Add jbt6k74 display driver.

4 files changed, 932 insertions, 0 deletions

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 09bfa9662e4..b075ac5b7f0 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -100,6 +100,20 @@ config LCD_HP700
 	  If you have an HP Jornada 700 series handheld (710/720/728)
 	  say Y to enable LCD control driver.
 
+config LCD_JBT6K74
+	tristate "TPO JBT6K74-AS TFT display ASIC control interface"
+	depends on SPI_MASTER && SYSFS && LCD_CLASS_DEVICE
+	help
+	  SPI driver for the control interface of TFT panels containing
+	  the TPO JBT6K74-AS controller ASIC, such as the TPO TD028TTEC1
+	  TFT diplay module used in the Openmoko Freerunner GSM phone.
+
+	  The control interface is required for display operation, as it
+	  controls power management, display timing and gamma calibration.
+
+	  This driver can also be build as a module, if so it will be called
+	  jbt6k74.
+
 #
 # Backlight
 #
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 9a405548874..2ec26fc766b 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_LCD_PLATFORM)	   += platform_lcd.o
 obj-$(CONFIG_LCD_VGG2432A4)	   += vgg2432a4.o
 obj-$(CONFIG_LCD_TDO24M)	   += tdo24m.o
 obj-$(CONFIG_LCD_TOSA)		   += tosa_lcd.o
+obj-$(CONFIG_LCD_JBT6K74) 	   += jbt6k74.o
 
 obj-$(CONFIG_BACKLIGHT_CLASS_DEVICE) += backlight.o
 obj-$(CONFIG_BACKLIGHT_ATMEL_PWM)    += atmel-pwm-bl.o
diff --git a/drivers/video/backlight/jbt6k74.c b/drivers/video/backlight/jbt6k74.c
new file mode 100644
index 00000000000..8450904d585
--- /dev/null
+++ b/drivers/video/backlight/jbt6k74.c
@@ -0,0 +1,896 @@
+/* Linux kernel driver for the tpo JBT6K74-AS LCM ASIC
+ *
+ * Copyright (C) 2006-2007 by Openmoko, Inc.
+ * Author: Harald Welte <laforge@openmoko.org>,
+ * 	   Stefan Schmidt <stefan@openmoko.org>
+ * Copyright (C) 2008 by Harald Welte <laforge@openmoko.org>
+ * Copyright (C) 2009 by Lars-Peter Clausen <lars@metafoo.de>
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+#include <linux/workqueue.h>
+#include <linux/jbt6k74.h>
+#include <linux/fb.h>
+#include <linux/lcd.h>
+#include <linux/time.h>
+#include <linux/regulator/consumer.h>
+#include <linux/gpio.h>
+
+enum jbt_register {
+	JBT_REG_SLEEP_IN		= 0x10,
+	JBT_REG_SLEEP_OUT		= 0x11,
+
+	JBT_REG_DISPLAY_OFF		= 0x28,
+	JBT_REG_DISPLAY_ON		= 0x29,
+
+	JBT_REG_RGB_FORMAT		= 0x3a,
+	JBT_REG_QUAD_RATE		= 0x3b,
+
+	JBT_REG_POWER_ON_OFF		= 0xb0,
+	JBT_REG_BOOSTER_OP		= 0xb1,
+	JBT_REG_BOOSTER_MODE		= 0xb2,
+	JBT_REG_BOOSTER_FREQ		= 0xb3,
+	JBT_REG_OPAMP_SYSCLK		= 0xb4,
+	JBT_REG_VSC_VOLTAGE		= 0xb5,
+	JBT_REG_VCOM_VOLTAGE		= 0xb6,
+	JBT_REG_EXT_DISPL		= 0xb7,
+	JBT_REG_OUTPUT_CONTROL		= 0xb8,
+	JBT_REG_DCCLK_DCEV		= 0xb9,
+	JBT_REG_DISPLAY_MODE1		= 0xba,
+	JBT_REG_DISPLAY_MODE2		= 0xbb,
+	JBT_REG_DISPLAY_MODE		= 0xbc,
+	JBT_REG_ASW_SLEW		= 0xbd,
+	JBT_REG_DUMMY_DISPLAY		= 0xbe,
+	JBT_REG_DRIVE_SYSTEM		= 0xbf,
+
+	JBT_REG_SLEEP_OUT_FR_A		= 0xc0,
+	JBT_REG_SLEEP_OUT_FR_B		= 0xc1,
+	JBT_REG_SLEEP_OUT_FR_C		= 0xc2,
+	JBT_REG_SLEEP_IN_LCCNT_D	= 0xc3,
+	JBT_REG_SLEEP_IN_LCCNT_E	= 0xc4,
+	JBT_REG_SLEEP_IN_LCCNT_F	= 0xc5,
+	JBT_REG_SLEEP_IN_LCCNT_G	= 0xc6,
+
+	JBT_REG_GAMMA1_FINE_1		= 0xc7,
+	JBT_REG_GAMMA1_FINE_2		= 0xc8,
+	JBT_REG_GAMMA1_INCLINATION	= 0xc9,
+	JBT_REG_GAMMA1_BLUE_OFFSET	= 0xca,
+
+	/* VGA */
+	JBT_REG_BLANK_CONTROL		= 0xcf,
+	JBT_REG_BLANK_TH_TV		= 0xd0,
+	JBT_REG_CKV_ON_OFF		= 0xd1,
+	JBT_REG_CKV_1_2			= 0xd2,
+	JBT_REG_OEV_TIMING		= 0xd3,
+	JBT_REG_ASW_TIMING_1		= 0xd4,
+	JBT_REG_ASW_TIMING_2		= 0xd5,
+
+	/* QVGA */
+	JBT_REG_BLANK_CONTROL_QVGA	= 0xd6,
+	JBT_REG_BLANK_TH_TV_QVGA	= 0xd7,
+	JBT_REG_CKV_ON_OFF_QVGA		= 0xd8,
+	JBT_REG_CKV_1_2_QVGA		= 0xd9,
+	JBT_REG_OEV_TIMING_QVGA		= 0xde,
+	JBT_REG_ASW_TIMING_1_QVGA	= 0xdf,
+	JBT_REG_ASW_TIMING_2_QVGA	= 0xe0,
+
+
+	JBT_REG_HCLOCK_VGA		= 0xec,
+	JBT_REG_HCLOCK_QVGA		= 0xed,
+};
+
+enum jbt_resolution {
+	JBT_RESOLUTION_VGA,
+	JBT_RESOLUTION_QVGA,
+};
+
+enum jbt_power_mode {
+	JBT_POWER_MODE_DEEP_STANDBY,
+	JBT_POWER_MODE_SLEEP,
+	JBT_POWER_MODE_NORMAL,
+};
+
+static const char *jbt_power_mode_names[] = {
+	[JBT_POWER_MODE_DEEP_STANDBY]	= "deep-standby",
+	[JBT_POWER_MODE_SLEEP]		= "sleep",
+	[JBT_POWER_MODE_NORMAL]		= "normal",
+};
+
+static const char *jbt_resolution_names[] = {
+	[JBT_RESOLUTION_VGA] = "vga",
+	[JBT_RESOLUTION_QVGA] = "qvga",
+};
+
+struct jbt_info {
+	struct mutex lock;		/* protects this structure */
+	enum jbt_resolution resolution;
+	enum jbt_power_mode power_mode;
+	enum jbt_power_mode suspend_mode;
+	int suspended;
+
+	struct spi_device *spi;
+	struct lcd_device *lcd_dev;
+
+	unsigned long next_sleep;
+	struct delayed_work blank_work;
+	int blank_mode;
+	struct regulator_bulk_data supplies[2];
+	uint16_t tx_buf[3];
+	uint16_t reg_cache[0xEE];
+};
+
+#define JBT_COMMAND	0x000
+#define JBT_DATA	0x100
+
+static int jbt_reg_write_nodata(struct jbt_info *jbt, uint8_t reg)
+{
+	int ret;
+
+	jbt->tx_buf[0] = JBT_COMMAND | reg;
+	ret = spi_write(jbt->spi, (uint8_t *)jbt->tx_buf,
+					sizeof(uint16_t));
+	if (ret == 0)
+		jbt->reg_cache[reg] = 0;
+	else
+		dev_err(&jbt->spi->dev, "Write failed: %d\n", ret);
+
+	return ret;
+}
+
+
+static int jbt_reg_write(struct jbt_info *jbt, uint8_t reg, uint8_t data)
+{
+	int ret;
+
+	jbt->tx_buf[0] = JBT_COMMAND | reg;
+	jbt->tx_buf[1] = JBT_DATA | data;
+	ret = spi_write(jbt->spi, (uint8_t *)jbt->tx_buf,
+			2*sizeof(uint16_t));
+	if (ret == 0)
+		jbt->reg_cache[reg] = data;
+	else
+		dev_err(&jbt->spi->dev, "Write failed: %d\n", ret);
+
+	return ret;
+}
+
+static int jbt_reg_write16(struct jbt_info *jbt, uint8_t reg, uint16_t data)
+{
+	int ret;
+
+	jbt->tx_buf[0] = JBT_COMMAND | reg;
+	jbt->tx_buf[1] = JBT_DATA | (data >> 8);
+	jbt->tx_buf[2] = JBT_DATA | (data & 0xff);
+
+	ret = spi_write(jbt->spi, (uint8_t *)jbt->tx_buf,
+			3*sizeof(uint16_t));
+	if (ret == 0)
+		jbt->reg_cache[reg] = data;
+	else
+		dev_err(&jbt->spi->dev, "Write failed: %d\n", ret);
+
+	return ret;
+}
+
+static int jbt_init_regs(struct jbt_info *jbt)
+{
+	int ret;
+
+	dev_dbg(&jbt->spi->dev, "entering %cVGA mode\n",
+			jbt->resolution == JBT_RESOLUTION_QVGA ? 'Q' : ' ');
+
+	ret = jbt_reg_write(jbt, JBT_REG_DISPLAY_MODE1, 0x01);
+	ret |= jbt_reg_write(jbt, JBT_REG_DISPLAY_MODE2, 0x00);
+	ret |= jbt_reg_write(jbt, JBT_REG_RGB_FORMAT, 0x60);
+	ret |= jbt_reg_write(jbt, JBT_REG_DRIVE_SYSTEM, 0x10);
+	ret |= jbt_reg_write(jbt, JBT_REG_BOOSTER_OP, 0x56);
+	ret |= jbt_reg_write(jbt, JBT_REG_BOOSTER_MODE, 0x33);
+	ret |= jbt_reg_write(jbt, JBT_REG_BOOSTER_FREQ, 0x11);
+	ret |= jbt_reg_write(jbt, JBT_REG_OPAMP_SYSCLK, 0x02);
+	ret |= jbt_reg_write(jbt, JBT_REG_VSC_VOLTAGE, 0x2b);
+	ret |= jbt_reg_write(jbt, JBT_REG_VCOM_VOLTAGE, 0x40);
+	ret |= jbt_reg_write(jbt, JBT_REG_EXT_DISPL, 0x03);
+	ret |= jbt_reg_write(jbt, JBT_REG_DCCLK_DCEV, 0x04);
+	/*
+	 * default of 0x02 in JBT_REG_ASW_SLEW responsible for 72Hz requirement
+	 * to avoid red / blue flicker
+	 */
+	ret |= jbt_reg_write(jbt, JBT_REG_ASW_SLEW, 0x00 | (1 << 5));
+	ret |= jbt_reg_write(jbt, JBT_REG_DUMMY_DISPLAY, 0x00);
+
+	ret |= jbt_reg_write(jbt, JBT_REG_SLEEP_OUT_FR_A, 0x11);
+	ret |= jbt_reg_write(jbt, JBT_REG_SLEEP_OUT_FR_B, 0x11);
+	ret |= jbt_reg_write(jbt, JBT_REG_SLEEP_OUT_FR_C, 0x11);
+	ret |= jbt_reg_write16(jbt, JBT_REG_SLEEP_IN_LCCNT_D, 0x2040);
+	ret |= jbt_reg_write16(jbt, JBT_REG_SLEEP_IN_LCCNT_E, 0x60c0);
+	ret |= jbt_reg_write16(jbt, JBT_REG_SLEEP_IN_LCCNT_F, 0x1020);
+	ret |= jbt_reg_write16(jbt, JBT_REG_SLEEP_IN_LCCNT_G, 0x60c0);
+
+	ret |= jbt_reg_write16(jbt, JBT_REG_GAMMA1_FINE_1, 0x5533);
+	ret |= jbt_reg_write(jbt, JBT_REG_GAMMA1_FINE_2, 0x00);
+	ret |= jbt_reg_write(jbt, JBT_REG_GAMMA1_INCLINATION, 0x00);
+	ret |= jbt_reg_write(jbt, JBT_REG_GAMMA1_BLUE_OFFSET, 0x00);
+
+	if (jbt->resolution != JBT_RESOLUTION_QVGA) {
+		ret |= jbt_reg_write16(jbt, JBT_REG_HCLOCK_VGA, 0x1f0);
+		ret |= jbt_reg_write(jbt, JBT_REG_BLANK_CONTROL, 0x02);
+		ret |= jbt_reg_write16(jbt, JBT_REG_BLANK_TH_TV, 0x0804);
+
+		ret |= jbt_reg_write(jbt, JBT_REG_CKV_ON_OFF, 0x01);
+		ret |= jbt_reg_write16(jbt, JBT_REG_CKV_1_2, 0x0000);
+
+		ret |= jbt_reg_write16(jbt, JBT_REG_OEV_TIMING, 0x0d0e);
+		ret |= jbt_reg_write16(jbt, JBT_REG_ASW_TIMING_1, 0x11a4);
+		ret |= jbt_reg_write(jbt, JBT_REG_ASW_TIMING_2, 0x0e);
+	} else {
+		ret |= jbt_reg_write16(jbt, JBT_REG_HCLOCK_QVGA, 0x00ff);
+		ret |= jbt_reg_write(jbt, JBT_REG_BLANK_CONTROL_QVGA, 0x02);
+		ret |= jbt_reg_write16(jbt, JBT_REG_BLANK_TH_TV_QVGA, 0x0804);
+
+		ret |= jbt_reg_write(jbt, JBT_REG_CKV_ON_OFF_QVGA, 0x01);
+		ret |= jbt_reg_write16(jbt, JBT_REG_CKV_1_2_QVGA, 0x0008);
+
+		ret |= jbt_reg_write16(jbt, JBT_REG_OEV_TIMING_QVGA, 0x050a);
+		ret |= jbt_reg_write16(jbt, JBT_REG_ASW_TIMING_1_QVGA, 0x0a19);
+		ret |= jbt_reg_write(jbt, JBT_REG_ASW_TIMING_2_QVGA, 0x0a);
+	}
+
+	return ret ? -EIO : 0;
+}
+
+static int jbt_standby_to_sleep(struct jbt_info *jbt)
+{
+	int ret;
+	struct jbt6k74_platform_data *pdata = jbt->spi->dev.platform_data;
+
+	gpio_set_value_cansleep(pdata->gpio_reset, 1);
+	ret = regulator_bulk_enable(ARRAY_SIZE(jbt->supplies), jbt->supplies);
+
+	/* three times command zero */
+	ret |= jbt_reg_write_nodata(jbt, 0x00);
+	mdelay(1);
+	ret |= jbt_reg_write_nodata(jbt, 0x00);
+	mdelay(1);
+	ret |= jbt_reg_write_nodata(jbt, 0x00);
+	mdelay(1);
+
+	/* deep standby out */
+	ret |= jbt_reg_write(jbt, JBT_REG_POWER_ON_OFF, 0x11);
+	mdelay(1);
+	ret = jbt_reg_write(jbt, JBT_REG_DISPLAY_MODE, 0x28);
+
+	/* (re)initialize register set */
+	ret |= jbt_init_regs(jbt);
+
+	return ret ? -EIO : 0;
+}
+
+static int jbt_sleep_to_normal(struct jbt_info *jbt)
+{
+	int ret;
+
+	/* Make sure we are 120 ms after SLEEP_OUT */
+	if (time_before(jiffies, jbt->next_sleep))
+		mdelay(jiffies_to_msecs(jbt->next_sleep - jiffies));
+
+	if (jbt->resolution == JBT_RESOLUTION_VGA) {
+		/* RGB I/F on, RAM wirte off, QVGA through, SIGCON enable */
+		ret = jbt_reg_write(jbt, JBT_REG_DISPLAY_MODE, 0x80);
+
+		/* Quad mode off */
+		ret |= jbt_reg_write(jbt, JBT_REG_QUAD_RATE, 0x00);
+	} else {
+		/* RGB I/F on, RAM wirte off, QVGA through, SIGCON enable */
+		ret = jbt_reg_write(jbt, JBT_REG_DISPLAY_MODE, 0x81);
+
+		/* Quad mode on */
+		ret |= jbt_reg_write(jbt, JBT_REG_QUAD_RATE, 0x22);
+	}
+
+	/* AVDD on, XVDD on */
+	ret |= jbt_reg_write(jbt, JBT_REG_POWER_ON_OFF, 0x16);
+
+	/* Output control */
+	ret |= jbt_reg_write16(jbt, JBT_REG_OUTPUT_CONTROL, 0xdff9);
+
+	/* Turn on display */
+	ret |= jbt_reg_write_nodata(jbt, JBT_REG_DISPLAY_ON);
+
+	/* Sleep mode off */
+	ret |= jbt_reg_write_nodata(jbt, JBT_REG_SLEEP_OUT);
+	jbt->next_sleep = jiffies + msecs_to_jiffies(120);
+
+	/* Allow the booster and display controller to restart stably */
+	mdelay(5);
+
+	return ret ? -EIO : 0;
+}
+
+static int jbt_normal_to_sleep(struct jbt_info *jbt)
+{
+	int ret;
+
+	/* Make sure we are 120 ms after SLEEP_OUT */
+	while (time_before(jiffies, jbt->next_sleep))
+		cpu_relax();
+
+	ret = jbt_reg_write_nodata(jbt, JBT_REG_DISPLAY_OFF);
+	ret |= jbt_reg_write16(jbt, JBT_REG_OUTPUT_CONTROL, 0x8000 | 1 << 3);
+	ret |= jbt_reg_write_nodata(jbt, JBT_REG_SLEEP_IN);
+	jbt->next_sleep = jiffies + msecs_to_jiffies(120);
+
+	/* Allow the internal circuits to stop automatically */
+	mdelay(5);
+
+	return ret ? -EIO : 0;
+}
+
+static int jbt_sleep_to_standby(struct jbt_info *jbt)
+{
+	int ret;
+	struct jbt6k74_platform_data *pdata = jbt->spi->dev.platform_data;
+
+	ret = jbt_reg_write(jbt, JBT_REG_POWER_ON_OFF, 0x00);
+
+	if (!ret)
+		ret = regulator_bulk_disable(ARRAY_SIZE(jbt->supplies), jbt->supplies);
+
+	if (!ret)
+		gpio_set_value_cansleep(pdata->gpio_reset, 0);
+
+	return ret;
+}
+
+static int jbt6k74_enter_power_mode(struct jbt_info *jbt,
+					enum jbt_power_mode new_mode)
+{
+	struct jbt6k74_platform_data *pdata = jbt->spi->dev.platform_data;
+	int ret = -EINVAL;
+
+	dev_dbg(&jbt->spi->dev, "entering (old_state=%s, new_state=%s)\n",
+			jbt_power_mode_names[jbt->power_mode],
+			jbt_power_mode_names[new_mode]);
+
+	mutex_lock(&jbt->lock);
+
+	if (jbt->suspended) {
+		switch (new_mode) {
+		case JBT_POWER_MODE_DEEP_STANDBY:
+		case JBT_POWER_MODE_SLEEP:
+		case JBT_POWER_MODE_NORMAL:
+			ret = 0;
+			jbt->suspend_mode = new_mode;
+			break;
+		default:
+			break;
+		}
+	} else if (new_mode == JBT_POWER_MODE_NORMAL &&
+			pdata->enable_pixel_clock) {
+		pdata->enable_pixel_clock(&jbt->spi->dev, 1);
+	}
+
+	switch (jbt->power_mode) {
+	case JBT_POWER_MODE_DEEP_STANDBY:
+		switch (new_mode) {
+		case JBT_POWER_MODE_DEEP_STANDBY:
+			ret = 0;
+			break;
+		case JBT_POWER_MODE_SLEEP:
+			ret = jbt_standby_to_sleep(jbt);
+			break;
+		case JBT_POWER_MODE_NORMAL:
+			/* first transition into sleep */
+			ret = jbt_standby_to_sleep(jbt);
+			/* then transition into normal */
+			ret |= jbt_sleep_to_normal(jbt);
+			break;
+		}
+		break;
+	case JBT_POWER_MODE_SLEEP:
+		switch (new_mode) {
+		case JBT_POWER_MODE_SLEEP:
+			ret = 0;
+			break;
+		case JBT_POWER_MODE_DEEP_STANDBY:
+			ret = jbt_sleep_to_standby(jbt);
+			break;
+		case JBT_POWER_MODE_NORMAL:
+			ret = jbt_sleep_to_normal(jbt);
+			break;
+		}
+		break;
+	case JBT_POWER_MODE_NORMAL:
+		switch (new_mode) {
+		case JBT_POWER_MODE_NORMAL:
+			ret = 0;
+			break;
+		case JBT_POWER_MODE_DEEP_STANDBY:
+			/* first transition into sleep */
+			ret = jbt_normal_to_sleep(jbt);
+			/* then transition into deep standby */
+			ret |= jbt_sleep_to_standby(jbt);
+			break;
+		case JBT_POWER_MODE_SLEEP:
+			ret = jbt_normal_to_sleep(jbt);
+			break;
+		}
+	}
+
+	if (ret == 0) {
+		jbt->power_mode = new_mode;
+		if (new_mode != JBT_POWER_MODE_NORMAL &&
+			pdata->enable_pixel_clock)
+			pdata->enable_pixel_clock(&jbt->spi->dev, 0);
+	} else {
+		dev_err(&jbt->spi->dev, "Failed enter state '%s': %d\n",
+				jbt_power_mode_names[new_mode], ret);
+	}
+
+	mutex_unlock(&jbt->lock);
+
+	return ret;
+}
+
+static int jbt6k74_set_resolution(struct jbt_info *jbt,
+					enum jbt_resolution new_resolution)
+{
+	int ret = 0;
+	enum jbt_resolution old_resolution;
+
+	mutex_lock(&jbt->lock);
+
+	if (jbt->resolution == new_resolution)
+		goto out_unlock;
+
+	old_resolution = jbt->resolution;
+	jbt->resolution = new_resolution;
+
+	if (jbt->power_mode == JBT_POWER_MODE_NORMAL) {
+
+		/* first transition into sleep */
+		ret = jbt_normal_to_sleep(jbt);
+		ret |= jbt_sleep_to_normal(jbt);
+
+		if (ret) {
+			jbt->resolution = old_resolution;
+			dev_err(&jbt->spi->dev, "Failed to set resolution '%s')\n",
+				jbt_resolution_names[new_resolution]);
+		}
+	}
+
+out_unlock:
+	mutex_unlock(&jbt->lock);
+
+	return ret;
+}
+
+static ssize_t resolution_read(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct jbt_info *jbt = dev_get_drvdata(dev);
+
+	if (jbt->resolution >= ARRAY_SIZE(jbt_resolution_names))
+		return -EIO;
+
+	return sprintf(buf, "%s\n", jbt_resolution_names[jbt->resolution]);
+}
+
+static ssize_t resolution_write(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct jbt_info *jbt = dev_get_drvdata(dev);
+	int i, ret;
+
+	for (i = 0; i < ARRAY_SIZE(jbt_resolution_names); i++) {
+		if (!strncmp(buf, jbt_resolution_names[i],
+			strlen(jbt_resolution_names[i]))) {
+			ret = jbt6k74_set_resolution(jbt, i);
+			if (ret)
+				return ret;
+			return count;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static DEVICE_ATTR(resolution, 0644, resolution_read, resolution_write);
+
+static int reg_by_string(const char *name)
+{
+	if (!strcmp(name, "gamma_fine1"))
+		return JBT_REG_GAMMA1_FINE_1;
+	else if (!strcmp(name, "gamma_fine2"))
+		return JBT_REG_GAMMA1_FINE_2;
+	else if (!strcmp(name, "gamma_inclination"))
+		return JBT_REG_GAMMA1_INCLINATION;
+	else
+		return JBT_REG_GAMMA1_BLUE_OFFSET;
+}
+
+static ssize_t gamma_read(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct jbt_info *jbt = dev_get_drvdata(dev);
+	int reg = reg_by_string(attr->attr.name);
+	uint16_t val;
+
+	mutex_lock(&jbt->lock);
+	val = jbt->reg_cache[reg];
+	mutex_unlock(&jbt->lock);
+
+	return sprintf(buf, "0x%04x\n", val);
+}
+
+static ssize_t gamma_write(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t count)
+{
+	int ret;
+	struct jbt_info *jbt = dev_get_drvdata(dev);
+	int reg = reg_by_string(attr->attr.name);
+	unsigned long val;
+
+	ret = strict_strtoul(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	mutex_lock(&jbt->lock);
+	jbt_reg_write(jbt, reg, val & 0xff);
+	mutex_unlock(&jbt->lock);
+
+	return count;
+}
+
+static ssize_t reset_write(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t count)
+{
+	int ret;
+	struct jbt_info *jbt = dev_get_drvdata(dev);
+	struct jbt6k74_platform_data *pdata = jbt->spi->dev.platform_data;
+	enum jbt_power_mode old_power_mode = jbt->power_mode;
+
+	mutex_lock(&jbt->lock);
+
+	if (gpio_is_valid(pdata->gpio_reset)) {
+		/* hard reset the jbt6k74 */
+		gpio_set_value_cansleep(pdata->gpio_reset, 0);
+		mdelay(120);
+		gpio_set_value_cansleep(pdata->gpio_reset, 1);
+		mdelay(120);
+	}
+
+	ret = jbt_reg_write_nodata(jbt, 0x01);
+	if (ret < 0)
+		dev_err(&jbt->spi->dev, "cannot soft reset\n");
+	mdelay(120);
+
+	mutex_unlock(&jbt->lock);
+
+	jbt->power_mode = JBT_POWER_MODE_DEEP_STANDBY;
+	jbt6k74_enter_power_mode(jbt, old_power_mode);
+
+	return count;
+}
+
+static DEVICE_ATTR(gamma_fine1, 0644, gamma_read, gamma_write);
+static DEVICE_ATTR(gamma_fine2, 0644, gamma_read, gamma_write);
+static DEVICE_ATTR(gamma_inclination, 0644, gamma_read, gamma_write);
+static DEVICE_ATTR(gamma_blue_offset, 0644, gamma_read, gamma_write);
+static DEVICE_ATTR(reset, 0600, NULL, reset_write);
+
+static struct attribute *jbt_sysfs_entries[] = {
+	&dev_attr_resolution.attr,
+	&dev_attr_gamma_fine1.attr,
+	&dev_attr_gamma_fine2.attr,
+	&dev_attr_gamma_inclination.attr,
+	&dev_attr_gamma_blue_offset.attr,
+	&dev_attr_reset.attr,
+	NULL,
+};
+
+static struct attribute_group jbt_attr_group = {
+	.name	= NULL,
+	.attrs	= jbt_sysfs_entries,
+};
+
+/* FIXME: This in an ugly hack to delay display blanking.
+  When the jbt is in sleep mode it displays an all white screen and thus one
+  will a see a short flash.
+  By delaying the blanking we will give the backlight a chance to turn off and
+  thus avoid getting the flash */
+static void jbt_blank_worker(struct work_struct *work)
+{
+	struct jbt_info *jbt  = container_of(work, struct jbt_info,
+						blank_work.work);
+
+	switch (jbt->blank_mode) {
+	case FB_BLANK_NORMAL:
+		jbt6k74_enter_power_mode(jbt, JBT_POWER_MODE_SLEEP);
+		break;
+	case FB_BLANK_POWERDOWN:
+		jbt6k74_enter_power_mode(jbt, JBT_POWER_MODE_DEEP_STANDBY);
+		break;
+	default:
+		break;
+	}
+}
+
+static int jbt6k74_set_mode(struct lcd_device *ld, struct fb_videomode *m)
+{
+	int ret = -EINVAL;
+	struct jbt_info *jbt = dev_get_drvdata(&ld->dev);
+
+	if (m->xres == 240 && m->yres == 320) {
+		ret = jbt6k74_set_resolution(jbt, JBT_RESOLUTION_QVGA);
+	} else if (m->xres == 480 && m->yres == 640) {
+		ret = jbt6k74_set_resolution(jbt, JBT_RESOLUTION_VGA);
+	} else {
+		dev_err(&jbt->spi->dev, "Unknown resolution.\n");
+		jbt6k74_enter_power_mode(jbt, JBT_POWER_MODE_SLEEP);
+	}
+
+	return ret;
+}
+
+static int jbt6k74_set_power(struct lcd_device *ld, int power)
+{
+	int ret = -EINVAL;
+	struct jbt_info *jbt = dev_get_drvdata(&ld->dev);
+
+	jbt->blank_mode = power;
+	cancel_rearming_delayed_work(&jbt->blank_work);
+
+	switch (power) {
+	case FB_BLANK_UNBLANK:
+		dev_dbg(&jbt->spi->dev, "unblank\n");
+		mdelay(20);
+		ret = jbt6k74_enter_power_mode(jbt, JBT_POWER_MODE_NORMAL);
+		break;
+	case FB_BLANK_NORMAL:
+		dev_dbg(&jbt->spi->dev, "blank\n");
+		ret = schedule_delayed_work(&jbt->blank_work, HZ);
+		break;
+	case FB_BLANK_POWERDOWN:
+		dev_dbg(&jbt->spi->dev, "powerdown\n");
+		ret = schedule_delayed_work(&jbt->blank_work, HZ);
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+static int jbt6k74_get_power(struct lcd_device *ld)
+{
+	struct jbt_info *jbt = dev_get_drvdata(&ld->dev);
+
+	switch (jbt->power_mode) {
+	case JBT_POWER_MODE_NORMAL:
+		return FB_BLANK_UNBLANK;
+	case JBT_POWER_MODE_SLEEP:
+		return FB_BLANK_NORMAL;
+	default:
+		return JBT_POWER_MODE_DEEP_STANDBY;
+	}
+}
+
+struct lcd_ops jbt6k74_lcd_ops = {
+	.set_power = jbt6k74_set_power,
+	.get_power = jbt6k74_get_power,
+	.set_mode  = jbt6k74_set_mode,
+};
+
+/* linux device model infrastructure */
+
+static int __devinit jbt_probe(struct spi_device *spi)
+{
+	int ret;
+	struct jbt_info *jbt;
+	struct jbt6k74_platform_data *pdata = spi->dev.platform_data;
+
+	/* the controller doesn't have a MISO pin; we can't do detection */
+
+	spi->mode = SPI_CPOL | SPI_CPHA;
+	spi->bits_per_word = 9;
+
+	ret = spi_setup(spi);
+	if (ret < 0) {
+		dev_err(&spi->dev,
+			"Failed to setup spi\n");
+		return ret;
+	}
+
+	jbt = kzalloc(sizeof(*jbt), GFP_KERNEL);
+	if (!jbt)
+		return -ENOMEM;
+
+	jbt->spi = spi;
+
+	jbt->lcd_dev = lcd_device_register("jbt6k74-lcd", &spi->dev, jbt,
+						&jbt6k74_lcd_ops);
+
+	if (IS_ERR(jbt->lcd_dev)) {
+		ret = PTR_ERR(jbt->lcd_dev);
+		goto err_free_drvdata;
+	}
+
+	INIT_DELAYED_WORK(&jbt->blank_work, jbt_blank_worker);
+
+	jbt->resolution = JBT_RESOLUTION_VGA;
+	jbt->power_mode = JBT_POWER_MODE_DEEP_STANDBY;
+	jbt->next_sleep = jiffies + msecs_to_jiffies(120);
+	mutex_init(&jbt->lock);
+
+	dev_set_drvdata(&spi->dev, jbt);
+
+	jbt->supplies[0].supply = "VDC";
+	jbt->supplies[1].supply = "VDDIO";
+
+	ret = regulator_bulk_get(&spi->dev, ARRAY_SIZE(jbt->supplies),
+					jbt->supplies);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to power get supplies: %d\n", ret);
+		goto err_unregister_lcd;
+	}
+
+	if (gpio_is_valid(pdata->gpio_reset)) {
+		ret = gpio_request(pdata->gpio_reset, "jbt6k74 reset");
+		if (ret) {
+			dev_err(&spi->dev, "Failed to request reset gpio: %d\n",
+				ret);
+			goto err_free_supplies;
+		}
+
+		ret = gpio_direction_output(pdata->gpio_reset, 1);
+		if (ret) {
+			dev_err(&spi->dev, "Failed to set reset gpio direction: %d\n",
+				ret);
+			goto err_gpio_free;
+		}
+	}
+
+	ret = sysfs_create_group(&spi->dev.kobj, &jbt_attr_group);
+	if (ret < 0) {
+		dev_err(&spi->dev, "cannot create sysfs group\n");
+		goto err_gpio_free;
+	}
+
+	mdelay(50);
+	ret = jbt6k74_enter_power_mode(jbt, JBT_POWER_MODE_NORMAL);
+	if (ret < 0) {
+		dev_err(&spi->dev, "cannot enter NORMAL state\n");
+		goto err_sysfs_remove;
+	}
+
+
+	if (pdata->probe_completed)
+		(pdata->probe_completed)(&spi->dev);
+
+	return 0;
+
+err_sysfs_remove:
+	sysfs_remove_group(&spi->dev.kobj, &jbt_attr_group);
+err_gpio_free:
+	gpio_free(pdata->gpio_reset);
+err_free_supplies:
+	regulator_bulk_free(ARRAY_SIZE(jbt->supplies), jbt->supplies);
+err_unregister_lcd:
+	lcd_device_unregister(jbt->lcd_dev);
+err_free_drvdata:
+	dev_set_drvdata(&spi->dev, NULL);
+	kfree(jbt);
+
+	return ret;
+}
+
+static int __devexit jbt_remove(struct spi_device *spi)
+{
+	struct jbt_info *jbt = dev_get_drvdata(&spi->dev);
+	struct jbt6k74_platform_data *pdata = jbt->spi->dev.platform_data;
+
+	/* We don't want to switch off the display in case the user
+	 * accidentially unloads the module (whose use count normally is 0) */
+	jbt6k74_enter_power_mode(jbt, JBT_POWER_MODE_NORMAL);
+
+	sysfs_remove_group(&spi->dev.kobj, &jbt_attr_group);
+
+	if (gpio_is_valid(pdata->gpio_reset))
+		gpio_free(pdata->gpio_reset);
+
+	lcd_device_unregister(jbt->lcd_dev);
+
+	dev_set_drvdata(&spi->dev, NULL);
+
+	regulator_bulk_free(ARRAY_SIZE(jbt->supplies), jbt->supplies);
+	kfree(jbt);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int jbt_suspend(struct spi_device *spi, pm_message_t state)
+{
+	struct jbt_info *jbt = dev_get_drvdata(&spi->dev);
+
+	jbt->suspend_mode = jbt->power_mode;
+
+	jbt6k74_enter_power_mode(jbt, JBT_POWER_MODE_DEEP_STANDBY);
+	jbt->suspended = 1;
+
+	dev_info(&spi->dev, "suspended\n");
+
+	return 0;
+}
+
+int jbt6k74_resume(struct spi_device *spi)
+{
+	struct jbt_info *jbt = dev_get_drvdata(&spi->dev);
+	dev_info(&spi->dev, "starting resume: %d\n", jbt->suspend_mode);
+
+	mdelay(20);
+
+	jbt->suspended = 0;
+	jbt6k74_enter_power_mode(jbt, jbt->suspend_mode);
+
+	dev_info(&spi->dev, "resumed: %d\n", jbt->suspend_mode);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(jbt6k74_resume);
+
+#else
+#define jbt_suspend	NULL
+#define jbt6k74_resume	NULL
+#endif
+
+static struct spi_driver jbt6k74_driver = {
+	.driver = {
+		.name	= "jbt6k74",
+		.owner	= THIS_MODULE,
+	},
+
+	.probe	 = jbt_probe,
+	.remove	 = __devexit_p(jbt_remove),
+	.suspend = jbt_suspend,
+	.resume	 = jbt6k74_resume,
+};
+
+static int __init jbt_init(void)
+{
+	return spi_register_driver(&jbt6k74_driver);
+}
+module_init(jbt_init);
+
+static void __exit jbt_exit(void)
+{
+	spi_unregister_driver(&jbt6k74_driver);
+}
+module_exit(jbt_exit);
+
+MODULE_DESCRIPTION("SPI driver for tpo JBT6K74-AS LCM control interface");
+MODULE_AUTHOR("Harald Welte <laforge@openmoko.org>");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/jbt6k74.h b/include/linux/jbt6k74.h
new file mode 100644
index 00000000000..75488c41136
--- /dev/null
+++ b/include/linux/jbt6k74.h
@@ -0,0 +1,21 @@
+#ifndef __JBT6K74_H__
+#define __JBT6K74_H__
+
+#include <linux/spi/spi.h>
+
+/*
+ *  struct jbt6k74_platform_data - Platform data for jbt6k74 driver
+ *  @probe_completed: Callback to be called when the driver has been
+ *  successfully probed.
+ *  @enable_pixel_clock: Callback to enable or disable the pixelclock of the
+ *  gpu.
+ *  @gpio_reset: Reset gpio pin number.
+ */
+struct jbt6k74_platform_data {
+	void (*probe_completed)(struct device *dev);
+	void (*enable_pixel_clock)(struct device *dev, int enable);
+
+	int gpio_reset;
+};
+
+#endif