From f752413e26bdc9f73a8a12e280770646555c82fc Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Fri, 21 Apr 2017 13:51:43 +0300
Subject: [PATCH 1/2] drm/mediatek: fix a timeout loop

This code causes a static checker warning because it treats "i == 0" as
a timeout but, because it's a post-op, the loop actually ends with "i"
set to -1.  Philipp Zabel points out that it would be cleaner to use
readl_poll_timeout() instead.

Fixes: 21898816831f ("drm/mediatek: add dsi transfer function")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: CK Hu <ck.hu@mediatek.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 808b995a990f5..b5cc6e12334cf 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -19,6 +19,7 @@
 #include <drm/drm_of.h>
 #include <linux/clk.h>
 #include <linux/component.h>
+#include <linux/iopoll.h>
 #include <linux/irq.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
@@ -900,16 +901,12 @@ static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
 
 static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
 {
-	u32 timeout_ms = 500000; /* total 1s ~ 2s timeout */
-
-	while (timeout_ms--) {
-		if (!(readl(dsi->regs + DSI_INTSTA) & DSI_BUSY))
-			break;
-
-		usleep_range(2, 4);
-	}
+	int ret;
+	u32 val;
 
-	if (timeout_ms == 0) {
+	ret = readl_poll_timeout(dsi->regs + DSI_INTSTA, val, !(val & DSI_BUSY),
+				 4, 2000000);
+	if (ret) {
 		DRM_WARN("polling dsi wait not busy timeout!\n");
 
 		mtk_dsi_enable(dsi);

From 014580ffab654bb83256783a2b185cf6c06dffaa Mon Sep 17 00:00:00 2001
From: YYS <nickey.yang@rock-chips.com>
Date: Tue, 21 Mar 2017 16:27:03 +0800
Subject: [PATCH 2/2] drm/mediatek: fix
 mtk_hdmi_setup_vendor_specific_infoframe mistake

mtk_hdmi_setup_vendor_specific_infoframe will return before handle
mtk_hdmi_hw_send_info_frame.Because hdmi_vendor_infoframe_pack
returns the number of bytes packed into the binary buffer or
a negative error code on failure.
So correct it.

Fixes: 8f83f26891e1 ("drm/mediatek: Add HDMI support")
Signed-off-by: Nickey Yang <nickey.yang@rock-chips.com>
Signed-off-by: CK Hu <ck.hu@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_hdmi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi.c b/drivers/gpu/drm/mediatek/mtk_hdmi.c
index 41a1c03b03476..0a4ffd7241468 100644
--- a/drivers/gpu/drm/mediatek/mtk_hdmi.c
+++ b/drivers/gpu/drm/mediatek/mtk_hdmi.c
@@ -1062,7 +1062,7 @@ static int mtk_hdmi_setup_vendor_specific_infoframe(struct mtk_hdmi *hdmi,
 	}
 
 	err = hdmi_vendor_infoframe_pack(&frame, buffer, sizeof(buffer));
-	if (err) {
+	if (err < 0) {
 		dev_err(hdmi->dev, "Failed to pack vendor infoframe: %zd\n",
 			err);
 		return err;