dm: net: macb: Implement link speed change callback

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@gmail.com>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Tested-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
This commit is contained in:
Bin Meng 2019-05-22 00:09:46 -07:00 committed by Joe Hershberger
parent a5e3d2350b
commit 3ef64444de

View file

@ -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