From: Jan Petrous (OSS) <jan.petrous@oss.nxp.com>
Date: Thu, 5 Dec 2024 16:43:01 +0000 (+0100)
Subject: net: phy: Add helper for mapping RGMII link speed to clock rate
X-Git-Tag: v6.14-rc1~162^2~253^2~11
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=386aa60abdb600a4e5ad818e6dba171685942e54;p=thirdparty%2Flinux.git

net: phy: Add helper for mapping RGMII link speed to clock rate

The RGMII interface supports three data rates: 10/100 Mbps
and 1 Gbps. These speeds correspond to clock frequencies
of 2.5/25 MHz and 125 MHz, respectively.

Many Ethernet drivers, including glues in stmmac, follow
a similar pattern of converting RGMII speed to clock frequency.

To simplify code, define the helper rgmii_clock(speed)
to convert connection speed to clock frequency.

Suggested-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jan Petrous (OSS) <jan.petrous@oss.nxp.com>
Link: https://patch.msgid.link/20241205-upstream_s32cc_gmac-v8-4-ec1d180df815@oss.nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/include/linux/phy.h b/include/linux/phy.h
index bb157136351e7..e597a32cc787a 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -298,6 +298,29 @@ static inline const char *phy_modes(phy_interface_t interface)
 	}
 }
 
+/**
+ * rgmii_clock - map link speed to the clock rate
+ * @speed: link speed value
+ *
+ * Description: maps RGMII supported link speeds
+ * into the clock rates.
+ *
+ * Returns: clock rate or negative errno
+ */
+static inline long rgmii_clock(int speed)
+{
+	switch (speed) {
+	case SPEED_10:
+		return 2500000;
+	case SPEED_100:
+		return 25000000;
+	case SPEED_1000:
+		return 125000000;
+	default:
+		return -EINVAL;
+	}
+}
+
 #define PHY_INIT_TIMEOUT	100000
 #define PHY_FORCE_TIMEOUT	10