[PATCH 1/9] drm: Add helpers for x16 fixed point values

[Imre Deak <imre.deak@intel.com>]

Add helpers to convert between x16 fixed point and integer/fraction
values. Also add the format/argument macros required to printk x16
fixed point variables.

These are needed by later patches dumping the Display Stream Compression
configuration in DRM core and in the i915 driver to replace the
corresponding bpp_x16 helpers defined locally in the driver.

Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 drivers/gpu/drm/display/drm_dp_helper.c |  5 +++--
 include/drm/drm_fixed.h                 | 23 +++++++++++++++++++++++
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/display/drm_dp_helper.c b/drivers/gpu/drm/display/drm_dp_helper.c
index 79a615667aab1..806f9c9764995 100644
--- a/drivers/gpu/drm/display/drm_dp_helper.c
+++ b/drivers/gpu/drm/display/drm_dp_helper.c
@@ -35,6 +35,7 @@
 #include <drm/display/drm_dp_helper.h>
 #include <drm/display/drm_dp_mst_helper.h>
 #include <drm/drm_edid.h>
+#include <drm/drm_fixed.h>
 #include <drm/drm_print.h>
 #include <drm/drm_vblank.h>
 #include <drm/drm_panel.h>
@@ -4151,9 +4152,9 @@ int drm_dp_bw_overhead(int lane_count, int hactive,
 	int symbol_cycles;
 
 	if (lane_count == 0 || hactive == 0 || bpp_x16 == 0) {
-		DRM_DEBUG_KMS("Invalid BW overhead params: lane_count %d, hactive %d, bpp_x16 %d.%04d\n",
+		DRM_DEBUG_KMS("Invalid BW overhead params: lane_count %d, hactive %d, bpp_x16 " DRM_X16_FMT "\n",
 			      lane_count, hactive,
-			      bpp_x16 >> 4, (bpp_x16 & 0xf) * 625);
+			      DRM_X16_ARGS(bpp_x16));
 		return 0;
 	}
 
diff --git a/include/drm/drm_fixed.h b/include/drm/drm_fixed.h
index 81572d32db0c2..0fe2a7f50d54e 100644
--- a/include/drm/drm_fixed.h
+++ b/include/drm/drm_fixed.h
@@ -214,4 +214,27 @@ static inline s64 drm_fixp_exp(s64 x)
 	return sum;
 }
 
+static inline int drm_x16_from_int(int val_int)
+{
+	return val_int << 4;
+}
+
+static inline int drm_x16_to_int(int val_x16)
+{
+	return val_x16 >> 4;
+}
+
+static inline int drm_x16_to_int_roundup(int val_x16)
+{
+	return (val_x16 + 0xf) >> 4;
+}
+
+static inline int drm_x16_to_frac(int val_x16)
+{
+	return val_x16 & 0xf;
+}
+
+#define DRM_X16_FMT		"%d.%04d"
+#define DRM_X16_ARGS(val_x16)	drm_x16_to_int(val_x16), (drm_x16_to_frac(val_x16) * 625)
+
 #endif
-- 
2.43.3