[PATCH 14/21] drm/i915: Abstract backlight registers a bit

[Ben Widawsky <benjamin.widawsky@intel.com>]

Many GENs generally perform the same actions just on different
registers. This is true going forward as well. To ease the transition a
bit, extract the common code where possible.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
---
 drivers/gpu/drm/i915/intel_panel.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index de15186..e8a749a 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -430,24 +430,25 @@ static u32 intel_panel_compute_brightness(struct drm_device *dev, u32 val)
 static u32 intel_panel_get_backlight(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	u32 val;
+	u32 reg, val;
 	unsigned long flags;
 
 	spin_lock_irqsave(&dev_priv->backlight.lock, flags);
 
-	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 (HAS_PCH_SPLIT(dev))
+		reg = BLC_PWM_CPU_CTL;
+	else
+		reg = BLC_PWM_CTL;
 
-		if (is_backlight_combination_mode(dev)) {
-			u8 lbpc;
+	val = I915_READ(reg) & BACKLIGHT_DUTY_CYCLE_MASK;
+	if (INTEL_INFO(dev)->gen < 4)
+		val >>= 1;
 
-			pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc);
-			val *= lbpc;
-		}
+	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);
-- 
1.8.4.2