1 files changed, 383 insertions, 142 deletions

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index e2ab3f6ed022..a24df35e11e7 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -105,59 +105,55 @@ intel_pch_panel_fitting(struct intel_crtc *intel_crtc,
 			struct intel_crtc_state *pipe_config,
 			int fitting_mode)
 {
-	struct drm_display_mode *adjusted_mode;
-	int x, y, width, height;
-
-	adjusted_mode = &pipe_config->base.adjusted_mode;
-
-	x = y = width = height = 0;
+	const struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
+	int x = 0, y = 0, width = 0, height = 0;
 
 	/* Native modes don't need fitting */
-	if (adjusted_mode->hdisplay == pipe_config->pipe_src_w &&
-	    adjusted_mode->vdisplay == pipe_config->pipe_src_h)
+	if (adjusted_mode->crtc_hdisplay == pipe_config->pipe_src_w &&
+	    adjusted_mode->crtc_vdisplay == pipe_config->pipe_src_h)
 		goto done;
 
 	switch (fitting_mode) {
 	case DRM_MODE_SCALE_CENTER:
 		width = pipe_config->pipe_src_w;
 		height = pipe_config->pipe_src_h;
-		x = (adjusted_mode->hdisplay - width + 1)/2;
-		y = (adjusted_mode->vdisplay - height + 1)/2;
+		x = (adjusted_mode->crtc_hdisplay - width + 1)/2;
+		y = (adjusted_mode->crtc_vdisplay - height + 1)/2;
 		break;
 
 	case DRM_MODE_SCALE_ASPECT:
 		/* Scale but preserve the aspect ratio */
 		{
-			u32 scaled_width = adjusted_mode->hdisplay
+			u32 scaled_width = adjusted_mode->crtc_hdisplay
 				* pipe_config->pipe_src_h;
 			u32 scaled_height = pipe_config->pipe_src_w
-				* adjusted_mode->vdisplay;
+				* adjusted_mode->crtc_vdisplay;
 			if (scaled_width > scaled_height) { /* pillar */
 				width = scaled_height / pipe_config->pipe_src_h;
 				if (width & 1)
 					width++;
-				x = (adjusted_mode->hdisplay - width + 1) / 2;
+				x = (adjusted_mode->crtc_hdisplay - width + 1) / 2;
 				y = 0;
-				height = adjusted_mode->vdisplay;
+				height = adjusted_mode->crtc_vdisplay;
 			} else if (scaled_width < scaled_height) { /* letter */
 				height = scaled_width / pipe_config->pipe_src_w;
 				if (height & 1)
 				    height++;
-				y = (adjusted_mode->vdisplay - height + 1) / 2;
+				y = (adjusted_mode->crtc_vdisplay - height + 1) / 2;
 				x = 0;
-				width = adjusted_mode->hdisplay;
+				width = adjusted_mode->crtc_hdisplay;
 			} else {
 				x = y = 0;
-				width = adjusted_mode->hdisplay;
-				height = adjusted_mode->vdisplay;
+				width = adjusted_mode->crtc_hdisplay;
+				height = adjusted_mode->crtc_vdisplay;
 			}
 		}
 		break;
 
 	case DRM_MODE_SCALE_FULLSCREEN:
 		x = y = 0;
-		width = adjusted_mode->hdisplay;
-		height = adjusted_mode->vdisplay;
+		width = adjusted_mode->crtc_hdisplay;
+		height = adjusted_mode->crtc_vdisplay;
 		break;
 
 	default:
@@ -172,46 +168,46 @@ done:
 }
 
 static void
-centre_horizontally(struct drm_display_mode *mode,
+centre_horizontally(struct drm_display_mode *adjusted_mode,
 		    int width)
 {
 	u32 border, sync_pos, blank_width, sync_width;
 
 	/* keep the hsync and hblank widths constant */
-	sync_width = mode->crtc_hsync_end - mode->crtc_hsync_start;
-	blank_width = mode->crtc_hblank_end - mode->crtc_hblank_start;
+	sync_width = adjusted_mode->crtc_hsync_end - adjusted_mode->crtc_hsync_start;
+	blank_width = adjusted_mode->crtc_hblank_end - adjusted_mode->crtc_hblank_start;
 	sync_pos = (blank_width - sync_width + 1) / 2;
 
-	border = (mode->hdisplay - width + 1) / 2;
+	border = (adjusted_mode->crtc_hdisplay - width + 1) / 2;
 	border += border & 1; /* make the border even */
 
-	mode->crtc_hdisplay = width;
-	mode->crtc_hblank_start = width + border;
-	mode->crtc_hblank_end = mode->crtc_hblank_start + blank_width;
+	adjusted_mode->crtc_hdisplay = width;
+	adjusted_mode->crtc_hblank_start = width + border;
+	adjusted_mode->crtc_hblank_end = adjusted_mode->crtc_hblank_start + blank_width;
 
-	mode->crtc_hsync_start = mode->crtc_hblank_start + sync_pos;
-	mode->crtc_hsync_end = mode->crtc_hsync_start + sync_width;
+	adjusted_mode->crtc_hsync_start = adjusted_mode->crtc_hblank_start + sync_pos;
+	adjusted_mode->crtc_hsync_end = adjusted_mode->crtc_hsync_start + sync_width;
 }
 
 static void
-centre_vertically(struct drm_display_mode *mode,
+centre_vertically(struct drm_display_mode *adjusted_mode,
 		  int height)
 {
 	u32 border, sync_pos, blank_width, sync_width;
 
 	/* keep the vsync and vblank widths constant */
-	sync_width = mode->crtc_vsync_end - mode->crtc_vsync_start;
-	blank_width = mode->crtc_vblank_end - mode->crtc_vblank_start;
+	sync_width = adjusted_mode->crtc_vsync_end - adjusted_mode->crtc_vsync_start;
+	blank_width = adjusted_mode->crtc_vblank_end - adjusted_mode->crtc_vblank_start;
 	sync_pos = (blank_width - sync_width + 1) / 2;
 
-	border = (mode->vdisplay - height + 1) / 2;
+	border = (adjusted_mode->crtc_vdisplay - height + 1) / 2;
 
-	mode->crtc_vdisplay = height;
-	mode->crtc_vblank_start = height + border;
-	mode->crtc_vblank_end = mode->crtc_vblank_start + blank_width;
+	adjusted_mode->crtc_vdisplay = height;
+	adjusted_mode->crtc_vblank_start = height + border;
+	adjusted_mode->crtc_vblank_end = adjusted_mode->crtc_vblank_start + blank_width;
 
-	mode->crtc_vsync_start = mode->crtc_vblank_start + sync_pos;
-	mode->crtc_vsync_end = mode->crtc_vsync_start + sync_width;
+	adjusted_mode->crtc_vsync_start = adjusted_mode->crtc_vblank_start + sync_pos;
+	adjusted_mode->crtc_vsync_end = adjusted_mode->crtc_vsync_start + sync_width;
 }
 
 static inline u32 panel_fitter_scaling(u32 source, u32 target)
@@ -230,11 +226,11 @@ static inline u32 panel_fitter_scaling(u32 source, u32 target)
 static void i965_scale_aspect(struct intel_crtc_state *pipe_config,
 			      u32 *pfit_control)
 {
-	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
-	u32 scaled_width = adjusted_mode->hdisplay *
+	const struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
+	u32 scaled_width = adjusted_mode->crtc_hdisplay *
 		pipe_config->pipe_src_h;
 	u32 scaled_height = pipe_config->pipe_src_w *
-		adjusted_mode->vdisplay;
+		adjusted_mode->crtc_vdisplay;
 
 	/* 965+ is easy, it does everything in hw */
 	if (scaled_width > scaled_height)
@@ -243,7 +239,7 @@ static void i965_scale_aspect(struct intel_crtc_state *pipe_config,
 	else if (scaled_width < scaled_height)
 		*pfit_control |= PFIT_ENABLE |
 			PFIT_SCALING_LETTER;
-	else if (adjusted_mode->hdisplay != pipe_config->pipe_src_w)
+	else if (adjusted_mode->crtc_hdisplay != pipe_config->pipe_src_w)
 		*pfit_control |= PFIT_ENABLE | PFIT_SCALING_AUTO;
 }
 
@@ -252,10 +248,10 @@ static void i9xx_scale_aspect(struct intel_crtc_state *pipe_config,
 			      u32 *border)
 {
 	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
-	u32 scaled_width = adjusted_mode->hdisplay *
+	u32 scaled_width = adjusted_mode->crtc_hdisplay *
 		pipe_config->pipe_src_h;
 	u32 scaled_height = pipe_config->pipe_src_w *
-		adjusted_mode->vdisplay;
+		adjusted_mode->crtc_vdisplay;
 	u32 bits;
 
 	/*
@@ -269,9 +265,9 @@ static void i9xx_scale_aspect(struct intel_crtc_state *pipe_config,
 				    pipe_config->pipe_src_h);
 
 		*border = LVDS_BORDER_ENABLE;
-		if (pipe_config->pipe_src_h != adjusted_mode->vdisplay) {
+		if (pipe_config->pipe_src_h != adjusted_mode->crtc_vdisplay) {
 			bits = panel_fitter_scaling(pipe_config->pipe_src_h,
-						    adjusted_mode->vdisplay);
+						    adjusted_mode->crtc_vdisplay);
 
 			*pfit_pgm_ratios |= (bits << PFIT_HORIZ_SCALE_SHIFT |
 					     bits << PFIT_VERT_SCALE_SHIFT);
@@ -285,9 +281,9 @@ static void i9xx_scale_aspect(struct intel_crtc_state *pipe_config,
 				  pipe_config->pipe_src_w);
 
 		*border = LVDS_BORDER_ENABLE;
-		if (pipe_config->pipe_src_w != adjusted_mode->hdisplay) {
+		if (pipe_config->pipe_src_w != adjusted_mode->crtc_hdisplay) {
 			bits = panel_fitter_scaling(pipe_config->pipe_src_w,
-						    adjusted_mode->hdisplay);
+						    adjusted_mode->crtc_hdisplay);
 
 			*pfit_pgm_ratios |= (bits << PFIT_HORIZ_SCALE_SHIFT |
 					     bits << PFIT_VERT_SCALE_SHIFT);
@@ -310,13 +306,11 @@ void intel_gmch_panel_fitting(struct intel_crtc *intel_crtc,
 {
 	struct drm_device *dev = intel_crtc->base.dev;
 	u32 pfit_control = 0, pfit_pgm_ratios = 0, border = 0;
-	struct drm_display_mode *adjusted_mode;
-
-	adjusted_mode = &pipe_config->base.adjusted_mode;
+	struct drm_display_mode *adjusted_mode = &pipe_config->base.adjusted_mode;
 
 	/* Native modes don't need fitting */
-	if (adjusted_mode->hdisplay == pipe_config->pipe_src_w &&
-	    adjusted_mode->vdisplay == pipe_config->pipe_src_h)
+	if (adjusted_mode->crtc_hdisplay == pipe_config->pipe_src_w &&
+	    adjusted_mode->crtc_vdisplay == pipe_config->pipe_src_h)
 		goto out;
 
 	switch (fitting_mode) {
@@ -342,8 +336,8 @@ void intel_gmch_panel_fitting(struct intel_crtc *intel_crtc,
 		 * Full scaling, even if it changes the aspect ratio.
 		 * Fortunately this is all done for us in hw.
 		 */
-		if (pipe_config->pipe_src_h != adjusted_mode->vdisplay ||
-		    pipe_config->pipe_src_w != adjusted_mode->hdisplay) {
+		if (pipe_config->pipe_src_h != adjusted_mode->crtc_vdisplay ||
+		    pipe_config->pipe_src_w != adjusted_mode->crtc_hdisplay) {
 			pfit_control |= PFIT_ENABLE;
 			if (INTEL_INFO(dev)->gen >= 4)
 				pfit_control |= PFIT_SCALING_AUTO;
@@ -387,7 +381,7 @@ intel_panel_detect(struct drm_device *dev)
 
 	/* Assume that the BIOS does not lie through the OpRegion... */
 	if (!i915.panel_ignore_lid && dev_priv->opregion.lid_state) {
-		return ioread32(dev_priv->opregion.lid_state) & 0x1 ?
+		return *dev_priv->opregion.lid_state & 0x1 ?
 			connector_status_connected :
 			connector_status_disconnected;
 	}
@@ -484,7 +478,7 @@ static u32 intel_panel_compute_brightness(struct intel_connector *connector,
 	return val;
 }
 
-static u32 bdw_get_backlight(struct intel_connector *connector)
+static u32 lpt_get_backlight(struct intel_connector *connector)
 {
 	struct drm_device *dev = connector->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -542,9 +536,10 @@ static u32 vlv_get_backlight(struct intel_connector *connector)
 static u32 bxt_get_backlight(struct intel_connector *connector)
 {
 	struct drm_device *dev = connector->base.dev;
+	struct intel_panel *panel = &connector->panel;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
-	return I915_READ(BXT_BLC_PWM_DUTY1);
+	return I915_READ(BXT_BLC_PWM_DUTY(panel->backlight.controller));
 }
 
 static u32 pwm_get_backlight(struct intel_connector *connector)
@@ -566,7 +561,7 @@ static u32 intel_panel_get_backlight(struct intel_connector *connector)
 	mutex_lock(&dev_priv->backlight_lock);
 
 	if (panel->backlight.enabled) {
-		val = dev_priv->display.get_backlight(connector);
+		val = panel->backlight.get(connector);
 		val = intel_panel_compute_brightness(connector, val);
 	}
 
@@ -576,7 +571,7 @@ static u32 intel_panel_get_backlight(struct intel_connector *connector)
 	return val;
 }
 
-static void bdw_set_backlight(struct intel_connector *connector, u32 level)
+static void lpt_set_backlight(struct intel_connector *connector, u32 level)
 {
 	struct drm_device *dev = connector->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -640,8 +635,9 @@ static void bxt_set_backlight(struct intel_connector *connector, u32 level)
 {
 	struct drm_device *dev = connector->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_panel *panel = &connector->panel;
 
-	I915_WRITE(BXT_BLC_PWM_DUTY1, level);
+	I915_WRITE(BXT_BLC_PWM_DUTY(panel->backlight.controller), level);
 }
 
 static void pwm_set_backlight(struct intel_connector *connector, u32 level)
@@ -655,13 +651,12 @@ static void pwm_set_backlight(struct intel_connector *connector, u32 level)
 static void
 intel_panel_actually_set_backlight(struct intel_connector *connector, u32 level)
 {
-	struct drm_device *dev = connector->base.dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_panel *panel = &connector->panel;
 
 	DRM_DEBUG_DRIVER("set backlight PWM = %d\n", level);
 
 	level = intel_panel_compute_brightness(connector, level);
-	dev_priv->display.set_backlight(connector, level);
+	panel->backlight.set(connector, level);
 }
 
 /* set backlight brightness to level in range [0..max], scaling wrt hw min */
@@ -729,6 +724,32 @@ void intel_panel_set_backlight_acpi(struct intel_connector *connector,
 	mutex_unlock(&dev_priv->backlight_lock);
 }
 
+static void lpt_disable_backlight(struct intel_connector *connector)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 tmp;
+
+	intel_panel_actually_set_backlight(connector, 0);
+
+	/*
+	 * Although we don't support or enable CPU PWM with LPT/SPT based
+	 * systems, it may have been enabled prior to loading the
+	 * driver. Disable to avoid warnings on LCPLL disable.
+	 *
+	 * This needs rework if we need to add support for CPU PWM on PCH split
+	 * platforms.
+	 */
+	tmp = I915_READ(BLC_PWM_CPU_CTL2);
+	if (tmp & BLM_PWM_ENABLE) {
+		DRM_DEBUG_KMS("cpu backlight was enabled, disabling\n");
+		I915_WRITE(BLC_PWM_CPU_CTL2, tmp & ~BLM_PWM_ENABLE);
+	}
+
+	tmp = I915_READ(BLC_PWM_PCH_CTL1);
+	I915_WRITE(BLC_PWM_PCH_CTL1, tmp & ~BLM_PCH_PWM_ENABLE);
+}
+
 static void pch_disable_backlight(struct intel_connector *connector)
 {
 	struct drm_device *dev = connector->base.dev;
@@ -781,12 +802,20 @@ static void bxt_disable_backlight(struct intel_connector *connector)
 {
 	struct drm_device *dev = connector->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	u32 tmp;
+	struct intel_panel *panel = &connector->panel;
+	u32 tmp, val;
 
 	intel_panel_actually_set_backlight(connector, 0);
 
-	tmp = I915_READ(BXT_BLC_PWM_CTL1);
-	I915_WRITE(BXT_BLC_PWM_CTL1, tmp & ~BXT_BLC_PWM_ENABLE);
+	tmp = I915_READ(BXT_BLC_PWM_CTL(panel->backlight.controller));
+	I915_WRITE(BXT_BLC_PWM_CTL(panel->backlight.controller),
+			tmp & ~BXT_BLC_PWM_ENABLE);
+
+	if (panel->backlight.controller == 1) {
+		val = I915_READ(UTIL_PIN_CTL);
+		val &= ~UTIL_PIN_ENABLE;
+		I915_WRITE(UTIL_PIN_CTL, val);
+	}
 }
 
 static void pwm_disable_backlight(struct intel_connector *connector)
@@ -809,7 +838,7 @@ void intel_panel_disable_backlight(struct intel_connector *connector)
 		return;
 
 	/*
-	 * Do not disable backlight on the vgaswitcheroo path. When switching
+	 * Do not disable backlight on the vga_switcheroo path. When switching
 	 * away from i915, the other client may depend on i915 to handle the
 	 * backlight. This will leave the backlight on unnecessarily when
 	 * another client is not activated.
@@ -824,12 +853,12 @@ void intel_panel_disable_backlight(struct intel_connector *connector)
 	if (panel->backlight.device)
 		panel->backlight.device->props.power = FB_BLANK_POWERDOWN;
 	panel->backlight.enabled = false;
-	dev_priv->display.disable_backlight(connector);
+	panel->backlight.disable(connector);
 
 	mutex_unlock(&dev_priv->backlight_lock);
 }
 
-static void bdw_enable_backlight(struct intel_connector *connector)
+static void lpt_enable_backlight(struct intel_connector *connector)
 {
 	struct drm_device *dev = connector->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -1018,16 +1047,38 @@ static void bxt_enable_backlight(struct intel_connector *connector)
 	struct drm_device *dev = connector->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_panel *panel = &connector->panel;
-	u32 pwm_ctl;
+	enum pipe pipe = intel_get_pipe_from_connector(connector);
+	u32 pwm_ctl, val;
+
+	/* To use 2nd set of backlight registers, utility pin has to be
+	 * enabled with PWM mode.
+	 * The field should only be changed when the utility pin is disabled
+	 */
+	if (panel->backlight.controller == 1) {
+		val = I915_READ(UTIL_PIN_CTL);
+		if (val & UTIL_PIN_ENABLE) {
+			DRM_DEBUG_KMS("util pin already enabled\n");
+			val &= ~UTIL_PIN_ENABLE;
+			I915_WRITE(UTIL_PIN_CTL, val);
+		}
 
-	pwm_ctl = I915_READ(BXT_BLC_PWM_CTL1);
+		val = 0;
+		if (panel->backlight.util_pin_active_low)
+			val |= UTIL_PIN_POLARITY;
+		I915_WRITE(UTIL_PIN_CTL, val | UTIL_PIN_PIPE(pipe) |
+				UTIL_PIN_MODE_PWM | UTIL_PIN_ENABLE);
+	}
+
+	pwm_ctl = I915_READ(BXT_BLC_PWM_CTL(panel->backlight.controller));
 	if (pwm_ctl & BXT_BLC_PWM_ENABLE) {
 		DRM_DEBUG_KMS("backlight already enabled\n");
 		pwm_ctl &= ~BXT_BLC_PWM_ENABLE;
-		I915_WRITE(BXT_BLC_PWM_CTL1, pwm_ctl);
+		I915_WRITE(BXT_BLC_PWM_CTL(panel->backlight.controller),
+				pwm_ctl);
 	}
 
-	I915_WRITE(BXT_BLC_PWM_FREQ1, panel->backlight.max);
+	I915_WRITE(BXT_BLC_PWM_FREQ(panel->backlight.controller),
+			panel->backlight.max);
 
 	intel_panel_actually_set_backlight(connector, panel->backlight.level);
 
@@ -1035,9 +1086,10 @@ static void bxt_enable_backlight(struct intel_connector *connector)
 	if (panel->backlight.active_low_pwm)
 		pwm_ctl |= BXT_BLC_PWM_POLARITY;
 
-	I915_WRITE(BXT_BLC_PWM_CTL1, pwm_ctl);
-	POSTING_READ(BXT_BLC_PWM_CTL1);
-	I915_WRITE(BXT_BLC_PWM_CTL1, pwm_ctl | BXT_BLC_PWM_ENABLE);
+	I915_WRITE(BXT_BLC_PWM_CTL(panel->backlight.controller), pwm_ctl);
+	POSTING_READ(BXT_BLC_PWM_CTL(panel->backlight.controller));
+	I915_WRITE(BXT_BLC_PWM_CTL(panel->backlight.controller),
+			pwm_ctl | BXT_BLC_PWM_ENABLE);
 }
 
 static void pwm_enable_backlight(struct intel_connector *connector)
@@ -1073,7 +1125,7 @@ void intel_panel_enable_backlight(struct intel_connector *connector)
 						 panel->backlight.device->props.max_brightness);
 	}
 
-	dev_priv->display.enable_backlight(connector);
+	panel->backlight.enable(connector);
 	panel->backlight.enabled = true;
 	if (panel->backlight.device)
 		panel->backlight.device->props.power = FB_BLANK_UNBLANK;
@@ -1101,10 +1153,10 @@ static int intel_backlight_device_update_status(struct backlight_device *bd)
 	 * callback needs to take this into account.
 	 */
 	if (panel->backlight.enabled) {
-		if (panel->backlight_power) {
+		if (panel->backlight.power) {
 			bool enable = bd->props.power == FB_BLANK_UNBLANK &&
 				bd->props.brightness != 0;
-			panel->backlight_power(connector, enable);
+			panel->backlight.power(connector, enable);
 		}
 	} else {
 		bd->props.power = FB_BLANK_POWERDOWN;
@@ -1212,10 +1264,150 @@ static void intel_backlight_device_unregister(struct intel_connector *connector)
 #endif /* CONFIG_BACKLIGHT_CLASS_DEVICE */
 
 /*
- * Note: The setup hooks can't assume pipe is set!
+ * SPT: This value represents the period of the PWM stream in clock periods
+ * multiplied by 16 (default increment) or 128 (alternate increment selected in
+ * SCHICKEN_1 bit 0). PWM clock is 24 MHz.
+ */
+static u32 spt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 mul, clock;
+
+	if (I915_READ(SOUTH_CHICKEN1) & SPT_PWM_GRANULARITY)
+		mul = 128;
+	else
+		mul = 16;
+
+	clock = MHz(24);
+
+	return clock / (pwm_freq_hz * mul);
+}
+
+/*
+ * LPT: This value represents the period of the PWM stream in clock periods
+ * multiplied by 128 (default increment) or 16 (alternate increment, selected in
+ * LPT SOUTH_CHICKEN2 register bit 5).
+ */
+static u32 lpt_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 mul, clock;
+
+	if (I915_READ(SOUTH_CHICKEN2) & LPT_PWM_GRANULARITY)
+		mul = 16;
+	else
+		mul = 128;
+
+	if (dev_priv->pch_id == INTEL_PCH_LPT_DEVICE_ID_TYPE)
+		clock = MHz(135); /* LPT:H */
+	else
+		clock = MHz(24); /* LPT:LP */
+
+	return clock / (pwm_freq_hz * mul);
+}
+
+/*
+ * ILK/SNB/IVB: This value represents the period of the PWM stream in PCH
+ * display raw clocks multiplied by 128.
+ */
+static u32 pch_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_device *dev = connector->base.dev;
+	int clock = MHz(intel_pch_rawclk(dev));
+
+	return clock / (pwm_freq_hz * 128);
+}
+
+/*
+ * Gen2: This field determines the number of time base events (display core
+ * clock frequency/32) in total for a complete cycle of modulated backlight
+ * control.
  *
- * XXX: Query mode clock or hardware clock and program PWM modulation frequency
- * appropriately when it's 0. Use VBT and/or sane defaults.
+ * Gen3: A time base event equals the display core clock ([DevPNV] HRAW clock)
+ * divided by 32.
+ */
+static u32 i9xx_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	int clock;
+
+	if (IS_PINEVIEW(dev))
+		clock = intel_hrawclk(dev);
+	else
+		clock = 1000 * dev_priv->display.get_display_clock_speed(dev);
+
+	return clock / (pwm_freq_hz * 32);
+}
+
+/*
+ * Gen4: This value represents the period of the PWM stream in display core
+ * clocks multiplied by 128.
+ */
+static u32 i965_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	int clock = 1000 * dev_priv->display.get_display_clock_speed(dev);
+
+	return clock / (pwm_freq_hz * 128);
+}
+
+/*
+ * VLV: This value represents the period of the PWM stream in display core
+ * clocks ([DevCTG] 200MHz HRAW clocks) multiplied by 128 or 25MHz S0IX clocks
+ * multiplied by 16. CHV uses a 19.2MHz S0IX clock.
+ */
+static u32 vlv_hz_to_pwm(struct intel_connector *connector, u32 pwm_freq_hz)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	int clock;
+
+	if ((I915_READ(CBR1_VLV) & CBR_PWM_CLOCK_MUX_SELECT) == 0) {
+		if (IS_CHERRYVIEW(dev))
+			return KHz(19200) / (pwm_freq_hz * 16);
+		else
+			return MHz(25) / (pwm_freq_hz * 16);
+	} else {
+		clock = intel_hrawclk(dev);
+		return MHz(clock) / (pwm_freq_hz * 128);
+	}
+}
+
+static u32 get_backlight_max_vbt(struct intel_connector *connector)
+{
+	struct drm_device *dev = connector->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_panel *panel = &connector->panel;
+	u16 pwm_freq_hz = dev_priv->vbt.backlight.pwm_freq_hz;
+	u32 pwm;
+
+	if (!pwm_freq_hz) {
+		DRM_DEBUG_KMS("backlight frequency not specified in VBT\n");
+		return 0;
+	}
+
+	if (!panel->backlight.hz_to_pwm) {
+		DRM_DEBUG_KMS("backlight frequency setting from VBT currently not supported on this platform\n");
+		return 0;
+	}
+
+	pwm = panel->backlight.hz_to_pwm(connector, pwm_freq_hz);
+	if (!pwm) {
+		DRM_DEBUG_KMS("backlight frequency conversion failed\n");
+		return 0;
+	}
+
+	DRM_DEBUG_KMS("backlight frequency %u Hz from VBT\n", pwm_freq_hz);
+
+	return pwm;
+}
+
+/*
+ * Note: The setup hooks can't assume pipe is set!
  */
 static u32 get_backlight_min_vbt(struct intel_connector *connector)
 {
@@ -1243,7 +1435,7 @@ static u32 get_backlight_min_vbt(struct intel_connector *connector)
 	return scale(min, 0, 255, 0, panel->backlight.max);
 }
 
-static int bdw_setup_backlight(struct intel_connector *connector, enum pipe unused)
+static int lpt_setup_backlight(struct intel_connector *connector, enum pipe unused)
 {
 	struct drm_device *dev = connector->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -1255,12 +1447,16 @@ static int bdw_setup_backlight(struct intel_connector *connector, enum pipe unus
 
 	pch_ctl2 = I915_READ(BLC_PWM_PCH_CTL2);
 	panel->backlight.max = pch_ctl2 >> 16;
+
+	if (!panel->backlight.max)
+		panel->backlight.max = get_backlight_max_vbt(connector);
+
 	if (!panel->backlight.max)
 		return -ENODEV;
 
 	panel->backlight.min = get_backlight_min_vbt(connector);
 
-	val = bdw_get_backlight(connector);
+	val = lpt_get_backlight(connector);
 	panel->backlight.level = intel_panel_compute_brightness(connector, val);
 
 	panel->backlight.enabled = (pch_ctl1 & BLM_PCH_PWM_ENABLE) &&
@@ -1281,6 +1477,10 @@ static int pch_setup_backlight(struct intel_connector *connector, enum pipe unus
 
 	pch_ctl2 = I915_READ(BLC_PWM_PCH_CTL2);
 	panel->backlight.max = pch_ctl2 >> 16;
+
+	if (!panel->backlight.max)
+		panel->backlight.max = get_backlight_max_vbt(connector);
+
 	if (!panel->backlight.max)
 		return -ENODEV;
 
@@ -1312,12 +1512,18 @@ static int i9xx_setup_backlight(struct intel_connector *connector, enum pipe unu
 		panel->backlight.active_low_pwm = ctl & BLM_POLARITY_PNV;
 
 	panel->backlight.max = ctl >> 17;
-	if (panel->backlight.combination_mode)
-		panel->backlight.max *= 0xff;
+
+	if (!panel->backlight.max) {
+		panel->backlight.max = get_backlight_max_vbt(connector);
+		panel->backlight.max >>= 1;
+	}
 
 	if (!panel->backlight.max)
 		return -ENODEV;
 
+	if (panel->backlight.combination_mode)
+		panel->backlight.max *= 0xff;
+
 	panel->backlight.min = get_backlight_min_vbt(connector);
 
 	val = i9xx_get_backlight(connector);
@@ -1341,12 +1547,16 @@ static int i965_setup_backlight(struct intel_connector *connector, enum pipe unu
 
 	ctl = I915_READ(BLC_PWM_CTL);
 	panel->backlight.max = ctl >> 16;
-	if (panel->backlight.combination_mode)
-		panel->backlight.max *= 0xff;
+
+	if (!panel->backlight.max)
+		panel->backlight.max = get_backlight_max_vbt(connector);
 
 	if (!panel->backlight.max)
 		return -ENODEV;
 
+	if (panel->backlight.combination_mode)
+		panel->backlight.max *= 0xff;
+
 	panel->backlight.min = get_backlight_min_vbt(connector);
 
 	val = i9xx_get_backlight(connector);
@@ -1363,21 +1573,8 @@ static int vlv_setup_backlight(struct intel_connector *connector, enum pipe pipe
 	struct drm_device *dev = connector->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_panel *panel = &connector->panel;
-	enum pipe p;
 	u32 ctl, ctl2, val;
 
-	for_each_pipe(dev_priv, p) {
-		u32 cur_val = I915_READ(VLV_BLC_PWM_CTL(p));
-
-		/* Skip if the modulation freq is already set */
-		if (cur_val & ~BACKLIGHT_DUTY_CYCLE_MASK)
-			continue;
-
-		cur_val &= BACKLIGHT_DUTY_CYCLE_MASK;
-		I915_WRITE(VLV_BLC_PWM_CTL(p), (0xf42 << 16) |
-			   cur_val);
-	}
-
 	if (WARN_ON(pipe != PIPE_A && pipe != PIPE_B))
 		return -ENODEV;
 
@@ -1386,6 +1583,10 @@ static int vlv_setup_backlight(struct intel_connector *connector, enum pipe pipe
 
 	ctl = I915_READ(VLV_BLC_PWM_CTL(pipe));
 	panel->backlight.max = ctl >> 16;
+
+	if (!panel->backlight.max)
+		panel->backlight.max = get_backlight_max_vbt(connector);
+
 	if (!panel->backlight.max)
 		return -ENODEV;
 
@@ -1408,10 +1609,32 @@ bxt_setup_backlight(struct intel_connector *connector, enum pipe unused)
 	struct intel_panel *panel = &connector->panel;
 	u32 pwm_ctl, val;
 
-	pwm_ctl = I915_READ(BXT_BLC_PWM_CTL1);
+	/*
+	 * For BXT hard coding the Backlight controller to 0.
+	 * TODO : Read the controller value from VBT and generalize
+	 */
+	panel->backlight.controller = 0;
+
+	pwm_ctl = I915_READ(BXT_BLC_PWM_CTL(panel->backlight.controller));
+
+	/* Keeping the check if controller 1 is to be programmed.
+	 * This will come into affect once the VBT parsing
+	 * is fixed for controller selection, and controller 1 is used
+	 * for a prticular display configuration.
+	 */
+	if (panel->backlight.controller == 1) {
+		val = I915_READ(UTIL_PIN_CTL);
+		panel->backlight.util_pin_active_low =
+					val & UTIL_PIN_POLARITY;
+	}
+
 	panel->backlight.active_low_pwm = pwm_ctl & BXT_BLC_PWM_POLARITY;
+	panel->backlight.max =
+		I915_READ(BXT_BLC_PWM_FREQ(panel->backlight.controller));
+
+	if (!panel->backlight.max)
+		panel->backlight.max = get_backlight_max_vbt(connector);
 
-	panel->backlight.max = I915_READ(BXT_BLC_PWM_FREQ1);
 	if (!panel->backlight.max)
 		return -ENODEV;
 
@@ -1475,9 +1698,13 @@ int intel_panel_setup_backlight(struct drm_connector *connector, enum pipe pipe)
 		}
 	}
 
+	/* ensure intel_panel has been initialized first */
+	if (WARN_ON(!panel->backlight.setup))
+		return -ENODEV;
+
 	/* set level and max in panel struct */
 	mutex_lock(&dev_priv->backlight_lock);
-	ret = dev_priv->display.setup_backlight(intel_connector, pipe);
+	ret = panel->backlight.setup(intel_connector, pipe);
 	mutex_unlock(&dev_priv->backlight_lock);
 
 	if (ret) {
@@ -1509,54 +1736,66 @@ void intel_panel_destroy_backlight(struct drm_connector *connector)
 }
 
 /* Set up chip specific backlight functions */
-void intel_panel_init_backlight_funcs(struct drm_device *dev)
+static void
+intel_panel_init_backlight_funcs(struct intel_panel *panel)
 {
+	struct intel_connector *intel_connector =
+		container_of(panel, struct intel_connector, panel);
+	struct drm_device *dev = intel_connector->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
 	if (IS_BROXTON(dev)) {
-		dev_priv->display.setup_backlight = bxt_setup_backlight;
-		dev_priv->display.enable_backlight = bxt_enable_backlight;
-		dev_priv->display.disable_backlight = bxt_disable_backlight;
-		dev_priv->display.set_backlight = bxt_set_backlight;
-		dev_priv->display.get_backlight = bxt_get_backlight;
-	} else if (IS_BROADWELL(dev) || IS_SKYLAKE(dev)) {
-		dev_priv->display.setup_backlight = bdw_setup_backlight;
-		dev_priv->display.enable_backlight = bdw_enable_backlight;
-		dev_priv->display.disable_backlight = pch_disable_backlight;
-		dev_priv->display.set_backlight = bdw_set_backlight;
-		dev_priv->display.get_backlight = bdw_get_backlight;
+		panel->backlight.setup = bxt_setup_backlight;
+		panel->backlight.enable = bxt_enable_backlight;
+		panel->backlight.disable = bxt_disable_backlight;
+		panel->backlight.set = bxt_set_backlight;
+		panel->backlight.get = bxt_get_backlight;
+	} else if (HAS_PCH_LPT(dev) || HAS_PCH_SPT(dev)) {
+		panel->backlight.setup = lpt_setup_backlight;
+		panel->backlight.enable = lpt_enable_backlight;
+		panel->backlight.disable = lpt_disable_backlight;
+		panel->backlight.set = lpt_set_backlight;
+		panel->backlight.get = lpt_get_backlight;
+		if (HAS_PCH_LPT(dev))
+			panel->backlight.hz_to_pwm = lpt_hz_to_pwm;
+		else
+			panel->backlight.hz_to_pwm = spt_hz_to_pwm;
 	} else if (HAS_PCH_SPLIT(dev)) {
-		dev_priv->display.setup_backlight = pch_setup_backlight;
-		dev_priv->display.enable_backlight = pch_enable_backlight;
-		dev_priv->display.disable_backlight = pch_disable_backlight;
-		dev_priv->display.set_backlight = pch_set_backlight;
-		dev_priv->display.get_backlight = pch_get_backlight;
+		panel->backlight.setup = pch_setup_backlight;
+		panel->backlight.enable = pch_enable_backlight;
+		panel->backlight.disable = pch_disable_backlight;
+		panel->backlight.set = pch_set_backlight;
+		panel->backlight.get = pch_get_backlight;
+		panel->backlight.hz_to_pwm = pch_hz_to_pwm;
 	} else if (IS_VALLEYVIEW(dev)) {
 		if (dev_priv->vbt.has_mipi) {
-			dev_priv->display.setup_backlight = pwm_setup_backlight;
-			dev_priv->display.enable_backlight = pwm_enable_backlight;
-			dev_priv->display.disable_backlight = pwm_disable_backlight;
-			dev_priv->display.set_backlight = pwm_set_backlight;
-			dev_priv->display.get_backlight = pwm_get_backlight;
+			panel->backlight.setup = pwm_setup_backlight;
+			panel->backlight.enable = pwm_enable_backlight;
+			panel->backlight.disable = pwm_disable_backlight;
+			panel->backlight.set = pwm_set_backlight;
+			panel->backlight.get = pwm_get_backlight;
 		} else {
-			dev_priv->display.setup_backlight = vlv_setup_backlight;
-			dev_priv->display.enable_backlight = vlv_enable_backlight;
-			dev_priv->display.disable_backlight = vlv_disable_backlight;
-			dev_priv->display.set_backlight = vlv_set_backlight;
-			dev_priv->display.get_backlight = vlv_get_backlight;
+			panel->backlight.setup = vlv_setup_backlight;
+			panel->backlight.enable = vlv_enable_backlight;
+			panel->backlight.disable = vlv_disable_backlight;
+			panel->backlight.set = vlv_set_backlight;
+			panel->backlight.get = vlv_get_backlight;
+			panel->backlight.hz_to_pwm = vlv_hz_to_pwm;
 		}
 	} else if (IS_GEN4(dev)) {
-		dev_priv->display.setup_backlight = i965_setup_backlight;
-		dev_priv->display.enable_backlight = i965_enable_backlight;
-		dev_priv->display.disable_backlight = i965_disable_backlight;
-		dev_priv->display.set_backlight = i9xx_set_backlight;
-		dev_priv->display.get_backlight = i9xx_get_backlight;
+		panel->backlight.setup = i965_setup_backlight;
+		panel->backlight.enable = i965_enable_backlight;
+		panel->backlight.disable = i965_disable_backlight;
+		panel->backlight.set = i9xx_set_backlight;
+		panel->backlight.get = i9xx_get_backlight;
+		panel->backlight.hz_to_pwm = i965_hz_to_pwm;
 	} else {
-		dev_priv->display.setup_backlight = i9xx_setup_backlight;
-		dev_priv->display.enable_backlight = i9xx_enable_backlight;
-		dev_priv->display.disable_backlight = i9xx_disable_backlight;
-		dev_priv->display.set_backlight = i9xx_set_backlight;
-		dev_priv->display.get_backlight = i9xx_get_backlight;
+		panel->backlight.setup = i9xx_setup_backlight;
+		panel->backlight.enable = i9xx_enable_backlight;
+		panel->backlight.disable = i9xx_disable_backlight;
+		panel->backlight.set = i9xx_set_backlight;
+		panel->backlight.get = i9xx_get_backlight;
+		panel->backlight.hz_to_pwm = i9xx_hz_to_pwm;
 	}
 }
 
@@ -1564,6 +1803,8 @@ int intel_panel_init(struct intel_panel *panel,
 		     struct drm_display_mode *fixed_mode,
 		     struct drm_display_mode *downclock_mode)
 {
+	intel_panel_init_backlight_funcs(panel);
+
 	panel->fixed_mode = fixed_mode;
 	panel->downclock_mode = downclock_mode;