From f00d17d94a2552813e73733ea0f56583342955ee Mon Sep 17 00:00:00 2001
From: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Date: Tue, 19 Nov 2019 17:41:44 +0300
Subject: DRM: ARC: PGU: fix framebuffer format switching
Git-commit: 4c5b36ee73359b92355394adbd722823bf66806f
Patch-mainline: v5.6-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

Current implementation don't switch to RGB565 format if BGR888 was
previously used. Fix that.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/arc/arcpgu_crtc.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/arc/arcpgu_crtc.c b/drivers/gpu/drm/arc/arcpgu_crtc.c
index dfaddbb7da0d..31d9824c46cc 100644
--- a/drivers/gpu/drm/arc/arcpgu_crtc.c
+++ b/drivers/gpu/drm/arc/arcpgu_crtc.c
@@ -32,6 +32,7 @@ static void arc_pgu_set_pxl_fmt(struct drm_crtc *crtc)
 	uint32_t pixel_format = fb->format->format;
 	struct simplefb_format *format = NULL;
 	int i;
+	u32 reg_ctrl;
 
 	for (i = 0; i < ARRAY_SIZE(supported_formats); i++) {
 		if (supported_formats[i].fourcc == pixel_format)
@@ -41,11 +42,12 @@ static void arc_pgu_set_pxl_fmt(struct drm_crtc *crtc)
 	if (WARN_ON(!format))
 		return;
 
-	if (format->fourcc == DRM_FORMAT_RGB888)
-		arc_pgu_write(arcpgu, ARCPGU_REG_CTRL,
-			      arc_pgu_read(arcpgu, ARCPGU_REG_CTRL) |
-					   ARCPGU_MODE_RGB888_MASK);
-
+	reg_ctrl = arc_pgu_read(arcpgu, ARCPGU_REG_CTRL);
+	if (format->fourcc == DRM_FORMAT_RGB565)
+		reg_ctrl &= ~ARCPGU_MODE_RGB888_MASK;
+	else
+		reg_ctrl |= ARCPGU_MODE_RGB888_MASK;
+	arc_pgu_write(arcpgu, ARCPGU_REG_CTRL, reg_ctrl);
 }
 
 static const struct drm_crtc_funcs arc_pgu_crtc_funcs = {
-- 
2.28.0