1 files changed, 74 insertions, 0 deletions
diff --git a/drivers/net/phy/realtek/realtek_hwmon.c b/drivers/net/phy/realtek/realtek_hwmon.c
new file mode 100644
index 000000000000..ac96e2d1ebe8
--- /dev/null
+++ b/drivers/net/phy/realtek/realtek_hwmon.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * HWMON support for Realtek PHY's
+ *
+ * Author: Heiner Kallweit <hkallweit1@gmail.com>
+ */
+
+#include <linux/hwmon.h>
+#include <linux/phy.h>
+
+#include "realtek.h"
+
+#define RTL822X_VND2_TSALRM				0xa662
+#define RTL822X_VND2_TSRR				0xbd84
+#define RTL822X_VND2_TSSR				0xb54c
+
+static int rtl822x_hwmon_get_temp(int raw)
+{
+	if (raw >= 512)
+		raw -= 1024;
+
+	return 1000 * raw / 2;
+}
+
+static int rtl822x_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+			      u32 attr, int channel, long *val)
+{
+	struct phy_device *phydev = dev_get_drvdata(dev);
+	int raw;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		raw = phy_read_mmd(phydev, MDIO_MMD_VEND2, RTL822X_VND2_TSRR) & 0x3ff;
+		*val = rtl822x_hwmon_get_temp(raw);
+		break;
+	case hwmon_temp_max:
+		/* Chip reduces speed to 1G if threshold is exceeded */
+		raw = phy_read_mmd(phydev, MDIO_MMD_VEND2, RTL822X_VND2_TSSR) >> 6;
+		*val = rtl822x_hwmon_get_temp(raw);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static const struct hwmon_ops rtl822x_hwmon_ops = {
+	.visible = 0444,
+	.read = rtl822x_hwmon_read,
+};
+
+static const struct hwmon_channel_info * const rtl822x_hwmon_info[] = {
+	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_MAX),
+	NULL
+};
+
+static const struct hwmon_chip_info rtl822x_hwmon_chip_info = {
+	.ops = &rtl822x_hwmon_ops,
+	.info = rtl822x_hwmon_info,
+};
+
+int rtl822x_hwmon_init(struct phy_device *phydev)
+{
+	struct device *hwdev, *dev = &phydev->mdio.dev;
+
+	/* Ensure over-temp alarm is reset. */
+	phy_clear_bits_mmd(phydev, MDIO_MMD_VEND2, RTL822X_VND2_TSALRM, 3);
+
+	hwdev = devm_hwmon_device_register_with_info(dev, NULL, phydev,
+						     &rtl822x_hwmon_chip_info,
+						     NULL);
+	return PTR_ERR_OR_ZERO(hwdev);
+}