RE: [PATCH 04/10] video: exynos_dp: Get pll lock before pattern set
flat view
From: Jingoo Han <hidden>
Date: 2012-08-20 09:13:10
On Wednesday, August 08, 2012 12:54 PM Sean Paul wrote:
quoted hunk ↗ jump to hunk
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 <redacted> Reviewed-by: Mandeep Singh Baines <redacted> --- 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); + } +
You don't need to add 'PLL_MAX_TRIES', please use 'DP_TIMEOUT_LOOP_COUNT' as below:
/* Wait for PLL lock */
while (exynos_dp_get_pll_lock_status(dp) = PLL_UNLOCKED) {
timeout_loop++;
if (DP_TIMEOUT_LOOP_COUNT < timeout_loop) {
dev_err(dp->dev, "failed to get pll lock status\n");
return -ETIMEDOUT;
}
udelay(100);
}
Also, could you use usleep_range() instead of udelay()?
/* Set training pattern 1 */ exynos_dp_set_training_pattern(dp, TRAINING_PTN1); -- 1.7.7.3