video: exynos_dp: Improve EDID error handling

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.

[jg1.han@samsung.com: reduced the retry count of exynos_dp_read_byte_from_dpcd()]
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Jingoo Han <jg1.han@samsung.com>

diff --git a/drivers/video/exynos/exynos_dp_core.c b/drivers/video/exynos/exynos_dp_core.c
index d60f8da..a4c1dec 100644 (file)
--- a/drivers/video/exynos/exynos_dp_core.c
+++ b/drivers/video/exynos/exynos_dp_core.c
@@ -91,9 +91,11 @@ 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");
@@ -182,14 +184,15 @@ 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..fc19ef6 100644 (file)
--- a/drivers/video/exynos/exynos_dp_reg.c
+++ b/drivers/video/exynos/exynos_dp_reg.c
@@ -491,7 +491,7 @@ int exynos_dp_read_byte_from_dpcd(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);
@@ -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);
@@ -700,17 +700,15 @@ 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);
 
                /* 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");
+               if (retval != 0)
                        continue;
-               }
 
                /*
                 * Set I2C transaction and read data
@@ -750,7 +748,7 @@ 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);