drm/i915/glk: Set DCC delay range 2 in PLL enable sequence

Follow the PLL enable sequence updated in bspec, which requires the DCC
delay range 2 bit to be set.

v2: Moved from DDI init sequence to PLL enable.
v3: Don't read value from GRP register. (Rodrido)

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Ander Conselvan De Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1480667037-11215-5-git-send-email-ander.conselvan.de.oliveira@intel.com

drivers/gpu/drm/i915/i915_reg.h

@@ -1784,6 +1784,21 @@ enum skl_disp_power_wells {
 #define   DEEMPH_SHIFT			24
 #define   DE_EMPHASIS			(0xFF << DEEMPH_SHIFT)
 
+#define _PORT_TX_DW5_LN0_A		0x162514
+#define _PORT_TX_DW5_LN0_B		0x6C514
+#define _PORT_TX_DW5_LN0_C		0x6C914
+#define _PORT_TX_DW5_GRP_A		0x162D14
+#define _PORT_TX_DW5_GRP_B		0x6CD14
+#define _PORT_TX_DW5_GRP_C		0x6CF14
+#define BXT_PORT_TX_DW5_LN0(phy, ch)	_MMIO_BXT_PHY_CH(phy, ch, \
+							 _PORT_TX_DW5_LN0_B, \
+							 _PORT_TX_DW5_LN0_C)
+#define BXT_PORT_TX_DW5_GRP(phy, ch)	_MMIO_BXT_PHY_CH(phy, ch, \
+							 _PORT_TX_DW5_GRP_B, \
+							 _PORT_TX_DW5_GRP_C)
+#define   DCC_DELAY_RANGE_1		(1 << 9)
+#define   DCC_DELAY_RANGE_2		(1 << 8)
+
 #define _PORT_TX_DW14_LN0_A		0x162538
 #define _PORT_TX_DW14_LN0_B		0x6C538
 #define _PORT_TX_DW14_LN0_C		0x6C938

drivers/gpu/drm/i915/intel_dpll_mgr.c

@@ -1458,6 +1458,12 @@ static void bxt_ddi_pll_enable(struct drm_i915_private *dev_priv,
 			200))
 		DRM_ERROR("PLL %d not locked\n", port);
 
+	if (IS_GEMINILAKE(dev_priv)) {
+		temp = I915_READ(BXT_PORT_TX_DW5_LN0(phy, ch));
+		temp |= DCC_DELAY_RANGE_2;
+		I915_WRITE(BXT_PORT_TX_DW5_GRP(phy, ch), temp);
+	}
+
 	/*
 	 * While we write to the group register to program all lanes at once we
 	 * can read only lane registers and we pick lanes 0/1 for that.