[U-Boot] [PATCH 3/4] dm: net: macb: Implement link speed change callback

[Bin Meng]

At present the link speed change callback is a nop. According to
macb device tree bindings, an optional "tx_clk" is used to clock
the ethernet controller's TX_CLK under different link speed.

In 10/100 MII mode, transmit logic must be clocked from a free
running clock generated by the external PHY. In gigabit GMII mode,
the controller, not the external PHY, must generate the 125 MHz
transmit clock towards the PHY.

Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
---

 drivers/net/macb.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/net/macb.c b/drivers/net/macb.c
index b7f404e..7d86fa1 100644
--- a/drivers/net/macb.c
+++ b/drivers/net/macb.c
@@ -497,6 +497,32 @@ static int macb_phy_find(struct macb_device *macb, const char *name)
 #ifdef CONFIG_DM_ETH
 int __weak macb_linkspd_cb(struct udevice *dev, unsigned int speed)
 {
+#ifdef CONFIG_CLK
+	struct clk tx_clk;
+	ulong rate;
+	int ret;
+
+	ret = clk_get_by_name(dev, "tx_clk", &tx_clk);
+	if (ret)
+		return 0;
+
+	switch (speed) {
+	case _10BASET:
+		rate = 2500000;
+		break;
+	case _100BASET:
+		rate = 25000000;
+		break;
+	case _1000BASET:
+	default:
+		rate = 125000000;
+		break;
+	}
+
+	if (tx_clk.dev)
+		clk_set_rate(&tx_clk, rate);
+#endif
+
 	return 0;
 }
 #else
-- 
2.7.4