net: phy: add driver for Motorcomm yt8511 phy

Add a driver for the Motorcomm yt8511 phy that will be used in the
production Pine64 rk3566-quartz64 development board.
It supports gigabit transfer speeds, rgmii, and 125mhz clk output.
Signed-off-by: NPeter Geis <pgwipeout@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

MAINTAINERS

@@ -12378,6 +12378,12 @@ F:	Documentation/userspace-api/media/drivers/meye*
 F:	drivers/media/pci/meye/
 F:	include/uapi/linux/meye.h
 
+MOTORCOMM PHY DRIVER
+M:	Peter Geis <pgwipeout@gmail.com>
+L:	netdev@vger.kernel.org
+S:	Maintained
+F:	drivers/net/phy/motorcomm.c
+
 MOXA SMARTIO/INDUSTIO/INTELLIO SERIAL CARD
 S:	Orphan
 F:	Documentation/driver-api/serial/moxa-smartio.rst

drivers/net/phy/Kconfig

@@ -234,6 +234,12 @@ config MICROSEMI_PHY
 	help
 	  Currently supports VSC8514, VSC8530, VSC8531, VSC8540 and VSC8541 PHYs
 
+config MOTORCOMM_PHY
+	tristate "Motorcomm PHYs"
+	help
+	  Enables support for Motorcomm network PHYs.
+	  Currently supports the YT8511 gigabit PHY.
+
 config NATIONAL_PHY
 	tristate "National Semiconductor PHYs"
 	help

drivers/net/phy/Makefile

@@ -71,6 +71,7 @@ obj-$(CONFIG_MICREL_PHY)	+= micrel.o
 obj-$(CONFIG_MICROCHIP_PHY)	+= microchip.o
 obj-$(CONFIG_MICROCHIP_T1_PHY)	+= microchip_t1.o
 obj-$(CONFIG_MICROSEMI_PHY)	+= mscc/
+obj-$(CONFIG_MOTORCOMM_PHY)	+= motorcomm.o
 obj-$(CONFIG_NATIONAL_PHY)	+= national.o
 obj-$(CONFIG_NXP_C45_TJA11XX_PHY)	+= nxp-c45-tja11xx.o
 obj-$(CONFIG_NXP_TJA11XX_PHY)	+= nxp-tja11xx.o

drivers/net/phy/motorcomm.c

+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for Motorcomm PHYs
+ *
+ * Author: Peter Geis <pgwipeout@gmail.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/phy.h>
+
+#define PHY_ID_YT8511		0x0000010a
+
+#define YT8511_PAGE_SELECT	0x1e
+#define YT8511_PAGE		0x1f
+#define YT8511_EXT_CLK_GATE	0x0c
+#define YT8511_EXT_DELAY_DRIVE	0x0d
+#define YT8511_EXT_SLEEP_CTRL	0x27
+
+/* 2b00 25m from pll
+ * 2b01 25m from xtl *default*
+ * 2b10 62.m from pll
+ * 2b11 125m from pll
+ */
+#define YT8511_CLK_125M		(BIT(2) | BIT(1))
+#define YT8511_PLLON_SLP	BIT(14)
+
+/* RX Delay enabled = 1.8ns 1000T, 8ns 10/100T */
+#define YT8511_DELAY_RX		BIT(0)
+
+/* TX Gig-E Delay is bits 7:4, default 0x5
+ * TX Fast-E Delay is bits 15:12, default 0xf
+ * Delay = 150ps * N - 250ps
+ * On = 2000ps, off = 50ps
+ */
+#define YT8511_DELAY_GE_TX_EN	(0xf << 4)
+#define YT8511_DELAY_GE_TX_DIS	(0x2 << 4)
+#define YT8511_DELAY_FE_TX_EN	(0xf << 12)
+#define YT8511_DELAY_FE_TX_DIS	(0x2 << 12)
+
+static int yt8511_read_page(struct phy_device *phydev)
+{
+	return __phy_read(phydev, YT8511_PAGE_SELECT);
+};
+
+static int yt8511_write_page(struct phy_device *phydev, int page)
+{
+	return __phy_write(phydev, YT8511_PAGE_SELECT, page);
+};
+
+static int yt8511_config_init(struct phy_device *phydev)
+{
+	unsigned int ge, fe;
+	int ret, oldpage;
+
+	/* set clock mode to 125mhz */
+	oldpage = phy_select_page(phydev, YT8511_EXT_CLK_GATE);
+	if (oldpage < 0)
+		goto err_restore_page;
+
+	ret = __phy_modify(phydev, YT8511_PAGE, 0, YT8511_CLK_125M);
+	if (ret < 0)
+		goto err_restore_page;
+
+	/* set rgmii delay mode */
+	switch (phydev->interface) {
+	case PHY_INTERFACE_MODE_RGMII:
+		ge = YT8511_DELAY_GE_TX_DIS;
+		fe = YT8511_DELAY_FE_TX_DIS;
+		break;
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+		ge = YT8511_DELAY_RX | YT8511_DELAY_GE_TX_DIS;
+		fe = YT8511_DELAY_FE_TX_DIS;
+		break;
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+		ge = YT8511_DELAY_GE_TX_EN;
+		fe = YT8511_DELAY_FE_TX_EN;
+		break;
+	case PHY_INTERFACE_MODE_RGMII_ID:
+		ge = YT8511_DELAY_RX | YT8511_DELAY_GE_TX_EN;
+		fe = YT8511_DELAY_FE_TX_EN;
+		break;
+	default: /* leave everything alone in other modes */
+		break;
+	}
+
+	ret = __phy_modify(phydev, YT8511_PAGE, (YT8511_DELAY_RX | YT8511_DELAY_GE_TX_EN), ge);
+	if (ret < 0)
+		goto err_restore_page;
+
+	/* fast ethernet delay is in a separate page */
+	ret = __phy_write(phydev, YT8511_PAGE_SELECT, YT8511_EXT_DELAY_DRIVE);
+	if (ret < 0)
+		goto err_restore_page;
+
+	ret = __phy_modify(phydev, YT8511_PAGE, YT8511_DELAY_FE_TX_EN, fe);
+	if (ret < 0)
+		goto err_restore_page;
+
+	/* leave pll enabled in sleep */
+	ret = __phy_write(phydev, YT8511_PAGE_SELECT, YT8511_EXT_SLEEP_CTRL);
+	if (ret < 0)
+		goto err_restore_page;
+
+	ret = __phy_modify(phydev, YT8511_PAGE, 0, YT8511_PLLON_SLP);
+	if (ret < 0)
+		goto err_restore_page;
+
+err_restore_page:
+	return phy_restore_page(phydev, oldpage, ret);
+}
+
+static struct phy_driver motorcomm_phy_drvs[] = {
+	{
+		PHY_ID_MATCH_EXACT(PHY_ID_YT8511),
+		.name		= "YT8511 Gigabit Ethernet",
+		.config_init	= yt8511_config_init,
+		.suspend	= genphy_suspend,
+		.resume		= genphy_resume,
+		.read_page	= yt8511_read_page,
+		.write_page	= yt8511_write_page,
+	},
+};
+
+module_phy_driver(motorcomm_phy_drvs);
+
+MODULE_DESCRIPTION("Motorcomm PHY driver");
+MODULE_AUTHOR("Peter Geis");
+MODULE_LICENSE("GPL");
+
+static const struct mdio_device_id __maybe_unused motorcomm_tbl[] = {
+	{ PHY_ID_MATCH_EXACT(PHY_ID_YT8511) },
+	{ /* sentinal */ }
+};
+
+MODULE_DEVICE_TABLE(mdio, motorcomm_tbl);