[PATCH 5/7] net: phy: at803x: add support for configuring SmartEEE

[Marco Felsch <m.felsch@pengutronix.de>]

This commit port Linux commit:

| commit 390b4cad81484124db2b676ed20a265adc032bae
| Author: Russell King <rmk+kernel@armlinux.org.uk>
| Date:   Thu Jan 14 10:45:49 2021 +0000
|
|     net: phy: at803x: add support for configuring SmartEEE
|
|     SmartEEE for the atheros phy was deemed buggy by Freescale and commits
|     were added to disable it for their boards.
|
|     In initial testing, SolidRun found that the default settings were
|     causing disconnects but by increasing the Tw buffer time we could allow
|     enough time for all parts of the link to come out of a low power state
|     and function properly without causing a disconnect. This allows us to
|     have functional power savings of between 300 and 400mW, rather than
|     disabling the feature altogether.
|
|     This commit adds support for disabling SmartEEE and configuring the Tw
|     parameters for 1G and 100M speeds.
|
|     Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
|     Signed-off-by: Jakub Kicinski <kuba@kernel.org>

I slightly adapted the at803x_config_init() as well to be more in line
with the Linux code base.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
---
 drivers/net/phy/at803x.c | 75 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 73 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/at803x.c b/drivers/net/phy/at803x.c
index 41010c58ad..cc425c318f 100644
--- a/drivers/net/phy/at803x.c
+++ b/drivers/net/phy/at803x.c
@@ -59,6 +59,15 @@
  */
 #define AT8035_CLK_OUT_MASK			GENMASK(4, 3)
 
+#define AT803X_MMD3_SMARTEEE_CTL1		0x805b
+#define AT803X_MMD3_SMARTEEE_CTL3		0x805d
+#define AT803X_MMD3_SMARTEEE_CTL3_LPI_EN	BIT(8)
+
+#define AT803X_DISABLE_SMARTEEE			BIT(1)
+
+/* disable hibernation mode */
+#define AT803X_DISABLE_HIBERNATION_MODE		BIT(2)
+
 #define AT803X_CLK_OUT_STRENGTH_MASK		GENMASK(8, 7)
 #define AT803X_CLK_OUT_STRENGTH_FULL		0
 #define AT803X_CLK_OUT_STRENGTH_HALF		1
@@ -72,8 +81,11 @@
 #define AT8030_PHY_ID_MASK			0xffffffef
 
 struct at803x_priv {
+	int flags;
 	u16 clk_25m_reg;
 	u16 clk_25m_mask;
+	u8 smarteee_lpi_tw_1g;
+	u8 smarteee_lpi_tw_100m;
 };
 
 static int at803x_debug_reg_read(struct phy_device *phydev, u16 reg)
@@ -141,10 +153,29 @@ static int at803x_parse_dt(struct phy_device *phydev)
 	const struct device *dev = &phydev->dev;
 	const struct device_node *node = dev->of_node;
 	struct at803x_priv *priv = phydev->priv;
+	u32 freq, strength, tw;
 	unsigned int sel;
-	u32 freq, strength;
 	int ret;
 
+	if (of_property_read_bool(node, "qca,disable-smarteee"))
+		priv->flags |= AT803X_DISABLE_SMARTEEE;
+
+	if (!of_property_read_u32(node, "qca,smarteee-tw-us-1g", &tw)) {
+		if (!tw || tw > 255) {
+			phydev_err(phydev, "invalid qca,smarteee-tw-us-1g\n");
+			return -EINVAL;
+		}
+		priv->smarteee_lpi_tw_1g = tw;
+	}
+
+	if (!of_property_read_u32(node, "qca,smarteee-tw-us-100m", &tw)) {
+		if (!tw || tw > 255) {
+			phydev_err(phydev, "invalid qca,smarteee-tw-us-100m\n");
+			return -EINVAL;
+		}
+		priv->smarteee_lpi_tw_100m = tw;
+	}
+
 	ret = of_property_read_u32(node, "qca,clk-out-frequency", &freq);
 	if (!ret) {
 		switch (freq) {
@@ -221,6 +252,38 @@ static int at803x_probe(struct phy_device *phydev)
 	return at803x_parse_dt(phydev);
 }
 
+static int at803x_smarteee_config(struct phy_device *phydev)
+{
+	struct at803x_priv *priv = phydev->priv;
+	u16 mask = 0, val = 0;
+	int ret;
+
+	if (priv->flags & AT803X_DISABLE_SMARTEEE)
+		return phy_modify_mmd_indirect(phydev, MDIO_MMD_PCS,
+					       AT803X_MMD3_SMARTEEE_CTL3,
+					       AT803X_MMD3_SMARTEEE_CTL3_LPI_EN, 0);
+
+	if (priv->smarteee_lpi_tw_1g) {
+		mask |= 0xff00;
+		val |= priv->smarteee_lpi_tw_1g << 8;
+	}
+	if (priv->smarteee_lpi_tw_100m) {
+		mask |= 0x00ff;
+		val |= priv->smarteee_lpi_tw_100m;
+	}
+	if (!mask)
+		return 0;
+
+	ret = phy_modify_mmd_indirect(phydev, MDIO_MMD_PCS, AT803X_MMD3_SMARTEEE_CTL1,
+				      mask, val);
+	if (ret)
+		return ret;
+
+	return phy_modify_mmd_indirect(phydev, MDIO_MMD_PCS, AT803X_MMD3_SMARTEEE_CTL3,
+				       AT803X_MMD3_SMARTEEE_CTL3_LPI_EN,
+				       AT803X_MMD3_SMARTEEE_CTL3_LPI_EN);
+}
+
 static int at803x_clk_out_config(struct phy_device *phydev)
 {
 	struct at803x_priv *priv = phydev->priv;
@@ -270,7 +333,15 @@ static int at803x_config_init(struct phy_device *phydev)
 	if (ret < 0)
 		return ret;
 
-	return at803x_clk_out_config(phydev);
+	ret = at803x_smarteee_config(phydev);
+	if (ret < 0)
+		return ret;
+
+	ret = at803x_clk_out_config(phydev);
+	if (ret < 0)
+		return ret;
+
+	return 0;
 }
 
 static struct phy_driver at803x_driver[] = {
-- 
2.39.2