/*
   * Power control for Samsung LTV350QV Quarter VGA LCD Panel
   *
   * Copyright (C) 2006, 2007 Atmel Corporation
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  #include <linux/delay.h>
  #include <linux/err.h>
  #include <linux/fb.h>
  #include <linux/init.h>
  #include <linux/lcd.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/spi/spi.h>
  
  #include "ltv350qv.h"
  
  #define POWER_IS_ON(pwr)	((pwr) <= FB_BLANK_NORMAL)
  
  struct ltv350qv {
  	struct spi_device	*spi;
  	u8			*buffer;
  	int			power;
  	struct lcd_device	*ld;
  };
  
  /*
   * The power-on and power-off sequences are taken from the
   * LTV350QV-F04 data sheet from Samsung. The register definitions are
   * taken from the S6F2002 command list also from Samsung. Both
   * documents are distributed with the AVR32 Linux BSP CD from Atmel.
   *
   * There's still some voodoo going on here, but it's a lot better than
   * in the first incarnation of the driver where all we had was the raw
   * numbers from the initialization sequence.
   */
  static int ltv350qv_write_reg(struct ltv350qv *lcd, u8 reg, u16 val)
  {
  	struct spi_message msg;
  	struct spi_transfer index_xfer = {
  		.len		= 3,
  		.cs_change	= 1,
  	};
  	struct spi_transfer value_xfer = {
  		.len		= 3,
  	};
  
  	spi_message_init(&msg);
  
  	/* register index */
  	lcd->buffer[0] = LTV_OPC_INDEX;
  	lcd->buffer[1] = 0x00;
  	lcd->buffer[2] = reg & 0x7f;
  	index_xfer.tx_buf = lcd->buffer;
  	spi_message_add_tail(&index_xfer, &msg);
  
  	/* register value */
  	lcd->buffer[4] = LTV_OPC_DATA;
  	lcd->buffer[5] = val >> 8;
  	lcd->buffer[6] = val;
  	value_xfer.tx_buf = lcd->buffer + 4;
  	spi_message_add_tail(&value_xfer, &msg);
  
  	return spi_sync(lcd->spi, &msg);
  }
  
  /* The comments are taken straight from the data sheet */
  static int ltv350qv_power_on(struct ltv350qv *lcd)
  {
  	int ret;
  
  	/* Power On Reset Display off State */
  	if (ltv350qv_write_reg(lcd, LTV_PWRCTL1, 0x0000))
  		goto err;
  	usleep_range(15000, 16000);
  
  	/* Power Setting Function 1 */
  	if (ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE))
  		goto err;
  	if (ltv350qv_write_reg(lcd, LTV_PWRCTL2, LTV_VCOML_ENABLE))
  		goto err_power1;
  
  	/* Power Setting Function 2 */
  	if (ltv350qv_write_reg(lcd, LTV_PWRCTL1,
  			       LTV_VCOM_DISABLE | LTV_DRIVE_CURRENT(5)
  			       | LTV_SUPPLY_CURRENT(5)))
  		goto err_power2;
  
  	msleep(55);
  
  	/* Instruction Setting */
  	ret = ltv350qv_write_reg(lcd, LTV_IFCTL,
  				 LTV_NMD | LTV_REV | LTV_NL(0x1d));
  	ret |= ltv350qv_write_reg(lcd, LTV_DATACTL,
  				  LTV_DS_SAME | LTV_CHS_480
  				  | LTV_DF_RGB | LTV_RGB_BGR);
  	ret |= ltv350qv_write_reg(lcd, LTV_ENTRY_MODE,
  				  LTV_VSPL_ACTIVE_LOW
  				  | LTV_HSPL_ACTIVE_LOW
  				  | LTV_DPL_SAMPLE_RISING
  				  | LTV_EPL_ACTIVE_LOW
  				  | LTV_SS_RIGHT_TO_LEFT);
  	ret |= ltv350qv_write_reg(lcd, LTV_GATECTL1, LTV_CLW(3));
  	ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
  				  LTV_NW_INV_1LINE | LTV_FWI(3));
  	ret |= ltv350qv_write_reg(lcd, LTV_VBP, 0x000a);
  	ret |= ltv350qv_write_reg(lcd, LTV_HBP, 0x0021);
  	ret |= ltv350qv_write_reg(lcd, LTV_SOTCTL, LTV_SDT(3) | LTV_EQ(0));
  	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(0), 0x0103);
  	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(1), 0x0301);
  	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(2), 0x1f0f);
  	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(3), 0x1f0f);
  	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(4), 0x0707);
  	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(5), 0x0307);
  	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(6), 0x0707);
  	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(7), 0x0000);
  	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(8), 0x0004);
  	ret |= ltv350qv_write_reg(lcd, LTV_GAMMA(9), 0x0000);
  	if (ret)
  		goto err_settings;
  
  	/* Wait more than 2 frames */
  	msleep(20);
  
  	/* Display On Sequence */
  	ret = ltv350qv_write_reg(lcd, LTV_PWRCTL1,
  				 LTV_VCOM_DISABLE | LTV_VCOMOUT_ENABLE
  				 | LTV_POWER_ON | LTV_DRIVE_CURRENT(5)
  				 | LTV_SUPPLY_CURRENT(5));
  	ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
  				  LTV_NW_INV_1LINE | LTV_DSC | LTV_FWI(3));
  	if (ret)
  		goto err_disp_on;
  
  	/* Display should now be ON. Phew. */
  	return 0;
  
  err_disp_on:
  	/*
  	 * Try to recover. Error handling probably isn't very useful
  	 * at this point, just make a best effort to switch the panel
  	 * off.
  	 */
  	ltv350qv_write_reg(lcd, LTV_PWRCTL1,
  			   LTV_VCOM_DISABLE | LTV_DRIVE_CURRENT(5)
  			   | LTV_SUPPLY_CURRENT(5));
  	ltv350qv_write_reg(lcd, LTV_GATECTL2,
  			   LTV_NW_INV_1LINE | LTV_FWI(3));
  err_settings:
  err_power2:
  err_power1:
  	ltv350qv_write_reg(lcd, LTV_PWRCTL2, 0x0000);
  	usleep_range(1000, 1100);
  err:
  	ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE);
  	return -EIO;
  }
  
  static int ltv350qv_power_off(struct ltv350qv *lcd)
  {
  	int ret;
  
  	/* Display Off Sequence */
  	ret = ltv350qv_write_reg(lcd, LTV_PWRCTL1,
  				 LTV_VCOM_DISABLE
  				 | LTV_DRIVE_CURRENT(5)
  				 | LTV_SUPPLY_CURRENT(5));
  	ret |= ltv350qv_write_reg(lcd, LTV_GATECTL2,
  				  LTV_NW_INV_1LINE | LTV_FWI(3));
  
  	/* Power down setting 1 */
  	ret |= ltv350qv_write_reg(lcd, LTV_PWRCTL2, 0x0000);
  
  	/* Wait at least 1 ms */
  	usleep_range(1000, 1100);
  
  	/* Power down setting 2 */
  	ret |= ltv350qv_write_reg(lcd, LTV_PWRCTL1, LTV_VCOM_DISABLE);
  
  	/*
  	 * No point in trying to recover here. If we can't switch the
  	 * panel off, what are we supposed to do other than inform the
  	 * user about the failure?
  	 */
  	if (ret)
  		return -EIO;
  
  	/* Display power should now be OFF */
  	return 0;
  }
  
  static int ltv350qv_power(struct ltv350qv *lcd, int power)
  {
  	int ret = 0;
  
  	if (POWER_IS_ON(power) && !POWER_IS_ON(lcd->power))
  		ret = ltv350qv_power_on(lcd);
  	else if (!POWER_IS_ON(power) && POWER_IS_ON(lcd->power))
  		ret = ltv350qv_power_off(lcd);
  
  	if (!ret)
  		lcd->power = power;
  
  	return ret;
  }
  
  static int ltv350qv_set_power(struct lcd_device *ld, int power)
  {
  	struct ltv350qv *lcd = lcd_get_data(ld);
  
  	return ltv350qv_power(lcd, power);
  }
  
  static int ltv350qv_get_power(struct lcd_device *ld)
  {
  	struct ltv350qv *lcd = lcd_get_data(ld);
  
  	return lcd->power;
  }
  
  static struct lcd_ops ltv_ops = {
  	.get_power	= ltv350qv_get_power,
  	.set_power	= ltv350qv_set_power,
  };
  
  static int ltv350qv_probe(struct spi_device *spi)
  {
  	struct ltv350qv *lcd;
  	struct lcd_device *ld;
  	int ret;
  
  	lcd = devm_kzalloc(&spi->dev, sizeof(struct ltv350qv), GFP_KERNEL);
  	if (!lcd)
  		return -ENOMEM;
  
  	lcd->spi = spi;
  	lcd->power = FB_BLANK_POWERDOWN;
  	lcd->buffer = devm_kzalloc(&spi->dev, 8, GFP_KERNEL);
  	if (!lcd->buffer)
  		return -ENOMEM;
  
  	ld = devm_lcd_device_register(&spi->dev, "ltv350qv", &spi->dev, lcd,
  					&ltv_ops);
  	if (IS_ERR(ld))
  		return PTR_ERR(ld);
  
  	lcd->ld = ld;
  
  	ret = ltv350qv_power(lcd, FB_BLANK_UNBLANK);
  	if (ret)
  		return ret;
  
  	spi_set_drvdata(spi, lcd);
  
  	return 0;
  }
  
  static int ltv350qv_remove(struct spi_device *spi)
  {
  	struct ltv350qv *lcd = spi_get_drvdata(spi);
  
  	ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
  	return 0;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static int ltv350qv_suspend(struct device *dev)
  {
  	struct ltv350qv *lcd = dev_get_drvdata(dev);
  
  	return ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
  }
  
  static int ltv350qv_resume(struct device *dev)
  {
  	struct ltv350qv *lcd = dev_get_drvdata(dev);
  
  	return ltv350qv_power(lcd, FB_BLANK_UNBLANK);
  }
  #endif
  
  static SIMPLE_DEV_PM_OPS(ltv350qv_pm_ops, ltv350qv_suspend, ltv350qv_resume);
  
  /* Power down all displays on reboot, poweroff or halt */
  static void ltv350qv_shutdown(struct spi_device *spi)
  {
  	struct ltv350qv *lcd = spi_get_drvdata(spi);
  
  	ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
  }
  
  static struct spi_driver ltv350qv_driver = {
  	.driver = {
  		.name		= "ltv350qv",
  		.owner		= THIS_MODULE,
  		.pm		= &ltv350qv_pm_ops,
  	},
  
  	.probe		= ltv350qv_probe,
  	.remove		= ltv350qv_remove,
  	.shutdown	= ltv350qv_shutdown,
  };
  
  module_spi_driver(ltv350qv_driver);
  
  MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
  MODULE_DESCRIPTION("Samsung LTV350QV LCD Driver");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("spi:ltv350qv");