On Tue, Jun 23, 2020 at 11:46:15AM +0200, Bartosz Golaszewski wrote: > wt., 23 cze 2020 o 11:43 Russell King - ARM Linux admin > <linux@xxxxxxxxxxxxxxx> napisał(a): > > > > On Tue, Jun 23, 2020 at 11:41:11AM +0200, Bartosz Golaszewski wrote: > > > pon., 22 cze 2020 o 15:29 Russell King - ARM Linux admin > > > <linux@xxxxxxxxxxxxxxx> napisał(a): > > > > > > > > > > [snip!] > > > > > > > > > > > This is likely to cause issues for some PHY drivers. Note that we have > > > > some PHY drivers which register a temperature sensor in the probe > > > > function, which means they can be accessed independently of the lifetime > > > > of the PHY bound to the network driver (which may only be while the > > > > network device is "up".) We certainly do not want hwmon failing just > > > > because the network device is down. > > > > > > > > That's kind of worked around for the reset stuff, because there are two > > > > layers to that: the mdio device layer reset support which knows nothing > > > > of the PHY binding state to the network driver, and the phylib reset > > > > support, but it is not nice. > > > > > > > > > > Regulators are reference counted so if the hwmon driver enables it > > > using mdio_device_power_on() it will stay on even after the PHY driver > > > calls phy_device_power_off(), right? Am I missing something? > > > > If that is true, you will need to audit the PHY drivers to add that. > > > > This change doesn't have any effect on devices which don't have a > regulator assigned in DT though. The one I'm adding in the last patch > is the first to use this. It's quality of implementation. Should we wait for someone else to make use of the new regulator support that has been added with a PHY that uses hwmon, and they don't realise that it breaks hwmon on it, and several kernel versions go by without it being noticed. It will only be a noticable issue when the associated network device is down, and that network device driver detaches from the PHY, so _is_ likely not to be noticed. Or should we do a small amount of work now to properly implement regulator support, which includes a trivial grep for "hwmon" amongst the PHY drivers, and add the necessary call to avoid the regulator being shut off. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
