net: phy: micrel: disable NAND-tree for KSZ8051

NAND-tree is used to check wiring between MAC and PHY using NAND gates
on the PHY side, hence the name.

NAND-tree initial status is latched at reset by probing the IRQ pin.
However some devices are sharing the PHY IRQ pin with other peripherals
such as Atmel SAMA5D[34]x-EK boards when using the optional TM7000
display module, therefore they are switching the PHY in NAND-tree test
mode depending on the current IRQ line status at reset.

This patch ensure PHY is not in NAND-tree test mode only for the Micrel
KSZ8051 PHY used by Atmel. There are other Micrel PHY affected but I
doubt they are used on such weird hardware design.

Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index cbec928ce4bfa5c480a9177e411206ec660e45c3..5e49666bbb34e1a12d748db7a8c1107828311f78 100644 (file)
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -32,6 +32,34 @@ static struct phy_driver KSZ8031_driver = {
        .shutdown = &genphy_shutdown,
 };
 
+/**
+ * KSZ8051
+ */
+#define MII_KSZ8051_PHY_OMSO                   0x16
+#define MII_KSZ8051_PHY_OMSO_NAND_TREE_ON      (1 << 5)
+
+static int ksz8051_config(struct phy_device *phydev)
+{
+       unsigned val;
+
+       /* Disable NAND-tree */
+       val = phy_read(phydev, MDIO_DEVAD_NONE, MII_KSZ8051_PHY_OMSO);
+       val &= ~MII_KSZ8051_PHY_OMSO_NAND_TREE_ON;
+       phy_write(phydev, MDIO_DEVAD_NONE, MII_KSZ8051_PHY_OMSO, val);
+
+       return genphy_config(phydev);
+}
+
+static struct phy_driver KSZ8051_driver = {
+       .name = "Micrel KSZ8051",
+       .uid = 0x221550,
+       .mask = 0xfffff0,
+       .features = PHY_BASIC_FEATURES,
+       .config = &ksz8051_config,
+       .startup = &genphy_startup,
+       .shutdown = &genphy_shutdown,
+};
+
 static struct phy_driver KSZ8081_driver = {
        .name = "Micrel KSZ8081",
        .uid = 0x221560,
@@ -293,6 +321,7 @@ int phy_micrel_init(void)
 {
        phy_register(&KSZ804_driver);
        phy_register(&KSZ8031_driver);
+       phy_register(&KSZ8051_driver);
        phy_register(&KSZ8081_driver);
 #ifdef CONFIG_PHY_MICREL_KSZ9021
        phy_register(&ksz9021_driver);