From mboxrd@z Thu Jan 1 00:00:00 1970 From: tony@atomide.com (Tony Lindgren) Date: Wed, 23 Jul 2014 23:32:51 -0700 Subject: [PATCH V2 1/2] power: twl4030_charger: detect battery presence prior to enabling charger In-Reply-To: <20140723120326.GA18172@earth.universe> References: <1401313610-14252-1-git-send-email-nm@ti.com> <1401313610-14252-2-git-send-email-nm@ti.com> <20140723092420.GE22006@atomide.com> <20140723120326.GA18172@earth.universe> Message-ID: <20140724063250.GG22006@atomide.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org * Sebastian Reichel [140723 05:05]: > On Wed, Jul 23, 2014 at 02:24:20AM -0700, Tony Lindgren wrote: > > * Nishanth Menon [140528 14:48]: > > > TWL4030's Battery Charger seems to be designed for non-hotpluggable > > > batteries. > > > > > > If battery is not present in the system, BATSTS is always set with the > > > expectation that software will take actions to move to a required safe > > > state (could be power down or disable various charger paths). > > > > > > It does not seem possible even by manipulating the edge detection > > > of the event (using BCIEDR2 register) to have a consistent hotplug > > > handling. This seems to be the result of BATSTS interrupt generated > > > when the thermistor of the battery pack is disconnected from the > > > dedicated ADIN1 pin. Clearing the status just results in the status > > > being regenerated by the monitoring ADC(MADC) and disabling the > > > edges of event just makes hotplug no longer function. The only > > > other option is to disable the detection of the MADC by disabling > > > BCIMFEN4::BATSTSMCHGEN (battery presence detector) - but then, we can > > > never again detect battery reconnection. > > > > > > So, detect battery presence based on precharge(which is hardware > > > automatic state) or default main charger configuration at the time of > > > probe and enable charger logic only if battery was present. > > > > > > Reported-by: Russell King > > > Tested-by: Tony Lindgren > > > Signed-off-by: Nishanth Menon > > > > Dmitry, can we please get this first patch merged? This is needed > > on some omap3 platforms for DT based booting when no battery is > > present. > > > > Only the second patch in this series is still being discussed AFAIK. > > applied to battery-2.6.git: > > http://git.infradead.org/battery-2.6.git/commit/61a7784efd3c89ffb6242f29bcee170dd7f55e6b Thanks! Tony