net: dsa: rtl8366rb: Support port 4 (WAN)

The totally undocumented IO mode needs to be set to enumerator
0 to enable port 4 also known as WAN in most configurations,
for ordinary traffic. The 3 bits in the register come up as
010 after reset, but need to be set to 000.

The Realtek source code contains a name for these bits, but
no explanation of what the 8 different IO modes may be.

Set it to zero for the time being and drop a comment so
people know what is going on if they run into trouble. This
"mode zero" works fine with the D-Link DIR-685 with
RTL8366RB.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/rtl8366rb.c b/drivers/net/dsa/rtl8366rb.c
index 1e55b9b..a4d5049 100644 (file)
--- a/drivers/net/dsa/rtl8366rb.c
+++ b/drivers/net/dsa/rtl8366rb.c
@@ -48,6 +48,23 @@
 #define RTL8366RB_SSCR2                                0x0004
 #define RTL8366RB_SSCR2_DROP_UNKNOWN_DA                BIT(0)
 
+/* Port Mode Control registers */
+#define RTL8366RB_PMC0                         0x0005
+#define RTL8366RB_PMC0_SPI                     BIT(0)
+#define RTL8366RB_PMC0_EN_AUTOLOAD             BIT(1)
+#define RTL8366RB_PMC0_PROBE                   BIT(2)
+#define RTL8366RB_PMC0_DIS_BISR                        BIT(3)
+#define RTL8366RB_PMC0_ADCTEST                 BIT(4)
+#define RTL8366RB_PMC0_SRAM_DIAG               BIT(5)
+#define RTL8366RB_PMC0_EN_SCAN                 BIT(6)
+#define RTL8366RB_PMC0_P4_IOMODE_SHIFT         7
+#define RTL8366RB_PMC0_P4_IOMODE_MASK          GENMASK(9, 7)
+#define RTL8366RB_PMC0_P5_IOMODE_SHIFT         10
+#define RTL8366RB_PMC0_P5_IOMODE_MASK          GENMASK(12, 10)
+#define RTL8366RB_PMC0_SDSMODE_SHIFT           13
+#define RTL8366RB_PMC0_SDSMODE_MASK            GENMASK(15, 13)
+#define RTL8366RB_PMC1                         0x0006
+
 /* Port Mirror Control Register */
 #define RTL8366RB_PMCR                         0x0007
 #define RTL8366RB_PMCR_SOURCE_PORT(a)          (a)
@@ -860,6 +877,19 @@ static int rtl8366rb_setup(struct dsa_switch *ds)
        if (ret)
                return ret;
 
+       /* Port 4 setup: this enables Port 4, usually the WAN port,
+        * common PHY IO mode is apparently mode 0, and this is not what
+        * the port is initialized to. There is no explanation of the
+        * IO modes in the Realtek source code, if your WAN port is
+        * connected to something exotic such as fiber, then this might
+        * be worth experimenting with.
+        */
+       ret = regmap_update_bits(smi->map, RTL8366RB_PMC0,
+                                RTL8366RB_PMC0_P4_IOMODE_MASK,
+                                0 << RTL8366RB_PMC0_P4_IOMODE_SHIFT);
+       if (ret)
+               return ret;
+
        /* Discard VLAN tagged packets if the port is not a member of
         * the VLAN with which the packets is associated.
         */