linux-kernel - [PATCH v2] drm/bridge: adv7511: Attach to DSI host at probe time

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Message-ID: <20190627151740.2277-1-matt.redfearn@thinci.com>
Date:   Thu, 27 Jun 2019 15:18:00 +0000
From:   Matt Redfearn <matt.redfearn@...nci.com>
To:     Archit Taneja <architt@...eaurora.org>,
        Andrzej Hajda <a.hajda@...sung.com>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...l.net>,
        Thierry Reding <thierry.reding@...il.com>
CC:     "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        Matthew Redfearn <matthew.redfearn@...nci.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        David Airlie <airlied@...ux.ie>,
        Sean Paul <seanpaul@...omium.org>,
        Daniel Vetter <daniel@...ll.ch>
Subject: [PATCH v2] drm/bridge: adv7511: Attach to DSI host at probe time

In contrast to all of the DSI panel drivers in drivers/gpu/drm/panel
which attach to the DSI host via mipi_dsi_attach() at probe time, the
ADV7533 bridge device does not. Instead it defers this to the point that
the upstream device connects to its bridge via drm_bridge_attach().
The generic Synopsys MIPI DSI host driver does not register it's own
drm_bridge until the MIPI DSI has attached. But it does not call
drm_bridge_attach() on the downstream device until the upstream device
has attached. This leads to a chicken and the egg failure and the DRM
pipeline does not complete.
Since all other mipi_dsi_device drivers call mipi_dsi_attach() in
probe(), make the adv7533 mipi_dsi_device do the same. This ensures that
the Synopsys MIPI DSI host registers it's bridge such that it is
available for the upstream device to connect to.

Signed-off-by: Matt Redfearn <matt.redfearn@...nci.com>

---

Changes in v2:
Cleanup if adv7533_attach_dsi fails.

 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
index e7ddd3e3db9..807827bd910 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
@@ -874,9 +874,6 @@ static int adv7511_bridge_attach(struct drm_bridge *bridge)
 				 &adv7511_connector_helper_funcs);
 	drm_connector_attach_encoder(&adv->connector, bridge->encoder);
 
-	if (adv->type == ADV7533)
-		ret = adv7533_attach_dsi(adv);
-
 	if (adv->i2c_main->irq)
 		regmap_write(adv->regmap, ADV7511_REG_INT_ENABLE(0),
 			     ADV7511_INT0_HPD);
@@ -1222,8 +1219,17 @@ static int adv7511_probe(struct i2c_client *i2c, const struct i2c_device_id *id)
 	drm_bridge_add(&adv7511->bridge);
 
 	adv7511_audio_init(dev, adv7511);
+
+	if (adv7511->type == ADV7533) {
+		ret = adv7533_attach_dsi(adv7511);
+		if (ret)
+			goto err_remove_bridge;
+	}
+
 	return 0;
 
+err_remove_bridge:
+	drm_bridge_remove(&adv7511->bridge);
 err_unregister_cec:
 	i2c_unregister_device(adv7511->i2c_cec);
 	if (adv7511->cec_clk)
-- 
2.17.1