net: stmmac: dwmac-meson8b: Fetch the "timing-adjustment" clock

The PRG_ETHERNET registers have a built-in timing adjustment circuit
which can provide the RX delay in RGMII mode. This is driven by an
external (to this IP, but internal to the SoC) clock input. Fetch this
clock as optional (even though it's there on all supported SoCs) since
we just learned about it and existing .dtbs don't specify it.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
index 70075628c58eba801e6434db15eb65fc336c5a23..41f3ef6bea66070e4611c5abe625f54e62a5f84e 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
@@ -85,6 +85,7 @@ struct meson8b_dwmac {
        phy_interface_t                 phy_mode;
        struct clk                      *rgmii_tx_clk;
        u32                             tx_delay_ns;
+       struct clk                      *timing_adj_clk;
 };
 
 struct meson8b_dwmac_clk_configs {
@@ -380,6 +381,13 @@ static int meson8b_dwmac_probe(struct platform_device *pdev)
                                 &dwmac->tx_delay_ns))
                dwmac->tx_delay_ns = 2;
 
+       dwmac->timing_adj_clk = devm_clk_get_optional(dwmac->dev,
+                                                     "timing-adjustment");
+       if (IS_ERR(dwmac->timing_adj_clk)) {
+               ret = PTR_ERR(dwmac->timing_adj_clk);
+               goto err_remove_config_dt;
+       }
+
        ret = meson8b_init_rgmii_tx_clk(dwmac);
        if (ret)
                goto err_remove_config_dt;