[PATCH RFC v2 3/5] net: stmmac: dwmac-meson8b: use picoseconds for the RGMII RX delay

[Martin Blumenstingl]

Amlogic Meson G12A, G12B and SM1 SoCs have a more advanced RGMII RX
delay register which allows picoseconds precision. Parse the new
"amlogic,rgmii-rx-delay-ps" property or fall back to the old
"amlogic,rx-delay-ns".

Signed-off-by: Martin Blumenstingl <martin.blumensti...@googlemail.com>
---
 .../ethernet/stmicro/stmmac/dwmac-meson8b.c   | 22 ++++++++++++-------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c 
b/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
index e27e2e7a53fd..03fce678b9f5 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c
@@ -83,7 +83,7 @@ struct meson8b_dwmac {
        phy_interface_t                 phy_mode;
        struct clk                      *rgmii_tx_clk;
        u32                             tx_delay_ns;
-       u32                             rx_delay_ns;
+       u32                             rx_delay_ps;
        struct clk                      *timing_adj_clk;
 };
 
@@ -276,7 +276,7 @@ static int meson8b_init_prg_eth(struct meson8b_dwmac *dwmac)
        tx_dly_config = FIELD_PREP(PRG_ETH0_TXDLY_MASK,
                                   dwmac->tx_delay_ns >> 1);
 
-       if (dwmac->rx_delay_ns == 2)
+       if (dwmac->rx_delay_ps == 2000)
                rx_dly_config = PRG_ETH0_ADJ_ENABLE | PRG_ETH0_ADJ_SETUP;
        else
                rx_dly_config = 0;
@@ -406,14 +406,20 @@ static int meson8b_dwmac_probe(struct platform_device 
*pdev)
                                 &dwmac->tx_delay_ns))
                dwmac->tx_delay_ns = 2;
 
-       /* use 0ns as fallback since this is what most boards actually use */
-       if (of_property_read_u32(pdev->dev.of_node, "amlogic,rx-delay-ns",
-                                &dwmac->rx_delay_ns))
-               dwmac->rx_delay_ns = 0;
+       /* RX delay defaults to 0ps since this is what many boards use */
+       if (of_property_read_u32(pdev->dev.of_node,
+                                "amlogic,rgmii-rx-delay-ps",
+                                 &dwmac->rx_delay_ps)) {
+               if (!of_property_read_u32(pdev->dev.of_node,
+                                         "amlogic,rx-delay-ns",
+                                         &dwmac->rx_delay_ps))
+                       /* convert ns to ps */
+                       dwmac->rx_delay_ps *= 1000;
+       }
 
-       if (dwmac->rx_delay_ns != 0 && dwmac->rx_delay_ns != 2) {
+       if (dwmac->rx_delay_ps != 0 && dwmac->rx_delay_ps != 2000) {
                dev_err(&pdev->dev,
-                       "The only allowed RX delays values are: 0ns, 2ns");
+                       "The only allowed RX delays values are: 0ps, 2000ps");
                ret = -EINVAL;
                goto err_remove_config_dt;
        }
-- 
2.29.2