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.ct@bp.renesas.com Reviewed-by: Marek Vasut marek.vasut+renesas@mailbox.org --- Changes v1->v2: - Split out of series adding RZ/G2L Ethernet support [1] - Added Marek's Reviewed-by tag
[1]: https://lore.kernel.org/all/20241024152448.102-1-paul.barker.ct@bp.renesas.c...
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 b33457910795..e0b36f3fcdf9 100644 --- a/drivers/net/phy/micrel_ksz90x1.c +++ b/drivers/net/phy/micrel_ksz90x1.c @@ -395,6 +395,117 @@ U_BOOT_PHY_DRIVER(ksz9031) = { #define KSZ9131RN_LED_ERRATA_REG 0x1e #define KSZ9131RN_LED_ERRATA_BITS BIT(9)
+#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; @@ -474,6 +585,10 @@ 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;