From 49ec39fa7f05c4a3d320b5a60593108e1affb19f Mon Sep 17 00:00:00 2001
From: Werner Zeh <werner.zeh@siemens.com>
Date: Tue, 15 Nov 2022 08:27:19 +0100
Subject: [PATCH] device/mdio: Provide helper functions for read and write

This patch provides helper functions to read or write a register via the
MDIO bus. They can be used from drivers to easily access registers on
the MDIO bus.

Change-Id: I293d93435d27269a071b4b9b94a1b55307c575a7
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69611
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
---
 src/device/mdio.c         | 24 ++++++++++++++++++++++++
 src/include/device/mdio.h |  3 +++
 2 files changed, 27 insertions(+)

diff --git a/src/device/mdio.c b/src/device/mdio.c
index 9f560e6bdf..39ac40bca7 100644
--- a/src/device/mdio.c
+++ b/src/device/mdio.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <assert.h>
 #include <console/console.h>
 #include <device/device.h>
 #include <device/mdio.h>
@@ -14,3 +15,26 @@ const struct mdio_bus_operations *dev_get_mdio_ops(struct device *dev)
 
 	return dev->ops->ops_mdio;
 }
+
+uint16_t mdio_read(struct device *dev, uint8_t offset)
+{
+	const struct mdio_bus_operations *mdio_ops;
+	struct device *parent = dev->bus->dev;
+
+	assert(dev->path.type == DEVICE_PATH_MDIO);
+	mdio_ops = dev_get_mdio_ops(parent);
+	if (!mdio_ops)
+		return 0;
+	return mdio_ops->read(parent, dev->path.mdio.addr, offset);
+}
+void mdio_write(struct device *dev, uint8_t offset, uint16_t val)
+{
+	const struct mdio_bus_operations *mdio_ops;
+	struct device *parent = dev->bus->dev;
+
+	assert(dev->path.type == DEVICE_PATH_MDIO);
+	mdio_ops = dev_get_mdio_ops(parent);
+	if (!mdio_ops)
+		return;
+	mdio_ops->write(parent, dev->path.mdio.addr, offset, val);
+}
diff --git a/src/include/device/mdio.h b/src/include/device/mdio.h
index 39e60f582d..44ce48b7f3 100644
--- a/src/include/device/mdio.h
+++ b/src/include/device/mdio.h
@@ -14,4 +14,7 @@ struct mdio_bus_operations {
 /* Helper for getting mdio operations from a device */
 const struct mdio_bus_operations *dev_get_mdio_ops(struct device *dev);
 
+uint16_t mdio_read(struct device *dev, uint8_t offset);
+void mdio_write(struct device *dev, uint8_t offset, uint16_t val);
+
 #endif	/* __DEVICE_MDIO_H__ */