phy: atheros: add device tree bindings and config

Add support for configuring the CLK_25M pin as well as the RGMII I/O
voltage by the device tree.

By default the AT803x PHYs outputs the 25MHz clock of the XTAL input.
But this output can also be changed by software to other frequencies.
This commit introduces a generic way to configure this output.

Also the PHY supports different RGMII I/O voltages: 1.5V, 1.8V and 2.5V.
An internal LDO is able to provide 1.5V (default) and 1.8V. The 2.5V
option needs an external supply voltage. This commit adds support to
switch the internal LDO to 1.8V.

Signed-off-by: Michael Walle <michael@walle.cc>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>

3 files changed, 270 insertions, 2 deletions

diff --git a/doc/device-tree-bindings/net/phy/atheros.txt b/doc/device-tree-bindings/net/phy/atheros.txt
new file mode 100644
index 0000000000..97e97b8c13
--- /dev/null
+++ b/doc/device-tree-bindings/net/phy/atheros.txt
@@ -0,0 +1,35 @@
+* Qualcomm Atheros PHY Device Tree binding
+
+Required properties:
+- reg: PHY address
+
+Optional properties:
+- qca,clk-out-frequency: Clock frequency of the CLK_25M pin in Hz.
+	Either 25000000, 50000000, 62500000 or 125000000.
+- qca,clk-out-strength: Clock output buffer driver strength.
+    Supported values are defined in dt-bindings/net/qca-ar803x.h
+- qca,keep-pll-enabled: Keep the PLL running if no link is present.
+	Don't go into hibernation mode.
+	Only supported on the AR8031/AR8033.
+- vddio-supply: RGMII I/O voltage regulator
+	Only supported on the AR8031/AR8033.
+
+Optional subnodes:
+- vddio-regulator: Initial data for the VDDIO regulator, as covered
+    doc/device-tree-bindings/regulator/regulator.txt
+
+Example:
+	#include <dt-bindings/net/qca-ar803x.h>
+
+	ethernet-phy@0 {
+		reg = <0>;
+		qca-clk-out-frequency = <125000000>;
+		qca,keep-pll-enabled;
+
+		vddio-supply = <&vddio>;
+
+		vddio: vddio-regulator {
+			regulator-min-microvolt = <1800000>;
+			regulator-max-microvolt = <1800000>;
+		};
+	};
diff --git a/drivers/net/phy/atheros.c b/drivers/net/phy/atheros.c
index 22035c2496..3cd301c50e 100644
--- a/drivers/net/phy/atheros.c
+++ b/drivers/net/phy/atheros.c
@@ -4,21 +4,41 @@
  *
  * Copyright 2011, 2013 Freescale Semiconductor, Inc.
  * author Andy Fleming
+ * Copyright (c) 2019 Michael Walle <michael@walle.cc>
  */
 #include <common.h>
 #include <phy.h>
+#include <dm/device_compat.h>
+#include <linux/bitfield.h>
+#include <dt-bindings/net/qca-ar803x.h>
 
 #define AR803x_PHY_DEBUG_ADDR_REG	0x1d
 #define AR803x_PHY_DEBUG_DATA_REG	0x1e
 
+/* Debug registers */
+#define AR803x_DEBUG_REG_0		0x0
+#define AR803x_RGMII_RX_CLK_DLY		BIT(15)
+
 #define AR803x_DEBUG_REG_5		0x5
 #define AR803x_RGMII_TX_CLK_DLY		BIT(8)
 
-#define AR803x_DEBUG_REG_0		0x0
-#define AR803x_RGMII_RX_CLK_DLY		BIT(15)
+#define AR803x_DEBUG_REG_1F		0x1f
+#define AR803x_PLL_ON			BIT(2)
+#define AR803x_RGMII_1V8		BIT(3)
 
 /* CLK_25M register is at MMD 7, address 0x8016 */
 #define AR803x_CLK_25M_SEL_REG		0x8016
+
+#define AR803x_CLK_25M_MASK		GENMASK(4, 2)
+#define AR803x_CLK_25M_25MHZ_XTAL	0
+#define AR803x_CLK_25M_25MHZ_DSP	1
+#define AR803x_CLK_25M_50MHZ_PLL	2
+#define AR803x_CLK_25M_50MHZ_DSP	3
+#define AR803x_CLK_25M_62_5MHZ_PLL	4
+#define AR803x_CLK_25M_62_5MHZ_DSP	5
+#define AR803x_CLK_25M_125MHZ_PLL	6
+#define AR803x_CLK_25M_125MHZ_DSP	7
+
 /* AR8035: Select frequency on CLK_25M pin through bits 4:3 */
 #define AR8035_CLK_25M_FREQ_25M		(0 | 0)
 #define AR8035_CLK_25M_FREQ_50M		(0 | BIT(3))
@@ -26,10 +46,23 @@
 #define AR8035_CLK_25M_FREQ_125M	(BIT(4) | BIT(3))
 #define AR8035_CLK_25M_MASK		GENMASK(4, 3)
 
+#define AR803x_CLK_25M_DR_MASK		GENMASK(8, 7)
+#define AR803x_CLK_25M_DR_FULL		0
+#define AR803x_CLK_25M_DR_HALF		1
+#define AR803x_CLK_25M_DR_QUARTER	2
+
 #define AR8021_PHY_ID 0x004dd040
 #define AR8031_PHY_ID 0x004dd074
 #define AR8035_PHY_ID 0x004dd072
 
+struct ar803x_priv {
+	int flags;
+#define AR803x_FLAG_KEEP_PLL_ENABLED	BIT(0) /* don't turn off internal PLL */
+#define AR803x_FLAG_RGMII_1V8		BIT(1) /* use 1.8V RGMII I/O voltage */
+	u16 clk_25m_reg;
+	u16 clk_25m_mask;
+};
+
 static int ar803x_debug_reg_read(struct phy_device *phydev, u16 reg)
 {
 	int ret;
@@ -113,14 +146,193 @@ static int ar803x_delay_config(struct phy_device *phydev)
 	return ret;
 }
 
+static int ar803x_regs_config(struct phy_device *phydev)
+{
+	struct ar803x_priv *priv = phydev->priv;
+	u16 set = 0, clear = 0;
+	int val;
+	int ret;
+
+	/* no configuration available */
+	if (!priv)
+		return 0;
+
+	/*
+	 * Only supported on the AR8031, AR8035 has strappings for the PLL mode
+	 * as well as the RGMII voltage.
+	 */
+	if (phydev->drv->uid == AR8031_PHY_ID) {
+		if (priv->flags & AR803x_FLAG_KEEP_PLL_ENABLED)
+			set |= AR803x_PLL_ON;
+		else
+			clear |= AR803x_PLL_ON;
+
+		if (priv->flags & AR803x_FLAG_RGMII_1V8)
+			set |= AR803x_RGMII_1V8;
+		else
+			clear |= AR803x_RGMII_1V8;
+
+		ret = ar803x_debug_reg_mask(phydev, AR803x_DEBUG_REG_1F, clear,
+					    set);
+		if (ret < 0)
+			return ret;
+	}
+
+	/* save the write access if the mask is empty */
+	if (priv->clk_25m_mask) {
+		val = phy_read_mmd(phydev, MDIO_MMD_AN, AR803x_CLK_25M_SEL_REG);
+		if (val < 0)
+			return val;
+		val &= ~priv->clk_25m_mask;
+		val |= priv->clk_25m_reg;
+		ret = phy_write_mmd(phydev, MDIO_MMD_AN,
+				    AR803x_CLK_25M_SEL_REG, val);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int ar803x_of_init(struct phy_device *phydev)
+{
+#if defined(CONFIG_DM_ETH)
+	struct ar803x_priv *priv;
+	ofnode node, vddio_reg_node;
+	u32 strength, freq, min_uV, max_uV;
+	int sel;
+
+	node = phy_get_ofnode(phydev);
+	if (!ofnode_valid(node))
+		return -EINVAL;
+
+	priv = malloc(sizeof(*priv));
+	if (!priv)
+		return -ENOMEM;
+	memset(priv, 0, sizeof(*priv));
+
+	phydev->priv = priv;
+
+	debug("%s: found PHY node: %s\n", __func__, ofnode_get_name(node));
+
+	if (ofnode_read_bool(node, "qca,keep-pll-enabled"))
+		priv->flags |= AR803x_FLAG_KEEP_PLL_ENABLED;
+
+	/*
+	 * We can't use the regulator framework because the regulator is
+	 * a subnode of the PHY. So just read the two properties we are
+	 * interested in.
+	 */
+	vddio_reg_node = ofnode_find_subnode(node, "vddio-regulator");
+	if (ofnode_valid(vddio_reg_node)) {
+		min_uV = ofnode_read_u32_default(vddio_reg_node,
+						 "regulator-min-microvolt", 0);
+		max_uV = ofnode_read_u32_default(vddio_reg_node,
+						 "regulator-max-microvolt", 0);
+
+		if (min_uV != max_uV) {
+			free(priv);
+			return -EINVAL;
+		}
+
+		switch (min_uV) {
+		case 1500000:
+			break;
+		case 1800000:
+			priv->flags |= AR803x_FLAG_RGMII_1V8;
+			break;
+		default:
+			free(priv);
+			return -EINVAL;
+		}
+	}
+
+	/*
+	 * Get the CLK_25M frequency from the device tree. Only XTAL and PLL
+	 * sources are supported right now. There is also the possibilty to use
+	 * the DSP as frequency reference, this is used for synchronous
+	 * ethernet.
+	 */
+	if (!ofnode_read_u32(node, "qca,clk-out-frequency", &freq)) {
+		switch (freq) {
+		case 25000000:
+			sel = AR803x_CLK_25M_25MHZ_XTAL;
+			break;
+		case 50000000:
+			sel = AR803x_CLK_25M_50MHZ_PLL;
+			break;
+		case 62500000:
+			sel = AR803x_CLK_25M_62_5MHZ_PLL;
+			break;
+		case 125000000:
+			sel = AR803x_CLK_25M_125MHZ_PLL;
+			break;
+		default:
+			dev_err(phydev->dev,
+				"invalid qca,clk-out-frequency\n");
+			free(priv);
+			return -EINVAL;
+		}
+
+		priv->clk_25m_mask |= AR803x_CLK_25M_MASK;
+		priv->clk_25m_reg |= FIELD_PREP(AR803x_CLK_25M_MASK, sel);
+		/*
+		 * Fixup for the AR8035 which only has two bits. The two
+		 * remaining bits map to the same frequencies.
+		 */
+		if (phydev->drv->uid == AR8035_PHY_ID) {
+			u16 clear = AR803x_CLK_25M_MASK & AR8035_CLK_25M_MASK;
+
+			priv->clk_25m_mask &= ~clear;
+			priv->clk_25m_reg &= ~clear;
+		}
+	}
+
+	if (phydev->drv->uid == AR8031_PHY_ID &&
+	    !ofnode_read_u32(node, "qca,clk-out-strength", &strength)) {
+		switch (strength) {
+		case AR803X_STRENGTH_FULL:
+			sel = AR803x_CLK_25M_DR_FULL;
+			break;
+		case AR803X_STRENGTH_HALF:
+			sel = AR803x_CLK_25M_DR_HALF;
+			break;
+		case AR803X_STRENGTH_QUARTER:
+			sel = AR803x_CLK_25M_DR_QUARTER;
+			break;
+		default:
+			dev_err(phydev->dev,
+				"invalid qca,clk-out-strength\n");
+			free(priv);
+			return -EINVAL;
+		}
+		priv->clk_25m_mask |= AR803x_CLK_25M_DR_MASK;
+		priv->clk_25m_reg |= FIELD_PREP(AR803x_CLK_25M_DR_MASK, sel);
+	}
+
+	debug("%s: flags=%x clk_25m_reg=%04x clk_25m_mask=%04x\n", __func__,
+	      priv->flags, priv->clk_25m_reg, priv->clk_25m_mask);
+#endif
+
+	return 0;
+}
+
 static int ar8031_config(struct phy_device *phydev)
 {
 	int ret;
 
+	ret = ar803x_of_init(phydev);
+	if (ret < 0)
+		return ret;
+
 	ret = ar803x_delay_config(phydev);
 	if (ret < 0)
 		return ret;
 
+	ret = ar803x_regs_config(phydev);
+	if (ret < 0)
+		return ret;
+
 	phydev->supported = phydev->drv->features;
 
 	genphy_config_aneg(phydev);
@@ -134,6 +346,10 @@ static int ar8035_config(struct phy_device *phydev)
 	int ret;
 	int regval;
 
+	ret = ar803x_of_init(phydev);
+	if (ret < 0)
+		return ret;
+
 	/* Configure CLK_25M output clock at 125 MHz */
 	regval = phy_read_mmd(phydev, MDIO_MMD_AN, AR803x_CLK_25M_SEL_REG);
 	regval &= ~AR8035_CLK_25M_MASK; /* No surprises */
@@ -144,6 +360,10 @@ static int ar8035_config(struct phy_device *phydev)
 	if (ret < 0)
 		return ret;
 
+	ret = ar803x_regs_config(phydev);
+	if (ret < 0)
+		return ret;
+
 	phydev->supported = phydev->drv->features;
 
 	genphy_config_aneg(phydev);
diff --git a/include/dt-bindings/net/qca-ar803x.h b/include/dt-bindings/net/qca-ar803x.h
new file mode 100644
index 0000000000..9c046c7242
--- /dev/null
+++ b/include/dt-bindings/net/qca-ar803x.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Device Tree constants for the Qualcomm Atheros AR803x PHYs
+ */
+
+#ifndef _DT_BINDINGS_QCA_AR803X_H
+#define _DT_BINDINGS_QCA_AR803X_H
+
+#define AR803X_STRENGTH_FULL		0
+#define AR803X_STRENGTH_HALF		1
+#define AR803X_STRENGTH_QUARTER		2
+
+#endif