drivers/video/backlight/ltv350qv.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Power control for Samsung LTV350QV Quarter VGA LCD Panel
   4  *
   5  * Copyright (C) 2006, 2007 Atmel Corporation
   6  */
   7 #include <linux/delay.h>
   8 #include <linux/err.h>
   9 #include <linux/fb.h>
  10 #include <linux/init.h>
  11 #include <linux/lcd.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/spi/spi.h>
  15
  16 #include "ltv350qv.h"
  17
  18 #define POWER_IS_ON(pwr)        ((pwr) <= FB_BLANK_NORMAL)
  19
  20 struct ltv350qv {
  21         struct spi_device       *spi;
  22         u8                      *buffer;
  23         int                     power;
  24         struct lcd_device       *ld;
  25 };
  26
  27 /*
  28  * The power-on and power-off sequences are taken from the
  29  * LTV350QV-F04 data sheet from Samsung. The register definitions are
  30  * taken from the S6F2002 command list also from Samsung.
  31  *
  32  * There's still some voodoo going on here, but it's a lot better than
  33  * in the first incarnation of the driver where all we had was the raw
  34  * numbers from the initialization sequence.
  35  */
  36 static int ltv350qv_write_reg(struct ltv350qv *lcd, u8 reg, u16 val)
  37 {
  38         struct spi_message msg;
  39         struct spi_transfer index_xfer = {
  40                 .len            = 3,
  41                 .cs_change      = 1,
  42         };
  43         struct spi_transfer value_xfer = {
  44                 .len            = 3,
  45         };
  46
  47         spi_message_init(&msg);
  48
  49         /* register index */
  50         lcd->buffer[0] = LTV_OPC_INDEX;
  51         lcd->buffer[1] = 0x00;
  52         lcd->buffer[2] = reg & 0x7f;
  53         index_xfer.tx_buf = lcd->buffer;
  54         spi_message_add_tail(&index_xfer, &msg);
  55
  56         /* register value */
  57         lcd->buffer[4] = LTV_OPC_DATA;
  58         lcd->buffer[5] = val >> 8;
  59         lcd->buffer[6] = val;
  60         value_xfer.tx_buf = lcd->buffer + 4;
  61         spi_message_add_tail(&value_xfer, &msg);
  62
  63         return spi_sync(lcd->spi, &msg);
  64 }
  65
  66 /* The comments are taken straight from the data sheet */
  67 static int ltv350qv_power_on(struct ltv350qv *lcd)
  68 {
  69         int ret;
  70
  71         /* Power On Reset Display off State */
  72         if (ltv350qv_write_reg(lcd, LTV_PWRCTL1, 0x0000))
  73                 goto err;
  74         usleep_range(15000, 16000);
  75
  76         /* Power Setting Function 1 */
  77         if (ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE))
  78                 goto err;
  79         if (ltv350qv_write_reg(lcd, LTV_PWRCTL2, LTV_VCOML_ENABLE))
  80                 goto err_power1;
  81
  82         /* Power Setting Function 2 */
  83         if (ltv350qv_write_reg(lcd, LTV_PWRCTL1,
  84                                LTV_VCOM_DISABLE | LTV_DRIVE_CURRENT(5)
  85                                | LTV_SUPPLY_CURRENT(5)))
  86                 goto err_power2;
  87
  88         msleep(55);
  89
  90         /* Instruction Setting */
  91         ret = ltv350qv_write_reg(lcd, LTV_IFCTL,
  92                                  LTV_NMD | LTV_REV | LTV_NL(0x1d));
  93         ret |= ltv350qv_write_reg(lcd, LTV_DATACTL,
  94                                   LTV_DS_SAME | LTV_CHS_480
  95                                   | LTV_DF_RGB | LTV_RGB_BGR);
  96         ret |= ltv350qv_write_reg(lcd, LTV_ENTRY_MODE,
  97                                   LTV_VSPL_ACTIVE_LOW
  98                                   | LTV_HSPL_ACTIVE_LOW
  99                                   | LTV_DPL_SAMPLE_RISING
 100                                   | LTV_EPL_ACTIVE_LOW
 101                                   | LTV_SS_RIGHT_TO_LEFT);
 102         ret |= ltv350qv_write_reg(lcd, LTV_GATECTL1, LTV_CLW(3));
 103         ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
 104                                   LTV_NW_INV_1LINE | LTV_FWI(3));
 105         ret |= ltv350qv_write_reg(lcd, LTV_VBP, 0x000a);
 106         ret |= ltv350qv_write_reg(lcd, LTV_HBP, 0x0021);
 107         ret |= ltv350qv_write_reg(lcd, LTV_SOTCTL, LTV_SDT(3) | LTV_EQ(0));
 108         ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(0), 0x0103);
 109         ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(1), 0x0301);
 110         ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(2), 0x1f0f);
 111         ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(3), 0x1f0f);
 112         ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(4), 0x0707);
 113         ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(5), 0x0307);
 114         ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(6), 0x0707);
 115         ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(7), 0x0000);
 116         ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(8), 0x0004);
 117         ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(9), 0x0000);
 118         if (ret)
 119                 goto err_settings;
 120
 121         /* Wait more than 2 frames */
 122         msleep(20);
 123
 124         /* Display On Sequence */
 125         ret = ltv350qv_write_reg(lcd, LTV_PWRCTL1,
 126                                  LTV_VCOM_DISABLE | LTV_VCOMOUT_ENABLE
 127                                  | LTV_POWER_ON | LTV_DRIVE_CURRENT(5)
 128                                  | LTV_SUPPLY_CURRENT(5));
 129         ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
 130                                   LTV_NW_INV_1LINE | LTV_DSC | LTV_FWI(3));
 131         if (ret)
 132                 goto err_disp_on;
 133
 134         /* Display should now be ON. Phew. */
 135         return 0;
 136
 137 err_disp_on:
 138         /*
 139          * Try to recover. Error handling probably isn't very useful
 140          * at this point, just make a best effort to switch the panel
 141          * off.
 142          */
 143         ltv350qv_write_reg(lcd, LTV_PWRCTL1,
 144                            LTV_VCOM_DISABLE | LTV_DRIVE_CURRENT(5)
 145                            | LTV_SUPPLY_CURRENT(5));
 146         ltv350qv_write_reg(lcd, LTV_GATECTL2,
 147                            LTV_NW_INV_1LINE | LTV_FWI(3));
 148 err_settings:
 149 err_power2:
 150 err_power1:
 151         ltv350qv_write_reg(lcd, LTV_PWRCTL2, 0x0000);
 152         usleep_range(1000, 1100);
 153 err:
 154         ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE);
 155         return -EIO;
 156 }
 157
 158 static int ltv350qv_power_off(struct ltv350qv *lcd)
 159 {
 160         int ret;
 161
 162         /* Display Off Sequence */
 163         ret = ltv350qv_write_reg(lcd, LTV_PWRCTL1,
 164                                  LTV_VCOM_DISABLE
 165                                  | LTV_DRIVE_CURRENT(5)
 166                                  | LTV_SUPPLY_CURRENT(5));
 167         ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
 168                                   LTV_NW_INV_1LINE | LTV_FWI(3));
 169
 170         /* Power down setting 1 */
 171         ret |= ltv350qv_write_reg(lcd, LTV_PWRCTL2, 0x0000);
 172
 173         /* Wait at least 1 ms */
 174         usleep_range(1000, 1100);
 175
 176         /* Power down setting 2 */
 177         ret |= ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE);
 178
 179         /*
 180          * No point in trying to recover here. If we can't switch the
 181          * panel off, what are we supposed to do other than inform the
 182          * user about the failure?
 183          */
 184         if (ret)
 185                 return -EIO;
 186
 187         /* Display power should now be OFF */
 188         return 0;
 189 }
 190
 191 static int ltv350qv_power(struct ltv350qv *lcd, int power)
 192 {
 193         int ret = 0;
 194
 195         if (POWER_IS_ON(power) && !POWER_IS_ON(lcd->power))
 196                 ret = ltv350qv_power_on(lcd);
 197         else if (!POWER_IS_ON(power) && POWER_IS_ON(lcd->power))
 198                 ret = ltv350qv_power_off(lcd);
 199
 200         if (!ret)
 201                 lcd->power = power;
 202
 203         return ret;
 204 }
 205
 206 static int ltv350qv_set_power(struct lcd_device *ld, int power)
 207 {
 208         struct ltv350qv *lcd = lcd_get_data(ld);
 209
 210         return ltv350qv_power(lcd, power);
 211 }
 212
 213 static int ltv350qv_get_power(struct lcd_device *ld)
 214 {
 215         struct ltv350qv *lcd = lcd_get_data(ld);
 216
 217         return lcd->power;
 218 }
 219
 220 static struct lcd_ops ltv_ops = {
 221         .get_power      = ltv350qv_get_power,
 222         .set_power      = ltv350qv_set_power,
 223 };
 224
 225 static int ltv350qv_probe(struct spi_device *spi)
 226 {
 227         struct ltv350qv *lcd;
 228         struct lcd_device *ld;
 229         int ret;
 230
 231         lcd = devm_kzalloc(&spi->dev, sizeof(struct ltv350qv), GFP_KERNEL);
 232         if (!lcd)
 233                 return -ENOMEM;
 234
 235         lcd->spi = spi;
 236         lcd->power = FB_BLANK_POWERDOWN;
 237         lcd->buffer = devm_kzalloc(&spi->dev, 8, GFP_KERNEL);
 238         if (!lcd->buffer)
 239                 return -ENOMEM;
 240
 241         ld = devm_lcd_device_register(&spi->dev, "ltv350qv", &spi->dev, lcd,
 242                                         &ltv_ops);
 243         if (IS_ERR(ld))
 244                 return PTR_ERR(ld);
 245
 246         lcd->ld = ld;
 247
 248         ret = ltv350qv_power(lcd, FB_BLANK_UNBLANK);
 249         if (ret)
 250                 return ret;
 251
 252         spi_set_drvdata(spi, lcd);
 253
 254         return 0;
 255 }
 256
 257 static void ltv350qv_remove(struct spi_device *spi)
 258 {
 259         struct ltv350qv *lcd = spi_get_drvdata(spi);
 260
 261         ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
 262 }
 263
 264 #ifdef CONFIG_PM_SLEEP
 265 static int ltv350qv_suspend(struct device *dev)
 266 {
 267         struct ltv350qv *lcd = dev_get_drvdata(dev);
 268
 269         return ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
 270 }
 271
 272 static int ltv350qv_resume(struct device *dev)
 273 {
 274         struct ltv350qv *lcd = dev_get_drvdata(dev);
 275
 276         return ltv350qv_power(lcd, FB_BLANK_UNBLANK);
 277 }
 278 #endif
 279
 280 static SIMPLE_DEV_PM_OPS(ltv350qv_pm_ops, ltv350qv_suspend, ltv350qv_resume);
 281
 282 /* Power down all displays on reboot, poweroff or halt */
 283 static void ltv350qv_shutdown(struct spi_device *spi)
 284 {
 285         struct ltv350qv *lcd = spi_get_drvdata(spi);
 286
 287         ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
 288 }
 289
 290 static struct spi_driver ltv350qv_driver = {
 291         .driver = {
 292                 .name           = "ltv350qv",
 293                 .pm             = &ltv350qv_pm_ops,
 294         },
 295
 296         .probe          = ltv350qv_probe,
 297         .remove         = ltv350qv_remove,
 298         .shutdown       = ltv350qv_shutdown,
 299 };
 300
 301 module_spi_driver(ltv350qv_driver);
 302
 303 MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
 304 MODULE_DESCRIPTION("Samsung LTV350QV LCD Driver");
 305 MODULE_LICENSE("GPL");
 306 MODULE_ALIAS("spi:ltv350qv");