* [net-next,PATCH v4 2/3] dt-bindings: net: realtek,rtl82xx: Document realtek,*-ssc-enable property
2026-03-21 18:47 [net-next,PATCH v4 1/3] dt-bindings: net: realtek,rtl82xx: Keep property list sorted Marek Vasut
@ 2026-03-21 18:47 ` Marek Vasut
2026-03-21 18:47 ` [net-next,PATCH v4 3/3] net: phy: realtek: Add property to enable SSC Marek Vasut
1 sibling, 0 replies; 3+ messages in thread
From: Marek Vasut @ 2026-03-21 18:47 UTC (permalink / raw)
To: netdev
Cc: Marek Vasut, Krzysztof Kozlowski, David S. Miller,
Aleksander Jan Bajkowski, Andrew Lunn, Conor Dooley, Eric Dumazet,
Florian Fainelli, Heiner Kallweit, Ivan Galkin, Jakub Kicinski,
Krzysztof Kozlowski, Michael Klein, Paolo Abeni, Rob Herring,
Russell King, Vladimir Oltean, devicetree
Document support for spread spectrum clocking (SSC) on RTL8211F(D)(I)-CG,
RTL8211FS(I)(-VS)-CG, RTL8211FG(I)(-VS)-CG PHYs. Introduce DT properties
'realtek,clkout-ssc-enable', 'realtek,rxc-ssc-enable' and
'realtek,sysclk-ssc-enable' which control CLKOUT, RXC and SYSCLK
SSC spread spectrum clocking enablement on these signals. These
clock are not exposed via the clock API, therefore assigned-clock-sscs
property does not apply.
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Marek Vasut <marek.vasut@mailbox.org>
---
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Aleksander Jan Bajkowski <olek2@wp.pl>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Ivan Galkin <ivan.galkin@axis.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Michael Klein <michael@fossekall.de>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vladimir Oltean <vladimir.oltean@nxp.com>
Cc: devicetree@vger.kernel.org
Cc: netdev@vger.kernel.org
---
V2: Split SSC clock control for each CLKOUT, RXC, SYSCLK signal
V3: - Add RB from krzk
- Update commit subject, use realtek,*-ssc-enable to be accurate
V4: No change
---
.../devicetree/bindings/net/realtek,rtl82xx.yaml | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/Documentation/devicetree/bindings/net/realtek,rtl82xx.yaml b/Documentation/devicetree/bindings/net/realtek,rtl82xx.yaml
index eafcc2f3e3d66..45033c31a2d51 100644
--- a/Documentation/devicetree/bindings/net/realtek,rtl82xx.yaml
+++ b/Documentation/devicetree/bindings/net/realtek,rtl82xx.yaml
@@ -50,6 +50,21 @@ properties:
description:
Disable CLKOUT clock, CLKOUT clock default is enabled after hardware reset.
+ realtek,clkout-ssc-enable:
+ type: boolean
+ description:
+ Enable CLKOUT SSC mode, CLKOUT SSC mode default is disabled after hardware reset.
+
+ realtek,rxc-ssc-enable:
+ type: boolean
+ description:
+ Enable RXC SSC mode, RXC SSC mode default is disabled after hardware reset.
+
+ realtek,sysclk-ssc-enable:
+ type: boolean
+ description:
+ Enable SYSCLK SSC mode, SYSCLK SSC mode default is disabled after hardware reset.
+
wakeup-source:
type: boolean
description:
--
2.53.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* [net-next,PATCH v4 3/3] net: phy: realtek: Add property to enable SSC
2026-03-21 18:47 [net-next,PATCH v4 1/3] dt-bindings: net: realtek,rtl82xx: Keep property list sorted Marek Vasut
2026-03-21 18:47 ` [net-next,PATCH v4 2/3] dt-bindings: net: realtek,rtl82xx: Document realtek,*-ssc-enable property Marek Vasut
@ 2026-03-21 18:47 ` Marek Vasut
1 sibling, 0 replies; 3+ messages in thread
From: Marek Vasut @ 2026-03-21 18:47 UTC (permalink / raw)
To: netdev
Cc: Marek Vasut, David S. Miller, Aleksander Jan Bajkowski,
Andrew Lunn, Conor Dooley, Eric Dumazet, Florian Fainelli,
Heiner Kallweit, Ivan Galkin, Jakub Kicinski, Krzysztof Kozlowski,
Michael Klein, Paolo Abeni, Rob Herring, Russell King,
Vladimir Oltean, devicetree
Add support for spread spectrum clocking (SSC) on RTL8211F(D)(I)-CG,
RTL8211FS(I)(-VS)-CG, RTL8211FG(I)(-VS)-CG PHYs. The implementation
follows EMI improvement application note Rev. 1.2 for these PHYs.
The current implementation enables SSC for both RXC and SYSCLK clock
signals. Introduce DT properties 'realtek,clkout-ssc-enable',
'realtek,rxc-ssc-enable' and 'realtek,sysclk-ssc-enable' which control
CLKOUT, RXC and SYSCLK SSC spread spectrum clocking enablement on these
signals.
Signed-off-by: Marek Vasut <marek.vasut@mailbox.org>
---
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Aleksander Jan Bajkowski <olek2@wp.pl>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Ivan Galkin <ivan.galkin@axis.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Michael Klein <michael@fossekall.de>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vladimir Oltean <vladimir.oltean@nxp.com>
Cc: devicetree@vger.kernel.org
Cc: netdev@vger.kernel.org
---
V2: Split SSC clock control for each CLKOUT, RXC, SYSCLK signal
V3: Update RTL8211FVD PHYCR2 comment to state this PHY has PHYCR2 register,
but SSC configuration is not supported due to different layout.
V4: - Perform all SSC configuration before disabling CLKOUT
- Perform all SSC configuration in the same order as in the SSC appnote
- Rebase on current next, retest using spectrum analyzer again
---
drivers/net/phy/realtek/realtek_main.c | 131 +++++++++++++++++++++++++
1 file changed, 131 insertions(+)
diff --git a/drivers/net/phy/realtek/realtek_main.c b/drivers/net/phy/realtek/realtek_main.c
index 530b4e26d16ef..1dc64bf2ec73d 100644
--- a/drivers/net/phy/realtek/realtek_main.c
+++ b/drivers/net/phy/realtek/realtek_main.c
@@ -75,10 +75,18 @@
#define RTL8211F_PHYCR2 0x19
#define RTL8211F_CLKOUT_EN BIT(0)
+#define RTL8211F_SYSCLK_SSC_EN BIT(3)
#define RTL8211F_PHYCR2_PHY_EEE_ENABLE BIT(5)
+#define RTL8211F_CLKOUT_SSC_EN BIT(7)
#define RTL8211F_INSR 0x1d
+/* RTL8211F SSC settings */
+#define RTL8211F_SSC_PAGE 0xc44
+#define RTL8211F_SSC_RXC 0x13
+#define RTL8211F_SSC_SYSCLK 0x17
+#define RTL8211F_SSC_CLKOUT 0x19
+
/* RTL8211F LED configuration */
#define RTL8211F_LEDCR_PAGE 0xd04
#define RTL8211F_LEDCR 0x10
@@ -212,6 +220,9 @@ MODULE_LICENSE("GPL");
struct rtl821x_priv {
bool enable_aldps;
bool disable_clk_out;
+ bool enable_clkout_ssc;
+ bool enable_rxc_ssc;
+ bool enable_sysclk_ssc;
struct clk *clk;
/* rtl8211f */
u16 iner;
@@ -275,6 +286,12 @@ static int rtl821x_probe(struct phy_device *phydev)
"realtek,aldps-enable");
priv->disable_clk_out = of_property_read_bool(dev->of_node,
"realtek,clkout-disable");
+ priv->enable_clkout_ssc = of_property_read_bool(dev->of_node,
+ "realtek,clkout-ssc-enable");
+ priv->enable_rxc_ssc = of_property_read_bool(dev->of_node,
+ "realtek,rxc-ssc-enable");
+ priv->enable_sysclk_ssc = of_property_read_bool(dev->of_node,
+ "realtek,sysclk-ssc-enable");
phydev->priv = priv;
@@ -704,6 +721,108 @@ static int rtl8211f_config_phy_eee(struct phy_device *phydev)
RTL8211F_PHYCR2_PHY_EEE_ENABLE, 0);
}
+static int rtl8211f_config_clkout_ssc(struct phy_device *phydev)
+{
+ struct rtl821x_priv *priv = phydev->priv;
+ struct device *dev = &phydev->mdio.dev;
+ int ret;
+
+ /* The value is preserved if the device tree property is absent */
+ if (!priv->enable_clkout_ssc)
+ return 0;
+
+ /* RTL8211FVD has PHYCR2 register, but configuration of CLKOUT SSC
+ * is not currently supported by this driver due to different bit
+ * layout.
+ */
+ if (phydev->drv->phy_id == RTL_8211FVD_PHYID)
+ return 0;
+
+ /* Unnamed registers from EMI improvement parameters application note 1.2 */
+ ret = phy_write_paged(phydev, 0xd09, 0x10, 0xcf00);
+ if (ret < 0) {
+ dev_err(dev, "CLKOUT SCC initialization failed: %pe\n", ERR_PTR(ret));
+ return ret;
+ }
+
+ ret = phy_write(phydev, RTL8211F_SSC_CLKOUT, 0x38c3);
+ if (ret < 0) {
+ dev_err(dev, "CLKOUT SCC configuration failed: %pe\n", ERR_PTR(ret));
+ return ret;
+ }
+
+ /*
+ * Enable CLKOUT SSC using PHYCR2 bit 7 , this step is missing from the
+ * EMI improvement parameters application note 1.2 section 2.3
+ */
+ ret = phy_set_bits(phydev, RTL8211F_PHYCR2, RTL8211F_CLKOUT_SSC_EN);
+ if (ret < 0) {
+ dev_err(dev, "CLKOUT SCC enable failed: %pe\n", ERR_PTR(ret));
+ return ret;
+ }
+
+ return 0;
+}
+
+static int rtl8211f_config_rxc_ssc(struct phy_device *phydev)
+{
+ struct rtl821x_priv *priv = phydev->priv;
+ struct device *dev = &phydev->mdio.dev;
+ int ret;
+
+ /* The value is preserved if the device tree property is absent */
+ if (!priv->enable_rxc_ssc)
+ return 0;
+
+ /* RTL8211FVD has PHYCR2 register, but configuration of RXC SSC
+ * is not currently supported by this driver due to different bit
+ * layout.
+ */
+ if (phydev->drv->phy_id == RTL_8211FVD_PHYID)
+ return 0;
+
+ ret = phy_write_paged(phydev, RTL8211F_SSC_PAGE, RTL8211F_SSC_RXC, 0x5f00);
+ if (ret < 0) {
+ dev_err(dev, "RXC SCC configuration failed: %pe\n", ERR_PTR(ret));
+ return ret;
+ }
+
+ return 0;
+}
+
+static int rtl8211f_config_sysclk_ssc(struct phy_device *phydev)
+{
+ struct rtl821x_priv *priv = phydev->priv;
+ struct device *dev = &phydev->mdio.dev;
+ int ret;
+
+ /* The value is preserved if the device tree property is absent */
+ if (!priv->enable_sysclk_ssc)
+ return 0;
+
+ /* RTL8211FVD has PHYCR2 register, but configuration of SYSCLK SSC
+ * is not currently supported by this driver due to different bit
+ * layout.
+ */
+ if (phydev->drv->phy_id == RTL_8211FVD_PHYID)
+ return 0;
+
+ ret = phy_write_paged(phydev, RTL8211F_SSC_PAGE, RTL8211F_SSC_SYSCLK, 0x4f00);
+ if (ret < 0) {
+ dev_err(dev, "SYSCLK SCC configuration failed: %pe\n", ERR_PTR(ret));
+ return ret;
+ }
+
+ /* Enable SSC */
+ ret = phy_set_bits(phydev, RTL8211F_PHYCR2, RTL8211F_SYSCLK_SSC_EN);
+ if (ret < 0) {
+ dev_err(dev, "SYSCLK SCC enable failed: %pe\n", ERR_PTR(ret));
+ return ret;
+ }
+
+ return 0;
+}
+
static int rtl8211f_config_init(struct phy_device *phydev)
{
struct device *dev = &phydev->mdio.dev;
@@ -720,6 +839,18 @@ static int rtl8211f_config_init(struct phy_device *phydev)
if (ret)
return ret;
+ ret = rtl8211f_config_rxc_ssc(phydev);
+ if (ret)
+ return ret;
+
+ ret = rtl8211f_config_sysclk_ssc(phydev);
+ if (ret)
+ return ret;
+
+ ret = rtl8211f_config_clkout_ssc(phydev);
+ if (ret)
+ return ret;
+
ret = rtl8211f_config_clk_out(phydev);
if (ret) {
dev_err(dev, "clkout configuration failed: %pe\n",
--
2.53.0
^ permalink raw reply related [flat|nested] 3+ messages in thread