[PATCH 2/3] net: macb: adjust clk_tx rate for link speed changes
Michael Tretter
m.tretter at pengutronix.de
Thu Oct 15 09:20:47 EDT 2020
Changes of the link speed might require an adjustment of the clk_tx.
Read the clk_tx from the device tree and change the rate if the link
speed changes.
If the clk_tx rate is already correct, changing the clock is not
required and, thus, not being able to get the clock rate is not fatal.
Signed-off-by: Michael Tretter <m.tretter at pengutronix.de>
---
drivers/net/macb.c | 35 +++++++++++++++++++++++++++++++++++
1 file changed, 35 insertions(+)
diff --git a/drivers/net/macb.c b/drivers/net/macb.c
index 09b58ffd017f..fa530cfe8e4c 100644
--- a/drivers/net/macb.c
+++ b/drivers/net/macb.c
@@ -258,9 +258,38 @@ static int macb_recv(struct eth_device *edev)
return 0;
}
+static int macb_set_tx_clk(struct macb_device *macb, int speed)
+{
+ int rate;
+ int rate_rounded;
+
+ if (!macb->txclk) {
+ dev_dbg(macb->dev, "txclk not available\n");
+ return 0;
+ }
+
+ switch (speed) {
+ case SPEED_100:
+ rate = 25000000;
+ break;
+ case SPEED_1000:
+ rate = 125000000;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ rate_rounded = clk_round_rate(macb->txclk, rate);
+ if (rate_rounded <= 0)
+ return -EINVAL;
+
+ return clk_set_rate(macb->txclk, rate_rounded);
+}
+
static void macb_adjust_link(struct eth_device *edev)
{
struct macb_device *macb = edev->priv;
+ int err;
u32 reg;
reg = macb_readl(macb, NCFGR);
@@ -276,6 +305,10 @@ static void macb_adjust_link(struct eth_device *edev)
reg |= GEM_BIT(GBE);
macb_or_gem_writel(macb, NCFGR, reg);
+
+ err = macb_set_tx_clk(macb, edev->phydev->speed);
+ if (err)
+ dev_warn(macb->dev, "cannot set txclk\n");
}
static int macb_open(struct eth_device *edev)
@@ -724,6 +757,8 @@ static int macb_probe(struct device_d *dev)
macb->txclk = clk_get(dev, "tx_clk");
if (!IS_ERR(macb->txclk))
clk_enable(macb->txclk);
+ else
+ macb->txclk = NULL;
macb->rxclk = clk_get(dev, "rx_clk");
if (!IS_ERR(macb->rxclk))
--
2.20.1
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