drm/i915: Addition wrapper for fixed16.16 operation

This patch introduce addition wrapper for fixed point 16.16 operations.
Which will be used by later patches to avoid direct member variables
access of fixed_16_16_t structure.

add_fixed16 : takes 2 fixed_16_16_t variable & returns fixed_16_16_t
add_fixed16_u32 : takes fixed_16_16_t & u32 variable & returns fixed_16_16_t

Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170705143154.32132-5-mahesh1.kumar@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -224,6 +224,25 @@ static inline uint_fixed_16_16_t mul_u32_fixed16(uint32_t val,
 	return clamp_u64_to_fixed16(intermediate_val);
 }
 
+static inline uint_fixed_16_16_t add_fixed16(uint_fixed_16_16_t add1,
+					     uint_fixed_16_16_t add2)
+{
+	uint64_t interm_sum;
+
+	interm_sum = (uint64_t) add1.val + add2.val;
+	return clamp_u64_to_fixed16(interm_sum);
+}
+
+static inline uint_fixed_16_16_t add_fixed16_u32(uint_fixed_16_16_t add1,
+						 uint32_t add2)
+{
+	uint64_t interm_sum;
+	uint_fixed_16_16_t interm_add2 = u32_to_fixed16(add2);
+
+	interm_sum = (uint64_t) add1.val + interm_add2.val;
+	return clamp_u64_to_fixed16(interm_sum);
+}
+
 static inline const char *yesno(bool v)
 {
 	return v ? "yes" : "no";