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From:   Michael Walle <michael@walle.cc>
To:     Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Rob Herring <robh+dt@kernel.org>,
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        Jakub Kicinski <kuba@kernel.org>,
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        Frank Rowand <frowand.list@gmail.com>
Cc:     linux-mtd@lists.infradead.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        netdev@vger.kernel.org, Ahmad Fatoum <a.fatoum@pengutronix.de>,
        Michael Walle <michael@walle.cc>
Subject: [PATCH v1 01/14] net: add helper eth_addr_add()
Date:   Thu, 25 Aug 2022 23:44:10 +0200
Message-Id: <20220825214423.903672-2-michael@walle.cc>
In-Reply-To: <20220825214423.903672-1-michael@walle.cc>
References: <20220825214423.903672-1-michael@walle.cc>
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Add a helper to add an offset to a ethernet address. This comes in handy
if you have a base ethernet address for multiple interfaces.

Signed-off-by: Michael Walle <michael@walle.cc>
---
 include/linux/etherdevice.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index 92b10e67d5f8..d1be5ca4d5cb 100644
--- a/include/linux/etherdevice.h
+++ b/include/linux/etherdevice.h
@@ -485,6 +485,20 @@ static inline void eth_addr_inc(u8 *addr)
 	u64_to_ether_addr(u, addr);
 }
 
+/**
+ * eth_addr_add() - Add (or subtract) and offset to/from the given MAC address.
+ *
+ * @offset: Offset to add.
+ * @addr: Pointer to a six-byte array containing Ethernet address to increment.
+ */
+static inline void eth_addr_add(u8 *addr, long offset)
+{
+	u64 u = ether_addr_to_u64(addr);
+
+	u += offset;
+	u64_to_ether_addr(u, addr);
+}
+
 /**
  * is_etherdev_addr - Tell if given Ethernet address belongs to the device.
  * @dev: Pointer to a device structure
-- 
2.30.2