[PATCH net-next v3 3/4] net: phy: Add helper for getting MAC termination resistance

[Dimitri Fedrau via B4 Relay]

From: Dimitri Fedrau <dimitri.fedrau@xxxxxxxxxxxx>

Add helper which returns the MAC termination resistance value. Modifying
the resistance to an appropriate value can reduce signal reflections and
therefore improve signal quality.

Reviewed-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
Signed-off-by: Dimitri Fedrau <dimitri.fedrau@xxxxxxxxxxxx>
---
 drivers/net/phy/phy_device.c | 15 +++++++++++++++
 include/linux/phy.h          |  3 +++
 2 files changed, 18 insertions(+)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index cc6c209fe702293c25e619899a699a53638f0f66..f85c172c446c56e1da1d13baa18c581f2213dcc5 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -2975,6 +2975,21 @@ int phy_get_tx_amplitude_gain(struct phy_device *phydev, struct device *dev,
 }
 EXPORT_SYMBOL_GPL(phy_get_tx_amplitude_gain);
 
+/**
+ * phy_get_mac_termination - stores MAC termination in @val
+ * @phydev: phy_device struct
+ * @dev: pointer to the devices device struct
+ * @val: MAC termination
+ *
+ * Returns: 0 on success, < 0 on failure
+ */
+int phy_get_mac_termination(struct phy_device *phydev, struct device *dev,
+			    u32 *val)
+{
+	return phy_get_u32_property(dev, "mac-termination-ohms", val);
+}
+EXPORT_SYMBOL_GPL(phy_get_mac_termination);
+
 static int phy_led_set_brightness(struct led_classdev *led_cdev,
 				  enum led_brightness value)
 {
diff --git a/include/linux/phy.h b/include/linux/phy.h
index fb755358d965b728d502bfc1c0d6e5a6b779f1ef..066a28a4b64b25a7c6033a3bb1e3bc48b20c96dc 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -2040,6 +2040,9 @@ int phy_get_tx_amplitude_gain(struct phy_device *phydev, struct device *dev,
 			      enum ethtool_link_mode_bit_indices linkmode,
 			      u32 *val);
 
+int phy_get_mac_termination(struct phy_device *phydev, struct device *dev,
+			    u32 *val);
+
 void phy_resolve_pause(unsigned long *local_adv, unsigned long *partner_adv,
 		       bool *tx_pause, bool *rx_pause);
 

-- 
2.39.5