According to the exynos datasheet (Figure 49-10), we should wait for PLL
lock before programming the training pattern when doing software eDP
link training.
Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx>
Reviewed-by: Mandeep Singh Baines <msb@xxxxxxxxxxxx>
---
drivers/video/exynos/exynos_dp_core.c | 14 +++++++++++++-
1 files changed, 13 insertions(+), 1 deletions(-)
diff --git a/drivers/video/exynos/exynos_dp_core.c b/drivers/video/exynos/exynos_dp_core.c
index 3deded2..207bd7e 100644
--- a/drivers/video/exynos/exynos_dp_core.c
+++ b/drivers/video/exynos/exynos_dp_core.c
@@ -23,6 +23,8 @@
#include "exynos_dp_core.h"
+#define PLL_MAX_TRIES 100
+
static int exynos_dp_init_dp(struct exynos_dp_device *dp)
{
exynos_dp_reset(dp);
@@ -260,7 +262,7 @@ static void exynos_dp_set_lane_lane_pre_emphasis(struct exynos_dp_device *dp,
static int exynos_dp_link_start(struct exynos_dp_device *dp)
{
- int ret, lane, lane_count;
+ int ret, lane, lane_count, pll_tries;
u8 buf[4];
lane_count = dp->link_train.lane_count;
@@ -293,6 +295,16 @@ static int exynos_dp_link_start(struct exynos_dp_device *dp)
exynos_dp_set_lane_lane_pre_emphasis(dp,
PRE_EMPHASIS_LEVEL_0, lane);
+ /* Wait for PLL lock */
+ pll_tries = 0;
+ while (exynos_dp_get_pll_lock_status(dp) == PLL_UNLOCKED) {
+ if (pll_tries == PLL_MAX_TRIES)
+ return -ETIMEDOUT;
+
+ pll_tries++;
+ udelay(100);
+ }
+
/* Set training pattern 1 */
exynos_dp_set_training_pattern(dp, TRAINING_PTN1);
--
1.7.7.3
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