linux/drivers/video/backlight/ltv350qv.c
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   1/*
   2 * Power control for Samsung LTV350QV Quarter VGA LCD Panel
   3 *
   4 * Copyright (C) 2006, 2007 Atmel Corporation
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License version 2 as
   8 * published by the Free Software Foundation.
   9 */
  10#include <linux/delay.h>
  11#include <linux/err.h>
  12#include <linux/fb.h>
  13#include <linux/init.h>
  14#include <linux/lcd.h>
  15#include <linux/module.h>
  16#include <linux/slab.h>
  17#include <linux/spi/spi.h>
  18
  19#include "ltv350qv.h"
  20
  21#define POWER_IS_ON(pwr)        ((pwr) <= FB_BLANK_NORMAL)
  22
  23struct ltv350qv {
  24        struct spi_device       *spi;
  25        u8                      *buffer;
  26        int                     power;
  27        struct lcd_device       *ld;
  28};
  29
  30/*
  31 * The power-on and power-off sequences are taken from the
  32 * LTV350QV-F04 data sheet from Samsung. The register definitions are
  33 * taken from the S6F2002 command list also from Samsung. Both
  34 * documents are distributed with the AVR32 Linux BSP CD from Atmel.
  35 *
  36 * There's still some voodoo going on here, but it's a lot better than
  37 * in the first incarnation of the driver where all we had was the raw
  38 * numbers from the initialization sequence.
  39 */
  40static int ltv350qv_write_reg(struct ltv350qv *lcd, u8 reg, u16 val)
  41{
  42        struct spi_message msg;
  43        struct spi_transfer index_xfer = {
  44                .len            = 3,
  45                .cs_change      = 1,
  46        };
  47        struct spi_transfer value_xfer = {
  48                .len            = 3,
  49        };
  50
  51        spi_message_init(&msg);
  52
  53        /* register index */
  54        lcd->buffer[0] = LTV_OPC_INDEX;
  55        lcd->buffer[1] = 0x00;
  56        lcd->buffer[2] = reg & 0x7f;
  57        index_xfer.tx_buf = lcd->buffer;
  58        spi_message_add_tail(&index_xfer, &msg);
  59
  60        /* register value */
  61        lcd->buffer[4] = LTV_OPC_DATA;
  62        lcd->buffer[5] = val >> 8;
  63        lcd->buffer[6] = val;
  64        value_xfer.tx_buf = lcd->buffer + 4;
  65        spi_message_add_tail(&value_xfer, &msg);
  66
  67        return spi_sync(lcd->spi, &msg);
  68}
  69
  70/* The comments are taken straight from the data sheet */
  71static int ltv350qv_power_on(struct ltv350qv *lcd)
  72{
  73        int ret;
  74
  75        /* Power On Reset Display off State */
  76        if (ltv350qv_write_reg(lcd, LTV_PWRCTL1, 0x0000))
  77                goto err;
  78        usleep_range(15000, 16000);
  79
  80        /* Power Setting Function 1 */
  81        if (ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE))
  82                goto err;
  83        if (ltv350qv_write_reg(lcd, LTV_PWRCTL2, LTV_VCOML_ENABLE))
  84                goto err_power1;
  85
  86        /* Power Setting Function 2 */
  87        if (ltv350qv_write_reg(lcd, LTV_PWRCTL1,
  88                               LTV_VCOM_DISABLE | LTV_DRIVE_CURRENT(5)
  89                               | LTV_SUPPLY_CURRENT(5)))
  90                goto err_power2;
  91
  92        msleep(55);
  93
  94        /* Instruction Setting */
  95        ret = ltv350qv_write_reg(lcd, LTV_IFCTL,
  96                                 LTV_NMD | LTV_REV | LTV_NL(0x1d));
  97        ret |= ltv350qv_write_reg(lcd, LTV_DATACTL,
  98                                  LTV_DS_SAME | LTV_CHS_480
  99                                  | LTV_DF_RGB | LTV_RGB_BGR);
 100        ret |= ltv350qv_write_reg(lcd, LTV_ENTRY_MODE,
 101                                  LTV_VSPL_ACTIVE_LOW
 102                                  | LTV_HSPL_ACTIVE_LOW
 103                                  | LTV_DPL_SAMPLE_RISING
 104                                  | LTV_EPL_ACTIVE_LOW
 105                                  | LTV_SS_RIGHT_TO_LEFT);
 106        ret |= ltv350qv_write_reg(lcd, LTV_GATECTL1, LTV_CLW(3));
 107        ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
 108                                  LTV_NW_INV_1LINE | LTV_FWI(3));
 109        ret |= ltv350qv_write_reg(lcd, LTV_VBP, 0x000a);
 110        ret |= ltv350qv_write_reg(lcd, LTV_HBP, 0x0021);
 111        ret |= ltv350qv_write_reg(lcd, LTV_SOTCTL, LTV_SDT(3) | LTV_EQ(0));
 112        ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(0), 0x0103);
 113        ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(1), 0x0301);
 114        ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(2), 0x1f0f);
 115        ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(3), 0x1f0f);
 116        ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(4), 0x0707);
 117        ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(5), 0x0307);
 118        ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(6), 0x0707);
 119        ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(7), 0x0000);
 120        ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(8), 0x0004);
 121        ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(9), 0x0000);
 122        if (ret)
 123                goto err_settings;
 124
 125        /* Wait more than 2 frames */
 126        msleep(20);
 127
 128        /* Display On Sequence */
 129        ret = ltv350qv_write_reg(lcd, LTV_PWRCTL1,
 130                                 LTV_VCOM_DISABLE | LTV_VCOMOUT_ENABLE
 131                                 | LTV_POWER_ON | LTV_DRIVE_CURRENT(5)
 132                                 | LTV_SUPPLY_CURRENT(5));
 133        ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
 134                                  LTV_NW_INV_1LINE | LTV_DSC | LTV_FWI(3));
 135        if (ret)
 136                goto err_disp_on;
 137
 138        /* Display should now be ON. Phew. */
 139        return 0;
 140
 141err_disp_on:
 142        /*
 143         * Try to recover. Error handling probably isn't very useful
 144         * at this point, just make a best effort to switch the panel
 145         * off.
 146         */
 147        ltv350qv_write_reg(lcd, LTV_PWRCTL1,
 148                           LTV_VCOM_DISABLE | LTV_DRIVE_CURRENT(5)
 149                           | LTV_SUPPLY_CURRENT(5));
 150        ltv350qv_write_reg(lcd, LTV_GATECTL2,
 151                           LTV_NW_INV_1LINE | LTV_FWI(3));
 152err_settings:
 153err_power2:
 154err_power1:
 155        ltv350qv_write_reg(lcd, LTV_PWRCTL2, 0x0000);
 156        usleep_range(1000, 1100);
 157err:
 158        ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE);
 159        return -EIO;
 160}
 161
 162static int ltv350qv_power_off(struct ltv350qv *lcd)
 163{
 164        int ret;
 165
 166        /* Display Off Sequence */
 167        ret = ltv350qv_write_reg(lcd, LTV_PWRCTL1,
 168                                 LTV_VCOM_DISABLE
 169                                 | LTV_DRIVE_CURRENT(5)
 170                                 | LTV_SUPPLY_CURRENT(5));
 171        ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
 172                                  LTV_NW_INV_1LINE | LTV_FWI(3));
 173
 174        /* Power down setting 1 */
 175        ret |= ltv350qv_write_reg(lcd, LTV_PWRCTL2, 0x0000);
 176
 177        /* Wait at least 1 ms */
 178        usleep_range(1000, 1100);
 179
 180        /* Power down setting 2 */
 181        ret |= ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE);
 182
 183        /*
 184         * No point in trying to recover here. If we can't switch the
 185         * panel off, what are we supposed to do other than inform the
 186         * user about the failure?
 187         */
 188        if (ret)
 189                return -EIO;
 190
 191        /* Display power should now be OFF */
 192        return 0;
 193}
 194
 195static int ltv350qv_power(struct ltv350qv *lcd, int power)
 196{
 197        int ret = 0;
 198
 199        if (POWER_IS_ON(power) && !POWER_IS_ON(lcd->power))
 200                ret = ltv350qv_power_on(lcd);
 201        else if (!POWER_IS_ON(power) && POWER_IS_ON(lcd->power))
 202                ret = ltv350qv_power_off(lcd);
 203
 204        if (!ret)
 205                lcd->power = power;
 206
 207        return ret;
 208}
 209
 210static int ltv350qv_set_power(struct lcd_device *ld, int power)
 211{
 212        struct ltv350qv *lcd = lcd_get_data(ld);
 213
 214        return ltv350qv_power(lcd, power);
 215}
 216
 217static int ltv350qv_get_power(struct lcd_device *ld)
 218{
 219        struct ltv350qv *lcd = lcd_get_data(ld);
 220
 221        return lcd->power;
 222}
 223
 224static struct lcd_ops ltv_ops = {
 225        .get_power      = ltv350qv_get_power,
 226        .set_power      = ltv350qv_set_power,
 227};
 228
 229static int ltv350qv_probe(struct spi_device *spi)
 230{
 231        struct ltv350qv *lcd;
 232        struct lcd_device *ld;
 233        int ret;
 234
 235        lcd = devm_kzalloc(&spi->dev, sizeof(struct ltv350qv), GFP_KERNEL);
 236        if (!lcd)
 237                return -ENOMEM;
 238
 239        lcd->spi = spi;
 240        lcd->power = FB_BLANK_POWERDOWN;
 241        lcd->buffer = devm_kzalloc(&spi->dev, 8, GFP_KERNEL);
 242        if (!lcd->buffer)
 243                return -ENOMEM;
 244
 245        ld = devm_lcd_device_register(&spi->dev, "ltv350qv", &spi->dev, lcd,
 246                                        &ltv_ops);
 247        if (IS_ERR(ld))
 248                return PTR_ERR(ld);
 249
 250        lcd->ld = ld;
 251
 252        ret = ltv350qv_power(lcd, FB_BLANK_UNBLANK);
 253        if (ret)
 254                return ret;
 255
 256        spi_set_drvdata(spi, lcd);
 257
 258        return 0;
 259}
 260
 261static int ltv350qv_remove(struct spi_device *spi)
 262{
 263        struct ltv350qv *lcd = spi_get_drvdata(spi);
 264
 265        ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
 266        return 0;
 267}
 268
 269#ifdef CONFIG_PM_SLEEP
 270static int ltv350qv_suspend(struct device *dev)
 271{
 272        struct ltv350qv *lcd = dev_get_drvdata(dev);
 273
 274        return ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
 275}
 276
 277static int ltv350qv_resume(struct device *dev)
 278{
 279        struct ltv350qv *lcd = dev_get_drvdata(dev);
 280
 281        return ltv350qv_power(lcd, FB_BLANK_UNBLANK);
 282}
 283#endif
 284
 285static SIMPLE_DEV_PM_OPS(ltv350qv_pm_ops, ltv350qv_suspend, ltv350qv_resume);
 286
 287/* Power down all displays on reboot, poweroff or halt */
 288static void ltv350qv_shutdown(struct spi_device *spi)
 289{
 290        struct ltv350qv *lcd = spi_get_drvdata(spi);
 291
 292        ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
 293}
 294
 295static struct spi_driver ltv350qv_driver = {
 296        .driver = {
 297                .name           = "ltv350qv",
 298                .pm             = &ltv350qv_pm_ops,
 299        },
 300
 301        .probe          = ltv350qv_probe,
 302        .remove         = ltv350qv_remove,
 303        .shutdown       = ltv350qv_shutdown,
 304};
 305
 306module_spi_driver(ltv350qv_driver);
 307
 308MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
 309MODULE_DESCRIPTION("Samsung LTV350QV LCD Driver");
 310MODULE_LICENSE("GPL");
 311MODULE_ALIAS("spi:ltv350qv");
 312
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