[PATCH] net: phy: Add sysfs attribute for PHY c45 identifiers.

[Jianhui Zhao <zhaojh329@gmail.com>]

If a phydevice use c45, its phy_id property is always 0, so
this adds a phy_c45_ids sysfs attribute to MDIO devices. This
attribute can be useful when debugging problems related to
phy drivers.

Signed-off-by: Jianhui Zhao <zhaojh329@gmail.com>
---
 drivers/net/phy/phy_device.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 17d0d0555a79..521228792840 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -560,6 +560,29 @@ phy_id_show(struct device *dev, struct device_attribute *attr, char *buf)
 }
 static DEVICE_ATTR_RO(phy_id);
 
+static ssize_t
+phy_c45_ids_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct phy_device *phydev = to_phy_device(dev);
+	const int num_ids = ARRAY_SIZE(phydev->c45_ids.device_ids);
+	int ret = 0;
+	int i;
+
+	if (!phydev->is_c45)
+		return 0;
+
+	for (i = 1; i < num_ids; i++) {
+		if (phydev->c45_ids.device_ids[i] == 0xffffffff)
+			continue;
+
+		ret += sprintf(buf + ret, "%d: 0x%.8lx\n", i,
+			(unsigned long)phydev->c45_ids.device_ids[i]);
+	}
+
+	return ret;
+}
+static DEVICE_ATTR_RO(phy_c45_ids);
+
 static ssize_t
 phy_interface_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
@@ -597,6 +620,7 @@ static DEVICE_ATTR_RO(phy_dev_flags);
 
 static struct attribute *phy_dev_attrs[] = {
 	&dev_attr_phy_id.attr,
+	&dev_attr_phy_c45_ids.attr,
 	&dev_attr_phy_interface.attr,
 	&dev_attr_phy_has_fixups.attr,
 	&dev_attr_phy_dev_flags.attr,
-- 
2.34.1