[PATCH v2] net: phy: add driver for Motorcomm yt8511 phy

[Peter Geis]

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: Peter Geis <pgwipeout at gmail.com>
---
Changes v2:
- Change to __phy_modify
- Handle return errors
- Remove unnecessary &

 MAINTAINERS                 |  6 +++
 drivers/net/phy/Kconfig     |  6 +++
 drivers/net/phy/Makefile    |  1 +
 drivers/net/phy/motorcomm.c | 87 +++++++++++++++++++++++++++++++++++++
 4 files changed, 100 insertions(+)
 create mode 100644 drivers/net/phy/motorcomm.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 601b5ae0368a..2a2e406238fc 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12388,6 +12388,12 @@ 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 at gmail.com>
+L:	netdev at 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
diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 288bf405ebdb..16db9f8037b5 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -229,6 +229,12 @@ 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
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index bcda7ed2455d..37ffbc6e3c87 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -70,6 +70,7 @@ 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
diff --git a/drivers/net/phy/motorcomm.c b/drivers/net/phy/motorcomm.c
new file mode 100644
index 000000000000..580926f25dfc
--- /dev/null
+++ b/drivers/net/phy/motorcomm.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for Motorcomm PHYs
+ *
+ * Author: Peter Geis <pgwipeout at 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_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))
+
+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)
+{
+	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;
+
+	/* disable auto 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, BIT(15), 0);
+	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,
+		.get_features	= genphy_read_abilities,
+		.config_aneg	= genphy_config_aneg,
+		.read_status	= genphy_read_status,
+		.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);
-- 
2.25.1