[PATCH v2] Samsung LTV350QV LCD driver

[Haavard Skinnemoen <hskinnemoen@atmel.com>]

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, and it
can also be controlled through sysfs. The panel is powered up when the
module is loaded and off when the module is unloaded.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
---
I agree that the write_reg() macro with embedded goto is ugly, so I've
removed it. I've also added some code that tries to recover by powering
down the display if the power-on sequence fails halfway through.

The driver has been rebased onto
http://git.o-hand.com/?p=linux-rpurdie-backlight;a=shortlog;h=for-mm

so it should apply nicely on top of David's Kconfig patch.

 drivers/video/backlight/Kconfig    |   12 ++
 drivers/video/backlight/Makefile   |    2 +
 drivers/video/backlight/ltv350qv.c |  340 ++++++++++++++++++++++++++++++++++++
 drivers/video/backlight/ltv350qv.h |   95 ++++++++++
 4 files changed, 449 insertions(+), 0 deletions(-)

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 2580f5f..b6f936a 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -24,6 +24,18 @@ config LCD_CLASS_DEVICE
 	  To have support for your specific LCD panel you will have to
 	  select the proper drivers which depend on this option.
 
+config LCD_LTV350QV
+	tristate "Samsung LTV350QV LCD Panel"
+	depends on LCD_CLASS_DEVICE && SPI_MASTER
+	default n
+	help
+	  If you have a Samsung LTV350QV LCD panel, say y to include a
+	  power control driver for it.  The panel starts up in power
+	  off state, so you need this driver in order to see any
+	  output.
+
+	  The LTV350QV panel is present on all ATSTK1000 boards.
+
 #
 # Backlight
 #
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index c6e2266..965a78b 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -1,6 +1,8 @@
 # Backlight & LCD drivers
 
 obj-$(CONFIG_LCD_CLASS_DEVICE)     += lcd.o
+obj-$(CONFIG_LCD_LTV350QV)	+= ltv350qv.o
+
 obj-$(CONFIG_BACKLIGHT_CLASS_DEVICE) += backlight.o
 obj-$(CONFIG_BACKLIGHT_CORGI)	+= corgi_bl.o
 obj-$(CONFIG_BACKLIGHT_HP680)	+= hp680_bl.o
diff --git a/drivers/video/backlight/ltv350qv.c b/drivers/video/backlight/ltv350qv.c
new file mode 100644
index 0000000..342b97a
--- /dev/null
+++ b/drivers/video/backlight/ltv350qv.c
@@ -0,0 +1,340 @@
+/*
+ * 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,
+		.cs_change	= 1,
+	};
+
+	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 = class_get_devdata(&ld->class_dev);
+	return ltv350qv_power(lcd, power);
+}
+
+static int ltv350qv_get_power(struct lcd_device *ld)
+{
+	struct ltv350qv *lcd;
+
+	lcd = class_get_devdata(&ld->class_dev);
+	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", 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, u32 level)
+{
+	struct ltv350qv *lcd = dev_get_drvdata(&spi->dev);
+
+	if (level == SUSPEND_POWER_DOWN)
+		return ltv350qv_power(lcd, FB_BLANK_POWERDOWN);
+
+	return 0;
+}
+
+static int ltv350qv_resume(struct spi_device *spi, u32 level)
+{
+	struct ltv350qv *lcd = dev_get_drvdata(&spi->dev);
+
+	if (level == RESUME_POWER_ON)
+		return ltv350qv_power(lcd, FB_BLANK_UNBLANK);
+
+	return 0;
+}
+#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");
diff --git a/drivers/video/backlight/ltv350qv.h b/drivers/video/backlight/ltv350qv.h
new file mode 100644
index 0000000..189112e
--- /dev/null
+++ b/drivers/video/backlight/ltv350qv.h
@@ -0,0 +1,95 @@
+/*
+ * Register definitions 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.
+ */
+#ifndef __LTV350QV_H
+#define __LTV350QV_H
+
+#define LTV_OPC_INDEX	0x74
+#define LTV_OPC_DATA	0x76
+
+#define LTV_ID		0x00		/* ID Read */
+#define LTV_IFCTL	0x01		/* Display Interface Control */
+#define LTV_DATACTL	0x02		/* Display Data Control */
+#define LTV_ENTRY_MODE	0x03		/* Entry Mode */
+#define LTV_GATECTL1	0x04		/* Gate Control 1 */
+#define LTV_GATECTL2	0x05		/* Gate Control 2 */
+#define LTV_VBP		0x06		/* Vertical Back Porch */
+#define LTV_HBP		0x07		/* Horizontal Back Porch */
+#define LTV_SOTCTL	0x08		/* Source Output Timing Control */
+#define LTV_PWRCTL1	0x09		/* Power Control 1 */
+#define LTV_PWRCTL2	0x0a		/* Power Control 2 */
+#define LTV_GAMMA(x)	(0x10 + (x))	/* Gamma control */
+
+/* Bit definitions for LTV_IFCTL */
+#define LTV_IM			(1 << 15)
+#define LTV_NMD			(1 << 14)
+#define LTV_SSMD		(1 << 13)
+#define LTV_REV			(1 <<  7)
+#define LTV_NL(x)		(((x) & 0x001f) << 0)
+
+/* Bit definitions for LTV_DATACTL */
+#define LTV_DS_SAME		(0 << 12)
+#define LTV_DS_D_TO_S		(1 << 12)
+#define LTV_DS_S_TO_D		(2 << 12)
+#define LTV_CHS_384		(0 <<  9)
+#define LTV_CHS_480		(1 <<  9)
+#define LTV_CHS_492		(2 <<  9)
+#define LTV_DF_RGB		(0 <<  6)
+#define LTV_DF_RGBX		(1 <<  6)
+#define LTV_DF_XRGB		(2 <<  6)
+#define LTV_RGB_RGB		(0 <<  2)
+#define LTV_RGB_BGR		(1 <<  2)
+#define LTV_RGB_GRB		(2 <<  2)
+#define LTV_RGB_RBG		(3 <<  2)
+
+/* Bit definitions for LTV_ENTRY_MODE */
+#define LTV_VSPL_ACTIVE_LOW	(0 << 15)
+#define LTV_VSPL_ACTIVE_HIGH	(1 << 15)
+#define LTV_HSPL_ACTIVE_LOW	(0 << 14)
+#define LTV_HSPL_ACTIVE_HIGH	(1 << 14)
+#define LTV_DPL_SAMPLE_RISING	(0 << 13)
+#define LTV_DPL_SAMPLE_FALLING	(1 << 13)
+#define LTV_EPL_ACTIVE_LOW	(0 << 12)
+#define LTV_EPL_ACTIVE_HIGH	(1 << 12)
+#define LTV_SS_LEFT_TO_RIGHT	(0 <<  8)
+#define LTV_SS_RIGHT_TO_LEFT	(1 <<  8)
+#define LTV_STB			(1 <<  1)
+
+/* Bit definitions for LTV_GATECTL1 */
+#define LTV_CLW(x)		(((x) & 0x0007) << 12)
+#define LTV_GAON		(1 <<  5)
+#define LTV_SDR			(1 <<  3)
+
+/* Bit definitions for LTV_GATECTL2 */
+#define LTV_NW_INV_FRAME	(0 << 14)
+#define LTV_NW_INV_1LINE	(1 << 14)
+#define LTV_NW_INV_2LINE	(2 << 14)
+#define LTV_DSC			(1 << 12)
+#define LTV_GIF			(1 <<  8)
+#define LTV_FHN			(1 <<  7)
+#define LTV_FTI(x)		(((x) & 0x0003) << 4)
+#define LTV_FWI(x)		(((x) & 0x0003) << 0)
+
+/* Bit definitions for LTV_SOTCTL */
+#define LTV_SDT(x)		(((x) & 0x0007) << 10)
+#define LTV_EQ(x)		(((x) & 0x0007) <<  2)
+
+/* Bit definitions for LTV_PWRCTL1 */
+#define LTV_VCOM_DISABLE	(1 << 14)
+#define LTV_VCOMOUT_ENABLE	(1 << 11)
+#define LTV_POWER_ON		(1 <<  9)
+#define LTV_DRIVE_CURRENT(x)	(((x) & 0x0007) << 4)	/* 0=off, 5=max */
+#define LTV_SUPPLY_CURRENT(x)	(((x) & 0x0007) << 0)	/* 0=off, 5=max */
+
+/* Bit definitions for LTV_PWRCTL2 */
+#define LTV_VCOML_ENABLE	(1 << 13)
+#define LTV_VCOML_VOLTAGE(x)	(((x) & 0x001f) << 8)	/* 0=1V, 31=-1V */
+#define LTV_VCOMH_VOLTAGE(x)	(((x) & 0x001f) << 0)	/* 0=3V, 31=4.5V */
+
+#endif /* __LTV350QV_H */
-- 
1.4.4.4

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