[RFC PATCH 34/40] drm/amd/display: add dc_fixpt_from_s3132 helper

[Melissa Wen <mwen@igalia.com>]

From: Joshua Ashton <joshua@froggi.es>

Detach value translation from CTM to reuse it for programming HDR
multiplier property.

Signed-off-by: Joshua Ashton <joshua@froggi.es>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c  |  8 +-------
 drivers/gpu/drm/amd/display/include/fixed31_32.h     | 12 ++++++++++++
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
index 07303c9f3618..d714728ca143 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c
@@ -182,7 +182,6 @@ static void __drm_lut_to_dc_gamma(const struct drm_color_lut *lut,
 static void __drm_ctm_to_dc_matrix(const struct drm_color_ctm *ctm,
 				   struct fixed31_32 *matrix)
 {
-	int64_t val;
 	int i;
 
 	/*
@@ -201,12 +200,7 @@ static void __drm_ctm_to_dc_matrix(const struct drm_color_ctm *ctm,
 		}
 
 		/* gamut_remap_matrix[i] = ctm[i - floor(i/4)] */
-		val = ctm->matrix[i - (i / 4)];
-		/* If negative, convert to 2's complement. */
-		if (val & (1ULL << 63))
-			val = -(val & ~(1ULL << 63));
-
-		matrix[i].value = val;
+		matrix[i] = dc_fixpt_from_s3132(ctm->matrix[i - (i / 4)]);
 	}
 }
 
diff --git a/drivers/gpu/drm/amd/display/include/fixed31_32.h b/drivers/gpu/drm/amd/display/include/fixed31_32.h
index ece97ae0e826..f4cc7f97329f 100644
--- a/drivers/gpu/drm/amd/display/include/fixed31_32.h
+++ b/drivers/gpu/drm/amd/display/include/fixed31_32.h
@@ -69,6 +69,18 @@ static const struct fixed31_32 dc_fixpt_epsilon = { 1LL };
 static const struct fixed31_32 dc_fixpt_half = { 0x80000000LL };
 static const struct fixed31_32 dc_fixpt_one = { 0x100000000LL };
 
+static inline struct fixed31_32 dc_fixpt_from_s3132(__u64 x)
+{
+	struct fixed31_32 val;
+
+	/* If negative, convert to 2's complement. */
+	if (x & (1ULL << 63))
+		x = -(x & ~(1ULL << 63));
+
+	val.value = x;
+	return val;
+}
+
 /*
  * @brief
  * Initialization routines
-- 
2.39.2