On Wed, Apr 04, 2018 at 03:12:39PM +0200, Andrew Lunn wrote: > > What about the 'reset' functionality? Is there something in the power > > supply API for hooking in a GPIO based power switch (in my case it > > would be i2c) as I would think that would be common for ATX supplies? > > I didn't see anything in Documentation/power. > > This is what led me to the restart handler idea. Ultimately when > > someone issues a 'reboot' I would like it to use the GSC to > > power-cycle the board. > I think you end up with the same problem. By the time you need to turn > the power supply off, too much of the kernel is shut down to be able > to use I2C. And if you are in the middle of an Oops, you have no idea > of the current state. Another I2C transaction could be under way etc. > All the current reset drivers are pretty much self contained, atomic > and use KISS hardware like a GPIO. > Maybe you best bet is to see if you can find any other I2C PMICs which > the kernel supports. Most systems have a handshake for final power down via asserting signals rather than using register writes, the final power down sequence usually runs way after software. There's a few things that don't which just unceremoniously cut the power earlier on without completing the full power down sequence which for all practical purposes mostly works.
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