linux-kernel - [PATCH v3 35/37] drm/bridge: tc358768: Stop disabling when failing to enable

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Message-Id: <20250213-bridge-connector-v3-35-e71598f49c8f@kernel.org>
Date: Thu, 13 Feb 2025 15:43:54 +0100
From: Maxime Ripard <mripard@...nel.org>
To: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, 
 Simona Vetter <simona@...ll.ch>, Andrzej Hajda <andrzej.hajda@...el.com>, 
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>, 
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>, 
 Douglas Anderson <dianders@...omium.org>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 Maxime Ripard <mripard@...nel.org>
Subject: [PATCH v3 35/37] drm/bridge: tc358768: Stop disabling when failing
 to enable

The tc358768 bridge driver, if enabling it fails, tries to disable it.
This is pretty uncommon in bridge drivers, and also stands in the way
for further reworks.

Worse, since pre_enable and enable aren't expected to fail, disable and
post_disable might be called twice: once to handle the failure, and once
to actually disable the bridge.

Since post_disable uses regulators and clocks, this would lead to enable
count imbalances.

In order to prevent that imbalance, and to allow further reworks, let's
drop the calls to disable and post_disable, but keep the warning to let
users know about what's going on.

Signed-off-by: Maxime Ripard <mripard@...nel.org>
---
 drivers/gpu/drm/bridge/tc358768.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index 6db18d1e8824dd7d387211d6d1e668645cf88bbe..6b65ba8aed86012bc0f464bd5ee44325dae677c6 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -1075,15 +1075,12 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	val = TC358768_DSI_CONFW_MODE_CLR | TC358768_DSI_CONFW_ADDR_DSI_CONTROL;
 	val |= TC358768_DSI_CONTROL_DIS_MODE; /* DSI mode */
 	tc358768_write(priv, TC358768_DSI_CONFW, val);
 
 	ret = tc358768_clear_error(priv);
-	if (ret) {
+	if (ret)
 		dev_err(dev, "Bridge pre_enable failed: %d\n", ret);
-		tc358768_bridge_disable(bridge);
-		tc358768_bridge_post_disable(bridge);
-	}
 }
 
 static void tc358768_bridge_enable(struct drm_bridge *bridge)
 {
 	struct tc358768_priv *priv = bridge_to_tc358768(bridge);
@@ -1099,15 +1096,12 @@ static void tc358768_bridge_enable(struct drm_bridge *bridge)
 
 	/* set PP_en */
 	tc358768_update_bits(priv, TC358768_CONFCTL, BIT(6), BIT(6));
 
 	ret = tc358768_clear_error(priv);
-	if (ret) {
+	if (ret)
 		dev_err(priv->dev, "Bridge enable failed: %d\n", ret);
-		tc358768_bridge_disable(bridge);
-		tc358768_bridge_post_disable(bridge);
-	}
 }
 
 #define MAX_INPUT_SEL_FORMATS	1
 
 static u32 *

-- 
2.48.0