drivers/gpu/drm/i915/dvo_ivch.c - maze/linux - Git at Google

 /*
  * Copyright © 2006 Intel Corporation
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice (including the next
  * paragraph) shall be included in all copies or substantial portions of the
  * Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  * DEALINGS IN THE SOFTWARE.
  *
  * Authors:
  *    Eric Anholt <eric@anholt.net>
  *
  */

 #include "dvo.h"

 /*
  * register definitions for the i82807aa.
  *
  * Documentation on this chipset can be found in datasheet #29069001 at
  * intel.com.
  */

 /*
  * VCH Revision & GMBus Base Addr
  */
 #define VR00		0x00
 # define VR00_BASE_ADDRESS_MASK		0x007f

 /*
  * Functionality Enable
  */
 #define VR01		0x01

 /*
  * Enable the panel fitter
  */
 # define VR01_PANEL_FIT_ENABLE		(1 << 3)
 /*
  * Enables the LCD display.
  *
  * This must not be set while VR01_DVO_BYPASS_ENABLE is set.
  */
 # define VR01_LCD_ENABLE		(1 << 2)
 /** Enables the DVO repeater. */
 # define VR01_DVO_BYPASS_ENABLE		(1 << 1)
 /** Enables the DVO clock */
 # define VR01_DVO_ENABLE		(1 << 0)

 /*
  * LCD Interface Format
  */
 #define VR10		0x10
 /** Enables LVDS output instead of CMOS */
 # define VR10_LVDS_ENABLE		(1 << 4)
 /** Enables 18-bit LVDS output. */
 # define VR10_INTERFACE_1X18		(0 << 2)
 /** Enables 24-bit LVDS or CMOS output */
 # define VR10_INTERFACE_1X24		(1 << 2)
 /** Enables 2x18-bit LVDS or CMOS output. */
 # define VR10_INTERFACE_2X18		(2 << 2)
 /** Enables 2x24-bit LVDS output */
 # define VR10_INTERFACE_2X24		(3 << 2)

 /*
  * VR20 LCD Horizontal Display Size
  */
 #define VR20	0x20

 /*
  * LCD Vertical Display Size
  */
 #define VR21	0x20

 /*
  * Panel power down status
  */
 #define VR30		0x30
 /** Read only bit indicating that the panel is not in a safe poweroff state. */
 # define VR30_PANEL_ON			(1 << 15)

 #define VR40		0x40
 # define VR40_STALL_ENABLE		(1 << 13)
 # define VR40_VERTICAL_INTERP_ENABLE	(1 << 12)
 # define VR40_ENHANCED_PANEL_FITTING	(1 << 11)
 # define VR40_HORIZONTAL_INTERP_ENABLE	(1 << 10)
 # define VR40_AUTO_RATIO_ENABLE		(1 << 9)
 # define VR40_CLOCK_GATING_ENABLE	(1 << 8)

 /*
  * Panel Fitting Vertical Ratio
  * (((image_height - 1) << 16) / ((panel_height - 1))) >> 2
  */
 #define VR41		0x41

 /*
  * Panel Fitting Horizontal Ratio
  * (((image_width - 1) << 16) / ((panel_width - 1))) >> 2
  */
 #define VR42		0x42

 /*
  * Horizontal Image Size
  */
 #define VR43		0x43

 /* VR80 GPIO 0
  */
 #define VR80	    0x80
 #define VR81	    0x81
 #define VR82	    0x82
 #define VR83	    0x83
 #define VR84	    0x84
 #define VR85	    0x85
 #define VR86	    0x86
 #define VR87	    0x87

 /* VR88 GPIO 8
  */
 #define VR88	    0x88

 /* Graphics BIOS scratch 0
  */
 #define VR8E	    0x8E
 # define VR8E_PANEL_TYPE_MASK		(0xf << 0)
 # define VR8E_PANEL_INTERFACE_CMOS	(0 << 4)
 # define VR8E_PANEL_INTERFACE_LVDS	(1 << 4)
 # define VR8E_FORCE_DEFAULT_PANEL	(1 << 5)

 /* Graphics BIOS scratch 1
  */
 #define VR8F	    0x8F
 # define VR8F_VCH_PRESENT		(1 << 0)
 # define VR8F_DISPLAY_CONN		(1 << 1)
 # define VR8F_POWER_MASK		(0x3c)
 # define VR8F_POWER_POS			(2)


 struct ivch_priv {
 	bool quiet;

 	uint16_t width, height;
 };


 static void ivch_dump_regs(struct intel_dvo_device *dvo);

 /**
  * Reads a register on the ivch.
  *
  * Each of the 256 registers are 16 bits long.
  */
 static bool ivch_read(struct intel_dvo_device *dvo, int addr, uint16_t *data)
 {
 	struct ivch_priv *priv = dvo->dev_priv;
 	struct i2c_adapter *adapter = dvo->i2c_bus;
 	u8 out_buf[1];
 	u8 in_buf[2];

 	struct i2c_msg msgs[] = {
 		{
 			.addr = dvo->slave_addr,
 			.flags = I2C_M_RD,
 			.len = 0,
 		},
 		{
 			.addr = 0,
 			.flags = I2C_M_NOSTART,
 			.len = 1,
 			.buf = out_buf,
 		},
 		{
 			.addr = dvo->slave_addr,
 			.flags = I2C_M_RD | I2C_M_NOSTART,
 			.len = 2,
 			.buf = in_buf,
 		}
 	};

 	out_buf[0] = addr;

 	if (i2c_transfer(adapter, msgs, 3) == 3) {
 		*data = (in_buf[1] << 8) | in_buf[0];
 		return true;
 	};

 	if (!priv->quiet) {
 		DRM_DEBUG_KMS("Unable to read register 0x%02x from "
 				"%s:%02x.\n",
 			  addr, adapter->name, dvo->slave_addr);
 	}
 	return false;
 }

 /** Writes a 16-bit register on the ivch */
 static bool ivch_write(struct intel_dvo_device *dvo, int addr, uint16_t data)
 {
 	struct ivch_priv *priv = dvo->dev_priv;
 	struct i2c_adapter *adapter = dvo->i2c_bus;
 	u8 out_buf[3];
 	struct i2c_msg msg = {
 		.addr = dvo->slave_addr,
 		.flags = 0,
 		.len = 3,
 		.buf = out_buf,
 	};

 	out_buf[0] = addr;
 	out_buf[1] = data & 0xff;
 	out_buf[2] = data >> 8;

 	if (i2c_transfer(adapter, &msg, 1) == 1)
 		return true;

 	if (!priv->quiet) {
 		DRM_DEBUG_KMS("Unable to write register 0x%02x to %s:%d.\n",
 			  addr, adapter->name, dvo->slave_addr);
 	}

 	return false;
 }

 /** Probes the given bus and slave address for an ivch */
 static bool ivch_init(struct intel_dvo_device *dvo,
 		      struct i2c_adapter *adapter)
 {
 	struct ivch_priv *priv;
 	uint16_t temp;

 	priv = kzalloc(sizeof(struct ivch_priv), GFP_KERNEL);
 	if (priv == NULL)
 		return false;

 	dvo->i2c_bus = adapter;
 	dvo->dev_priv = priv;
 	priv->quiet = true;

 	if (!ivch_read(dvo, VR00, &temp))
 		goto out;
 	priv->quiet = false;

 	/* Since the identification bits are probably zeroes, which doesn't seem
 	 * very unique, check that the value in the base address field matches
 	 * the address it's responding on.
 	 */
 	if ((temp & VR00_BASE_ADDRESS_MASK) != dvo->slave_addr) {
 		DRM_DEBUG_KMS("ivch detect failed due to address mismatch "
 			  "(%d vs %d)\n",
 			  (temp & VR00_BASE_ADDRESS_MASK), dvo->slave_addr);
 		goto out;
 	}

 	ivch_read(dvo, VR20, &priv->width);
 	ivch_read(dvo, VR21, &priv->height);

 	return true;

 out:
 	kfree(priv);
 	return false;
 }

 static enum drm_connector_status ivch_detect(struct intel_dvo_device *dvo)
 {
 	return connector_status_connected;
 }

 static enum drm_mode_status ivch_mode_valid(struct intel_dvo_device *dvo,
 					    struct drm_display_mode *mode)
 {
 	if (mode->clock > 112000)
 		return MODE_CLOCK_HIGH;

 	return MODE_OK;
 }

 /** Sets the power state of the panel connected to the ivch */
 static void ivch_dpms(struct intel_dvo_device *dvo, bool enable)
 {
 	int i;
 	uint16_t vr01, vr30, backlight;

 	/* Set the new power state of the panel. */
 	if (!ivch_read(dvo, VR01, &vr01))
 		return;

 	if (enable)
 		backlight = 1;
 	else
 		backlight = 0;
 	ivch_write(dvo, VR80, backlight);

 	if (enable)
 		vr01 |= VR01_LCD_ENABLE | VR01_DVO_ENABLE;
 	else
 		vr01 &= ~(VR01_LCD_ENABLE | VR01_DVO_ENABLE);

 	ivch_write(dvo, VR01, vr01);

 	/* Wait for the panel to make its state transition */
 	for (i = 0; i < 100; i++) {
 		if (!ivch_read(dvo, VR30, &vr30))
 			break;

 		if (((vr30 & VR30_PANEL_ON) != 0) == enable)
 			break;
 		udelay(1000);
 	}
 	/* wait some more; vch may fail to resync sometimes without this */
 	udelay(16 * 1000);
 }

 static bool ivch_get_hw_state(struct intel_dvo_device *dvo)
 {
 	uint16_t vr01;

 	/* Set the new power state of the panel. */
 	if (!ivch_read(dvo, VR01, &vr01))
 		return false;

 	if (vr01 & VR01_LCD_ENABLE)
 		return true;
 	else
 		return false;
 }

 static void ivch_mode_set(struct intel_dvo_device *dvo,
 			  struct drm_display_mode *mode,
 			  struct drm_display_mode *adjusted_mode)
 {
 	uint16_t vr40 = 0;
 	uint16_t vr01;

 	vr01 = 0;
 	vr40 = (VR40_STALL_ENABLE | VR40_VERTICAL_INTERP_ENABLE |
 		VR40_HORIZONTAL_INTERP_ENABLE);

 	if (mode->hdisplay != adjusted_mode->hdisplay ||
 	    mode->vdisplay != adjusted_mode->vdisplay) {
 		uint16_t x_ratio, y_ratio;

 		vr01 |= VR01_PANEL_FIT_ENABLE;
 		vr40 |= VR40_CLOCK_GATING_ENABLE;
 		x_ratio = (((mode->hdisplay - 1) << 16) /
 			   (adjusted_mode->hdisplay - 1)) >> 2;
 		y_ratio = (((mode->vdisplay - 1) << 16) /
 			   (adjusted_mode->vdisplay - 1)) >> 2;
 		ivch_write(dvo, VR42, x_ratio);
 		ivch_write(dvo, VR41, y_ratio);
 	} else {
 		vr01 &= ~VR01_PANEL_FIT_ENABLE;
 		vr40 &= ~VR40_CLOCK_GATING_ENABLE;
 	}
 	vr40 &= ~VR40_AUTO_RATIO_ENABLE;

 	ivch_write(dvo, VR01, vr01);
 	ivch_write(dvo, VR40, vr40);

 	ivch_dump_regs(dvo);
 }

 static void ivch_dump_regs(struct intel_dvo_device *dvo)
 {
 	uint16_t val;

 	ivch_read(dvo, VR00, &val);
 	DRM_DEBUG_KMS("VR00: 0x%04x\n", val);
 	ivch_read(dvo, VR01, &val);
 	DRM_DEBUG_KMS("VR01: 0x%04x\n", val);
 	ivch_read(dvo, VR30, &val);
 	DRM_DEBUG_KMS("VR30: 0x%04x\n", val);
 	ivch_read(dvo, VR40, &val);
 	DRM_DEBUG_KMS("VR40: 0x%04x\n", val);

 	/* GPIO registers */
 	ivch_read(dvo, VR80, &val);
 	DRM_DEBUG_KMS("VR80: 0x%04x\n", val);
 	ivch_read(dvo, VR81, &val);
 	DRM_DEBUG_KMS("VR81: 0x%04x\n", val);
 	ivch_read(dvo, VR82, &val);
 	DRM_DEBUG_KMS("VR82: 0x%04x\n", val);
 	ivch_read(dvo, VR83, &val);
 	DRM_DEBUG_KMS("VR83: 0x%04x\n", val);
 	ivch_read(dvo, VR84, &val);
 	DRM_DEBUG_KMS("VR84: 0x%04x\n", val);
 	ivch_read(dvo, VR85, &val);
 	DRM_DEBUG_KMS("VR85: 0x%04x\n", val);
 	ivch_read(dvo, VR86, &val);
 	DRM_DEBUG_KMS("VR86: 0x%04x\n", val);
 	ivch_read(dvo, VR87, &val);
 	DRM_DEBUG_KMS("VR87: 0x%04x\n", val);
 	ivch_read(dvo, VR88, &val);
 	DRM_DEBUG_KMS("VR88: 0x%04x\n", val);

 	/* Scratch register 0 - AIM Panel type */
 	ivch_read(dvo, VR8E, &val);
 	DRM_DEBUG_KMS("VR8E: 0x%04x\n", val);

 	/* Scratch register 1 - Status register */
 	ivch_read(dvo, VR8F, &val);
 	DRM_DEBUG_KMS("VR8F: 0x%04x\n", val);
 }

 static void ivch_destroy(struct intel_dvo_device *dvo)
 {
 	struct ivch_priv *priv = dvo->dev_priv;

 	if (priv) {
 		kfree(priv);
 		dvo->dev_priv = NULL;
 	}
 }

 struct intel_dvo_dev_ops ivch_ops = {
 	.init = ivch_init,
 	.dpms = ivch_dpms,
 	.get_hw_state = ivch_get_hw_state,
 	.mode_valid = ivch_mode_valid,
 	.mode_set = ivch_mode_set,
 	.detect = ivch_detect,
 	.dump_regs = ivch_dump_regs,
 	.destroy = ivch_destroy,
 };
	/*
	* Copyright © 2006 Intel Corporation
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice (including the next
	* paragraph) shall be included in all copies or substantial portions of the
	* Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
	* DEALINGS IN THE SOFTWARE.
	*
	* Authors:
	* Eric Anholt <eric@anholt.net>
	*
	*/

	#include "dvo.h"

	/*
	* register definitions for the i82807aa.
	*
	* Documentation on this chipset can be found in datasheet #29069001 at
	* intel.com.
	*/

	/*
	* VCH Revision & GMBus Base Addr
	*/
	#define VR00 0x00
	# define VR00_BASE_ADDRESS_MASK 0x007f

	/*
	* Functionality Enable
	*/
	#define VR01 0x01

	/*
	* Enable the panel fitter
	*/
	# define VR01_PANEL_FIT_ENABLE (1 << 3)
	/*
	* Enables the LCD display.
	*
	* This must not be set while VR01_DVO_BYPASS_ENABLE is set.
	*/
	# define VR01_LCD_ENABLE (1 << 2)
	/** Enables the DVO repeater. */
	# define VR01_DVO_BYPASS_ENABLE (1 << 1)
	/** Enables the DVO clock */
	# define VR01_DVO_ENABLE (1 << 0)

	/*
	* LCD Interface Format
	*/
	#define VR10 0x10
	/** Enables LVDS output instead of CMOS */
	# define VR10_LVDS_ENABLE (1 << 4)
	/** Enables 18-bit LVDS output. */
	# define VR10_INTERFACE_1X18 (0 << 2)
	/** Enables 24-bit LVDS or CMOS output */
	# define VR10_INTERFACE_1X24 (1 << 2)
	/** Enables 2x18-bit LVDS or CMOS output. */
	# define VR10_INTERFACE_2X18 (2 << 2)
	/** Enables 2x24-bit LVDS output */
	# define VR10_INTERFACE_2X24 (3 << 2)

	/*
	* VR20 LCD Horizontal Display Size
	*/
	#define VR20 0x20

	/*
	* LCD Vertical Display Size
	*/
	#define VR21 0x20

	/*
	* Panel power down status
	*/
	#define VR30 0x30
	/** Read only bit indicating that the panel is not in a safe poweroff state. */
	# define VR30_PANEL_ON (1 << 15)

	#define VR40 0x40
	# define VR40_STALL_ENABLE (1 << 13)
	# define VR40_VERTICAL_INTERP_ENABLE (1 << 12)
	# define VR40_ENHANCED_PANEL_FITTING (1 << 11)
	# define VR40_HORIZONTAL_INTERP_ENABLE (1 << 10)
	# define VR40_AUTO_RATIO_ENABLE (1 << 9)
	# define VR40_CLOCK_GATING_ENABLE (1 << 8)

	/*
	* Panel Fitting Vertical Ratio
	* (((image_height - 1) << 16) / ((panel_height - 1))) >> 2
	*/
	#define VR41 0x41

	/*
	* Panel Fitting Horizontal Ratio
	* (((image_width - 1) << 16) / ((panel_width - 1))) >> 2
	*/
	#define VR42 0x42

	/*
	* Horizontal Image Size
	*/
	#define VR43 0x43

	/* VR80 GPIO 0
	*/
	#define VR80 0x80
	#define VR81 0x81
	#define VR82 0x82
	#define VR83 0x83
	#define VR84 0x84
	#define VR85 0x85
	#define VR86 0x86
	#define VR87 0x87

	/* VR88 GPIO 8
	*/
	#define VR88 0x88

	/* Graphics BIOS scratch 0
	*/
	#define VR8E 0x8E
	# define VR8E_PANEL_TYPE_MASK (0xf << 0)
	# define VR8E_PANEL_INTERFACE_CMOS (0 << 4)
	# define VR8E_PANEL_INTERFACE_LVDS (1 << 4)
	# define VR8E_FORCE_DEFAULT_PANEL (1 << 5)

	/* Graphics BIOS scratch 1
	*/
	#define VR8F 0x8F
	# define VR8F_VCH_PRESENT (1 << 0)
	# define VR8F_DISPLAY_CONN (1 << 1)
	# define VR8F_POWER_MASK (0x3c)
	# define VR8F_POWER_POS (2)


	struct ivch_priv {
	bool quiet;

	uint16_t width, height;
	};


	static void ivch_dump_regs(struct intel_dvo_device *dvo);

	/**
	* Reads a register on the ivch.
	*
	* Each of the 256 registers are 16 bits long.
	*/
	static bool ivch_read(struct intel_dvo_device dvo, int addr, uint16_t data)
	{
	struct ivch_priv *priv = dvo->dev_priv;
	struct i2c_adapter *adapter = dvo->i2c_bus;
	u8 out_buf[1];
	u8 in_buf[2];

	struct i2c_msg msgs[] = {
	{
	.addr = dvo->slave_addr,
	.flags = I2C_M_RD,
	.len = 0,
	},
	{
	.addr = 0,
	.flags = I2C_M_NOSTART,
	.len = 1,
	.buf = out_buf,
	},
	{
	.addr = dvo->slave_addr,
	.flags = I2C_M_RD \| I2C_M_NOSTART,
	.len = 2,
	.buf = in_buf,
	}
	};

	out_buf[0] = addr;

	if (i2c_transfer(adapter, msgs, 3) == 3) {
	*data = (in_buf[1] << 8) \| in_buf[0];
	return true;
	};

	if (!priv->quiet) {
	DRM_DEBUG_KMS("Unable to read register 0x%02x from "
	"%s:%02x.\n",
	addr, adapter->name, dvo->slave_addr);
	}
	return false;
	}

	/** Writes a 16-bit register on the ivch */
	static bool ivch_write(struct intel_dvo_device *dvo, int addr, uint16_t data)
	{
	struct ivch_priv *priv = dvo->dev_priv;
	struct i2c_adapter *adapter = dvo->i2c_bus;
	u8 out_buf[3];
	struct i2c_msg msg = {
	.addr = dvo->slave_addr,
	.flags = 0,
	.len = 3,
	.buf = out_buf,
	};

	out_buf[0] = addr;
	out_buf[1] = data & 0xff;
	out_buf[2] = data >> 8;

	if (i2c_transfer(adapter, &msg, 1) == 1)
	return true;

	if (!priv->quiet) {
	DRM_DEBUG_KMS("Unable to write register 0x%02x to %s:%d.\n",
	addr, adapter->name, dvo->slave_addr);
	}

	return false;
	}

	/** Probes the given bus and slave address for an ivch */
	static bool ivch_init(struct intel_dvo_device *dvo,
	struct i2c_adapter *adapter)
	{
	struct ivch_priv *priv;
	uint16_t temp;

	priv = kzalloc(sizeof(struct ivch_priv), GFP_KERNEL);
	if (priv == NULL)
	return false;

	dvo->i2c_bus = adapter;
	dvo->dev_priv = priv;
	priv->quiet = true;

	if (!ivch_read(dvo, VR00, &temp))
	goto out;
	priv->quiet = false;

	/* Since the identification bits are probably zeroes, which doesn't seem
	* very unique, check that the value in the base address field matches
	* the address it's responding on.
	*/
	if ((temp & VR00_BASE_ADDRESS_MASK) != dvo->slave_addr) {
	DRM_DEBUG_KMS("ivch detect failed due to address mismatch "
	"(%d vs %d)\n",
	(temp & VR00_BASE_ADDRESS_MASK), dvo->slave_addr);
	goto out;
	}

	ivch_read(dvo, VR20, &priv->width);
	ivch_read(dvo, VR21, &priv->height);

	return true;

	out:
	kfree(priv);
	return false;
	}

	static enum drm_connector_status ivch_detect(struct intel_dvo_device *dvo)
	{
	return connector_status_connected;
	}

	static enum drm_mode_status ivch_mode_valid(struct intel_dvo_device *dvo,
	struct drm_display_mode *mode)
	{
	if (mode->clock > 112000)
	return MODE_CLOCK_HIGH;

	return MODE_OK;
	}

	/** Sets the power state of the panel connected to the ivch */
	static void ivch_dpms(struct intel_dvo_device *dvo, bool enable)
	{
	int i;
	uint16_t vr01, vr30, backlight;

	/* Set the new power state of the panel. */
	if (!ivch_read(dvo, VR01, &vr01))
	return;

	if (enable)
	backlight = 1;
	else
	backlight = 0;
	ivch_write(dvo, VR80, backlight);

	if (enable)
	vr01 \|= VR01_LCD_ENABLE \| VR01_DVO_ENABLE;
	else
	vr01 &= ~(VR01_LCD_ENABLE \| VR01_DVO_ENABLE);

	ivch_write(dvo, VR01, vr01);

	/* Wait for the panel to make its state transition */
	for (i = 0; i < 100; i++) {
	if (!ivch_read(dvo, VR30, &vr30))
	break;

	if (((vr30 & VR30_PANEL_ON) != 0) == enable)
	break;
	udelay(1000);
	}
	/* wait some more; vch may fail to resync sometimes without this */
	udelay(16 * 1000);
	}

	static bool ivch_get_hw_state(struct intel_dvo_device *dvo)
	{
	uint16_t vr01;

	/* Set the new power state of the panel. */
	if (!ivch_read(dvo, VR01, &vr01))
	return false;

	if (vr01 & VR01_LCD_ENABLE)
	return true;
	else
	return false;
	}

	static void ivch_mode_set(struct intel_dvo_device *dvo,
	struct drm_display_mode *mode,
	struct drm_display_mode *adjusted_mode)
	{
	uint16_t vr40 = 0;
	uint16_t vr01;

	vr01 = 0;
	vr40 = (VR40_STALL_ENABLE \| VR40_VERTICAL_INTERP_ENABLE \|
	VR40_HORIZONTAL_INTERP_ENABLE);

	if (mode->hdisplay != adjusted_mode->hdisplay \|\|
	mode->vdisplay != adjusted_mode->vdisplay) {
	uint16_t x_ratio, y_ratio;

	vr01 \|= VR01_PANEL_FIT_ENABLE;
	vr40 \|= VR40_CLOCK_GATING_ENABLE;
	x_ratio = (((mode->hdisplay - 1) << 16) /
	(adjusted_mode->hdisplay - 1)) >> 2;
	y_ratio = (((mode->vdisplay - 1) << 16) /
	(adjusted_mode->vdisplay - 1)) >> 2;
	ivch_write(dvo, VR42, x_ratio);
	ivch_write(dvo, VR41, y_ratio);
	} else {
	vr01 &= ~VR01_PANEL_FIT_ENABLE;
	vr40 &= ~VR40_CLOCK_GATING_ENABLE;
	}
	vr40 &= ~VR40_AUTO_RATIO_ENABLE;

	ivch_write(dvo, VR01, vr01);
	ivch_write(dvo, VR40, vr40);

	ivch_dump_regs(dvo);
	}

	static void ivch_dump_regs(struct intel_dvo_device *dvo)
	{
	uint16_t val;

	ivch_read(dvo, VR00, &val);
	DRM_DEBUG_KMS("VR00: 0x%04x\n", val);
	ivch_read(dvo, VR01, &val);
	DRM_DEBUG_KMS("VR01: 0x%04x\n", val);
	ivch_read(dvo, VR30, &val);
	DRM_DEBUG_KMS("VR30: 0x%04x\n", val);
	ivch_read(dvo, VR40, &val);
	DRM_DEBUG_KMS("VR40: 0x%04x\n", val);

	/* GPIO registers */
	ivch_read(dvo, VR80, &val);
	DRM_DEBUG_KMS("VR80: 0x%04x\n", val);
	ivch_read(dvo, VR81, &val);
	DRM_DEBUG_KMS("VR81: 0x%04x\n", val);
	ivch_read(dvo, VR82, &val);
	DRM_DEBUG_KMS("VR82: 0x%04x\n", val);
	ivch_read(dvo, VR83, &val);
	DRM_DEBUG_KMS("VR83: 0x%04x\n", val);
	ivch_read(dvo, VR84, &val);
	DRM_DEBUG_KMS("VR84: 0x%04x\n", val);
	ivch_read(dvo, VR85, &val);
	DRM_DEBUG_KMS("VR85: 0x%04x\n", val);
	ivch_read(dvo, VR86, &val);
	DRM_DEBUG_KMS("VR86: 0x%04x\n", val);
	ivch_read(dvo, VR87, &val);
	DRM_DEBUG_KMS("VR87: 0x%04x\n", val);
	ivch_read(dvo, VR88, &val);
	DRM_DEBUG_KMS("VR88: 0x%04x\n", val);

	/* Scratch register 0 - AIM Panel type */
	ivch_read(dvo, VR8E, &val);
	DRM_DEBUG_KMS("VR8E: 0x%04x\n", val);

	/* Scratch register 1 - Status register */
	ivch_read(dvo, VR8F, &val);
	DRM_DEBUG_KMS("VR8F: 0x%04x\n", val);
	}

	static void ivch_destroy(struct intel_dvo_device *dvo)
	{
	struct ivch_priv *priv = dvo->dev_priv;

	if (priv) {
	kfree(priv);
	dvo->dev_priv = NULL;
	}
	}

	struct intel_dvo_dev_ops ivch_ops = {
	.init = ivch_init,
	.dpms = ivch_dpms,
	.get_hw_state = ivch_get_hw_state,
	.mode_valid = ivch_mode_valid,
	.mode_set = ivch_mode_set,
	.detect = ivch_detect,
	.dump_regs = ivch_dump_regs,
	.destroy = ivch_destroy,
	};