drivers/gpu/drm/i915/intel_panel.c - kernel/msm-4.19 - Gitiles

 /*
  * Copyright © 2006-2010 Intel Corporation
  * Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
  *
  * 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>
  *      Dave Airlie <airlied@linux.ie>
  *      Jesse Barnes <jesse.barnes@intel.com>
  *      Chris Wilson <chris@chris-wilson.co.uk>
  */

 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

 #include <linux/moduleparam.h>
 #include "intel_drv.h"

 #define PCI_LBPC 0xf4 /* legacy/combination backlight modes */

 void
 intel_fixed_panel_mode(struct drm_display_mode *fixed_mode,
 		       struct drm_display_mode *adjusted_mode)
 {
 	adjusted_mode->hdisplay = fixed_mode->hdisplay;
 	adjusted_mode->hsync_start = fixed_mode->hsync_start;
 	adjusted_mode->hsync_end = fixed_mode->hsync_end;
 	adjusted_mode->htotal = fixed_mode->htotal;

 	adjusted_mode->vdisplay = fixed_mode->vdisplay;
 	adjusted_mode->vsync_start = fixed_mode->vsync_start;
 	adjusted_mode->vsync_end = fixed_mode->vsync_end;
 	adjusted_mode->vtotal = fixed_mode->vtotal;

 	adjusted_mode->clock = fixed_mode->clock;
 }

 /* adjusted_mode has been preset to be the panel's fixed mode */
 void
 intel_pch_panel_fitting(struct drm_device *dev,
 			int fitting_mode,
 			const struct drm_display_mode *mode,
 			struct drm_display_mode *adjusted_mode)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	int x, y, width, height;

 	x = y = width = height = 0;

 	/* Native modes don't need fitting */
 	if (adjusted_mode->hdisplay == mode->hdisplay &&
 	    adjusted_mode->vdisplay == mode->vdisplay)
 		goto done;

 	switch (fitting_mode) {
 	case DRM_MODE_SCALE_CENTER:
 		width = mode->hdisplay;
 		height = mode->vdisplay;
 		x = (adjusted_mode->hdisplay - width + 1)/2;
 		y = (adjusted_mode->vdisplay - height + 1)/2;
 		break;

 	case DRM_MODE_SCALE_ASPECT:
 		/* Scale but preserve the aspect ratio */
 		{
 			u32 scaled_width = adjusted_mode->hdisplay * mode->vdisplay;
 			u32 scaled_height = mode->hdisplay * adjusted_mode->vdisplay;
 			if (scaled_width > scaled_height) { /* pillar */
 				width = scaled_height / mode->vdisplay;
 				if (width & 1)
 					width++;
 				x = (adjusted_mode->hdisplay - width + 1) / 2;
 				y = 0;
 				height = adjusted_mode->vdisplay;
 			} else if (scaled_width < scaled_height) { /* letter */
 				height = scaled_width / mode->hdisplay;
 				if (height & 1)
 				    height++;
 				y = (adjusted_mode->vdisplay - height + 1) / 2;
 				x = 0;
 				width = adjusted_mode->hdisplay;
 			} else {
 				x = y = 0;
 				width = adjusted_mode->hdisplay;
 				height = adjusted_mode->vdisplay;
 			}
 		}
 		break;

 	default:
 	case DRM_MODE_SCALE_FULLSCREEN:
 		x = y = 0;
 		width = adjusted_mode->hdisplay;
 		height = adjusted_mode->vdisplay;
 		break;
 	}

 done:
 	dev_priv->pch_pf_pos = (x << 16) | y;
 	dev_priv->pch_pf_size = (width << 16) | height;
 }

 static int is_backlight_combination_mode(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;

 	if (INTEL_INFO(dev)->gen >= 4)
 		return I915_READ(BLC_PWM_CTL2) & BLM_COMBINATION_MODE;

 	if (IS_GEN2(dev))
 		return I915_READ(BLC_PWM_CTL) & BLM_LEGACY_MODE;

 	return 0;
 }

 static u32 i915_read_blc_pwm_ctl(struct drm_i915_private *dev_priv)
 {
 	u32 val;

 	/* Restore the CTL value if it lost, e.g. GPU reset */

 	if (HAS_PCH_SPLIT(dev_priv->dev)) {
 		val = I915_READ(BLC_PWM_PCH_CTL2);
 		if (dev_priv->saveBLC_PWM_CTL2 == 0) {
 			dev_priv->saveBLC_PWM_CTL2 = val;
 		} else if (val == 0) {
 			I915_WRITE(BLC_PWM_PCH_CTL2,
 				   dev_priv->saveBLC_PWM_CTL2);
 			val = dev_priv->saveBLC_PWM_CTL2;
 		}
 	} else {
 		val = I915_READ(BLC_PWM_CTL);
 		if (dev_priv->saveBLC_PWM_CTL == 0) {
 			dev_priv->saveBLC_PWM_CTL = val;
 			dev_priv->saveBLC_PWM_CTL2 = I915_READ(BLC_PWM_CTL2);
 		} else if (val == 0) {
 			I915_WRITE(BLC_PWM_CTL,
 				   dev_priv->saveBLC_PWM_CTL);
 			I915_WRITE(BLC_PWM_CTL2,
 				   dev_priv->saveBLC_PWM_CTL2);
 			val = dev_priv->saveBLC_PWM_CTL;
 		}
 	}

 	return val;
 }

 u32 intel_panel_get_max_backlight(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	u32 max;

 	max = i915_read_blc_pwm_ctl(dev_priv);
 	if (max == 0) {
 		/* XXX add code here to query mode clock or hardware clock
 		 * and program max PWM appropriately.
 		 */
 		pr_warn_once("fixme: max PWM is zero\n");
 		return 1;
 	}

 	if (HAS_PCH_SPLIT(dev)) {
 		max >>= 16;
 	} else {
 		if (INTEL_INFO(dev)->gen < 4)
 			max >>= 17;
 		else
 			max >>= 16;

 		if (is_backlight_combination_mode(dev))
 			max *= 0xff;
 	}

 	DRM_DEBUG_DRIVER("max backlight PWM = %d\n", max);
 	return max;
 }

 static int i915_panel_invert_brightness;
 MODULE_PARM_DESC(invert_brightness, "Invert backlight brightness "
 	"(-1 force normal, 0 machine defaults, 1 force inversion), please "
 	"report PCI device ID, subsystem vendor and subsystem device ID "
 	"to dri-devel@lists.freedesktop.org, if your machine needs it. "
 	"It will then be included in an upcoming module version.");
 module_param_named(invert_brightness, i915_panel_invert_brightness, int, 0600);
 static u32 intel_panel_compute_brightness(struct drm_device *dev, u32 val)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;

 	if (i915_panel_invert_brightness < 0)
 		return val;

 	if (i915_panel_invert_brightness > 0 ||
 	    dev_priv->quirks & QUIRK_INVERT_BRIGHTNESS)
 		return intel_panel_get_max_backlight(dev) - val;

 	return val;
 }

 u32 intel_panel_get_backlight(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	u32 val;

 	if (HAS_PCH_SPLIT(dev)) {
 		val = I915_READ(BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
 	} else {
 		val = I915_READ(BLC_PWM_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
 		if (INTEL_INFO(dev)->gen < 4)
 			val >>= 1;

 		if (is_backlight_combination_mode(dev)) {
 			u8 lbpc;

 			pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc);
 			val *= lbpc;
 		}
 	}

 	val = intel_panel_compute_brightness(dev, val);
 	DRM_DEBUG_DRIVER("get backlight PWM = %d\n", val);
 	return val;
 }

 static void intel_pch_panel_set_backlight(struct drm_device *dev, u32 level)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	u32 val = I915_READ(BLC_PWM_CPU_CTL) & ~BACKLIGHT_DUTY_CYCLE_MASK;
 	I915_WRITE(BLC_PWM_CPU_CTL, val | level);
 }

 static void intel_panel_actually_set_backlight(struct drm_device *dev, u32 level)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	u32 tmp;

 	DRM_DEBUG_DRIVER("set backlight PWM = %d\n", level);
 	level = intel_panel_compute_brightness(dev, level);

 	if (HAS_PCH_SPLIT(dev))
 		return intel_pch_panel_set_backlight(dev, level);

 	if (is_backlight_combination_mode(dev)) {
 		u32 max = intel_panel_get_max_backlight(dev);
 		u8 lbpc;

 		lbpc = level * 0xfe / max + 1;
 		level /= lbpc;
 		pci_write_config_byte(dev->pdev, PCI_LBPC, lbpc);
 	}

 	tmp = I915_READ(BLC_PWM_CTL);
 	if (INTEL_INFO(dev)->gen < 4)
 		level <<= 1;
 	tmp &= ~BACKLIGHT_DUTY_CYCLE_MASK;
 	I915_WRITE(BLC_PWM_CTL, tmp | level);
 }

 void intel_panel_set_backlight(struct drm_device *dev, u32 level)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;

 	dev_priv->backlight_level = level;
 	if (dev_priv->backlight_enabled)
 		intel_panel_actually_set_backlight(dev, level);
 }

 void intel_panel_disable_backlight(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;

 	dev_priv->backlight_enabled = false;
 	intel_panel_actually_set_backlight(dev, 0);

 	if (INTEL_INFO(dev)->gen >= 4) {
 		uint32_t reg;

 		reg = HAS_PCH_SPLIT(dev) ? BLC_PWM_CPU_CTL2 : BLC_PWM_CTL2;

 		I915_WRITE(reg, I915_READ(reg) & ~BLM_PWM_ENABLE);
 	}
 }

 void intel_panel_enable_backlight(struct drm_device *dev,
 				  enum pipe pipe)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;

 	if (dev_priv->backlight_level == 0)
 		dev_priv->backlight_level = intel_panel_get_max_backlight(dev);

 	dev_priv->backlight_enabled = true;
 	intel_panel_actually_set_backlight(dev, dev_priv->backlight_level);

 	if (INTEL_INFO(dev)->gen >= 4) {
 		uint32_t reg, tmp;

 		reg = HAS_PCH_SPLIT(dev) ? BLC_PWM_CPU_CTL2 : BLC_PWM_CTL2;


 		tmp = I915_READ(reg);

 		/* Note that this can also get called through dpms changes. And
 		 * we don't track the backlight dpms state, hence check whether
 		 * we have to do anything first. */
 		if (tmp & BLM_PWM_ENABLE)
 			return;

 		if (dev_priv->num_pipe == 3)
 			tmp &= ~BLM_PIPE_SELECT_IVB;
 		else
 			tmp &= ~BLM_PIPE_SELECT;

 		tmp |= BLM_PIPE(pipe);
 		tmp &= ~BLM_PWM_ENABLE;

 		I915_WRITE(reg, tmp);
 		POSTING_READ(reg);
 		I915_WRITE(reg, tmp | BLM_PWM_ENABLE);
 	}
 }

 static void intel_panel_init_backlight(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;

 	dev_priv->backlight_level = intel_panel_get_backlight(dev);
 	dev_priv->backlight_enabled = dev_priv->backlight_level != 0;
 }

 enum drm_connector_status
 intel_panel_detect(struct drm_device *dev)
 {
 #if 0
 	struct drm_i915_private *dev_priv = dev->dev_private;
 #endif

 	if (i915_panel_ignore_lid)
 		return i915_panel_ignore_lid > 0 ?
 			connector_status_connected :
 			connector_status_disconnected;

 	/* opregion lid state on HP 2540p is wrong at boot up,
 	 * appears to be either the BIOS or Linux ACPI fault */
 #if 0
 	/* Assume that the BIOS does not lie through the OpRegion... */
 	if (dev_priv->opregion.lid_state)
 		return ioread32(dev_priv->opregion.lid_state) & 0x1 ?
 			connector_status_connected :
 			connector_status_disconnected;
 #endif

 	return connector_status_unknown;
 }

 #ifdef CONFIG_BACKLIGHT_CLASS_DEVICE
 static int intel_panel_update_status(struct backlight_device *bd)
 {
 	struct drm_device *dev = bl_get_data(bd);
 	intel_panel_set_backlight(dev, bd->props.brightness);
 	return 0;
 }

 static int intel_panel_get_brightness(struct backlight_device *bd)
 {
 	struct drm_device *dev = bl_get_data(bd);
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	return dev_priv->backlight_level;
 }

 static const struct backlight_ops intel_panel_bl_ops = {
 	.update_status = intel_panel_update_status,
 	.get_brightness = intel_panel_get_brightness,
 };

 int intel_panel_setup_backlight(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct backlight_properties props;
 	struct drm_connector *connector;

 	intel_panel_init_backlight(dev);

 	if (dev_priv->int_lvds_connector)
 		connector = dev_priv->int_lvds_connector;
 	else if (dev_priv->int_edp_connector)
 		connector = dev_priv->int_edp_connector;
 	else
 		return -ENODEV;

 	memset(&props, 0, sizeof(props));
 	props.type = BACKLIGHT_RAW;
 	props.max_brightness = intel_panel_get_max_backlight(dev);
 	dev_priv->backlight =
 		backlight_device_register("intel_backlight",
 					  &connector->kdev, dev,
 					  &intel_panel_bl_ops, &props);

 	if (IS_ERR(dev_priv->backlight)) {
 		DRM_ERROR("Failed to register backlight: %ld\n",
 			  PTR_ERR(dev_priv->backlight));
 		dev_priv->backlight = NULL;
 		return -ENODEV;
 	}
 	dev_priv->backlight->props.brightness = intel_panel_get_backlight(dev);
 	return 0;
 }

 void intel_panel_destroy_backlight(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	if (dev_priv->backlight)
 		backlight_device_unregister(dev_priv->backlight);
 }
 #else
 int intel_panel_setup_backlight(struct drm_device *dev)
 {
 	intel_panel_init_backlight(dev);
 	return 0;
 }

 void intel_panel_destroy_backlight(struct drm_device *dev)
 {
 	return;
 }
 #endif
	/*
	* Copyright © 2006-2010 Intel Corporation
	* Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
	*
	* 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>
	* Dave Airlie <airlied@linux.ie>
	* Jesse Barnes <jesse.barnes@intel.com>
	* Chris Wilson <chris@chris-wilson.co.uk>
	*/

	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

	#include <linux/moduleparam.h>
	#include "intel_drv.h"

	#define PCI_LBPC 0xf4 /* legacy/combination backlight modes */

	void
	intel_fixed_panel_mode(struct drm_display_mode *fixed_mode,
	struct drm_display_mode *adjusted_mode)
	{
	adjusted_mode->hdisplay = fixed_mode->hdisplay;
	adjusted_mode->hsync_start = fixed_mode->hsync_start;
	adjusted_mode->hsync_end = fixed_mode->hsync_end;
	adjusted_mode->htotal = fixed_mode->htotal;

	adjusted_mode->vdisplay = fixed_mode->vdisplay;
	adjusted_mode->vsync_start = fixed_mode->vsync_start;
	adjusted_mode->vsync_end = fixed_mode->vsync_end;
	adjusted_mode->vtotal = fixed_mode->vtotal;

	adjusted_mode->clock = fixed_mode->clock;
	}

	/* adjusted_mode has been preset to be the panel's fixed mode */
	void
	intel_pch_panel_fitting(struct drm_device *dev,
	int fitting_mode,
	const struct drm_display_mode *mode,
	struct drm_display_mode *adjusted_mode)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;
	int x, y, width, height;

	x = y = width = height = 0;

	/* Native modes don't need fitting */
	if (adjusted_mode->hdisplay == mode->hdisplay &&
	adjusted_mode->vdisplay == mode->vdisplay)
	goto done;

	switch (fitting_mode) {
	case DRM_MODE_SCALE_CENTER:
	width = mode->hdisplay;
	height = mode->vdisplay;
	x = (adjusted_mode->hdisplay - width + 1)/2;
	y = (adjusted_mode->vdisplay - height + 1)/2;
	break;

	case DRM_MODE_SCALE_ASPECT:
	/* Scale but preserve the aspect ratio */
	{
	u32 scaled_width = adjusted_mode->hdisplay * mode->vdisplay;
	u32 scaled_height = mode->hdisplay * adjusted_mode->vdisplay;
	if (scaled_width > scaled_height) { /* pillar */
	width = scaled_height / mode->vdisplay;
	if (width & 1)
	width++;
	x = (adjusted_mode->hdisplay - width + 1) / 2;
	y = 0;
	height = adjusted_mode->vdisplay;
	} else if (scaled_width < scaled_height) { /* letter */
	height = scaled_width / mode->hdisplay;
	if (height & 1)
	height++;
	y = (adjusted_mode->vdisplay - height + 1) / 2;
	x = 0;
	width = adjusted_mode->hdisplay;
	} else {
	x = y = 0;
	width = adjusted_mode->hdisplay;
	height = adjusted_mode->vdisplay;
	}
	}
	break;

	default:
	case DRM_MODE_SCALE_FULLSCREEN:
	x = y = 0;
	width = adjusted_mode->hdisplay;
	height = adjusted_mode->vdisplay;
	break;
	}

	done:
	dev_priv->pch_pf_pos = (x << 16) \| y;
	dev_priv->pch_pf_size = (width << 16) \| height;
	}

	static int is_backlight_combination_mode(struct drm_device *dev)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;

	if (INTEL_INFO(dev)->gen >= 4)
	return I915_READ(BLC_PWM_CTL2) & BLM_COMBINATION_MODE;

	if (IS_GEN2(dev))
	return I915_READ(BLC_PWM_CTL) & BLM_LEGACY_MODE;

	return 0;
	}

	static u32 i915_read_blc_pwm_ctl(struct drm_i915_private *dev_priv)
	{
	u32 val;

	/* Restore the CTL value if it lost, e.g. GPU reset */

	if (HAS_PCH_SPLIT(dev_priv->dev)) {
	val = I915_READ(BLC_PWM_PCH_CTL2);
	if (dev_priv->saveBLC_PWM_CTL2 == 0) {
	dev_priv->saveBLC_PWM_CTL2 = val;
	} else if (val == 0) {
	I915_WRITE(BLC_PWM_PCH_CTL2,
	dev_priv->saveBLC_PWM_CTL2);
	val = dev_priv->saveBLC_PWM_CTL2;
	}
	} else {
	val = I915_READ(BLC_PWM_CTL);
	if (dev_priv->saveBLC_PWM_CTL == 0) {
	dev_priv->saveBLC_PWM_CTL = val;
	dev_priv->saveBLC_PWM_CTL2 = I915_READ(BLC_PWM_CTL2);
	} else if (val == 0) {
	I915_WRITE(BLC_PWM_CTL,
	dev_priv->saveBLC_PWM_CTL);
	I915_WRITE(BLC_PWM_CTL2,
	dev_priv->saveBLC_PWM_CTL2);
	val = dev_priv->saveBLC_PWM_CTL;
	}
	}

	return val;
	}

	u32 intel_panel_get_max_backlight(struct drm_device *dev)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;
	u32 max;

	max = i915_read_blc_pwm_ctl(dev_priv);
	if (max == 0) {
	/* XXX add code here to query mode clock or hardware clock
	* and program max PWM appropriately.
	*/
	pr_warn_once("fixme: max PWM is zero\n");
	return 1;
	}

	if (HAS_PCH_SPLIT(dev)) {
	max >>= 16;
	} else {
	if (INTEL_INFO(dev)->gen < 4)
	max >>= 17;
	else
	max >>= 16;

	if (is_backlight_combination_mode(dev))
	max *= 0xff;
	}

	DRM_DEBUG_DRIVER("max backlight PWM = %d\n", max);
	return max;
	}

	static int i915_panel_invert_brightness;
	MODULE_PARM_DESC(invert_brightness, "Invert backlight brightness "
	"(-1 force normal, 0 machine defaults, 1 force inversion), please "
	"report PCI device ID, subsystem vendor and subsystem device ID "
	"to dri-devel@lists.freedesktop.org, if your machine needs it. "
	"It will then be included in an upcoming module version.");
	module_param_named(invert_brightness, i915_panel_invert_brightness, int, 0600);
	static u32 intel_panel_compute_brightness(struct drm_device *dev, u32 val)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;

	if (i915_panel_invert_brightness < 0)
	return val;

	if (i915_panel_invert_brightness > 0 \|\|
	dev_priv->quirks & QUIRK_INVERT_BRIGHTNESS)
	return intel_panel_get_max_backlight(dev) - val;

	return val;
	}

	u32 intel_panel_get_backlight(struct drm_device *dev)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;
	u32 val;

	if (HAS_PCH_SPLIT(dev)) {
	val = I915_READ(BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
	} else {
	val = I915_READ(BLC_PWM_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
	if (INTEL_INFO(dev)->gen < 4)
	val >>= 1;

	if (is_backlight_combination_mode(dev)) {
	u8 lbpc;

	pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc);
	val *= lbpc;
	}
	}

	val = intel_panel_compute_brightness(dev, val);
	DRM_DEBUG_DRIVER("get backlight PWM = %d\n", val);
	return val;
	}

	static void intel_pch_panel_set_backlight(struct drm_device *dev, u32 level)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;
	u32 val = I915_READ(BLC_PWM_CPU_CTL) & ~BACKLIGHT_DUTY_CYCLE_MASK;
	I915_WRITE(BLC_PWM_CPU_CTL, val \| level);
	}

	static void intel_panel_actually_set_backlight(struct drm_device *dev, u32 level)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;
	u32 tmp;

	DRM_DEBUG_DRIVER("set backlight PWM = %d\n", level);
	level = intel_panel_compute_brightness(dev, level);

	if (HAS_PCH_SPLIT(dev))
	return intel_pch_panel_set_backlight(dev, level);

	if (is_backlight_combination_mode(dev)) {
	u32 max = intel_panel_get_max_backlight(dev);
	u8 lbpc;

	lbpc = level * 0xfe / max + 1;
	level /= lbpc;
	pci_write_config_byte(dev->pdev, PCI_LBPC, lbpc);
	}

	tmp = I915_READ(BLC_PWM_CTL);
	if (INTEL_INFO(dev)->gen < 4)
	level <<= 1;
	tmp &= ~BACKLIGHT_DUTY_CYCLE_MASK;
	I915_WRITE(BLC_PWM_CTL, tmp \| level);
	}

	void intel_panel_set_backlight(struct drm_device *dev, u32 level)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;

	dev_priv->backlight_level = level;
	if (dev_priv->backlight_enabled)
	intel_panel_actually_set_backlight(dev, level);
	}

	void intel_panel_disable_backlight(struct drm_device *dev)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;

	dev_priv->backlight_enabled = false;
	intel_panel_actually_set_backlight(dev, 0);

	if (INTEL_INFO(dev)->gen >= 4) {
	uint32_t reg;

	reg = HAS_PCH_SPLIT(dev) ? BLC_PWM_CPU_CTL2 : BLC_PWM_CTL2;

	I915_WRITE(reg, I915_READ(reg) & ~BLM_PWM_ENABLE);
	}
	}

	void intel_panel_enable_backlight(struct drm_device *dev,
	enum pipe pipe)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;

	if (dev_priv->backlight_level == 0)
	dev_priv->backlight_level = intel_panel_get_max_backlight(dev);

	dev_priv->backlight_enabled = true;
	intel_panel_actually_set_backlight(dev, dev_priv->backlight_level);

	if (INTEL_INFO(dev)->gen >= 4) {
	uint32_t reg, tmp;

	reg = HAS_PCH_SPLIT(dev) ? BLC_PWM_CPU_CTL2 : BLC_PWM_CTL2;


	tmp = I915_READ(reg);

	/* Note that this can also get called through dpms changes. And
	* we don't track the backlight dpms state, hence check whether
	* we have to do anything first. */
	if (tmp & BLM_PWM_ENABLE)
	return;

	if (dev_priv->num_pipe == 3)
	tmp &= ~BLM_PIPE_SELECT_IVB;
	else
	tmp &= ~BLM_PIPE_SELECT;

	tmp \|= BLM_PIPE(pipe);
	tmp &= ~BLM_PWM_ENABLE;

	I915_WRITE(reg, tmp);
	POSTING_READ(reg);
	I915_WRITE(reg, tmp \| BLM_PWM_ENABLE);
	}
	}

	static void intel_panel_init_backlight(struct drm_device *dev)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;

	dev_priv->backlight_level = intel_panel_get_backlight(dev);
	dev_priv->backlight_enabled = dev_priv->backlight_level != 0;
	}

	enum drm_connector_status
	intel_panel_detect(struct drm_device *dev)
	{
	#if 0
	struct drm_i915_private *dev_priv = dev->dev_private;
	#endif

	if (i915_panel_ignore_lid)
	return i915_panel_ignore_lid > 0 ?
	connector_status_connected :
	connector_status_disconnected;

	/* opregion lid state on HP 2540p is wrong at boot up,
	* appears to be either the BIOS or Linux ACPI fault */
	#if 0
	/* Assume that the BIOS does not lie through the OpRegion... */
	if (dev_priv->opregion.lid_state)
	return ioread32(dev_priv->opregion.lid_state) & 0x1 ?
	connector_status_connected :
	connector_status_disconnected;
	#endif

	return connector_status_unknown;
	}

	#ifdef CONFIG_BACKLIGHT_CLASS_DEVICE
	static int intel_panel_update_status(struct backlight_device *bd)
	{
	struct drm_device *dev = bl_get_data(bd);
	intel_panel_set_backlight(dev, bd->props.brightness);
	return 0;
	}

	static int intel_panel_get_brightness(struct backlight_device *bd)
	{
	struct drm_device *dev = bl_get_data(bd);
	struct drm_i915_private *dev_priv = dev->dev_private;
	return dev_priv->backlight_level;
	}

	static const struct backlight_ops intel_panel_bl_ops = {
	.update_status = intel_panel_update_status,
	.get_brightness = intel_panel_get_brightness,
	};

	int intel_panel_setup_backlight(struct drm_device *dev)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct backlight_properties props;
	struct drm_connector *connector;

	intel_panel_init_backlight(dev);

	if (dev_priv->int_lvds_connector)
	connector = dev_priv->int_lvds_connector;
	else if (dev_priv->int_edp_connector)
	connector = dev_priv->int_edp_connector;
	else
	return -ENODEV;

	memset(&props, 0, sizeof(props));
	props.type = BACKLIGHT_RAW;
	props.max_brightness = intel_panel_get_max_backlight(dev);
	dev_priv->backlight =
	backlight_device_register("intel_backlight",
	&connector->kdev, dev,
	&intel_panel_bl_ops, &props);

	if (IS_ERR(dev_priv->backlight)) {
	DRM_ERROR("Failed to register backlight: %ld\n",
	PTR_ERR(dev_priv->backlight));
	dev_priv->backlight = NULL;
	return -ENODEV;
	}
	dev_priv->backlight->props.brightness = intel_panel_get_backlight(dev);
	return 0;
	}

	void intel_panel_destroy_backlight(struct drm_device *dev)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;
	if (dev_priv->backlight)
	backlight_device_unregister(dev_priv->backlight);
	}
	#else
	int intel_panel_setup_backlight(struct drm_device *dev)
	{
	intel_panel_init_backlight(dev);
	return 0;
	}

	void intel_panel_destroy_backlight(struct drm_device *dev)
	{
	return;
	}
	#endif