[PATCH 3/5] drm/probe_helper: extract two helper functions

[Nicusor Huhulea]

From: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>

commit cbf143b282c64e59559cc8351c0b5b1ab4bbdcbe upstream

This is not a direct cherry-pick of the upstream commit. Only the helper
functions required as dependencies for "drm/i915: Fix HPD polling, reenabling
the output poll work as needed" were extracted from the original commit. The rest
of the code was not applied, as the codebase has diverged significantly.

This partial adaptation ensures that the required helpers are available for the
dependent fix, while minimizing changes to the existing code.

Extract drm_kms_helper_enable_hpd() and drm_kms_helper_disable_hpd(),
two helpers that enable and disable HPD handling on all device's
connectors.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
Reviewed-by: Neil Armstrong <neil.armstrong at linaro.org>
Reviewed-by: Jani Nikula <jani.nikula at intel.com>
Signed-off-by: Neil Armstrong <neil.armstrong at linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230124104548.3234554-1-dmitry.baryshkov@linaro.org
Signed-off-by: Nicusor Huhulea <nicusor.huhulea at siemens.com>
---
 drivers/gpu/drm/drm_probe_helper.c | 39 ++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 787f6699971f..938649e3a282 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -244,6 +244,45 @@ static void reschedule_output_poll_work(struct drm_device *dev)
 	schedule_delayed_work(&dev->mode_config.output_poll_work, delay);
 }
 
+static void drm_kms_helper_disable_hpd(struct drm_device *dev)
+{
+	struct drm_connector *connector;
+	struct drm_connector_list_iter conn_iter;
+
+	drm_connector_list_iter_begin(dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter) {
+		const struct drm_connector_helper_funcs *funcs =
+			connector->helper_private;
+
+		if (funcs && funcs->disable_hpd)
+			funcs->disable_hpd(connector);
+	}
+	drm_connector_list_iter_end(&conn_iter);
+}
+
+static bool drm_kms_helper_enable_hpd(struct drm_device *dev)
+{
+	bool poll = false;
+	struct drm_connector *connector;
+	struct drm_connector_list_iter conn_iter;
+
+	drm_connector_list_iter_begin(dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter) {
+		const struct drm_connector_helper_funcs *funcs =
+			connector->helper_private;
+
+		if (funcs && funcs->enable_hpd)
+			funcs->enable_hpd(connector);
+
+		if (connector->polled & (DRM_CONNECTOR_POLL_CONNECT |
+					 DRM_CONNECTOR_POLL_DISCONNECT))
+			poll = true;
+	}
+	drm_connector_list_iter_end(&conn_iter);
+
+	return poll;
+}
+
 /**
  * drm_kms_helper_poll_enable - re-enable output polling.
  * @dev: drm_device
-- 
2.39.2