drm/i915: Configure DPLL's for Cannonlake

DPLL's are defined in DPCLKA_CFGCR0 register (0x6C200). Let's use these
definitions when computing dpll's for ddi ports.

v2: (Rodrigo) Remove register that was defined in another patch with
    fixed name and more bits.

Signed-off-by: Kahola, Mika <mika.kahola@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1497047175-27250-6-git-send-email-rodrigo.vivi@intel.com

drivers/gpu/drm/i915/intel_display.c

@@ -8868,6 +8868,22 @@ static int haswell_crtc_compute_clock(struct intel_crtc *crtc,
 	return 0;
 }
 
+static void cannonlake_get_ddi_pll(struct drm_i915_private *dev_priv,
+				   enum port port,
+				   struct intel_crtc_state *pipe_config)
+{
+	enum intel_dpll_id id;
+	u32 temp;
+
+	temp = I915_READ(DPCLKA_CFGCR0) & DPCLKA_CFGCR0_DDI_CLK_SEL_MASK(port);
+	id = temp >> (port * 2);
+
+	if (WARN_ON(id < SKL_DPLL0 || id > SKL_DPLL2))
+		return;
+
+	pipe_config->shared_dpll = intel_get_shared_dpll_by_id(dev_priv, id);
+}
+
 static void bxt_get_ddi_pll(struct drm_i915_private *dev_priv,
 				enum port port,
 				struct intel_crtc_state *pipe_config)
@@ -9055,7 +9071,9 @@ static void haswell_get_ddi_port_state(struct intel_crtc *crtc,
 
 	port = (tmp & TRANS_DDI_PORT_MASK) >> TRANS_DDI_PORT_SHIFT;
 
-	if (IS_GEN9_BC(dev_priv))
+	if (IS_CANNONLAKE(dev_priv))
+		cannonlake_get_ddi_pll(dev_priv, port, pipe_config);
+	else if (IS_GEN9_BC(dev_priv))
 		skylake_get_ddi_pll(dev_priv, port, pipe_config);
 	else if (IS_GEN9_LP(dev_priv))
 		bxt_get_ddi_pll(dev_priv, port, pipe_config);