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...@gmail.com>
---
Changes in v2:
- add a comment for getting "tx_clk" via clk_get_by_name()
- does not change anything in the default case
- check the return value of clk_set_rate()
drivers/net/macb.c | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/drivers/net/macb.c b/drivers/net/macb.c
index b7f404e..c5560a7 100644
--- a/drivers/net/macb.c
+++ b/drivers/net/macb.c
@@ -497,6 +497,41 @@ 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;
+
+ /*
+ * "tx_clk" is an optional clock source for MACB.
+ * Ignore if it does not exist in DT.
+ */
+ ret = clk_get_by_name(dev, "tx_clk", &tx_clk);
+ if (ret)
+ return 0;
+
+ switch (speed) {
+ case _10BASET:
+ rate = 2500000; /* 2.5 MHz */
+ break;
+ case _100BASET:
+ rate = 25000000; /* 25 MHz */
+ break;
+ case _1000BASET:
+ rate = 125000000; /* 125 MHz */
+ break;
+ default:
+ /* does not change anything */
+ return 0;
+ }
+
+ if (tx_clk.dev) {
+ ret = clk_set_rate(&tx_clk, rate);
+ if (ret)
+ return ret;
+ }
+#endif
+
return 0;
}
#else
--
2.7.4
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