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From: "Pali Rohár" <pali.rohar@gmail.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: "Andrew F. Davis" <afd@ti.com>,
	Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>,
	Sebastian Reichel <sre@kernel.org>,
	Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>,
	David Woodhouse <dwmw2@infradead.org>,
	linux-pm@vger.kernel.org
Subject: Re: Should 9aafabc7fece be reverted?
Date: Fri, 20 May 2016 12:35:05 +0200	[thread overview]
Message-ID: <20160520103505.GW29844@pali> (raw)
In-Reply-To: <20160520093432.GC4580@amd>

On Friday 20 May 2016 11:34:32 Pavel Machek wrote:
> Hi!
> 
> > > I think it is insane to starts generating random numbers for IDR... Hard 
> > > to decide what happen if such situation occur...
> > > 
> > 
> > That's kind of what I'm looking for though, if the userspace break is
> > caused by software relying on the battery to be named "bq27200-0", then
> > nothing short of hard-coding this exact name will 100% safely fix the
> > N900 userspace software. And so using IDR and hoping it gives 0 is just
> > a hacky work-around way of just naming the device "bq27200-0".
> 
> BTW proposals how to fix that userspace would be welcome.
> 
> We have three "power supplies", but userspace does not know how they
> are connecting, resulting in strange results. For now, I have
> hardware-specific layer in userspace.
> 
> https://gitlab.com/tui/tui/blob/master/ofone/hardware.py
> 
> Kernel does not really give me other choice.

I have in my mind idea of "merged" power supply devices.

For Nokia N900 we have:
* bq27200 monitoring chip
* bq24150a charging chip
* isp1707 usb phy chargin chip (wallcharger detection + enable gpio)
* rx51_battery driver (export ADC values from battery pins: temperature + design capacity)

And each part export own power supply device in /sys/class/power_supply/
So there are 4 power supply devices!

In ideal world kernel should provide into userspace just two devices:
* power supply charger device (merged values from isp1707 and bq24150a)
* power supply battery device (merged values from rx51_battery and bq27200)

Problem is that e.g. design capacity value provide both drivers. But
bq27xxx just return constant and incorrect value from bq eeprom. Correct
design capacity return only rx51_battery (which read it via ADC, third
battery pin).

That should fix detection and discovery problem. On Nokia N900 there is
just one battery and one charger device.

-- 
Pali Rohár
pali.rohar@gmail.com

  reply	other threads:[~2016-05-20 10:35 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-18 16:58 Should 9aafabc7fece be reverted? Andrew F. Davis
2016-05-19  6:44 ` Ivaylo Dimitrov
2016-05-19  9:17   ` Pali Rohár
2016-05-19  9:34     ` Ivaylo Dimitrov
2016-05-19 15:38     ` Andrew F. Davis
2016-05-19 15:44       ` Pali Rohár
2016-05-19 15:48         ` Andrew F. Davis
2016-05-19 15:51           ` Pali Rohár
2016-05-19 15:57             ` Andrew F. Davis
2016-05-19 16:06               ` Pali Rohár
2016-05-19 16:11                 ` Andrew F. Davis
2016-05-19 16:18                   ` Pali Rohár
2016-05-19 16:46                     ` Andrew F. Davis
2016-05-20  9:29                       ` Pavel Machek
2016-05-23 15:55                         ` Andrew F. Davis
2016-05-23 16:10                           ` Pali Rohár
2016-05-23 16:29                             ` Andrew F. Davis
2016-05-20  9:34                       ` Pavel Machek
2016-05-20 10:35                         ` Pali Rohár [this message]
2016-05-23 16:05                           ` Andrew F. Davis
2016-05-20  9:22           ` Pavel Machek

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