Thank you @pali. Are there instructions for using this module?

You can find something here: http://atrey.karlin.mff.cuni.cz/~pal...o/bq2415x.html

Thank you @pali. Do I understand correctly that if I want to set the charge rate I need to write to /sys/class/power_supply/bq24150-0/current_limit, and the allowed values are 100, 500, 800 and unlimited? (what is this stuff about 1800?) Is there any GUI available or planned to set these values, and/or can I help?

1800 is unlimited. There is no gui. Just open terminal and write values.

Would there be a way to smartly sense incoming power from a dumb charger or add the dumb mode toggle to USB mode in a settings menu? I would love to be able to send the charge from my frankenPalm touchstone charger through the built in chargng system where the N900 hardware/software could manage it rather than using the charging board stuffed inside my Mugen battery cover.
Also probably less scary if the airport security were to open my phone.
http://talk.maemo.org/showthread.php?t=56950

A dumb mode toggle also might make more N900's repairable for USB charging even if they can't use the difficult to repair data lines.

Thank you very much, Pali, for this awesome application.

- With the old h-e-n app, I often had problems enumerating some devices and with this app, it works far better (don't know why, maybe due to the flat delay between vbus boost on and enumeration ?)
- With the old h-e-n app, when trying to enumerate a few different devices in a row, it did a mess with my usb port, disabling it until a reboot. With this app, it doesn't happen anymore, so it seems cleaner.

Anyway, I've spotted a few minor problems.
I still haven't tried "hostmode with charging" as I don't already own an Y USB cable, so the following points are only related to "USB Host mode with boost".

- Sometimes, after enumerating a simple device such as a mouse or a keyboard, I get the message "unable to connect, no file system available".
- The same message always appears when the enumeration fails.
- Hotplug doesn't seem to be handled (even when unplugging and plugging the same device). Is it normal ?
- When unplugging an enumerated device, and plugging a new one, pressing "USB host mode" only says "device already visible in system". I have to go in USB peripheral mode then go again to USB host mode to enumerate the new device.
- I own a D-Link powered USB-Hub : DUB-H7. The enumeration fails about one time out of three (or four). Once associated, it works like a charm (even hotplug). It works powered AND unpowered.
- I own a SD-card reader : Cardette Moshi (which is also a mini unpowered 2-ports USB-hub). The enumeration works but the mount often fails when the SD card is already plugged during enumeration ("unable to connect, no file system available"). I have to remove the SD card and plug it again. The unpowered USB-hub works well (even hotplug)
- When enumerating a full speed device (such as a sd card reader), going through the three speeds turns the device on/off on each change. Couldn't it stress the device a bit and (lightly) shorten it's lifetime ?

If you care about, I have some improvement suggestions :

- Get a new "Peripheral without charging" mode. I often use my phone as an USB key to store files, and I don't like to keep plugged when battery is already at full charge. Being able to connect the phone whitout charging it would be great !
- Handle direct hotplug. Because hotplug is possible through an USB hub, I think it could work directly on the phone too.
- Being able to choose between the three speeds (such as h-e-n) AND automatic detection. If the appropriate speed is already known, directly setting it would speed up enumeration and avoid the usb device to be turned on/off too many times.

You probably don't want to do peripheral without charging, keeping musb_core alive eats a flat 80mA.

Pali, I have tried USB mode with charging with an external HDD and battery pod; I got an error "charger attached" and it refused to allow the connection putting me back in the peripheral mode and charging starts.

Now that I am used to getting connected over 95% of the time using a flash drive (vs ~30% connect on first try with h-e-n) and have a custom swappolube profile for big USB transfers I don't bother with moving big files over wifi anymore.
Kickass work Pali!

Maybe very low charging rate flash drive mode.

I'm not an expert on this subject (and I know many experts able to validate/invalidate my arguments are on this forum), but I have read a Li-Ion battery is supposed to last longer if it runs full charge/discharge cycles.

So I believe that being able to preserve our battery lifetime at the price of changing USB mode every few hours (to charge the battery when it's discharged) would be an improvement.