Re: [PATCH net-next] net: phy: microchip_t1: add cable test support for lan87xx phy

quoted

quoted

+     /* start cable diag */
+     /* check if part is alive - if not, return diagnostic error */
+     rc = access_ereg(phydev, PHYACC_ATTR_MODE_READ,

PHYACC_ATTR_BANK_SMI,

quoted

+                      0x00, 0);
+     if (rc < 0)
+             return rc;
+
+     if (rc != 0x2100)
+             return -ENODEV;

What does this actually mean? Would -EOPNOTSUPP be better?

This register should return the value of 0x2100. So if the return value is different, then I assume there is no device.

If the device does not exist, can we have go this far? Would probe of
the PHY failed? Or are you talking about a device within a device? Is
cable test implemented using an optional component?

      Andrew