LXR linux/drivers/video/backlight/ili922x.c

   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 */
 129static int ili922x_id = 1;
 130module_param(ili922x_id, int, 0);
 131
 132static int tx_invert;
 133module_param(tx_invert, int, 0);
 134
 135/*
 136 * driver's private structure
 137 */
 138struct 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 */
 149static 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 */
 192static 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 */
 246static 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 */
 301static 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
 314static 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 */
 321static 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 */
 352static 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 */
 381static 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 */
 402static 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
 442static 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
 457static 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
 464static int ili922x_get_power(struct lcd_device *ld)
 465{
 466        struct ili922x *ili = lcd_get_data(ld);
 467
 468        return ili->power;
 469}
 470
 471static struct lcd_ops ili922x_ops = {
 472        .get_power = ili922x_get_power,
 473        .set_power = ili922x_set_power,
 474};
 475
 476static 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, &reg);
 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, &reg);
 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
 529static void ili922x_remove(struct spi_device *spi)
 530{
 531        ili922x_poweroff(spi);
 532}
 533
 534static struct spi_driver ili922x_driver = {
 535        .driver = {
 536                .name = "ili922x",
 537        },
 538        .probe = ili922x_probe,
 539        .remove = ili922x_remove,
 540};
 541
 542module_spi_driver(ili922x_driver);
 543
 544MODULE_AUTHOR("Stefano Babic <sbabic@denx.de>");
 545MODULE_DESCRIPTION("ILI9221/9222 LCD driver");
 546MODULE_LICENSE("GPL");
 547MODULE_PARM_DESC(ili922x_id, "set controller identifier (default=1)");
 548MODULE_PARM_DESC(tx_invert, "invert bytes before sending");
 549