In case anyone wants to test it out, here is the change in the source code
(NOTE: ignore the line and column numbers; just search for the struct
"static struct omap_musb_board_data musb_board_data" ):
...
--- a/arch/arm/mach-omap2/board-am335xevm.c
+++ b/arch/arm/mach-omap2/board-am335xevm.c
...
@@ -3956,7 +4125,8 @@ static struct omap_musb_board_data musb_board_data = {
* mode[4:7] = USB1PORT's mode
* AM335X beta EVM has USB0 in OTG mode and USB1 in host mode.
*/
- .mode = (MUSB_HOST << 4) | MUSB_OTG,
+// .mode = (MUSB_HOST << 4) | MUSB_OTG,
+ .mode = (MUSB_HOST << 4) | MUSB_PERIPHERAL,
.power = 500,
.instances = 1,
};
Please let me know the results.
Thank.
On Thursday, December 5, 2013 12:10:18 PM UTC-5, Lei Wang wrote:
>
> I can confirm that the pulsing detected by PMIC on USB_DC signal is the
> probing from USB-OTG.
>
> After I disabled the USB-OTG in the kernel, the system has never rebooted.
> Btw I also re-loaded Angstrom image (3.8 kernel) and Andrew's Android image
> (with 3.8 kernel). I did not observe USB-OTG probing pulses on the VBus. I
> believe in the 3.8 kernel, the USB-OTG has not been implemented/enabled.
> That might be reason why it seems that 3.8 kernel doesn't have the random
> reboot behavior.
>
>
>
> On Wednesday, December 4, 2013 6:15:13 PM UTC-5, [email protected] wrote:
>>
>>
>> On Wednesday, December 4, 2013 1:45:02 PM UTC-5, lisarden wrote:
>>>
>>> The abstract from the TPS65217 datasheet to describe what is going on
>>> here:
>>>
>>> The linear charger periodically applies a 10-mA current source to the
>>> BAT pin to check for the presence of a
>>>
>>> battery. This will cause the BAT terminal to float up to > 3 V which may
>>> interfere with AC removal detection and
>>>
>>> the ability to switch from AC to USB input. For this reason, it is not
>>> recommended to use both AC and USB
>>>
>>> inputs when the battery is absent.
>>>
>> I wonder when the BAT terminal drifts > 3 V, if the PMIC behaves as
>> if V_BAT > V_UVLO.
>>
>> If so, I wonder what happens if AM335x USB-OTG probing drives VBUS >
>> V_BAT + 190 mV. That would exceed V_IN(DT).
>>
>>
>
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