net: stmmac: sun8i: drop unneeded default syscon value

For some odd reason we were very jealous about the value of the EMAC
clock register from the syscon block, insisting on a reset value and
only doing read-modify-write operations on that register, even though we
pretty much know the register layout.
This already led to a basically redundant entry for the H6, which only
differs by that value. We seem to have the same situation with the new
A523 SoC, which again is compatible to the A64, but has a different
syscon reset value.

Drop any assumptions about that value, and set or clear the bits that we
want to program, from scratch (starting with a value of 0). For the
remove() implementation, we just turn on the POWERDOWN bit, and deselect
the internal PHY, which mimics the existing code.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Acked-by: Corentin LABBE <clabbe.montjoie@gmail.com>
Tested-by: Corentin LABBE <clabbe.montjoie@gmail.com>
Tested-by: Paul Kocialkowski <paulk@sys-base.io>
Reviewed-by: Paul Kocialkowski <paulk@sys-base.io>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20250825172055.19794-1-andre.przywara@arm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
index 2796dc426943e1cf93fa2805b0c235b61508f4e2..690f3650f84ed1266fce5cb8aa1c09e4e9100ba0 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c
@@ -31,10 +31,6 @@
  */
 
 /* struct emac_variant - Describe dwmac-sun8i hardware variant
- * @default_syscon_value:      The default value of the EMAC register in syscon
- *                             This value is used for disabling properly EMAC
- *                             and used as a good starting value in case of the
- *                             boot process(uboot) leave some stuff.
  * @syscon_field               reg_field for the syscon's gmac register
  * @soc_has_internal_phy:      Does the MAC embed an internal PHY
  * @support_mii:               Does the MAC handle MII
@@ -48,7 +44,6 @@
  *                             value of zero indicates this is not supported.
  */
 struct emac_variant {
-       u32 default_syscon_value;
        const struct reg_field *syscon_field;
        bool soc_has_internal_phy;
        bool support_mii;
@@ -94,7 +89,6 @@ static const struct reg_field sun8i_ccu_reg_field = {
 };
 
 static const struct emac_variant emac_variant_h3 = {
-       .default_syscon_value = 0x58000,
        .syscon_field = &sun8i_syscon_reg_field,
        .soc_has_internal_phy = true,
        .support_mii = true,
@@ -105,14 +99,12 @@ static const struct emac_variant emac_variant_h3 = {
 };
 
 static const struct emac_variant emac_variant_v3s = {
-       .default_syscon_value = 0x38000,
        .syscon_field = &sun8i_syscon_reg_field,
        .soc_has_internal_phy = true,
        .support_mii = true
 };
 
 static const struct emac_variant emac_variant_a83t = {
-       .default_syscon_value = 0,
        .syscon_field = &sun8i_syscon_reg_field,
        .soc_has_internal_phy = false,
        .support_mii = true,
@@ -122,7 +114,6 @@ static const struct emac_variant emac_variant_a83t = {
 };
 
 static const struct emac_variant emac_variant_r40 = {
-       .default_syscon_value = 0,
        .syscon_field = &sun8i_ccu_reg_field,
        .support_mii = true,
        .support_rgmii = true,
@@ -130,7 +121,6 @@ static const struct emac_variant emac_variant_r40 = {
 };
 
 static const struct emac_variant emac_variant_a64 = {
-       .default_syscon_value = 0,
        .syscon_field = &sun8i_syscon_reg_field,
        .soc_has_internal_phy = false,
        .support_mii = true,
@@ -141,7 +131,6 @@ static const struct emac_variant emac_variant_a64 = {
 };
 
 static const struct emac_variant emac_variant_h6 = {
-       .default_syscon_value = 0x50000,
        .syscon_field = &sun8i_syscon_reg_field,
        /* The "Internal PHY" of H6 is not on the die. It's on the
         * co-packaged AC200 chip instead.
@@ -933,25 +922,11 @@ static int sun8i_dwmac_set_syscon(struct device *dev,
        struct sunxi_priv_data *gmac = plat->bsp_priv;
        struct device_node *node = dev->of_node;
        int ret;
-       u32 reg, val;
-
-       ret = regmap_field_read(gmac->regmap_field, &val);
-       if (ret) {
-               dev_err(dev, "Fail to read from regmap field.\n");
-               return ret;
-       }
-
-       reg = gmac->variant->default_syscon_value;
-       if (reg != val)
-               dev_warn(dev,
-                        "Current syscon value is not the default %x (expect %x)\n",
-                        val, reg);
+       u32 reg = 0, val;
 
        if (gmac->variant->soc_has_internal_phy) {
                if (of_property_read_bool(node, "allwinner,leds-active-low"))
                        reg |= H3_EPHY_LED_POL;
-               else
-                       reg &= ~H3_EPHY_LED_POL;
 
                /* Force EPHY xtal frequency to 24MHz. */
                reg |= H3_EPHY_CLK_SEL;
@@ -965,11 +940,6 @@ static int sun8i_dwmac_set_syscon(struct device *dev,
                 * address. No need to mask it again.
                 */
                reg |= ret << H3_EPHY_ADDR_SHIFT;
-       } else {
-               /* For SoCs without internal PHY the PHY selection bit should be
-                * set to 0 (external PHY).
-                */
-               reg &= ~H3_EPHY_SELECT;
        }
 
        if (!of_property_read_u32(node, "allwinner,tx-delay-ps", &val)) {
@@ -980,8 +950,6 @@ static int sun8i_dwmac_set_syscon(struct device *dev,
                val /= 100;
                dev_dbg(dev, "set tx-delay to %x\n", val);
                if (val <= gmac->variant->tx_delay_max) {
-                       reg &= ~(gmac->variant->tx_delay_max <<
-                                SYSCON_ETXDC_SHIFT);
                        reg |= (val << SYSCON_ETXDC_SHIFT);
                } else {
                        dev_err(dev, "Invalid TX clock delay: %d\n",
@@ -998,8 +966,6 @@ static int sun8i_dwmac_set_syscon(struct device *dev,
                val /= 100;
                dev_dbg(dev, "set rx-delay to %x\n", val);
                if (val <= gmac->variant->rx_delay_max) {
-                       reg &= ~(gmac->variant->rx_delay_max <<
-                                SYSCON_ERXDC_SHIFT);
                        reg |= (val << SYSCON_ERXDC_SHIFT);
                } else {
                        dev_err(dev, "Invalid RX clock delay: %d\n",
@@ -1008,11 +974,6 @@ static int sun8i_dwmac_set_syscon(struct device *dev,
                }
        }
 
-       /* Clear interface mode bits */
-       reg &= ~(SYSCON_ETCS_MASK | SYSCON_EPIT);
-       if (gmac->variant->support_rmii)
-               reg &= ~SYSCON_RMII_EN;
-
        switch (plat->mac_interface) {
        case PHY_INTERFACE_MODE_MII:
                /* default */
@@ -1039,9 +1000,9 @@ static int sun8i_dwmac_set_syscon(struct device *dev,
 
 static void sun8i_dwmac_unset_syscon(struct sunxi_priv_data *gmac)
 {
-       u32 reg = gmac->variant->default_syscon_value;
-
-       regmap_field_write(gmac->regmap_field, reg);
+       if (gmac->variant->soc_has_internal_phy)
+               regmap_field_write(gmac->regmap_field,
+                                  (H3_EPHY_SHUTDOWN | H3_EPHY_SELECT));
 }
 
 static void sun8i_dwmac_exit(struct platform_device *pdev, void *priv)