backlight: Add Samsung LTV350QV LCD driver

This patch adds support for powering on and off the Samsung LTV350QV LCD
panel via SPI.  The driver responds to framebuffer power management, it
powers off the panel on reboot/halt/poweroff.  It can also be controlled
through sysfs.  The panel is powered up when the module is loaded, and off
when the module is unloaded.  Verified on AVR32 STK1000.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>

1 files changed, 330 insertions, 0 deletions

diff --git a/drivers/video/backlight/ltv350qv.c b/drivers/video/backlight/ltv350qv.c
new file mode 100644
index 00000000000..2eb206bf73e
--- /dev/null
+++ b/drivers/video/backlight/ltv350qv.c
@@ -0,0 +1,330 @@
+/*
+ * 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/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;
+	msleep(15);
+
+	/* 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);
+	msleep(1);
+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 */
+	msleep(1);
+
+	/* 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 __devinit ltv350qv_probe(struct spi_device *spi)
+{
+	struct ltv350qv *lcd;
+	struct lcd_device *ld;
+	int ret;
+
+	lcd = kzalloc(sizeof(struct ltv350qv), GFP_KERNEL);
+	if (!lcd)
+		return -ENOMEM;
+
+	lcd->spi = spi;
+	lcd->power = FB_BLANK_POWERDOWN;
+	lcd->buffer = kzalloc(8, GFP_KERNEL);
+
+	ld = lcd_device_register("ltv350qv", &spi->dev, lcd, &ltv_ops);
+	if (IS_ERR(ld)) {
+		ret = PTR_ERR(ld);
+		goto out_free_lcd;
+	}
+	lcd->ld = ld;
+
+	ret = ltv350qv_power(lcd, FB_BLANK_UNBLANK);
+	if (ret)
+		goto out_unregister;
+
+	dev_set_drvdata(&spi->dev, lcd);
+
+	return 0;
+
+out_unregister:
+	lcd_device_unregister(ld);
+out_free_lcd:
+	kfree(lcd);
+	return ret;
+}
+
+static int __devexit ltv350qv_remove(struct spi_device *spi)
+{
+	struct ltv350qv *lcd = dev_get_drvdata(&spi->dev);
+
+	ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
+	lcd_device_unregister(lcd->ld);
+	kfree(lcd);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int ltv350qv_suspend(struct spi_device *spi, pm_message_t state)
+{
+	struct ltv350qv *lcd = dev_get_drvdata(&spi->dev);
+
+	return ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
+}
+
+static int ltv350qv_resume(struct spi_device *spi)
+{
+	struct ltv350qv *lcd = dev_get_drvdata(&spi->dev);
+
+	return ltv350qv_power(lcd, FB_BLANK_UNBLANK);
+}
+#else
+#define ltv350qv_suspend	NULL
+#define ltv350qv_resume		NULL
+#endif
+
+/* Power down all displays on reboot, poweroff or halt */
+static void ltv350qv_shutdown(struct spi_device *spi)
+{
+	struct ltv350qv *lcd = dev_get_drvdata(&spi->dev);
+
+	ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
+}
+
+static struct spi_driver ltv350qv_driver = {
+	.driver = {
+		.name		= "ltv350qv",
+		.bus		= &spi_bus_type,
+		.owner		= THIS_MODULE,
+	},
+
+	.probe		= ltv350qv_probe,
+	.remove		= __devexit_p(ltv350qv_remove),
+	.shutdown	= ltv350qv_shutdown,
+	.suspend	= ltv350qv_suspend,
+	.resume		= ltv350qv_resume,
+};
+
+static int __init ltv350qv_init(void)
+{
+	return spi_register_driver(&ltv350qv_driver);
+}
+
+static void __exit ltv350qv_exit(void)
+{
+	spi_unregister_driver(&ltv350qv_driver);
+}
+module_init(ltv350qv_init);
+module_exit(ltv350qv_exit);
+
+MODULE_AUTHOR("Haavard Skinnemoen <hskinnemoen@atmel.com>");
+MODULE_DESCRIPTION("Samsung LTV350QV LCD Driver");
+MODULE_LICENSE("GPL");