net: phy: realtek: allow CLKOUT to be disabled on RTL8211F(D)(I)-VD-CG

Add CLKOUT disable support for RTL8211F(D)(I)-VD-CG. Like with other PHY
variants, this feature might be requested by customers when the clock
output is not used, in order to reduce electromagnetic interference (EMI).

In the common driver, the CLKOUT configuration is done through PHYCR2.
The RTL_8211FVD_PHYID is singled out as not having that register, and
execution in rtl8211f_config_init() returns early after commit
2c67301584f2 ("net: phy: realtek: Avoid PHYCR2 access if PHYCR2 not
present").

But actually CLKOUT is configured through a different register for this
PHY. Instead of pretending this is PHYCR2 (which it is not), just add
some code for modifying this register inside the rtl8211f_disable_clk_out()
function, and move that outside the code portion that runs only if
PHYCR2 exists.

In practice this reorders the PHYCR2 writes to disable PHY-mode EEE and
to disable the CLKOUT for the normal RTL8211F variants, but this should
be perfectly fine.

It was not noted that RTL8211F(D)(I)-VD-CG would need a genphy_soft_reset()
call after disabling the CLKOUT. Despite that, we do it out of caution
and for symmetry with the other RTL8211F models.

Co-developed-by: Clark Wang <xiaoning.wang@nxp.com>
Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20251117234033.345679-5-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/phy/realtek/realtek_main.c b/drivers/net/phy/realtek/realtek_main.c
index da1db6499c384db7f3a101e107ef1634e8df38c1..da30cdb522a33a65a1a22e24616d51def5b4cdde 100644 (file)
--- a/drivers/net/phy/realtek/realtek_main.c
+++ b/drivers/net/phy/realtek/realtek_main.c
@@ -90,6 +90,14 @@
 #define RTL8211F_LEDCR_MASK                    GENMASK(4, 0)
 #define RTL8211F_LEDCR_SHIFT                   5
 
+/* RTL8211F(D)(I)-VD-CG CLKOUT configuration is specified via magic values
+ * to undocumented register pages. The names here do not reflect the datasheet.
+ * Unlike other PHY models, CLKOUT configuration does not go through PHYCR2.
+ */
+#define RTL8211FVD_CLKOUT_PAGE                 0xd05
+#define RTL8211FVD_CLKOUT_REG                  0x11
+#define RTL8211FVD_CLKOUT_EN                   BIT(8)
+
 /* RTL8211F RGMII configuration */
 #define RTL8211F_RGMII_PAGE                    0xd08
 
@@ -653,8 +661,13 @@ static int rtl8211f_config_clk_out(struct phy_device *phydev)
        if (!priv->disable_clk_out)
                return 0;
 
-       ret = phy_modify_paged(phydev, RTL8211F_PHYCR_PAGE,
-                              RTL8211F_PHYCR2, RTL8211F_CLKOUT_EN, 0);
+       if (phydev->drv->phy_id == RTL_8211FVD_PHYID)
+               ret = phy_modify_paged(phydev, RTL8211FVD_CLKOUT_PAGE,
+                                      RTL8211FVD_CLKOUT_REG,
+                                      RTL8211FVD_CLKOUT_EN, 0);
+       else
+               ret = phy_modify_paged(phydev, RTL8211F_PHYCR_PAGE,
+                                      RTL8211F_PHYCR2, RTL8211F_CLKOUT_EN, 0);
        if (ret)
                return ret;
 
@@ -680,6 +693,13 @@ static int rtl8211f_config_init(struct phy_device *phydev)
        if (ret)
                return ret;
 
+       ret = rtl8211f_config_clk_out(phydev);
+       if (ret) {
+               dev_err(dev, "clkout configuration failed: %pe\n",
+                       ERR_PTR(ret));
+               return ret;
+       }
+
        /* RTL8211FVD has no PHYCR2 register */
        if (phydev->drv->phy_id == RTL_8211FVD_PHYID)
                return 0;
@@ -690,13 +710,6 @@ static int rtl8211f_config_init(struct phy_device *phydev)
        if (ret)
                return ret;
 
-       ret = rtl8211f_config_clk_out(phydev);
-       if (ret) {
-               dev_err(dev, "clkout configuration failed: %pe\n",
-                       ERR_PTR(ret));
-               return ret;
-       }
-
        return 0;
 }