[3]; 183 return 0; 184 } 185 186 /** 187 * ili922x_read - read register from display 188 * @spi: spi device 189 * @reg: offset of the register to be read 190 * @rx: output value 191 */ 192 static int ili922x_read(struct spi_device *spi, u8 reg, u16 *rx) 193 { 194 struct spi_message msg; 195 struct spi_transfer xfer_regindex, xfer_regvalue; 196 unsigned char tbuf[CMD_BUFSIZE]; 197 unsigned char rbuf[CMD_BUFSIZE]; 198 int ret, len = 0, send_bytes; 199 200 memset(&xfer_regindex, 0, sizeof(struct spi_transfer)); 201 memset(&xfer_regvalue, 0, sizeof(struct spi_transfer)); 202 spi_message_init(&msg); 203 xfer_regindex.tx_buf = tbuf; 204 xfer_regindex.rx_buf = rbuf; 205 xfer_regindex.cs_change = 1; 206 CHECK_FREQ_REG(spi, &xfer_regindex); 207 208 tbuf[0] = set_tx_byte(START_BYTE(ili922x_id, START_RS_INDEX, 209 START_RW_WRITE)); 210 tbuf[1] = set_tx_byte(0); 211 tbuf[2] = set_tx_byte(reg); 212 xfer_regindex.bits_per_word = 8; 213 len = xfer_regindex.len = 3; 214 spi_message_add_tail(&xfer_regindex, &msg); 215 216 send_bytes = len; 217 218 tbuf[len++] = set_tx_byte(START_BYTE(ili922x_id, START_RS_REG, 219 START_RW_READ)); 220 tbuf[len++] = set_tx_byte(0); 221 tbuf[len] = set_tx_byte(0); 222 223 xfer_regvalue.cs_change = 1; 224 xfer_regvalue.len = 3; 225 xfer_regvalue.tx_buf = &tbuf[send_bytes]; 226 xfer_regvalue.rx_buf = &rbuf[send_bytes]; 227 CHECK_FREQ_REG(spi, &xfer_regvalue); 228 229 spi_message_add_tail(&xfer_regvalue, &msg); 230 ret = spi_sync(spi, &msg); 231 if (ret < 0) { 232 dev_dbg(&spi->dev, "Error sending SPI message 0x%x", ret); 233 return ret; 234 } 235 236 *rx = (rbuf[1 + send_bytes] << 8) + rbuf[2 + send_bytes]; 237 return 0; 238 } 239 240 /** 241 * ili922x_write - write a controller register 242 * @spi: struct spi_device * 243 * @reg: offset of the register to be written 244 * @value: value to be written 245 */ 246 static int ili922x_write(struct spi_device *spi, u8 reg, u16 value) 247 { 248 struct spi_message msg; 249 struct spi_transfer xfer_regindex, xfer_regvalue; 250 unsigned char tbuf[CMD_BUFSIZE]; 251 unsigned char rbuf[CMD_BUFSIZE]; 252 int ret; 253 254 memset(&xfer_regindex, 0, sizeof(struct spi_transfer)); 255 memset(&xfer_regvalue, 0, sizeof(struct spi_transfer)); 256 257 spi_message_init(&msg); 258 xfer_regindex.tx_buf = tbuf; 259 xfer_regindex.rx_buf = rbuf; 260 xfer_regindex.cs_change = 1; 261 CHECK_FREQ_REG(spi, &xfer_regindex); 262 263 tbuf[0] = set_tx_byte(START_BYTE(ili922x_id, START_RS_INDEX, 264 START_RW_WRITE)); 265 tbuf[1] = set_tx_byte(0); 266 tbuf[2] = set_tx_byte(reg); 267 xfer_regindex.bits_per_word = 8; 268 xfer_regindex.len = 3; 269 spi_message_add_tail(&xfer_regindex, &msg); 270 271 ret = spi_sync(spi, &msg); 272 273 spi_message_init(&msg); 274 tbuf[0] = set_tx_byte(START_BYTE(ili922x_id, START_RS_REG, 275 START_RW_WRITE)); 276 tbuf[1] = set_tx_byte((value & 0xFF00) >> 8); 277 tbuf[2] = set_tx_byte(value & 0x00FF); 278 279 xfer_regvalue.cs_change = 1; 280 xfer_regvalue.len = 3; 281 xfer_regvalue.tx_buf = tbuf; 282 xfer_regvalue.rx_buf = rbuf; 283 CHECK_FREQ_REG(spi, &xfer_regvalue); 284 285 spi_message_add_tail(&xfer_regvalue, &msg); 286 287 ret = spi_sync(spi, &msg); 288 if (ret < 0) { 289 dev_err(&spi->dev, "Error sending SPI message 0x%x", ret); 290 return ret; 291 } 292 return 0; 293 } 294 295 #ifdef DEBUG 296 /** 297 * ili922x_reg_dump - dump all registers 298 * 299 * @spi: pointer to an SPI device 300 */ 301 static void ili922x_reg_dump(struct spi_device *spi) 302 { 303 u8 reg; 304 u16 rx; 305 306 dev_dbg(&spi->dev, "ILI922x configuration registers:\n"); 307 for (reg = REG_START_OSCILLATION; 308 reg <= REG_OTP_PROGRAMMING_ID_KEY; reg++) { 309 ili922x_read(spi, reg, &rx); 310 dev_dbg(&spi->dev, "reg @ 0x%02X: 0x%04X\n", reg, rx); 311 } 312 } 313 #else 314 static inline void ili922x_reg_dump(struct spi_device *spi) {} 315 #endif 316 317 /** 318 * set_write_to_gram_reg - initialize the display to write the GRAM 319 * @spi: spi device 320 */ 321 static void set_write_to_gram_reg(struct spi_device *spi) 322 { 323 struct spi_message msg; 324 struct spi_transfer xfer; 325 unsigned char tbuf[CMD_BUFSIZE]; 326 327 memset(&xfer, 0, sizeof(struct spi_transfer)); 328 329 spi_message_init(&msg); 330 xfer.tx_buf = tbuf; 331 xfer.rx_buf = NULL; 332 xfer.cs_change = 1; 333 334 tbuf[0] = START_BYTE(ili922x_id, START_RS_INDEX, START_RW_WRITE); 335 tbuf[1] = 0; 336 tbuf[2] = REG_WRITE_DATA_TO_GRAM; 337 338 xfer.bits_per_word = 8; 339 xfer.len = 3; 340 spi_message_add_tail(&xfer, &msg); 341 spi_sync(spi, &msg); 342 } 343 344 /** 345 * ili922x_poweron - turn the display on 346 * @spi: spi device 347 * 348 * The sequence to turn on the display is taken from 349 * the datasheet and/or the example code provided by the 350 * manufacturer. 351 */ 352 static int ili922x_poweron(struct spi_device *spi) 353 { 354 int ret; 355 356 /* Power on */ 357 ret = ili922x_write(spi, REG_POWER_CONTROL_1, 0x0000); 358 usleep_range(10000, 10500); 359 ret += ili922x_write(spi, REG_POWER_CONTROL_2, 0x0000); 360 ret += ili922x_write(spi, REG_POWER_CONTROL_3, 0x0000); 361 msleep(40); 362 ret += ili922x_write(spi, REG_POWER_CONTROL_4, 0x0000); 363 msleep(40); 364 /* register 0x56 is not documented in the datasheet */ 365 ret += ili922x_write(spi, 0x56, 0x080F); 366 ret += ili922x_write(spi, REG_POWER_CONTROL_1, 0x4240); 367 usleep_range(10000, 10500); 368 ret += ili922x_write(spi, REG_POWER_CONTROL_2, 0x0000); 369 ret += ili922x_write(spi, REG_POWER_CONTROL_3, 0x0014); 370 msleep(40); 371 ret += ili922x_write(spi, REG_POWER_CONTROL_4, 0x1319); 372 msleep(40); 373 374 return ret; 375 } 376 377 /** 378 * ili922x_poweroff - turn the display off 379 * @spi: spi device 380 */ 381 static int ili922x_poweroff(struct spi_device *spi) 382 { 383 int ret; 384 385 /* Power off */ 386 ret = ili922x_write(spi, REG_POWER_CONTROL_1, 0x0000); 387 usleep_range(10000, 10500); 388 ret += ili922x_write(spi, REG_POWER_CONTROL_2, 0x0000); 389 ret += ili922x_write(spi, REG_POWER_CONTROL_3, 0x0000); 390 msleep(40); 391 ret += ili922x_write(spi, REG_POWER_CONTROL_4, 0x0000); 392 msleep(40); 393 394 return ret; 395 } 396 397 /** 398 * ili922x_display_init - initialize the display by setting 399 * the configuration registers 400 * @spi: spi device 401 */ 402 static void ili922x_display_init(struct spi_device *spi) 403 { 404 ili922x_write(spi, REG_START_OSCILLATION, 1); 405 usleep_range(10000, 10500); 406 ili922x_write(spi, REG_DRIVER_OUTPUT_CONTROL, 0x691B); 407 ili922x_write(spi, REG_LCD_AC_DRIVEING_CONTROL, 0x0700); 408 ili922x_write(spi, REG_ENTRY_MODE, 0x1030); 409 ili922x_write(spi, REG_COMPARE_1, 0x0000); 410 ili922x_write(spi, REG_COMPARE_2, 0x0000); 411 ili922x_write(spi, REG_DISPLAY_CONTROL_1, 0x0037); 412 ili922x_write(spi, REG_DISPLAY_CONTROL_2, 0x0202); 413 ili922x_write(spi, REG_DISPLAY_CONTROL_3, 0x0000); 414 ili922x_write(spi, REG_FRAME_CYCLE_CONTROL, 0x0000); 415 416 /* Set RGB interface */ 417 ili922x_write(spi, REG_EXT_INTF_CONTROL, 0x0110); 418 419 ili922x_poweron(spi); 420 421 ili922x_write(spi, REG_GAMMA_CONTROL_1, 0x0302); 422 ili922x_write(spi, REG_GAMMA_CONTROL_2, 0x0407); 423 ili922x_write(spi, REG_GAMMA_CONTROL_3, 0x0304); 424 ili922x_write(spi, REG_GAMMA_CONTROL_4, 0x0203); 425 ili922x_write(spi, REG_GAMMA_CONTROL_5, 0x0706); 426 ili922x_write(spi, REG_GAMMA_CONTROL_6, 0x0407); 427 ili922x_write(spi, REG_GAMMA_CONTROL_7, 0x0706); 428 ili922x_write(spi, REG_GAMMA_CONTROL_8, 0x0000); 429 ili922x_write(spi, REG_GAMMA_CONTROL_9, 0x0C06); 430 ili922x_write(spi, REG_GAMMA_CONTROL_10, 0x0F00); 431 ili922x_write(spi, REG_RAM_ADDRESS_SET, 0x0000); 432 ili922x_write(spi, REG_GATE_SCAN_CONTROL, 0x0000); 433 ili922x_write(spi, REG_VERT_SCROLL_CONTROL, 0x0000); 434 ili922x_write(spi, REG_FIRST_SCREEN_DRIVE_POS, 0xDB00); 435 ili922x_write(spi, REG_SECOND_SCREEN_DRIVE_POS, 0xDB00); 436 ili922x_write(spi, REG_RAM_ADDR_POS_H, 0xAF00); 437 ili922x_write(spi, REG_RAM_ADDR_POS_V, 0xDB00); 438 ili922x_reg_dump(spi); 439 set_write_to_gram_reg(spi); 440 } 441 442 static int ili922x_lcd_power(struct ili922x *lcd, int power) 443 { 444 int ret = 0; 445 446 if (POWER_IS_ON(power) && !POWER_IS_ON(lcd->power)) 447 ret = ili922x_poweron(lcd->spi); 448 else if (!POWER_IS_ON(power) && POWER_IS_ON(lcd->power)) 449 ret = ili922x_poweroff(lcd->spi); 450 451 if (!ret) 452 lcd->power = power; 453 454 return ret; 455 } 456 457 static int ili922x_set_power(struct lcd_device *ld, int power) 458 { 459 struct ili922x *ili = lcd_get_data(ld); 460 461 return ili922x_lcd_power(ili, power); 462 } 463 464 static int ili922x_get_power(struct lcd_device *ld) 465 { 466 struct ili922x *ili = lcd_get_data(ld); 467 468 return ili->power; 469 } 470 471 static struct lcd_ops ili922x_ops = { 472 .get_power = ili922x_get_power, 473 .set_power = ili922x_set_power, 474 }; 475 476 static int ili922x_probe(struct spi_device *spi) 477 { 478 struct ili922x *ili; 479 struct lcd_device *lcd; 480 int ret; 481 u16 reg = 0; 482 483 ili = devm_kzalloc(&spi->dev, sizeof(*ili), GFP_KERNEL); 484 if (!ili) 485 return -ENOMEM; 486 487 ili->spi = spi; 488 spi_set_drvdata(spi, ili); 489 490 /* check if the device is connected */ 491 ret = ili922x_read(spi, REG_DRIVER_CODE_READ, ®); 492 if (ret || ((reg & ILITEK_DEVICE_ID_MASK) != ILITEK_DEVICE_ID)) { 493 dev_err(&spi->dev, 494 "no LCD found: Chip ID 0x%x, ret %d\n", 495 reg, ret); 496 return -ENODEV; 497 } 498 499 dev_info(&spi->dev, "ILI%x found, SPI freq %d, mode %d\n", 500 reg, spi->max_speed_hz, spi->mode); 501 502 ret = ili922x_read_status(spi, ®); 503 if (ret) { 504 dev_err(&spi->dev, "reading RS failed...\n"); 505 return ret; 506 } 507 508 dev_dbg(&spi->dev, "status: 0x%x\n", reg); 509 510 ili922x_display_init(spi); 511 512 ili->power = FB_BLANK_POWERDOWN; 513 514 lcd = devm_lcd_device_register(&spi->dev, "ili922xlcd", &spi->dev, ili, 515 &ili922x_ops); 516 if (IS_ERR(lcd)) { 517 dev_err(&spi->dev, "cannot register LCD\n"); 518 return PTR_ERR(lcd); 519 } 520 521 ili->ld = lcd; 522 spi_set_drvdata(spi, ili); 523 524 ili922x_lcd_power(ili, FB_BLANK_UNBLANK); 525 526 return 0; 527 } 528 529 static void ili922x_remove(struct spi_device *spi) 530 { 531 ili922x_poweroff(spi); 532 } 533 534 static struct spi_driver ili922x_driver = { 535 .driver = { 536 .name = "ili922x", 537 }, 538 .probe = ili922x_probe, 539 .remove = ili922x_remove, 540 }; 541 542 module_spi_driver(ili922x_driver); 543 544 MODULE_AUTHOR("Stefano Babic <sbabic@denx.de>"); 545 MODULE_DESCRIPTION("ILI9221/9222 LCD driver"); 546 MODULE_LICENSE("GPL"); 547 MODULE_PARM_DESC(ili922x_id, "set controller identifier (default=1)"); 548 MODULE_PARM_DESC(tx_invert, "invert bytes before sending"); 549