Month: August 2013

more battery charging

So reading the Battery Charging Implementers spec, and in particular, this doc, Section 6 is the gory details. (and table 5.3). Table 5.3 suggests that RID_A  should be 124K (oops, I used 100K), RID_B = 68K, and RID_C = 36.5K.

Even more OTG charging

Time to dig in to the differences in the various code branches. On AOSP for MSM,  https://android.googlesource.com/kernel/msm.git, there is a ‘newer’ branch. Newer in the sense that it is a newer kernel. To diff the version shipped w/ the Nexus

More on the charging USB OTG Nexus 7

So i can reliably charge now with the USB OTG cable. I found I had a problem wit the cable I had bought: it should have 100K between pin 4 & pin 5, but pin 4 was No-Connect. E.g. see

USB OTG charging Nexus 7 (2013) flo: some success!

OK, enabled CONFIG_USB_MSM_ACA=y, and made the diffs as per previous post, and echo enabled > /sys/kernel/debug/msm_otg/aca now the device recognises (and starts charging) when I plug in the Y cable and to the power. And it recognises it is not charging when

USB OTG power, take 2

bq27541, smb345, pm8921 (all in drivers/powr) and ektf3k (drivers/input/touchscreen) seem to know when power state changes. The latter relates to slimport hdmi and receiving power through it. drivers/usb/otg/msm_otg is the other spot the work happens The BQ27541 is a ‘fuel-gauge’

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