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/init.h> 10 #include <linux/lcd.h> 11 #include <linux/module.h> 12 #include <linux/slab.h> 13 #include <linux/spi/spi.h> 14 15 #include "ltv350qv.h" 16 17 #define POWER_IS_ON(pwr) ((pwr) <= LCD_POWER_REDUCED) 18 19 struct ltv350qv { 20 struct spi_device *spi; 21 u8 *buffer; 22 int power; 23 struct lcd_device *ld; 24 }; 25 26 /* 27 * The power-on and power-off sequences are taken from the 28 * LTV350QV-F04 data sheet from Samsung. The register definitions are 29 * taken from the S6F2002 command list also from Samsung. 30 * 31 * There's still some voodoo going on here, but it's a lot better than 32 * in the first incarnation of the driver where all we had was the raw 33 * numbers from the initialization sequence. 34 */ 35 static int ltv350qv_write_reg(struct ltv350qv *lcd, u8 reg, u16 val) 36 { 37 struct spi_message msg; 38 struct spi_transfer index_xfer = { 39 .len = 3, 40 .cs_change = 1, 41 }; 42 struct spi_transfer value_xfer = { 43 .len = 3, 44 }; 45 46 spi_message_init(&msg); 47 48 /* register index */ 49 lcd->buffer[0] = LTV_OPC_INDEX; 50 lcd->buffer[1] = 0x00; 51 lcd->buffer[2] = reg & 0x7f; 52 index_xfer.tx_buf = lcd->buffer; 53 spi_message_add_tail(&index_xfer, &msg); 54 55 /* register value */ 56 lcd->buffer[4] = LTV_OPC_DATA; 57 lcd->buffer[5] = val >> 8; 58 lcd->buffer[6] = val; 59 value_xfer.tx_buf = lcd->buffer + 4; 60 spi_message_add_tail(&value_xfer, &msg); 61 62 return spi_sync(lcd->spi, &msg); 63 } 64 65 /* The comments are taken straight from the data sheet */ 66 static int ltv350qv_power_on(struct ltv350qv *lcd) 67 { 68 int ret; 69 70 /* Power On Reset Display off State */ 71 if (ltv350qv_write_reg(lcd, LTV_PWRCTL1, 0x0000)) 72 goto err; 73 usleep_range(15000, 16000); 74 75 /* Power Setting Function 1 */ 76 if (ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE)) 77 goto err; 78 if (ltv350qv_write_reg(lcd, LTV_PWRCTL2, LTV_VCOML_ENABLE)) 79 goto err_power1; 80 81 /* Power Setting Function 2 */ 82 if (ltv350qv_write_reg(lcd, LTV_PWRCTL1, 83 LTV_VCOM_DISABLE | LTV_DRIVE_CURRENT(5) 84 | LTV_SUPPLY_CURRENT(5))) 85 goto err_power2; 86 87 msleep(55); 88 89 /* Instruction Setting */ 90 ret = ltv350qv_write_reg(lcd, LTV_IFCTL, 91 LTV_NMD | LTV_REV | LTV_NL(0x1d)); 92 ret |= ltv350qv_write_reg(lcd, LTV_DATACTL, 93 LTV_DS_SAME | LTV_CHS_480 94 | LTV_DF_RGB | LTV_RGB_BGR); 95 ret |= ltv350qv_write_reg(lcd, LTV_ENTRY_MODE, 96 LTV_VSPL_ACTIVE_LOW 97 | LTV_HSPL_ACTIVE_LOW 98 | LTV_DPL_SAMPLE_RISING 99 | LTV_EPL_ACTIVE_LOW 100 | LTV_SS_RIGHT_TO_LEFT); 101 ret |= ltv350qv_write_reg(lcd, LTV_GATECTL1, LTV_CLW(3)); 102 ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2, 103 LTV_NW_INV_1LINE | LTV_FWI(3)); 104 ret |= ltv350qv_write_reg(lcd, LTV_VBP, 0x000a); 105 ret |= ltv350qv_write_reg(lcd, LTV_HBP, 0x0021); 106 ret |= ltv350qv_write_reg(lcd, LTV_SOTCTL, LTV_SDT(3) | LTV_EQ(0)); 107 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(0), 0x0103); 108 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(1), 0x0301); 109 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(2), 0x1f0f); 110 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(3), 0x1f0f); 111 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(4), 0x0707); 112 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(5), 0x0307); 113 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(6), 0x0707); 114 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(7), 0x0000); 115 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(8), 0x0004); 116 ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(9), 0x0000); 117 if (ret) 118 goto err_settings; 119 120 /* Wait more than 2 frames */ 121 msleep(20); 122 123 /* Display On Sequence */ 124 ret = ltv350qv_write_reg(lcd, LTV_PWRCTL1, 125 LTV_VCOM_DISABLE | LTV_VCOMOUT_ENABLE 126 | LTV_POWER_ON | LTV_DRIVE_CURRENT(5) 127 | LTV_SUPPLY_CURRENT(5)); 128 ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2, 129 LTV_NW_INV_1LINE | LTV_DSC | LTV_FWI(3)); 130 if (ret) 131 goto err_disp_on; 132 133 /* Display should now be ON. Phew. */ 134 return 0; 135 136 err_disp_on: 137 /* 138 * Try to recover. Error handling probably isn't very useful 139 * at this point, just make a best effort to switch the panel 140 * off. 141 */ 142 ltv350qv_write_reg(lcd, LTV_PWRCTL1, 143 LTV_VCOM_DISABLE | LTV_DRIVE_CURRENT(5) 144 | LTV_SUPPLY_CURRENT(5)); 145 ltv350qv_write_reg(lcd, LTV_GATECTL2, 146 LTV_NW_INV_1LINE | LTV_FWI(3)); 147 err_settings: 148 err_power2: 149 err_power1: 150 ltv350qv_write_reg(lcd, LTV_PWRCTL2, 0x0000); 151 usleep_range(1000, 1100); 152 err: 153 ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE); 154 return -EIO; 155 } 156 157 static int ltv350qv_power_off(struct ltv350qv *lcd) 158 { 159 int ret; 160 161 /* Display Off Sequence */ 162 ret = ltv350qv_write_reg(lcd, LTV_PWRCTL1, 163 LTV_VCOM_DISABLE 164 | LTV_DRIVE_CURRENT(5) 165 | LTV_SUPPLY_CURRENT(5)); 166 ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2, 167 LTV_NW_INV_1LINE | LTV_FWI(3)); 168 169 /* Power down setting 1 */ 170 ret |= ltv350qv_write_reg(lcd, LTV_PWRCTL2, 0x0000); 171 172 /* Wait at least 1 ms */ 173 usleep_range(1000, 1100); 174 175 /* Power down setting 2 */ 176 ret |= ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE); 177 178 /* 179 * No point in trying to recover here. If we can't switch the 180 * panel off, what are we supposed to do other than inform the 181 * user about the failure? 182 */ 183 if (ret) 184 return -EIO; 185 186 /* Display power should now be OFF */ 187 return 0; 188 } 189 190 static int ltv350qv_power(struct ltv350qv *lcd, int power) 191 { 192 int ret = 0; 193 194 if (POWER_IS_ON(power) && !POWER_IS_ON(lcd->power)) 195 ret = ltv350qv_power_on(lcd); 196 else if (!POWER_IS_ON(power) && POWER_IS_ON(lcd->power)) 197 ret = ltv350qv_power_off(lcd); 198 199 if (!ret) 200 lcd->power = power; 201 202 return ret; 203 } 204 205 static int ltv350qv_set_power(struct lcd_device *ld, int power) 206 { 207 struct ltv350qv *lcd = lcd_get_data(ld); 208 209 return ltv350qv_power(lcd, power); 210 } 211 212 static int ltv350qv_get_power(struct lcd_device *ld) 213 { 214 struct ltv350qv *lcd = lcd_get_data(ld); 215 216 return lcd->power; 217 } 218 219 static const struct lcd_ops ltv_ops = { 220 .get_power = ltv350qv_get_power, 221 .set_power = ltv350qv_set_power, 222 }; 223 224 static int ltv350qv_probe(struct spi_device *spi) 225 { 226 struct ltv350qv *lcd; 227 struct lcd_device *ld; 228 int ret; 229 230 lcd = devm_kzalloc(&spi->dev, sizeof(struct ltv350qv), GFP_KERNEL); 231 if (!lcd) 232 return -ENOMEM; 233 234 lcd->spi = spi; 235 lcd->power = LCD_POWER_OFF; 236 lcd->buffer = devm_kzalloc(&spi->dev, 8, GFP_KERNEL); 237 if (!lcd->buffer) 238 return -ENOMEM; 239 240 ld = devm_lcd_device_register(&spi->dev, "ltv350qv", &spi->dev, lcd, 241 <v_ops); 242 if (IS_ERR(ld)) 243 return PTR_ERR(ld); 244 245 lcd->ld = ld; 246 247 ret = ltv350qv_power(lcd, LCD_POWER_ON); 248 if (ret) 249 return ret; 250 251 spi_set_drvdata(spi, lcd); 252 253 return 0; 254 } 255 256 static void ltv350qv_remove(struct spi_device *spi) 257 { 258 struct ltv350qv *lcd = spi_get_drvdata(spi); 259 260 ltv350qv_power(lcd, LCD_POWER_OFF); 261 } 262 263 #ifdef CONFIG_PM_SLEEP 264 static int ltv350qv_suspend(struct device *dev) 265 { 266 struct ltv350qv *lcd = dev_get_drvdata(dev); 267 268 return ltv350qv_power(lcd, LCD_POWER_OFF); 269 } 270 271 static int ltv350qv_resume(struct device *dev) 272 { 273 struct ltv350qv *lcd = dev_get_drvdata(dev); 274 275 return ltv350qv_power(lcd, LCD_POWER_ON); 276 } 277 #endif 278 279 static SIMPLE_DEV_PM_OPS(ltv350qv_pm_ops, ltv350qv_suspend, ltv350qv_resume); 280 281 /* Power down all displays on reboot, poweroff or halt */ 282 static void ltv350qv_shutdown(struct spi_device *spi) 283 { 284 struct ltv350qv *lcd = spi_get_drvdata(spi); 285 286 ltv350qv_power(lcd, LCD_POWER_OFF); 287 } 288 289 static struct spi_driver ltv350qv_driver = { 290 .driver = { 291 .name = "ltv350qv", 292 .pm = <v350qv_pm_ops, 293 }, 294 295 .probe = ltv350qv_probe, 296 .remove = ltv350qv_remove, 297 .shutdown = ltv350qv_shutdown, 298 }; 299 300 module_spi_driver(ltv350qv_driver); 301 302 MODULE_AUTHOR("Haavard Skinnemoen (Atmel)"); 303 MODULE_DESCRIPTION("Samsung LTV350QV LCD Driver"); 304 MODULE_LICENSE("GPL"); 305 MODULE_ALIAS("spi:ltv350qv"); 306