linux-kernel - [PATCH] drm: bridge: anx7625: Use of_property_read_variable_u8

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Message-ID: <20240731201407.1838385-4-robh@kernel.org>
Date: Wed, 31 Jul 2024 14:13:59 -0600
From: "Rob Herring (Arm)" <robh@...nel.org>
To: 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>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Maxime Ripard <mripard@...nel.org>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>,
	Daniel Vetter <daniel@...ll.ch>
Cc: dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] drm: bridge: anx7625: Use of_property_read_variable_u8_array()

There's no need to get the length of an DT array property before
parsing the array. of_property_read_variable_u8_array() takes a minimum
and maximum length and returns the actual length (or error code).

This is part of a larger effort to remove callers of of_get_property()
and similar functions. of_get_property() leaks the DT property data
pointer which is a problem for dynamically allocated nodes which may
be freed.

Signed-off-by: Rob Herring (Arm) <robh@...nel.org>
---
 drivers/gpu/drm/bridge/analogix/anx7625.c | 22 ++++++----------------
 1 file changed, 6 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index 88e4aa5830f3..a2e9bb485c36 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -1647,25 +1647,15 @@ static int anx7625_get_swing_setting(struct device *dev,
 {
 	int num_regs;
 
-	if (of_get_property(dev->of_node,
-			    "analogix,lane0-swing", &num_regs)) {
-		if (num_regs > DP_TX_SWING_REG_CNT)
-			num_regs = DP_TX_SWING_REG_CNT;
-
+	num_regs = of_property_read_variable_u8_array(dev->of_node, "analogix,lane0-swing",
+						      pdata->lane0_reg_data, 1, DP_TX_SWING_REG_CNT);
+	if (num_regs > 0)
 		pdata->dp_lane0_swing_reg_cnt = num_regs;
-		of_property_read_u8_array(dev->of_node, "analogix,lane0-swing",
-					  pdata->lane0_reg_data, num_regs);
-	}
-
-	if (of_get_property(dev->of_node,
-			    "analogix,lane1-swing", &num_regs)) {
-		if (num_regs > DP_TX_SWING_REG_CNT)
-			num_regs = DP_TX_SWING_REG_CNT;
 
+	num_regs = of_property_read_variable_u8_array(dev->of_node, "analogix,lane1-swing",
+						      pdata->lane1_reg_data, 1, DP_TX_SWING_REG_CNT);
+	if (num_regs > 0)
 		pdata->dp_lane1_swing_reg_cnt = num_regs;
-		of_property_read_u8_array(dev->of_node, "analogix,lane1-swing",
-					  pdata->lane1_reg_data, num_regs);
-	}
 
 	return 0;
 }
-- 
2.43.0