drm/i915/display: Add intel_legacy_aux_to_power_domain()

This is a similar function to intel_aux_power_domain() but it do not
care about TBT ports, this will be needed by ICL TC sequences.

v2:
- renamed to intel_legacy_aux_to_power_domain()

Cc: Imre Deak <imre.deak@intel.com>
Cc: Cooper Chiou <cooper.chiou@intel.com>
Cc: Kai-Heng Feng <kai.heng.feng@canonical.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Tested-by: You-Sheng Yang <vicamo.yang@canonical.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200414194956.164323-2-jose.souza@intel.com

drivers/gpu/drm/i915/display/intel_display.c

@@ -7296,7 +7296,17 @@ intel_aux_power_domain(struct intel_digital_port *dig_port)
 		}
 	}
 
-	switch (dig_port->aux_ch) {
+	return intel_legacy_aux_to_power_domain(dig_port->aux_ch);
+}
+
+/*
+ * Converts aux_ch to power_domain without caring about TBT ports for that use
+ * intel_aux_power_domain()
+ */
+enum intel_display_power_domain
+intel_legacy_aux_to_power_domain(enum aux_ch aux_ch)
+{
+	switch (aux_ch) {
 	case AUX_CH_A:
 		return POWER_DOMAIN_AUX_A;
 	case AUX_CH_B:
@@ -7312,7 +7322,7 @@ intel_aux_power_domain(struct intel_digital_port *dig_port)
 	case AUX_CH_G:
 		return POWER_DOMAIN_AUX_G;
 	default:
-		MISSING_CASE(dig_port->aux_ch);
+		MISSING_CASE(aux_ch);
 		return POWER_DOMAIN_AUX_A;
 	}
 }

drivers/gpu/drm/i915/display/intel_display.h

@@ -583,6 +583,8 @@ void hsw_disable_ips(const struct intel_crtc_state *crtc_state);
 enum intel_display_power_domain intel_port_to_power_domain(enum port port);
 enum intel_display_power_domain
 intel_aux_power_domain(struct intel_digital_port *dig_port);
+enum intel_display_power_domain
+intel_legacy_aux_to_power_domain(enum aux_ch aux_ch);
 void intel_mode_from_pipe_config(struct drm_display_mode *mode,
 				 struct intel_crtc_state *pipe_config);
 void intel_crtc_arm_fifo_underrun(struct intel_crtc *crtc,