Hi, On Tuesday 06 December 2011 02:12:47 you wrote: > Hi, > > On Tue, Dec 6, 2011 at 1:05 AM, Pali Rohár <pali.rohar@xxxxxxxxx> wrote: > > I started writing other implementaion of bq2415x charger driver, which > > should support also setting usb host mode. Code is still unfinished, > > but now is devided into 2 parts: one power_supply driver and one driver > > which cover all bq registers. See: > > > > http://atrey.karlin.mff.cuni.cz/~pali/bq2415x/ > > > > Felipe Contreras, I think that my implementation is better - it will > > export all bq registers (which is needed for hostmode boost) and will > > also register regulator interface. > > I took a look at your driver, and there's definitely good stuff in it. > However, I think there's a lot of unnecessary stuff, like the > miscdevice stuff (which was frowned upon for bq27x00), and a lot of > user-space interface. Moreover, it doesn't seem to do anything on its > own (it needs interaction from user-space). Ignore miscdevice, I will remove them from driver. I will add some debugfs interface for getting registers output (needed for debugging) > > IMO the first step should be to have a minimal driver that just works, > even if it doesn't achieve the absolute best charging performance. > More features could be added later on. > > Also, I'm not familiar with the regulator interface, but it seems to > be meant for real regulators, which have consumers, and based on those > consumers's needs the real voltage changes. This battery charger on > the other hand doesn't have anything like that. There will be no > consumer, and some stuff like the weak battery voltage is not even > related to a voltage supply, but rather a threshold that can be > configured to change some behavior of the charger, but there's no > point in changing it dynamically (or maybe at all). If regulator interface is not good, I can change it to some sysfs interface. But bq2415x chip driver is not only rx51 specified, so it should handle all chip capabilities. > > I guess the important one is the charge voltage, which is linked to a > real voltage, but what consumers would it have? I don't think there's > any. > > Finally, I don't think user-space interaction should be needed at all. > The driver should start charging immediately when there power supply > available, and stop when there isn't any. Maybe at some point a > user-space interface will be useful later on (I don't see why), but I > don't think it should be *necessary*. Userspace interfaction is needed. We need to tell driver to boost - for usb host mode. But of course, battery charging should be automatic without userspace interfaction. > > I'm not familiar with any of this stuff, so don't take my opinions too > seriously :) Consider my code. We do not need two (or more) implementation of same driver in kernel. And also we do not need only rx51 specified code. I separated bq2415x register access into one module (bq2415x.c - without any logic, only cover chip options) and real battery charging should be done in power_supply interface (bq2415x_charger.c) My code has also prepaired boost support - for usb host mode, which must be done in driver. If you do not agree with other parts, tell me about it - we can fix it. > > Cheers. -- Pali Rohár pali.rohar@xxxxxxxxx
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