Various signal skew values may be set in the device tree for the ksz9131
Ethernet PHY. For example, the RZ/G2L board requires non-default values
for rxc-skew-psec & txc-skew-psec.
This is based on the ksz9131 phy driver in Linux v6.11.
Signed-off-by: Paul Barker <paul.barker...@bp.renesas.com>
---
drivers/net/phy/micrel_ksz90x1.c | 115 +++++++++++++++++++++++++++++++
1 file changed, 115 insertions(+)
diff --git a/drivers/net/phy/micrel_ksz90x1.c b/drivers/net/phy/micrel_ksz90x1.c
index 4f99b115a3c7..b64046e0bc72 100644
--- a/drivers/net/phy/micrel_ksz90x1.c
+++ b/drivers/net/phy/micrel_ksz90x1.c
@@ -389,6 +389,117 @@ U_BOOT_PHY_DRIVER(ksz9031) = {
#define KSZ9131RN_DLL_ENABLE_DELAY 0
#define KSZ9131RN_DLL_DISABLE_DELAY BIT(12)
+#define KSZ9131RN_CONTROL_PAD_SKEW 4
+#define KSZ9131RN_RX_DATA_PAD_SKEW 5
+#define KSZ9131RN_TX_DATA_PAD_SKEW 6
+#define KSZ9131RN_CLK_PAD_SKEW 8
+
+#define KSZ9131RN_SKEW_5BIT_MAX 2400
+#define KSZ9131RN_SKEW_4BIT_MAX 800
+#define KSZ9131RN_OFFSET 700
+#define KSZ9131RN_STEP 100
+
+static int ksz9131_of_load_skew_values(struct phy_device *phydev,
+ ofnode of_node,
+ u16 reg, size_t field_sz,
+ const char *field[], u8 numfields)
+{
+ int val[4] = {-(1 + KSZ9131RN_OFFSET), -(2 + KSZ9131RN_OFFSET),
+ -(3 + KSZ9131RN_OFFSET), -(4 + KSZ9131RN_OFFSET)};
+ int skewval, skewmax = 0;
+ int matches = 0;
+ u16 maxval;
+ u16 newval;
+ u16 mask;
+ int i;
+
+ /* psec properties in dts should mean x pico seconds */
+ if (field_sz == 5)
+ skewmax = KSZ9131RN_SKEW_5BIT_MAX;
+ else
+ skewmax = KSZ9131RN_SKEW_4BIT_MAX;
+
+ for (i = 0; i < numfields; i++)
+ if (!ofnode_read_s32(of_node, field[i], &skewval)) {
+ if (skewval < -KSZ9131RN_OFFSET)
+ skewval = -KSZ9131RN_OFFSET;
+ else if (skewval > skewmax)
+ skewval = skewmax;
+
+ val[i] = skewval + KSZ9131RN_OFFSET;
+ matches++;
+ }
+
+ if (!matches)
+ return 0;
+
+ if (matches < numfields)
+ newval = phy_read_mmd(phydev, KSZ9131RN_MMD_COMMON_CTRL_REG,
reg);
+ else
+ newval = 0;
+
+ maxval = (field_sz == 4) ? 0xf : 0x1f;
+ for (i = 0; i < numfields; i++)
+ if (val[i] != -(i + 1 + KSZ9131RN_OFFSET)) {
+ mask = 0xffff;
+ mask ^= maxval << (field_sz * i);
+ newval = (newval & mask) |
+ (((val[i] / KSZ9131RN_STEP) & maxval)
+ << (field_sz * i));
+ }
+
+ return phy_write_mmd(phydev, KSZ9131RN_MMD_COMMON_CTRL_REG, reg,
newval);
+}
+
+static int ksz9131_of_load_all_skew_values(struct phy_device *phydev)
+{
+ const char *control_skews[2] = { "txen-skew-psec", "rxdv-skew-psec" };
+ const char *clk_skews[2] = { "rxc-skew-psec", "txc-skew-psec" };
+ const char *rx_data_skews[4] = {
+ "rxd0-skew-psec", "rxd1-skew-psec",
+ "rxd2-skew-psec", "rxd3-skew-psec"
+ };
+ const char *tx_data_skews[4] = {
+ "txd0-skew-psec", "txd1-skew-psec",
+ "txd2-skew-psec", "txd3-skew-psec"
+ };
+ struct ofnode_phandle_args phandle_args;
+ int ret;
+
+ /*
+ * Silently ignore failure here as the device tree is not required to
+ * contain a phy node.
+ */
+ if (dev_read_phandle_with_args(phydev->dev, "phy-handle", NULL, 0, 0,
+ &phandle_args))
+ return 0;
+
+ if (!ofnode_valid(phandle_args.node))
+ return 0;
+
+ ret = ksz9131_of_load_skew_values(phydev, phandle_args.node,
+ KSZ9131RN_CLK_PAD_SKEW, 5,
+ clk_skews, 2);
+ if (ret < 0)
+ return ret;
+
+ ret = ksz9131_of_load_skew_values(phydev, phandle_args.node,
+ KSZ9131RN_CONTROL_PAD_SKEW, 4,
+ control_skews, 2);
+ if (ret < 0)
+ return ret;
+
+ ret = ksz9131_of_load_skew_values(phydev, phandle_args.node,
+ KSZ9131RN_RX_DATA_PAD_SKEW, 4,
+ rx_data_skews, 4);
+ if (ret < 0)
+ return ret;
+
+ return ksz9131_of_load_skew_values(phydev, phandle_args.node,
+ KSZ9131RN_TX_DATA_PAD_SKEW, 4,
+ tx_data_skews, 4);
+}
+
static int ksz9131_config_rgmii_delay(struct phy_device *phydev)
{
struct phy_driver *drv = phydev->drv;
@@ -466,6 +577,10 @@ static int ksz9131_config(struct phy_device *phydev)
return ret;
}
+ ret = ksz9131_of_load_all_skew_values(phydev);
+ if (ret < 0)
+ return ret;
+
ret = ksz9131_led_errata(phydev);
if (ret < 0)
return ret;
--
2.43.0
