linux-kernel - [PATCH v2 1/3] drm/bridge: parade-ps8640: Don't try to enable VDO if poweron fails

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Date:   Tue,  2 Nov 2021 10:36:16 +0100
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     a.hajda@...sung.com
Cc:     narmstrong@...libre.com, robert.foss@...aro.org,
        Laurent.pinchart@...asonboard.com, jonas@...boo.se,
        jernej.skrabec@...il.com, airlied@...ux.ie, daniel@...ll.ch,
        dri-devel@...ts.freedesktop.org, kernel@...labora.com,
        linux-kernel@...r.kernel.org,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
Subject: [PATCH v2 1/3] drm/bridge: parade-ps8640: Don't try to enable VDO if poweron fails

If the bridge cannot get powered on, there's no reason to try to
communicate with it: change the ps8640_bridge_poweron function to
return an error value to the caller, so that we can avoid calling
ps8640_bridge_vdo_control() in ps8640_pre_enable() if the poweron
sequence fails.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
---
 drivers/gpu/drm/bridge/parade-ps8640.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/bridge/parade-ps8640.c b/drivers/gpu/drm/bridge/parade-ps8640.c
index 4b36e4dc78f1..8c5402947b3c 100644
--- a/drivers/gpu/drm/bridge/parade-ps8640.c
+++ b/drivers/gpu/drm/bridge/parade-ps8640.c
@@ -293,19 +293,19 @@ static int ps8640_bridge_vdo_control(struct ps8640 *ps_bridge,
 	return 0;
 }
 
-static void ps8640_bridge_poweron(struct ps8640 *ps_bridge)
+static int ps8640_bridge_poweron(struct ps8640 *ps_bridge)
 {
 	struct regmap *map = ps_bridge->regmap[PAGE2_TOP_CNTL];
 	int ret, status;
 
 	if (ps_bridge->powered)
-		return;
+		return 0;
 
 	ret = regulator_bulk_enable(ARRAY_SIZE(ps_bridge->supplies),
 				    ps_bridge->supplies);
 	if (ret < 0) {
 		DRM_ERROR("cannot enable regulators %d\n", ret);
-		return;
+		return ret;
 	}
 
 	gpiod_set_value(ps_bridge->gpio_powerdown, 0);
@@ -352,11 +352,13 @@ static void ps8640_bridge_poweron(struct ps8640 *ps_bridge)
 
 	ps_bridge->powered = true;
 
-	return;
+	return 0;
 
 err_regulators_disable:
 	regulator_bulk_disable(ARRAY_SIZE(ps_bridge->supplies),
 			       ps_bridge->supplies);
+
+	return ret;
 }
 
 static void ps8640_bridge_poweroff(struct ps8640 *ps_bridge)
@@ -381,7 +383,9 @@ static void ps8640_pre_enable(struct drm_bridge *bridge)
 	struct ps8640 *ps_bridge = bridge_to_ps8640(bridge);
 	int ret;
 
-	ps8640_bridge_poweron(ps_bridge);
+	ret = ps8640_bridge_poweron(ps_bridge);
+	if (ret)
+		return;
 
 	ret = ps8640_bridge_vdo_control(ps_bridge, ENABLE);
 	if (ret < 0)
-- 
2.33.1