[RFC][PATCH 2/5 v3] drm/bridge: adv7511: Switch to using drm_kms_helper_hotplug_event()

[John Stultz]

In chasing down a previous issue with EDID probing from calling
drm_helper_hpd_irq_event() from irq context, Laurent noticed
that the DRM documentation suggests that
drm_kms_helper_hotplug_event() should be used instead.

Thus this patch replaces drm_helper_hpd_irq_event() with
drm_kms_helper_hotplug_event(), which requires we update the
connector.status entry and only call _hotplug_event() when the
status changes.

Cc: David Airlie <airlied at linux.ie>
Cc: Archit Taneja <architt at codeaurora.org>
Cc: Wolfram Sang <wsa+renesas at sang-engineering.com>
Cc: Lars-Peter Clausen <lars at metafoo.de>
Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Cc: dri-devel at lists.freedesktop.org
Signed-off-by: John Stultz <john.stultz at linaro.org>
---
v3: Update connector.status value and only call __hotplug_event()
    when that status changes, as suggested by Laurent.
---
 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
index 4fcea44..d93d66f 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
@@ -405,8 +405,22 @@ static bool adv7511_hpd(struct adv7511 *adv7511)
 static void adv7511_hpd_work(struct work_struct *work)
 {
 	struct adv7511 *adv7511 = container_of(work, struct adv7511, hpd_work);
+	enum drm_connector_status status;
+	unsigned int val;
+	int ret;
+
+	ret = regmap_read(adv7511->regmap, ADV7511_REG_STATUS, &val);
+	if (ret < 0)
+		status = connector_status_disconnected;
+	else if (val & ADV7511_STATUS_HPD)
+		status = connector_status_connected;
+	else
+		status = connector_status_disconnected;
+
+	if (adv7511->connector.status != status)
+		drm_kms_helper_hotplug_event(adv7511->connector.dev);
 
-	drm_helper_hpd_irq_event(adv7511->connector.dev);
+	adv7511->connector.status = status;
 }
 
 static int adv7511_irq_process(struct adv7511 *adv7511, bool process_hpd)
-- 
2.7.4