linux-kernel - [PATCH net v4 1/4] net: dsa: lantiq_gswip: fix order in .remove operation

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Message-ID: <4ebd72a29edc1e4059b9666a26a0bb5d906a829a.1765241054.git.daniel@makrotopia.org>
Date: Tue, 9 Dec 2025 01:28:20 +0000
From: Daniel Golle <daniel@...rotopia.org>
To: Hauke Mehrtens <hauke@...ke-m.de>, Andrew Lunn <andrew@...n.ch>,
	Vladimir Oltean <olteanv@...il.com>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Russell King <linux@...linux.org.uk>,
	Daniel Golle <daniel@...rotopia.org>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Rasmus Villemoes <ravi@...vas.dk>,
	"Benny (Ying-Tsan) Weng" <yweng@...linear.com>,
	John Crispin <john@...ozen.org>
Subject: [PATCH net v4 1/4] net: dsa: lantiq_gswip: fix order in .remove
 operation

Russell King pointed out that disabling the switch by clearing
GSWIP_MDIO_GLOB_ENABLE before calling dsa_unregister_switch() is
problematic, as it violates a Golden Rule of driver development to
always first unpublish userspace interfaces and then disable the
hardware.

Fix this, and also simplify the probe() function, by introducing a
dsa_switch_ops teardown() operation which takes care of clearing the
GSWIP_MDIO_GLOB_ENABLE bit.

Fixes: 14fceff4771e5 ("net: dsa: Add Lantiq / Intel DSA driver for vrx200")
Suggested-by: "Russell King (Oracle)" <linux@...linux.org.uk>
Signed-off-by: Daniel Golle <daniel@...rotopia.org>
---
v4: initial submission, not present in previous versions

 drivers/net/dsa/lantiq/lantiq_gswip.c        |  3 ---
 drivers/net/dsa/lantiq/lantiq_gswip_common.c | 13 ++++++++++---
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/net/dsa/lantiq/lantiq_gswip.c b/drivers/net/dsa/lantiq/lantiq_gswip.c
index 57dd063c07403..b094001a7c805 100644
--- a/drivers/net/dsa/lantiq/lantiq_gswip.c
+++ b/drivers/net/dsa/lantiq/lantiq_gswip.c
@@ -444,9 +444,6 @@ static void gswip_remove(struct platform_device *pdev)
 	if (!priv)
 		return;
 
-	/* disable the switch */
-	gswip_disable_switch(priv);
-
 	dsa_unregister_switch(priv->ds);
 
 	for (i = 0; i < priv->num_gphy_fw; i++)
diff --git a/drivers/net/dsa/lantiq/lantiq_gswip_common.c b/drivers/net/dsa/lantiq/lantiq_gswip_common.c
index 9da39edf8f574..6b171d58e1862 100644
--- a/drivers/net/dsa/lantiq/lantiq_gswip_common.c
+++ b/drivers/net/dsa/lantiq/lantiq_gswip_common.c
@@ -752,6 +752,13 @@ static int gswip_setup(struct dsa_switch *ds)
 	return 0;
 }
 
+static void gswip_teardown(struct dsa_switch *ds)
+{
+	struct gswip_priv *priv = ds->priv;
+
+	regmap_clear_bits(priv->mdio, GSWIP_MDIO_GLOB, GSWIP_MDIO_GLOB_ENABLE);
+}
+
 static enum dsa_tag_protocol gswip_get_tag_protocol(struct dsa_switch *ds,
 						    int port,
 						    enum dsa_tag_protocol mp)
@@ -1629,6 +1636,7 @@ static const struct phylink_mac_ops gswip_phylink_mac_ops = {
 static const struct dsa_switch_ops gswip_switch_ops = {
 	.get_tag_protocol	= gswip_get_tag_protocol,
 	.setup			= gswip_setup,
+	.teardown		= gswip_teardown,
 	.port_setup		= gswip_port_setup,
 	.port_enable		= gswip_port_enable,
 	.port_disable		= gswip_port_disable,
@@ -1718,15 +1726,14 @@ int gswip_probe_common(struct gswip_priv *priv, u32 version)
 
 	err = gswip_validate_cpu_port(priv->ds);
 	if (err)
-		goto disable_switch;
+		goto unregister_switch;
 
 	dev_info(priv->dev, "probed GSWIP version %lx mod %lx\n",
 		 GSWIP_VERSION_REV(version), GSWIP_VERSION_MOD(version));
 
 	return 0;
 
-disable_switch:
-	gswip_disable_switch(priv);
+unregister_switch:
 	dsa_unregister_switch(priv->ds);
 
 	return err;
-- 
2.52.0