AM625: BQ25638 linux device driver

Hi Prathibha,

I can try to fetch it for you. Can you share an email address where you would like to receive the relevant files? 

Thanks

Hello TI,

Please share to same registered email id "prathibha.ningappa@tessolve.com"

Thank you,

Prathibha 

Hello TI,

Please let us know if any patchs available on "drivers/power/supply/bq256xx_charger.c" to validate BQ25638,

Thank you,

Prathibha

Hi Ning,

Part no:BQ25638

path:drivers/power/supply/bq256xx_charger.c

As informed in previous comment device driver for BQ25638 is not available, we are modifying the above mentioned driver as per BQ25638 datasheet,

I modified some registers based on the BQ25638 datasheet, but some registers were not available in the BQ25638 datasheet. Could you please provide the details of  unavailable registers?

I have attached the link for your reference, which includes details on which registers are already changed by referring to datasheet and which registers are not available.

Link:
/cfs-file/__key/communityserver-discussions-components-files/791/oto_5F00_track_5F00_charge_5F00_registe.txt

Regards,
Honnesh 

Hi Ning,

Part no:BQ25638

I have some questions regarding the identification of the following registers for battery charging, discharging, and status monitoring:

• • EN_CHG_REG (0x16): Enables/disables charging. Bit: 5 (0x00 = Disabled, 0x01 = Enabled)

  • VBAT_ADC_REG (0x35): Monitors battery voltage. Bits: 12:1

  • IBAT_ADC_REG (0x2F): Monitors battery current. Bits: 15:3 (Positive = Charging, Negative = Discharging)
    

  • CHG_STAT_REG (0x21): Checks status. Bits: 5:3

    • 000b = Not Charging

    • 001b = Trickle Charge

    • 010b = Pre-charge

    • 011b = Fast Charge (CC)

    • 100b = Taper Charge (CV)

    • 101b = Reserved

    • 110b = Top-off Timer Active Charging

    • 111b = Charge Termination Done

Could you please confirm if these registers and their values are correct for identifying battery charging, discharging, and status?

Regards,
Honnesh

Hi Ning,

Part No: BQ25638

Here is the current battery status:

• 0: Battery connected
• 1: No battery connected

If there's any additional registration required for either having the battery connected or no battery connected, could you please provide the necessary register details?

If there is any specific register, kindly provide the register information as well.

Regards,
Honnesh

Hi Ning,

Part No: BQ25638

We are working with the BQ25638 battery charge IC and need to monitor the battery voltage and battery current. However, we could not find dedicated registers for these parameters in the datasheet.

Could you please confirm the following:

• Is there a specific register for reading battery voltage ?
• Is there a specific register for reading battery current?
• If these values are not directly available, what alternative approach do you recommend for monitoring them while using the BQ25638?
• Any reference documents, datasheets that provide additional details.

Regards  

Honnesh

Hi Shuvam,

Part No: BQ25638

I am working with the BQ25638 IC and have the following queries:

Registers in Use:

• REG0x2F (IBAT ADC) for battery current
• REG0x35 (VBAT ADC) for battery voltage

Issue: Both registers are returning the default value 0x00 0x00

Request for Assistance:

• How can I enable these ADC readings?
• Are there any alternative registers available for reading battery voltage and current?

output:

root@am62xx-evm:~# i2cget -f -y 3 0x6B 0x35 i 2
0x00 0x00
root@am62xx-evm:~# i2cget -f -y 3 0x6B 0x2F i 2
0x00 0x00

Regards
Honnesh 

Hi Shuvam,

Part No: BQ25638

I am currently working with the BQ25638 battery charger IC and need to calculate the battery voltage (VBAT) and battery current (IBAT) from the ADC readings. Could you please provide the appropriate formulas for these calculations? 

Regards,

Honnesh 

Hi Honnesh,

What value do you get when reading a known voltage? For example when you know the VBAT is a fixed 3.6V?

Hi Shuvam,

Part No: BQ25638

I am currently working with the BQ25638 battery charger IC and reading VBAT and IBAT values from its ADC registers, and I need some clarification on the values obtained.

I first read the 0x2B register, and the value returned was 0x30 (0011 0000 in binary).

After enabling the 7th bit and writing back to the same register, the value changed to 0xB0 (1011 0000 in binary)

When this bit is enabled, I can read values from the 0x35 register; otherwise, it returns 0x00 0x00.

After enabling the bit, reading the 0x35 register returned 0x74 0x16 as the response. 

Regards,

Honnesh