[RFC PATCH 08/13] dwmac-meson8b: add support for phy selection

[Neil Armstrong]

The Meson GXL dwmac Glue Layer also provides switching between an external PHY
and an internal RMII 10/100 PHY.
Add a way to setup the correct PHY switching from a device tree attribute.

Currently, the register format is unknown and this is a temporary workaround
until a clarification on the registers fields is received from Amlogic.

Signed-off-by: Neil Armstrong <narmstr...@baylibre.com>
---
 .../net/ethernet/stmicro/stmmac/dwmac-meson8b.c    | 25 ++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c 
b/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
index 250e4ce..875cd7c 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
@@ -53,10 +53,15 @@
 
 #define MUX_CLK_NUM_PARENTS            2
 
+#define PHYSEL_REG0                    0x0
+#define PHYSEL_REG0_VALUE              0x10110181
+#define PHYSEL_REG1                    0x4
+
 struct meson8b_dwmac {
        struct platform_device  *pdev;
 
        void __iomem            *regs;
+       void __iomem            *physel_regs;
 
        phy_interface_t         phy_mode;
 
@@ -244,6 +249,23 @@ static int meson8b_init_prg_eth(struct meson8b_dwmac 
*dwmac)
        meson8b_dwmac_mask_bits(dwmac, PRG_ETH0, PRG_ETH0_TX_AND_PHY_REF_CLK,
                                PRG_ETH0_TX_AND_PHY_REF_CLK);
 
+       /* Select PHY, either internal or external if specified */
+       if (!IS_ERR(dwmac->physel_regs) &&
+           of_find_property(dwmac->pdev->dev.of_node,
+                            "amlogic,phy-select", NULL)) {
+               u32 val;
+
+               ret = of_property_read_u32(dwmac->pdev->dev.of_node,
+                                          "amlogic,phy-select", &val);
+               if (ret) {
+                       dev_err(&dwmac->pdev->dev, "invalid phy-select 
property\n");
+               } else {
+                       writel(PHYSEL_REG0_VALUE,
+                              dwmac->physel_regs + PHYSEL_REG0);
+                       writel(val, dwmac->physel_regs + PHYSEL_REG1);
+               }
+       }
+
        return 0;
 }
 
@@ -272,6 +294,9 @@ static int meson8b_dwmac_probe(struct platform_device *pdev)
        if (IS_ERR(dwmac->regs))
                return PTR_ERR(dwmac->regs);
 
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
+       dwmac->physel_regs = devm_ioremap_resource(&pdev->dev, res);
+
        dwmac->pdev = pdev;
        dwmac->phy_mode = of_get_phy_mode(pdev->dev.of_node);
        if (dwmac->phy_mode < 0) {
-- 
1.9.1