From 89e7ff5e58b8d18e3c5504d155d3c1f7ed6f3d49 Mon Sep 17 00:00:00 2001
From: baiywt <baiywt_gj@163.com>
Date: Thu, 18 May 2023 15:55:23 +0800
Subject: [PATCH] net: phy: add sysfs node for reading PHY's registers

---
 drivers/net/phy/phy_device.c | 58 ++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 7fbb0904b..a7f6e3a9f 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -563,11 +563,69 @@ static ssize_t phy_dev_flags_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(phy_dev_flags);
 
+static ssize_t
+phy_registers_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct phy_device *phydev = to_phy_device(dev);
+	int index;
+
+	for (index = 0; index < 32; index++)
+		sprintf(buf, "%s%2d: 0x%x\n", buf, index,
+			phy_read(phydev, index));
+
+	return strlen(buf);
+}
+
+static ssize_t
+phy_registers_store(struct device *dev,
+		    struct device_attribute *attr,
+		    const char *buf, size_t count)
+{
+	struct phy_device *phydev = to_phy_device(dev);
+	int index = 0, val = 0;
+	char tmp[32];
+	char *data;
+
+	if (count >= sizeof(tmp))
+		goto out;
+
+	memset(tmp, 0, sizeof(tmp));
+	memcpy(tmp, buf, count);
+
+	data = tmp;
+	data = strstr(data, " ");
+	if (!data)
+		goto out;
+	*data = 0;
+	data++;
+
+	if (kstrtoint(tmp, 0, &index) || index >= 32)
+		goto out;
+
+	if (kstrtoint(data, 0, &val) || val > 0xffff)
+		goto out;
+
+	pr_info("Set Ethernet PHY register %d to 0x%x\n", (int)index, (int)val);
+
+	phy_write(phydev, index, val);
+
+	return count;
+
+out:
+	pr_err("wrong register value input\n");
+	pr_err("usage: <reg index> <value>\n");
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(phy_registers);
+
 static struct attribute *phy_dev_attrs[] = {
 	&dev_attr_phy_id.attr,
 	&dev_attr_phy_interface.attr,
 	&dev_attr_phy_has_fixups.attr,
 	&dev_attr_phy_dev_flags.attr,
+	&dev_attr_phy_registers.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(phy_dev);