From 9ea339d70cfa03d39fecfc3d980c758ed67c4639 Mon Sep 17 00:00:00 2001
From: Jernej Skrabec <jernej.skrabec@siol.net>
Date: Fri, 16 Aug 2019 16:38:57 +0200
Subject: net: phy: Add support for AC200 EPHY

The X-Powers AC200 mixed signal chip contains a 100Mbit/s Ethernet PHY.
While its sporting a usable default setup, and can be controlled by the
generic IEEE802.3-C22 PHY driver, the BSP sets up some extra registers,
which this driver here covers.

Add a PHY driver matching the AC200 EPHY ID registers, and which
programs some PHY registers according to the BSP code.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 drivers/net/phy/Kconfig     |  7 ++++
 drivers/net/phy/Makefile    |  1 +
 drivers/net/phy/ac200-phy.c | 82 +++++++++++++++++++++++++++++++++++++
 3 files changed, 90 insertions(+)
 create mode 100644 drivers/net/phy/ac200-phy.c

diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 01b235b3bb7e..be4670e6b266 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -84,6 +84,13 @@ config AIR_EN8811H_PHY
 	help
 	  Currently supports the Airoha EN8811H PHY.
 
+config AC200_PHY
+	tristate "AC200 EPHY"
+	depends on NVMEM
+	depends on OF
+	help
+	  Fast ethernet PHY as found in X-Powers AC200 multi-function device.
+
 config AMD_PHY
 	tristate "AMD and Altima PHYs"
 	help
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index 90f886844381..4bba8c64bcc9 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_SFP)		+= sfp.o
 sfp-obj-$(CONFIG_SFP)		+= sfp-bus.o
 obj-y				+= $(sfp-obj-y) $(sfp-obj-m)
 
+obj-$(CONFIG_AC200_PHY)		+= ac200-phy.o
 obj-$(CONFIG_ADIN_PHY)		+= adin.o
 obj-$(CONFIG_ADIN1100_PHY)	+= adin1100.o
 obj-$(CONFIG_AIR_EN8811H_PHY)   += air_en8811h.o
diff --git a/drivers/net/phy/ac200-phy.c b/drivers/net/phy/ac200-phy.c
new file mode 100644
index 000000000000..8499914f49b8
--- /dev/null
+++ b/drivers/net/phy/ac200-phy.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0+
+/**
+ * Driver for AC200 Ethernet PHY
+ *
+ * Copyright (c) 2019 Jernej Skrabec <jernej.skrabec@gmail.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/phy.h>
+
+#define AC200_EPHY_ID			0x00441400
+#define AC200_EPHY_ID_MASK		0x0ffffff0
+
+static int ac200_ephy_config_init(struct phy_device *phydev)
+{
+	phy_write(phydev, 0x1f, 0x0100);	/* Switch to Page 1 */
+	phy_write(phydev, 0x12, 0x4824);	/* Disable APS */
+
+	phy_write(phydev, 0x1f, 0x0200);	/* Switch to Page 2 */
+	phy_write(phydev, 0x18, 0x0000);	/* PHYAFE TRX optimization */
+
+	phy_write(phydev, 0x1f, 0x0600);	/* Switch to Page 6 */
+	phy_write(phydev, 0x14, 0x708f);	/* PHYAFE TX optimization */
+	phy_write(phydev, 0x13, 0xF000);	/* PHYAFE RX optimization */
+	phy_write(phydev, 0x15, 0x1530);
+
+	phy_write(phydev, 0x1f, 0x0800);	/* Switch to Page 8 */
+	phy_write(phydev, 0x18, 0x00bc);	/* PHYAFE TRX optimization */
+
+	phy_write(phydev, 0x1f, 0x0100);	/* switch to page 1 */
+	phy_clear_bits(phydev, 0x17, BIT(3));	/* disable intelligent EEE */
+
+	/* disable 802.3az EEE */
+	phy_write(phydev, 0x1f, 0x0200);	/* switch to page 2 */
+	phy_write(phydev, 0x18, 0x0000);
+	phy_write(phydev, 0x1f, 0x0000);	/* switch to page 0 */
+	phy_clear_bits_mmd(phydev, 0x7, 0x3c, BIT(1));
+
+	/* FIXME: This is probably H6 specific */
+	phy_set_bits(phydev, 0x13, BIT(12));
+
+	return 0;
+}
+
+static int ac200_ephy_probe(struct phy_device *phydev)
+{
+	struct device *dev = &phydev->mdio.dev;
+	struct clk *clk;
+
+	clk = devm_clk_get_optional_enabled(dev, NULL);
+	if (IS_ERR(clk))
+		return dev_err_probe(dev, PTR_ERR(clk),
+				     "Failed to request clock\n");
+
+	return 0;
+}
+
+static struct phy_driver ac200_ephy_driver[] = {
+	{
+		.phy_id		= AC200_EPHY_ID,
+		.phy_id_mask	= AC200_EPHY_ID_MASK,
+		.name		= "Allwinner AC200 EPHY",
+		.soft_reset	= genphy_soft_reset,
+		.config_init	= ac200_ephy_config_init,
+		.probe		= ac200_ephy_probe,
+		.suspend	= genphy_suspend,
+		.resume		= genphy_resume,
+	}
+};
+module_phy_driver(ac200_ephy_driver);
+
+MODULE_AUTHOR("Jernej Skrabec <jernej.skrabec@gmail.com>");
+MODULE_DESCRIPTION("AC200 Ethernet PHY driver");
+MODULE_LICENSE("GPL");
+
+static const struct mdio_device_id __maybe_unused ac200_ephy_phy_tbl[] = {
+	{ AC200_EPHY_ID, AC200_EPHY_ID_MASK },
+	{ }
+};
+MODULE_DEVICE_TABLE(mdio, ac200_ephy_phy_tbl);
-- 
2.35.3

