[PATCH v8 07/13] drm/bridge: analogix_dp: Add support for &drm_dp_aux.wait_hpd_asserted()

[Damon Ding]

Add analogix_dpaux_wait_hpd_asserted() to help confirm the HPD state
before doing AUX transfers.

Signed-off-by: Damon Ding <damon.ding@xxxxxxxxxxxxxx>
---
 .../drm/bridge/analogix/analogix_dp_core.c    | 21 +++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 2b76a9cf3bcb..b7e143b3ff75 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -1548,6 +1548,26 @@ static ssize_t analogix_dpaux_transfer(struct drm_dp_aux *aux,
 	return ret;
 }
 
+static int analogix_dpaux_wait_hpd_asserted(struct drm_dp_aux *aux, unsigned long wait_us)
+{
+	struct analogix_dp_device *dp = to_dp(aux);
+	int val;
+	int ret;
+
+	if (dp->force_hpd)
+		return 0;
+
+	pm_runtime_get_sync(dp->dev);
+
+	ret = readx_poll_timeout(analogix_dp_get_plug_in_status, dp, val, !val,
+				 wait_us / 100, wait_us);
+
+	pm_runtime_mark_last_busy(dp->dev);
+	pm_runtime_put_autosuspend(dp->dev);
+
+	return ret;
+}
+
 struct analogix_dp_device *
 analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
 {
@@ -1652,6 +1672,7 @@ analogix_dp_probe(struct device *dev, struct analogix_dp_plat_data *plat_data)
 
 	dp->aux.name = "DP-AUX";
 	dp->aux.transfer = analogix_dpaux_transfer;
+	dp->aux.wait_hpd_asserted = analogix_dpaux_wait_hpd_asserted;
 	dp->aux.dev = dp->dev;
 	drm_dp_aux_init(&dp->aux);
 
-- 
2.34.1