Hi liyaoshi,

So how can I measure the charge percentage left in the battery? Is there an 
example that I can use? TPS65217 does not allow us to read the battery 
voltage if I am right or at least I cannot find it in datasheet. what 
voltage are you talking about? 

I did some progress with controlling PMIC and I can use i2c utilities to 
read and write to it. However I have to use -f to force it since kernel is 
using the I2C interface. How can I do this cleanly from user space without 
forcing it? One way would be to expand the driver to add extra features. 
Does anyone know a good example that I can use as starting point? Is there 
a better/easier way to do this?
my procedure is as follow:

 i2cdetect -l
on Beaglebone Black it will give you:

i2c-0   unknown         OMAP I2C adapter                        N/A

i2c-1   unknown         OMAP I2C adapter                        N/A


For reading status register of TPS65217. device is at 0x25 and status 
register is 0x0a on I2C0

i2cget [-f] [-y] i2cbus chip-address [data-address [mode]]


sudo i2cdet -f 0 0c24 0x0a

WARNING! This program can confuse your I2C bus, cause data loss and worse!

I will read from device file /dev/i2c-0, chip address 0x24, data address

0x0a, using read byte data.

Continue?
[Y/n]
0x88


To set battery charging voltage to 4.2V

i2cset [-f] [-y] [-m mask] [-r] i2cbus chip-address data-address [value] ... 
[mode]
sudo i2cset -f -m 0x30 0 0x24 0x05 0x20

WARNING! This program can confuse your I2C bus, cause data loss and worse!

I will write to device file /dev/i2c-0, chip address 0x24, data address

0x05, data 0x20 (masked), mode byte.

Continue? [Y/n]

Old value 0x80, write mask 0x30: Will write 0xa0 to register 0x05

Continue? [Y/n]


Thanks a lot



On Monday, November 24, 2014 6:08:45 PM UTC-8, liyaoshi wrote:
>
> As I know , if only 2 wires , you can not access the Li+battery status , 
> you can just get voltage value from PMU
>
> There always another 1 wire to get the communication with MCU in battery 
> module  
>
> 2014-11-25 8:52 GMT+08:00 <[email protected] <javascript:>>:
>
>> Hi All,
>>
>> I connected a rechargeable Li+ battery to my BBB TP5, TP6, TP7, and TP8. 
>> I shorted TP5 and TP6 and added a 10uF decoupling capacitor. In addition, I 
>> connected TS to GND with a 9K resistor which is 10K || 75K according to the 
>> datasheet and the board boots fine from battery. 
>> Now my question is that how can I monitor the battery status(how much 
>> they are charged) or change the setting of PMIC, TPS65127C from shell. For 
>> instance, I would like to set the charging voltage to 4.2 rather than the 
>> default 4.1V. Or I would like to turn on/off WLED etc. Is there a tool, 
>> like Alsamixer, for this? if not what would be the best approach for 
>> controlling PMIC from shell? I posted it here because PMIC uses I2C 
>> interface to talk to AM335x.
>>
>>
>> <https://lh4.googleusercontent.com/-E-wdJPfnG5U/VHPNaDDU9WI/AAAAAAAAAAo/tEjegAyAzAM/s1600/bbb-batt-srm.jpg>
>>
>>
>> <https://lh3.googleusercontent.com/-d7FQ9BVS6J4/VHPNtiSxI4I/AAAAAAAAAAw/3_g2aL5Q2K4/s1600/bbb-batt1.jpg>
>>
>> Thanks for your time and consideration.
>>
>>  -- 
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>

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