net: add Amlogic Meson G12A MDIO MUX driver

The Amlogic G12A & compatible SoCs embeds a mux to either communicate with
the external PHY or the internal 10/100 PHY.

This adds support for this mux as a MDIO MUX device.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>

drivers/net/Kconfig

@@ -797,4 +797,11 @@ config MDIO_MUX_MMIOREG
 	  This driver is used for MDIO muxes driven by writing to a register in
 	  the MMIO physical memory.
 
+config MDIO_MUX_MESON_G12A
+	bool "MDIO MUX for Amlogic Meson G12A SoCs"
+	depends on DM_MDIO_MUX
+	help
+	  This driver is used for the MDIO mux found on the Amlogic G12A & compatible
+	  SoCs.
+
 endif # NETDEVICES

drivers/net/Makefile

@@ -43,6 +43,7 @@ obj-$(CONFIG_MACB) += macb.o
 obj-$(CONFIG_MCFFEC) += mcffec.o mcfmii.o
 obj-$(CONFIG_MDIO_IPQ4019) += mdio-ipq4019.o
 obj-$(CONFIG_MDIO_MUX_I2CREG) += mdio_mux_i2creg.o
+obj-$(CONFIG_MDIO_MUX_MESON_G12A) += mdio_mux_meson_g12a.o
 obj-$(CONFIG_MDIO_MUX_MMIOREG) += mdio_mux_mmioreg.o
 obj-$(CONFIG_MDIO_MUX_SANDBOX) += mdio_mux_sandbox.o
 obj-$(CONFIG_MPC8XX_FEC) += mpc8xx_fec.o

drivers/net/mdio_mux_meson_g12a.c

@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * (C) Copyright 2021 BayLibre, SAS
+ * Author: Neil Armstrong <narmstrong@baylibre.com>
+ */
+
+#include <dm.h>
+#include <errno.h>
+#include <log.h>
+#include <miiphy.h>
+#include <asm/io.h>
+#include <linux/bitfield.h>
+
+#define ETH_PLL_STS		0x40
+#define ETH_PLL_CTL0		0x44
+#define  PLL_CTL0_LOCK_DIG	BIT(30)
+#define  PLL_CTL0_RST		BIT(29)
+#define  PLL_CTL0_EN		BIT(28)
+#define  PLL_CTL0_SEL		BIT(23)
+#define  PLL_CTL0_N		GENMASK(14, 10)
+#define  PLL_CTL0_M		GENMASK(8, 0)
+#define  PLL_LOCK_TIMEOUT	1000000
+#define  PLL_MUX_NUM_PARENT	2
+#define ETH_PLL_CTL1		0x48
+#define ETH_PLL_CTL2		0x4c
+#define ETH_PLL_CTL3		0x50
+#define ETH_PLL_CTL4		0x54
+#define ETH_PLL_CTL5		0x58
+#define ETH_PLL_CTL6		0x5c
+#define ETH_PLL_CTL7		0x60
+
+#define ETH_PHY_CNTL0		0x80
+#define   EPHY_G12A_ID		0x33010180
+#define ETH_PHY_CNTL1		0x84
+#define  PHY_CNTL1_ST_MODE	GENMASK(2, 0)
+#define  PHY_CNTL1_ST_PHYADD	GENMASK(7, 3)
+#define   EPHY_DFLT_ADD		8
+#define  PHY_CNTL1_MII_MODE	GENMASK(15, 14)
+#define   EPHY_MODE_RMII	0x1
+#define  PHY_CNTL1_CLK_EN	BIT(16)
+#define  PHY_CNTL1_CLKFREQ	BIT(17)
+#define  PHY_CNTL1_PHY_ENB	BIT(18)
+#define ETH_PHY_CNTL2		0x88
+#define  PHY_CNTL2_USE_INTERNAL	BIT(5)
+#define  PHY_CNTL2_SMI_SRC_MAC	BIT(6)
+#define  PHY_CNTL2_RX_CLK_EPHY	BIT(9)
+
+#define MESON_G12A_MDIO_EXTERNAL_ID 0
+#define MESON_G12A_MDIO_INTERNAL_ID 1
+
+struct mdio_mux_meson_g12a_priv {
+	struct udevice *chip;
+	phys_addr_t phys;
+};
+
+static int meson_g12a_ephy_pll_init(struct mdio_mux_meson_g12a_priv *priv)
+{
+	/* Fire up the PHY PLL */
+	writel(0x29c0040a, priv->phys + ETH_PLL_CTL0);
+	writel(0x927e0000, priv->phys + ETH_PLL_CTL1);
+	writel(0xac5f49e5, priv->phys + ETH_PLL_CTL2);
+	writel(0x00000000, priv->phys + ETH_PLL_CTL3);
+	writel(0x00000000, priv->phys + ETH_PLL_CTL4);
+	writel(0x20200000, priv->phys + ETH_PLL_CTL5);
+	writel(0x0000c002, priv->phys + ETH_PLL_CTL6);
+	writel(0x00000023, priv->phys + ETH_PLL_CTL7);
+	writel(0x39c0040a, priv->phys + ETH_PLL_CTL0);
+	writel(0x19c0040a, priv->phys + ETH_PLL_CTL0);
+
+	return 0;
+}
+
+static int meson_g12a_enable_internal_mdio(struct mdio_mux_meson_g12a_priv *priv)
+{
+	/* Initialize ephy control */
+	writel(EPHY_G12A_ID, priv->phys + ETH_PHY_CNTL0);
+	writel(FIELD_PREP(PHY_CNTL1_ST_MODE, 3) |
+	       FIELD_PREP(PHY_CNTL1_ST_PHYADD, EPHY_DFLT_ADD) |
+	       FIELD_PREP(PHY_CNTL1_MII_MODE, EPHY_MODE_RMII) |
+	       PHY_CNTL1_CLK_EN |
+	       PHY_CNTL1_CLKFREQ |
+	       PHY_CNTL1_PHY_ENB,
+	       priv->phys + ETH_PHY_CNTL1);
+	writel(PHY_CNTL2_USE_INTERNAL |
+	       PHY_CNTL2_SMI_SRC_MAC |
+	       PHY_CNTL2_RX_CLK_EPHY,
+	       priv->phys + ETH_PHY_CNTL2);
+
+	return 0;
+}
+
+static int meson_g12a_enable_external_mdio(struct mdio_mux_meson_g12a_priv *priv)
+{
+	/* Reset the mdio bus mux */
+	writel(0x0, priv->phys + ETH_PHY_CNTL2);
+
+	return 0;
+}
+
+static int mdio_mux_meson_g12a_select(struct udevice *mux, int cur, int sel)
+{
+	struct mdio_mux_meson_g12a_priv *priv = dev_get_priv(mux);
+
+	debug("%s: %x -> %x\n", __func__, (u32)cur, (u32)sel);
+
+	/* if last selection didn't change we're good to go */
+	if (cur == sel)
+		return 0;
+
+	switch (sel) {
+	case MESON_G12A_MDIO_EXTERNAL_ID:
+		return meson_g12a_enable_external_mdio(priv);
+	case MESON_G12A_MDIO_INTERNAL_ID:
+		return meson_g12a_enable_internal_mdio(priv);
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct mdio_mux_ops mdio_mux_meson_g12a_ops = {
+	.select = mdio_mux_meson_g12a_select,
+};
+
+static int mdio_mux_meson_g12a_probe(struct udevice *dev)
+{
+	struct mdio_mux_meson_g12a_priv *priv = dev_get_priv(dev);
+
+	priv->phys = dev_read_addr(dev);
+
+	meson_g12a_ephy_pll_init(priv);
+
+	return 0;
+}
+
+static const struct udevice_id mdio_mux_meson_g12a_ids[] = {
+	{ .compatible = "amlogic,g12a-mdio-mux" },
+	{ }
+};
+
+U_BOOT_DRIVER(mdio_mux_meson_g12a) = {
+	.name		= "mdio_mux_meson_g12a",
+	.id		= UCLASS_MDIO_MUX,
+	.of_match	= mdio_mux_meson_g12a_ids,
+	.probe		= mdio_mux_meson_g12a_probe,
+	.ops		= &mdio_mux_meson_g12a_ops,
+	.priv_auto	= sizeof(struct mdio_mux_meson_g12a_priv),
+};