r8169: add support for the temperature sensor being available from RT…

…L8125B

This adds support for the temperature sensor being available from
RTL8125B. Register information was taken from r8125 vendor driver.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/realtek/r8169_main.c

@@ -16,6 +16,7 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/ethtool.h>
+#include <linux/hwmon.h>
 #include <linux/phy.h>
 #include <linux/if_vlan.h>
 #include <linux/in.h>
@@ -5363,6 +5364,43 @@ static bool rtl_aspm_is_safe(struct rtl8169_private *tp)
 	return false;
 }
 
+static umode_t r8169_hwmon_is_visible(const void *drvdata,
+				      enum hwmon_sensor_types type,
+				      u32 attr, int channel)
+{
+	return 0444;
+}
+
+static int r8169_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+			    u32 attr, int channel, long *val)
+{
+	struct rtl8169_private *tp = dev_get_drvdata(dev);
+	int val_raw;
+
+	val_raw = phy_read_paged(tp->phydev, 0xbd8, 0x12) & 0x3ff;
+	if (val_raw >= 512)
+		val_raw -= 1024;
+
+	*val = 1000 * val_raw / 2;
+
+	return 0;
+}
+
+static const struct hwmon_ops r8169_hwmon_ops = {
+	.is_visible =  r8169_hwmon_is_visible,
+	.read = r8169_hwmon_read,
+};
+
+static const struct hwmon_channel_info * const r8169_hwmon_info[] = {
+	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
+	NULL
+};
+
+static const struct hwmon_chip_info r8169_hwmon_chip_info = {
+	.ops = &r8169_hwmon_ops,
+	.info = r8169_hwmon_info,
+};
+
 static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
 	struct rtl8169_private *tp;
@@ -5537,6 +5575,12 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (rc)
 		return rc;
 
+	/* The temperature sensor is available from RTl8125B */
+	if (IS_REACHABLE(CONFIG_HWMON) && tp->mac_version >= RTL_GIGA_MAC_VER_63)
+		/* ignore errors */
+		devm_hwmon_device_register_with_info(&pdev->dev, "nic_temp", tp,
+						     &r8169_hwmon_chip_info,
+						     NULL);
 	rc = register_netdev(dev);
 	if (rc)
 		return rc;