[PATCH] video: exynos_dp: Improve EDID error handling

[PATCH] video: exynos_dp: Improve EDID error handling

[Sean Paul]

EDID error handling has 2 problems:
 - It doesn't fail as early as it can
 - The retry counts for i2c and aux transactions are huge

This patch fails if the initial i2c transaction fails, and reduces the
aux and i2c retry counts down to 3.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
---
 drivers/video/exynos/exynos_dp_core.c |   13 ++++++++-----
 drivers/video/exynos/exynos_dp_reg.c  |    9 ++++-----
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/video/exynos/exynos_dp_core.c b/drivers/video/exynos/exynos_dp_core.c
index ef9b003..f761ec2 100644
--- a/drivers/video/exynos/exynos_dp_core.c
+++ b/drivers/video/exynos/exynos_dp_core.c
@@ -90,9 +90,11 @@ static int exynos_dp_read_edid(struct exynos_dp_device *dp)
 	 */
 
 	/* Read Extension Flag, Number of 128-byte EDID extension blocks */
-	exynos_dp_read_byte_from_i2c(dp, I2C_EDID_DEVICE_ADDR,
+	retval = exynos_dp_read_byte_from_i2c(dp, I2C_EDID_DEVICE_ADDR,
 				EDID_EXTENSION_FLAG,
 				&extend_block);
+	if (retval)
+		return retval;
 
 	if (extend_block > 0) {
 		dev_dbg(dp->dev, "EDID data includes a single extension!\n");
@@ -181,14 +183,15 @@ static int exynos_dp_handle_edid(struct exynos_dp_device *dp)
 	int retval;
 
 	/* Read DPCD DPCD_ADDR_DPCD_REV~RECEIVE_PORT1_CAP_1 */
-	exynos_dp_read_bytes_from_dpcd(dp,
-		DPCD_ADDR_DPCD_REV,
-		12, buf);
+	retval = exynos_dp_read_bytes_from_dpcd(dp, DPCD_ADDR_DPCD_REV, 12,
+			buf);
+	if (retval)
+		return retval;
 
 	/* Read EDID */
 	for (i = 0; i < 3; i++) {
 		retval = exynos_dp_read_edid(dp);
-		if (retval = 0)
+		if (!retval)
 			break;
 	}
 
diff --git a/drivers/video/exynos/exynos_dp_reg.c b/drivers/video/exynos/exynos_dp_reg.c
index 3f5ca8a..9a939aa 100644
--- a/drivers/video/exynos/exynos_dp_reg.c
+++ b/drivers/video/exynos/exynos_dp_reg.c
@@ -552,7 +552,7 @@ int exynos_dp_write_bytes_to_dpcd(struct exynos_dp_device *dp,
 		else
 			cur_data_count = count - start_offset;
 
-		for (i = 0; i < 10; i++) {
+		for (i = 0; i < 3; i++) {
 			/* Select DPCD device address */
 			reg = AUX_ADDR_7_0(reg_addr + start_offset);
 			writel(reg, dp->reg_base + EXYNOS_DP_AUX_ADDR_7_0);
@@ -617,7 +617,7 @@ int exynos_dp_read_bytes_from_dpcd(struct exynos_dp_device *dp,
 			cur_data_count = count - start_offset;
 
 		/* AUX CH Request Transaction process */
-		for (i = 0; i < 10; i++) {
+		for (i = 0; i < 3; i++) {
 			/* Select DPCD device address */
 			reg = AUX_ADDR_7_0(reg_addr + start_offset);
 			writel(reg, dp->reg_base + EXYNOS_DP_AUX_ADDR_7_0);
@@ -700,7 +700,7 @@ int exynos_dp_read_byte_from_i2c(struct exynos_dp_device *dp,
 	int i;
 	int retval;
 
-	for (i = 0; i < 10; i++) {
+	for (i = 0; i < 3; i++) {
 		/* Clear AUX CH data buffer */
 		reg = BUF_CLR;
 		writel(reg, dp->reg_base + EXYNOS_DP_BUFFER_DATA_CTL);
@@ -708,7 +708,6 @@ int exynos_dp_read_byte_from_i2c(struct exynos_dp_device *dp,
 		/* Select EDID device */
 		retval = exynos_dp_select_i2c_device(dp, device_addr, reg_addr);
 		if (retval != 0) {
-			dev_err(dp->dev, "Select EDID device fail!\n");
 			continue;
 		}
 
@@ -750,7 +749,7 @@ int exynos_dp_read_bytes_from_i2c(struct exynos_dp_device *dp,
 	int retval = 0;
 
 	for (i = 0; i < count; i += 16) {
-		for (j = 0; j < 100; j++) {
+		for (j = 0; j < 3; j++) {
 			/* Clear AUX CH data buffer */
 			reg = BUF_CLR;
 			writel(reg, dp->reg_base + EXYNOS_DP_BUFFER_DATA_CTL);
-- 
1.7.7.3