linux-kernel - [PATCH net-next 6/8] net: phy: mscc: restore the base page in vsc8514/8584_config

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Date:   Thu, 25 Jun 2020 17:42:09 +0200
From:   Antoine Tenart <antoine.tenart@...tlin.com>
To:     davem@...emloft.net, andrew@...n.ch, f.fainelli@...il.com,
        hkallweit1@...il.com
Cc:     Antoine Tenart <antoine.tenart@...tlin.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        thomas.petazzoni@...tlin.com
Subject: [PATCH net-next 6/8] net: phy: mscc: restore the base page in vsc8514/8584_config_init

In the vsc8584_config_init and vsc8514_config_init, the base page is set
to 'GPIO', configuration is done, and the page is never explicitly
restored to the standard page. No bug was triggered as it turns out
helpers called in those config_init functions do modify the base page,
and set it back to standard. But that is dangerous and any modification
to those functions would introduce bugs. This patch fixes this, to
improve maintenance, by restoring the base page to 'standard' once
'GPIO' accesses are completed.

Signed-off-by: Antoine Tenart <antoine.tenart@...tlin.com>
---
 drivers/net/phy/mscc/mscc_main.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/net/phy/mscc/mscc_main.c b/drivers/net/phy/mscc/mscc_main.c
index 03680933f530..f625109df00a 100644
--- a/drivers/net/phy/mscc/mscc_main.c
+++ b/drivers/net/phy/mscc/mscc_main.c
@@ -1395,6 +1395,11 @@ static int vsc8584_config_init(struct phy_device *phydev)
 	if (ret)
 		goto err;
 
+	ret = phy_base_write(phydev, MSCC_EXT_PAGE_ACCESS,
+			     MSCC_PHY_PAGE_STANDARD);
+	if (ret)
+		goto err;
+
 	if (!phy_interface_is_rgmii(phydev)) {
 		val = PROC_CMD_MCB_ACCESS_MAC_CONF | PROC_CMD_RST_CONF_PORT |
 			PROC_CMD_READ_MOD_WRITE_PORT;
@@ -1779,7 +1784,11 @@ static int vsc8514_config_init(struct phy_device *phydev)
 	val &= ~MAC_CFG_MASK;
 	val |= MAC_CFG_QSGMII;
 	ret = phy_base_write(phydev, MSCC_PHY_MAC_CFG_FASTLINK, val);
+	if (ret)
+		goto err;
 
+	ret = phy_base_write(phydev, MSCC_EXT_PAGE_ACCESS,
+			     MSCC_PHY_PAGE_STANDARD);
 	if (ret)
 		goto err;
 
-- 
2.26.2