[PATCH 2/2] drm/bridge: dw-hdmi: Always add the bridge in the global bridge list

[Liu Ying]

It doesn't hurt to add the bridge in the global bridge list also for
platform specific dw-hdmi drivers which are based on the component
framework.  This can be achieved by moving the drm_bridge_add() function
call from dw_hdmi_probe() to __dw_hdmi_probe().  Moreover, putting the
drm_bridge_add() function call prior to the interrupt registration and
enablement ensures that the mutex hpd_mutex embedded in the structure
drm_bridge can be initialized in drm_bridge_add() beforehand, which
avoids accessing the uninitialized mutex in case people want to call
function drm_bridge_hpd_notify() with the mutex locked internally to
handle hot plug detection event in the interrupt handler dw_hdmi_irq().

Cc: Andrzej Hajda <a.hajda at samsung.com>
Cc: Neil Armstrong <narmstrong at baylibre.com>
Cc: Laurent Pinchart <Laurent.pinchart at ideasonboard.com>
Cc: Jonas Karlman <jonas at kwiboo.se>
Cc: Jernej Skrabec <jernej.skrabec at siol.net>
Cc: David Airlie <airlied at linux.ie>
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Boris Brezillon <boris.brezillon at collabora.com>
Cc: Jerome Brunet <jbrunet at baylibre.com>
Cc: Cheng-Yi Chiang <cychiang at chromium.org>
Cc: Dariusz Marcinkiewicz <darekm at google.com>
Cc: Archit Taneja <architt at codeaurora.org>
Cc: Jose Abreu <joabreu at synopsys.com>
Cc: dri-devel at lists.freedesktop.org
Cc: NXP Linux Team <linux-imx at nxp.com>
Signed-off-by: Liu Ying <victor.liu at nxp.com>
---
Laurent,

I may see the uninitialized mutex accessing issue with
i.MX dw-hdmi after applying your below patch set[1].
I think patch '[22/27] drm: bridge: dw-hdmi: Make connector creation optional'
triggers the issue.

[1] https://patchwork.kernel.org/cover/11569709/

 drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 34 ++++++++++++++-----------------
 1 file changed, 15 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index da84a91..4711700 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -3247,17 +3247,25 @@ __dw_hdmi_probe(struct platform_device *pdev,
 
 	dw_hdmi_init_hw(hdmi);
 
+	hdmi->bridge.driver_private = hdmi;
+	hdmi->bridge.funcs = &dw_hdmi_bridge_funcs;
+#ifdef CONFIG_OF
+	hdmi->bridge.of_node = pdev->dev.of_node;
+#endif
+
+	drm_bridge_add(&hdmi->bridge);
+
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
 		ret = irq;
-		goto err_iahb;
+		goto err_irq;
 	}
 
 	ret = devm_request_threaded_irq(dev, irq, dw_hdmi_hardirq,
 					dw_hdmi_irq, IRQF_SHARED,
 					dev_name(dev), hdmi);
 	if (ret)
-		goto err_iahb;
+		goto err_irq;
 
 	/*
 	 * To prevent overflows in HDMI_IH_FC_STAT2, set the clk regenerator
@@ -3290,12 +3298,6 @@ __dw_hdmi_probe(struct platform_device *pdev,
 			hdmi->ddc = NULL;
 	}
 
-	hdmi->bridge.driver_private = hdmi;
-	hdmi->bridge.funcs = &dw_hdmi_bridge_funcs;
-#ifdef CONFIG_OF
-	hdmi->bridge.of_node = pdev->dev.of_node;
-#endif
-
 	if (hdmi->version >= 0x200a)
 		hdmi->connector.ycbcr_420_allowed =
 			hdmi->plat_data->ycbcr_420_allowed;
@@ -3357,6 +3359,8 @@ __dw_hdmi_probe(struct platform_device *pdev,
 
 	return hdmi;
 
+err_irq:
+	drm_bridge_remove(&hdmi->bridge);
 err_iahb:
 	clk_disable_unprepare(hdmi->iahb_clk);
 	if (hdmi->cec_clk)
@@ -3371,6 +3375,8 @@ __dw_hdmi_probe(struct platform_device *pdev,
 
 static void __dw_hdmi_remove(struct dw_hdmi *hdmi)
 {
+	drm_bridge_remove(&hdmi->bridge);
+
 	if (hdmi->audio && !IS_ERR(hdmi->audio))
 		platform_device_unregister(hdmi->audio);
 	if (!IS_ERR(hdmi->cec))
@@ -3396,22 +3402,12 @@ static void __dw_hdmi_remove(struct dw_hdmi *hdmi)
 struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev,
 			      const struct dw_hdmi_plat_data *plat_data)
 {
-	struct dw_hdmi *hdmi;
-
-	hdmi = __dw_hdmi_probe(pdev, plat_data);
-	if (IS_ERR(hdmi))
-		return hdmi;
-
-	drm_bridge_add(&hdmi->bridge);
-
-	return hdmi;
+	return __dw_hdmi_probe(pdev, plat_data);
 }
 EXPORT_SYMBOL_GPL(dw_hdmi_probe);
 
 void dw_hdmi_remove(struct dw_hdmi *hdmi)
 {
-	drm_bridge_remove(&hdmi->bridge);
-
 	__dw_hdmi_remove(hdmi);
 }
 EXPORT_SYMBOL_GPL(dw_hdmi_remove);
-- 
2.7.4