[U-Boot] [PATCH 6/9] net: sun8i_emac: Support RX/TX delay chains

[Chen-Yu Tsai]

The EMAC syscon has configurable RX/TX delay chains for use with RGMII
PHYs.

This adds support for configuring them via device tree properties. The
property names and format were defined in Linux's dwmac-sun8i binding
that was merged at one point.

Signed-off-by: Chen-Yu Tsai <w...@csie.org>
---
 drivers/net/sun8i_emac.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/net/sun8i_emac.c b/drivers/net/sun8i_emac.c
index 09bbb2cdb5ca..5fa1b4c170d7 100644
--- a/drivers/net/sun8i_emac.c
+++ b/drivers/net/sun8i_emac.c
@@ -56,6 +56,10 @@
 #define H3_EPHY_SELECT         BIT(15) /* 1: internal PHY, 0: external PHY */
 
 #define SC_RMII_EN             BIT(13)
+#define SC_TXDC_SHIFT          10
+#define SC_TXDC_MASK           GENMASK(2, 0)
+#define SC_RXDC_SHIFT          5
+#define SC_RXDC_MASK           GENMASK(4, 0)
 #define SC_EPIT                        BIT(2) /* 1: RGMII, 0: MII */
 #define SC_ETCS_MASK           GENMASK(1, 0)
 #define SC_ETCS_EXT_GMII       0x1
@@ -125,6 +129,8 @@ struct emac_eth_dev {
        u32 addr;
        u32 tx_slot;
        bool use_internal_phy;
+       u32 tx_delay;
+       u32 rx_delay;
 
        enum emac_variant variant;
        void *mac_reg;
@@ -290,6 +296,12 @@ static int sun8i_emac_set_syscon(struct emac_eth_dev *priv)
        if (priv->variant == H3_EMAC || priv->variant == A64_EMAC)
                reg &= ~SC_RMII_EN;
 
+       /* Configure RX/TX delay chains */
+       reg &= ~(SC_RXDC_MASK << SC_RXDC_SHIFT);
+       reg &= ~(SC_TXDC_MASK << SC_TXDC_SHIFT);
+       reg |= (priv->rx_delay & SC_RXDC_MASK) << SC_RXDC_SHIFT;
+       reg |= (priv->tx_delay & SC_TXDC_MASK) << SC_TXDC_SHIFT;
+
        switch (priv->interface) {
        case PHY_INTERFACE_MODE_MII:
                /* default */
@@ -836,6 +848,19 @@ static int sun8i_emac_eth_ofdata_to_platdata(struct 
udevice *dev)
        }
 #endif
 
+       /* Get RX/TX delays for RGMII */
+       priv->rx_delay = fdtdec_get_uint(gd->fdt_blob, dev_of_offset(dev),
+                                        "allwinner,rx-delay-ps", 0);
+       if (priv->rx_delay % 100 || priv->rx_delay > 3100)
+               debug("%s: invalid rx delay value\n", __func__);
+       priv->rx_delay /= 100;
+
+       priv->tx_delay = fdtdec_get_uint(gd->fdt_blob, dev_of_offset(dev),
+                                        "allwinner,tx-delay-ps", 0);
+       if (priv->tx_delay % 100 || priv->tx_delay > 800)
+               debug("%s: invalid tx delay value\n", __func__);
+       priv->tx_delay /= 100;
+
        return 0;
 }
 
-- 
2.14.1

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