drm/msm/dp: return correct connection status after suspend

During suspend, dp host controller and hpd block are disabled due to
both ahb and aux clock are disabled. Therefore hpd plug/unplug interrupts
will not be generated. At dp_pm_resume(), reinitialize both dp host
controller and hpd block so that hpd plug/unplug interrupts will be
generated and handled by driver so that hpd connection state is updated
correctly. This patch will fix link training flaky issues.

Changes in v2:
-- use container_of to cast correct dp_display_private pointer
   at both dp_pm_suspend() and dp_pm_resume().

Changes in v3:
-- replace hpd_state atomic_t  with u32

Changes in v4
-- call dp_display_host_deinit() at dp_pm_suspend()
-- call dp_display_host_init() at msm_dp_display_enable()
-- fix phy->init_count unbalance which causes link training failed

Changes in v5
--  add Fixes tag

Fixes:  8ede2ecc3e5e (drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets)
Tested-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Kuogee Hsieh <khsieh@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index 7572264a7156..aa40429cad42 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1403,6 +1403,8 @@ int dp_ctrl_host_init(struct dp_ctrl *dp_ctrl, bool flip)
 void dp_ctrl_host_deinit(struct dp_ctrl *dp_ctrl)
 {
 	struct dp_ctrl_private *ctrl;
+	struct dp_io *dp_io;
+	struct phy *phy;
 
 	if (!dp_ctrl) {
 		DRM_ERROR("Invalid input data\n");
@@ -1410,8 +1412,11 @@ void dp_ctrl_host_deinit(struct dp_ctrl *dp_ctrl)
 	}
 
 	ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
+	dp_io = &ctrl->parser->io;
+	phy = dp_io->phy;
 
 	dp_catalog_ctrl_enable_irq(ctrl->catalog, false);
+	phy_exit(phy);
 
 	DRM_DEBUG_DP("Host deinitialized successfully\n");
 }