net: phy: micrel: disable NAND-tree for KSZ8021, KSZ8031, KSZ8051, KSZ8081

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 for all Micrel PHYs
using IRQ line as a NAND-tree toggle mode at reset.

Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 28 insertions, 0 deletions

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 3ad8ca76196d..1190fd8f0088 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -32,6 +32,7 @@
 /* Operation Mode Strap Override */
 #define MII_KSZPHY_OMSO                         0x16
 #define KSZPHY_OMSO_B_CAST_OFF                  BIT(9)
+#define KSZPHY_OMSO_NAND_TREE_ON                BIT(5)
 #define KSZPHY_OMSO_RMII_OVERRIDE               BIT(1)
 #define KSZPHY_OMSO_MII_OVERRIDE                BIT(0)
 
@@ -76,6 +77,7 @@ struct kszphy_type {
         u32 led_mode_reg;
         u16 interrupt_level_mask;
         bool has_broadcast_disable;
+        bool has_nand_tree_disable;
         bool has_rmii_ref_clk_sel;
 };
 
@@ -89,6 +91,7 @@ struct kszphy_priv {
 static const struct kszphy_type ksz8021_type = {
         .led_mode_reg           = MII_KSZPHY_CTRL_2,
         .has_broadcast_disable  = true,
+        .has_nand_tree_disable  = true,
         .has_rmii_ref_clk_sel   = true,
 };
 
@@ -98,11 +101,13 @@ static const struct kszphy_type ksz8041_type = {
 
 static const struct kszphy_type ksz8051_type = {
         .led_mode_reg           = MII_KSZPHY_CTRL_2,
+        .has_nand_tree_disable  = true,
 };
 
 static const struct kszphy_type ksz8081_type = {
         .led_mode_reg           = MII_KSZPHY_CTRL_2,
         .has_broadcast_disable  = true,
+        .has_nand_tree_disable  = true,
         .has_rmii_ref_clk_sel   = true,
 };
 
@@ -231,6 +236,26 @@ out:
         return ret;
 }
 
+static int kszphy_nand_tree_disable(struct phy_device *phydev)
+{
+        int ret;
+
+        ret = phy_read(phydev, MII_KSZPHY_OMSO);
+        if (ret < 0)
+                goto out;
+
+        if (!(ret & KSZPHY_OMSO_NAND_TREE_ON))
+                return 0;
+
+        ret = phy_write(phydev, MII_KSZPHY_OMSO,
+                        ret & ~KSZPHY_OMSO_NAND_TREE_ON);
+out:
+        if (ret)
+                dev_err(&phydev->dev, "failed to disable NAND tree mode\n");
+
+        return ret;
+}
+
 static int kszphy_config_init(struct phy_device *phydev)
 {
         struct kszphy_priv *priv = phydev->priv;
@@ -245,6 +270,9 @@ static int kszphy_config_init(struct phy_device *phydev)
         if (type->has_broadcast_disable)
                 kszphy_broadcast_disable(phydev);
 
+        if (type->has_nand_tree_disable)
+                kszphy_nand_tree_disable(phydev);
+
         if (priv->rmii_ref_clk_sel) {
                 ret = kszphy_rmii_clk_sel(phydev, priv->rmii_ref_clk_sel_val);
                 if (ret) {