[PATCH] net: ravb: Add additional refclk

[Adam Ford]

The ethernet requires an external reference clock, and the driver
currently assumes the clock is always running.  For devices using
a programmable clock, this may not be true.  Add an optional clock
called 'refclk' to open and enable the refclk for hardware running
with programmable clocks.

Signed-off-by: Adam Ford <aford...@gmail.com>
---
This was also done in the Linux kernel, see:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/net/ethernet/renesas/ravb_main.c?id=8ef7adc6beb2ef0bce83513dc9e4505e7b21e8c2

diff --git a/drivers/net/ravb.c b/drivers/net/ravb.c
index 6953b7286a..ced80485de 100644
--- a/drivers/net/ravb.c
+++ b/drivers/net/ravb.c
@@ -130,6 +130,7 @@ struct ravb_priv {
        struct mii_dev          *bus;
        void __iomem            *iobase;
        struct clk              clk;
+       struct clk              *refclk;
        struct gpio_desc        reset_gpio;
 };
 
@@ -489,6 +490,8 @@ static int ravb_probe(struct udevice *dev)
        if (ret < 0)
                goto err_mdio_alloc;
 
+       eth->refclk = devm_clk_get_optional(dev, "refclk");
+
        ret = dev_read_phandle_with_args(dev, "phy-handle", NULL, 0, 0, 
&phandle_args);
        if (!ret) {
                gpio_request_by_name_nodev(phandle_args.node, "reset-gpios", 0,
@@ -522,6 +525,10 @@ static int ravb_probe(struct udevice *dev)
        if (ret)
                goto err_mdio_register;
 
+       ret = clk_enable(eth->refclk);
+       if (ret)
+               goto err_disable_clk;
+
        ret = ravb_reset(dev);
        if (ret)
                goto err_mdio_reset;
@@ -533,6 +540,8 @@ static int ravb_probe(struct udevice *dev)
        return 0;
 
 err_mdio_reset:
+       clk_disable(eth->refclk);
+err_disable_clk:
        clk_disable(&eth->clk);
 err_mdio_register:
        mdio_free(mdiodev);
@@ -545,6 +554,7 @@ static int ravb_remove(struct udevice *dev)
 {
        struct ravb_priv *eth = dev_get_priv(dev);
 
+       clk_disable(eth->refclk);
        clk_disable(&eth->clk);
 
        free(eth->phydev);
-- 
2.25.1