drivers/video/backlight/ltv350qv.c

   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
  23 struct 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  */
  40 static 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 */
  71 static 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
 141 err_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));
 152 err_settings:
 153 err_power2:
 154 err_power1:
 155         ltv350qv_write_reg(lcd, LTV_PWRCTL2, 0x0000);
 156         usleep_range(1000, 1100);
 157 err:
 158         ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE);
 159         return -EIO;
 160 }
 161
 162 static 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
 195 static 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
 210 static 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
 217 static int ltv350qv_get_power(struct lcd_device *ld)
 218 {
 219         struct ltv350qv *lcd = lcd_get_data(ld);
 220
 221         return lcd->power;
 222 }
 223
 224 static struct lcd_ops ltv_ops = {
 225         .get_power      = ltv350qv_get_power,
 226         .set_power      = ltv350qv_set_power,
 227 };
 228
 229 static int __devinit 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 = lcd_device_register("ltv350qv", &spi->dev, lcd, &ltv_ops);
 246         if (IS_ERR(ld))
 247                 return PTR_ERR(ld);
 248
 249         lcd->ld = ld;
 250
 251         ret = ltv350qv_power(lcd, FB_BLANK_UNBLANK);
 252         if (ret)
 253                 goto out_unregister;
 254
 255         dev_set_drvdata(&spi->dev, lcd);
 256
 257         return 0;
 258
 259 out_unregister:
 260         lcd_device_unregister(ld);
 261         return ret;
 262 }
 263
 264 static int __devexit ltv350qv_remove(struct spi_device *spi)
 265 {
 266         struct ltv350qv *lcd = dev_get_drvdata(&spi->dev);
 267
 268         ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
 269         lcd_device_unregister(lcd->ld);
 270
 271         return 0;
 272 }
 273
 274 #ifdef CONFIG_PM
 275 static int ltv350qv_suspend(struct spi_device *spi, pm_message_t state)
 276 {
 277         struct ltv350qv *lcd = dev_get_drvdata(&spi->dev);
 278
 279         return ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
 280 }
 281
 282 static int ltv350qv_resume(struct spi_device *spi)
 283 {
 284         struct ltv350qv *lcd = dev_get_drvdata(&spi->dev);
 285
 286         return ltv350qv_power(lcd, FB_BLANK_UNBLANK);
 287 }
 288 #else
 289 #define ltv350qv_suspend        NULL
 290 #define ltv350qv_resume         NULL
 291 #endif
 292
 293 /* Power down all displays on reboot, poweroff or halt */
 294 static void ltv350qv_shutdown(struct spi_device *spi)
 295 {
 296         struct ltv350qv *lcd = dev_get_drvdata(&spi->dev);
 297
 298         ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
 299 }
 300
 301 static struct spi_driver ltv350qv_driver = {
 302         .driver = {
 303                 .name           = "ltv350qv",
 304                 .owner          = THIS_MODULE,
 305         },
 306
 307         .probe          = ltv350qv_probe,
 308         .remove         = __devexit_p(ltv350qv_remove),
 309         .shutdown       = ltv350qv_shutdown,
 310         .suspend        = ltv350qv_suspend,
 311         .resume         = ltv350qv_resume,
 312 };
 313
 314 module_spi_driver(ltv350qv_driver);
 315
 316 MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
 317 MODULE_DESCRIPTION("Samsung LTV350QV LCD Driver");
 318 MODULE_LICENSE("GPL");
 319 MODULE_ALIAS("spi:ltv350qv");