[RFC net-next 1/4] net: phy: add MediaTek PHY driver

[DENG Qingfang]

Add support for MediaTek PHYs found in MT7530 and MT7531 switches.
The initialization procedure is from the vendor driver, but due to lack
of documentation, the function of some register values remains unknown.

Signed-off-by: DENG Qingfang <dqfext at gmail.com>
---
 drivers/net/phy/Kconfig    |   5 ++
 drivers/net/phy/Makefile   |   1 +
 drivers/net/phy/mediatek.c | 109 +++++++++++++++++++++++++++++++++++++
 3 files changed, 115 insertions(+)
 create mode 100644 drivers/net/phy/mediatek.c

diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index a615b3660b05..edd858cec9ec 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -207,6 +207,11 @@ config MARVELL_88X2222_PHY
 	  Support for the Marvell 88X2222 Dual-port Multi-speed Ethernet
 	  Transceiver.
 
+config MEDIATEK_PHY
+	tristate "MediaTek PHYs"
+	help
+	  Supports the MediaTek switch integrated PHYs.
+
 config MICREL_PHY
 	tristate "Micrel PHYs"
 	help
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index de683e3abe63..9ed7dbab7770 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_LXT_PHY)		+= lxt.o
 obj-$(CONFIG_MARVELL_10G_PHY)	+= marvell10g.o
 obj-$(CONFIG_MARVELL_PHY)	+= marvell.o
 obj-$(CONFIG_MARVELL_88X2222_PHY)	+= marvell-88x2222.o
+obj-$(CONFIG_MEDIATEK_PHY)	+= mediatek.o
 obj-$(CONFIG_MESON_GXL_PHY)	+= meson-gxl.o
 obj-$(CONFIG_MICREL_KS8995MA)	+= spi_ks8995.o
 obj-$(CONFIG_MICREL_PHY)	+= micrel.o
diff --git a/drivers/net/phy/mediatek.c b/drivers/net/phy/mediatek.c
new file mode 100644
index 000000000000..18fefd79a9bd
--- /dev/null
+++ b/drivers/net/phy/mediatek.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include <linux/module.h>
+#include <linux/phy.h>
+#include <linux/version.h>
+
+#define MTK_EXT_PAGE_ACCESS		0x1f
+#define MTK_PHY_PAGE_STANDARD		0x0000
+#define MTK_PHY_PAGE_EXTENDED		0x0001
+#define MTK_PHY_PAGE_EXTENDED_2		0x0002
+#define MTK_PHY_PAGE_EXTENDED_3		0x0003
+#define MTK_PHY_PAGE_EXTENDED_2A30	0x2a30
+#define MTK_PHY_PAGE_EXTENDED_52B5	0x52b5
+
+static int mtk_phy_read_page(struct phy_device *phydev)
+{
+	return __phy_read(phydev, MTK_EXT_PAGE_ACCESS);
+}
+
+static int mtk_phy_write_page(struct phy_device *phydev, int page)
+{
+	return __phy_write(phydev, MTK_EXT_PAGE_ACCESS, page);
+}
+
+static void mtk_phy_config_init(struct phy_device *phydev)
+{
+	/* Disable EEE */
+	phy_write_mmd(phydev, MDIO_MMD_AN, MDIO_AN_EEE_ADV, 0);
+
+	/* Enable HW auto downshift */
+	phy_modify_paged(phydev, MTK_PHY_PAGE_EXTENDED, 0x14, 0, BIT(4));
+
+	/* Increase SlvDPSready time */
+	phy_select_page(phydev, MTK_PHY_PAGE_EXTENDED_52B5);
+	__phy_write(phydev, 0x10, 0xafae);
+	__phy_write(phydev, 0x12, 0x2f);
+	__phy_write(phydev, 0x10, 0x8fae);
+	phy_restore_page(phydev, MTK_PHY_PAGE_STANDARD, 0);
+
+	/* Adjust 100_mse_threshold */
+	phy_write_mmd(phydev, MDIO_MMD_VEND1, 0x123, 0xffff);
+
+	/* Disable mcc */
+	phy_write_mmd(phydev, MDIO_MMD_VEND1, 0xa6, 0x300);
+}
+
+static int mt7530_phy_config_init(struct phy_device *phydev)
+{
+	mtk_phy_config_init(phydev);
+
+	/* Increase post_update_timer */
+	phy_write_paged(phydev, MTK_PHY_PAGE_EXTENDED_3, 0x11, 0x4b);
+
+	return 0;
+}
+
+static int mt7531_phy_config_init(struct phy_device *phydev)
+{
+	mtk_phy_config_init(phydev);
+
+	/* PHY link down power saving enable */
+	phy_set_bits(phydev, 0x17, BIT(4));
+	phy_clear_bits_mmd(phydev, MDIO_MMD_VEND1, 0xc6, 0x300);
+
+	/* Set TX Pair delay selection */
+	phy_write_mmd(phydev, MDIO_MMD_VEND1, 0x13, 0x404);
+	phy_write_mmd(phydev, MDIO_MMD_VEND1, 0x14, 0x404);
+
+	return 0;
+}
+
+static struct phy_driver mtk_phy_driver[] = {
+	{
+		PHY_ID_MATCH_EXACT(0x03a29412),
+		.name		= "MediaTek MT7530 PHY",
+		.config_init	= mt7530_phy_config_init,
+		/* Interrupts are handled by the switch, not the PHY
+		 * itself.
+		 */
+		.config_intr	= genphy_no_config_intr,
+		.handle_interrupt = genphy_handle_interrupt_no_ack,
+		.read_page	= mtk_phy_read_page,
+		.write_page	= mtk_phy_write_page,
+	},
+	{
+		PHY_ID_MATCH_EXACT(0x03a29441),
+		.name		= "MediaTek MT7531 PHY",
+		.config_init	= mt7531_phy_config_init,
+		/* Interrupts are handled by the switch, not the PHY
+		 * itself.
+		 */
+		.config_intr	= genphy_no_config_intr,
+		.handle_interrupt = genphy_handle_interrupt_no_ack,
+		.read_page	= mtk_phy_read_page,
+		.write_page	= mtk_phy_write_page,
+	},
+};
+
+module_phy_driver(mtk_phy_driver);
+
+static struct mdio_device_id __maybe_unused mtk_phy_tbl[] = {
+	{ PHY_ID_MATCH_VENDOR(0x03a29400) },
+	{ }
+};
+
+MODULE_DESCRIPTION("MediaTek switch integrated PHY driver");
+MODULE_AUTHOR("DENG, Qingfang <dqfext at gmail.com>");
+MODULE_LICENSE("GPL");
+
+MODULE_DEVICE_TABLE(mdio, mtk_phy_tbl);
-- 
2.25.1