drm/i915/display: Add support for pack and unpack

Add support of pack and unpack for target_rr_divider.

--v2:
- Set Target Refresh Rate Divider bit when related
AS SDP bit is set (Ankit).

--v3:
- target_rr_divider is bools so set accordingly (Ankit).
Signed-off-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240610072203.24956-7-mitulkumar.ajitkumar.golani@intel.com

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

@@ -4232,6 +4232,9 @@ static ssize_t intel_dp_as_sdp_pack(const struct drm_dp_as_sdp *as_sdp,
 	sdp->db[3] = as_sdp->target_rr & 0xFF;
 	sdp->db[4] = (as_sdp->target_rr >> 8) & 0x3;
 
+	if (as_sdp->target_rr_divider)
+		sdp->db[4] |= 0x20;
+
 	return length;
 }
 
@@ -4413,6 +4416,7 @@ int intel_dp_as_sdp_unpack(struct drm_dp_as_sdp *as_sdp,
 	as_sdp->mode = sdp->db[0] & DP_ADAPTIVE_SYNC_SDP_OPERATION_MODE;
 	as_sdp->vtotal = (sdp->db[2] << 8) | sdp->db[1];
 	as_sdp->target_rr = (u64)sdp->db[3] | ((u64)sdp->db[4] & 0x3);
+	as_sdp->target_rr_divider = sdp->db[4] & 0x20 ? true : false;
 
 	return 0;
 }