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d4ee021c41
There have been some cases of droid4 battery bulging that seem to be related to being left connected to the charger for several weeks. It is suspected that the 4.35V charge voltage configured for the battery is too much in the long run, so lets limit the charge voltage to 4.2V. It could also be that the batteries are just getting old. We don't really want to just change the charge voltage to 4.2V as Android may have charged the battery to 4.35V as pointed out by Pavel Machek. To add checks for battery voltage, the driver needs to understand the voltage it's charging at, and also needs to better understand it's charger state. Right now it only understands connect and disconnect, while now we need to know also a connected state but not charging. So let's add better charger state handling with help of chrgcurr2 interrupt for detecting charge full and retry, and add a check for battery voltage before we start charging. And then we finally can lower the charge voltage to 4.2V. Note that we've been using the same register values as the Android distros on droid4, so it is suspected that the same problem also exists in Android. Cc: Pavel Machek <pavel@ucw.cz> Cc: Rob Herring <robh+dt@kernel.org> Reported-by: Merlijn Wajer <merlijn@wizzup.org> Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.