[PATCH v1] net: phy: dp83869: fix setting CLK_O_SEL field.

From: Heiko Schocher

Date: Fri Apr 24 2026 - 23:14:12 EST


Table 7-121 in datasheet says we have to set register 0xc6
to value 0x10 before CLK_O_SEL can be modified. No more infos
about this field found in datasheet. With this fix, setting
of CLK_O_SEL field in IO_MUX_CFG register worked through dts
property "ti,clk-output-sel" on a DP83869HMRGZR.

Signed-off-by: Heiko Schocher <hs@xxxxxxxxxxxx>
---

drivers/net/phy/dp83869.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/dp83869.c b/drivers/net/phy/dp83869.c
index 1f381d7b13ff..96a7d255f50f 100644
--- a/drivers/net/phy/dp83869.c
+++ b/drivers/net/phy/dp83869.c
@@ -31,6 +31,7 @@
#define DP83869_RGMIICTL 0x0032
#define DP83869_STRAP_STS1 0x006e
#define DP83869_RGMIIDCTL 0x0086
+#define DP83869_ANA_PLL_PROG_PI 0x00c6
#define DP83869_RXFCFG 0x0134
#define DP83869_RXFPMD1 0x0136
#define DP83869_RXFPMD2 0x0137
@@ -826,12 +827,22 @@ static int dp83869_config_init(struct phy_device *phydev)
dp83869_config_port_mirroring(phydev);

/* Clock output selection if muxing property is set */
- if (dp83869->clk_output_sel != DP83869_CLK_O_SEL_REF_CLK)
+ if (dp83869->clk_output_sel != DP83869_CLK_O_SEL_REF_CLK) {
+ /*
+ * Table 7-121 in datasheet says we have to set register 0xc6
+ * to value 0x10 before CLK_O_SEL can be modified.
+ */
+ ret = phy_write_mmd(phydev, DP83869_DEVADDR,
+ DP83869_ANA_PLL_PROG_PI, 0x10);
+ if (ret)
+ return ret;
+
ret = phy_modify_mmd(phydev,
DP83869_DEVADDR, DP83869_IO_MUX_CFG,
DP83869_IO_MUX_CFG_CLK_O_SEL_MASK,
dp83869->clk_output_sel <<
DP83869_IO_MUX_CFG_CLK_O_SEL_SHIFT);
+ }

if (phy_interface_is_rgmii(phydev)) {
ret = phy_write_mmd(phydev, DP83869_DEVADDR, DP83869_RGMIIDCTL,
--
2.20.1