https://github.com/torvalds/linux/blob/master/drivers/mfd/tps65217.c#L164
Nothing there at line 164, then on line 165 starts a function. Which
contains the code I linked to yesterday. Which is the power push button
code. Which again, is not helping . . . So let's walk through that
function. Which happens in this order . ..
variable type definitions declarations.
conditional check to find device tree definition node.
test chip_id, return if failure.
attempt and test to allocate memory for the tps object.
attempt to map the tps object to the PMIC registers
mfd device add, and test device add.
attempt to read the PMIC registers, and test return code.
Here it gets a bit fuzzy however, it seems as though the code is attempting
to reset the system by setting various register bits in the PMIC ?! I know
all about the registers of the PMIC, or rather can find otu what is what
really quick by reading the datasheet which I have right in front of me.
That is not what I'm having an issue grasping. It seems to me that a
shutdown in this manner would not be clean. However, it could be that
setting these register bits as such may not cause an immediate power down.
*That* is what I find unclear.
/* Set the PMIC to shutdown on PWR_EN toggle */
if (status_off) {
ret = tps65217_set_bits(tps, TPS65217_REG_STATUS,
TPS65217_STATUS_OFF, TPS65217_STATUS_OFF,
TPS65217_PROTECT_NONE);
if (ret)
dev_warn(tps->dev, "unable to set the status OFF\n");
}
The comment above the code seems to indicate that PWR_EN is causing a
shutdown based on being toggle. However, PWR_EN is *NOT* a button, or even
a line connected to a button. From the data sheet . . .
*PWR_EN*
> *Enable input for DCDC1, 2, 3 converters and LDO1, 2, 3, 4. Pull this pin
> high to start the*
> *power-up sequence.*
In the schematic, PWR_EN is not connected to any button. Period. The
button is connected to PB_IN.
Anyway, the rest of the code is inconsequential.
On Sun, Apr 17, 2016 at 3:23 PM, John Syne <john3...@gmail.com> wrote:
> Never mind, I found it.
>
> drivers/mfd/tps65217.c line 164
>
> Regards,
> John
>
>
>
>
> On Apr 17, 2016, at 2:37 PM, William Hermans <yyrk...@gmail.com> wrote:
>
> So no one has any idea ? I'm looking for the module, that traps power
> events, and shuts down the BBB. All I need is a file name. It's pretty hard
> making sense of the mess that is /drivers/mfd, and the documentation does
> not seem to be helpful either.
>
> Documentation/power/regulator/charger-management.txt does not exist in my
> repo, nor in Linus' repo either. There is a similar file, but nothing
> apparently related to our hardware. Passed that, most of the stuff int the
> Documentation/power directory seems to be related to ACPI, which again, has
> nothing to do with even our architecture . . .
>
> On Sat, Apr 16, 2016 at 9:09 PM, William Hermans <yyrk...@gmail.com>
> wrote:
>
>> So I've only found this so far.
>> https://github.com/torvalds/linux/blob/master/drivers/mfd/tps65217.c#L222-#L229
>>
>> Which I pretty much had already figured out this morning right after I
>> posted. Pretty much, the PMIC sees a condition, that needs attention. It
>> writes some values to registers that relate to the given condition, and
>> then sends an NMI out to the am335x processor. Where the am335x processor
>> immediately picks up that the PMIC needs attention( the whole point of an
>> NMI ), reads the register values out of the PMIC to determine what action
>> needs to be taken. Which in the case of the power button being pressed. the
>> am335x issues a shutdown now -h ( Linux ) Which looking at the code,
>> actually seems like the LKM is actually writing to the PMIC registers to do
>> this ?!
>>
>> Anyway, no idea how a power good condition is being acted on *still*.
>> Meaning, no idea how when a battery is connected, when the external power
>> somehow goes missing. How that particular shutdown is happening, and from
>> where.
>>
>> On Sat, Apr 16, 2016 at 4:32 PM, John Syne <john3...@gmail.com> wrote:
>>
>>> I’m not sure, but best place to look would be
>>> Documentation/power/regulator/charger-management.txt. I believe the PMIC
>>> issues event when AC is removed.
>>>
>>> Regards,
>>> John
>>>
>>>
>>>
>>>
>>> On Apr 16, 2016, at 12:59 PM, William Hermans <yyrk...@gmail.com> wrote:
>>>
>>> Also from what I've read this behavior is different between console and
>>> LXDE images. So if this is true I understand that. I do not want the
>>> behaviors that each of these images provides, but wish to customize my own.
>>>
>>>
>>> On Sat, Apr 16, 2016 at 12:55 PM, William Hermans <yyrk...@gmail.com>
>>> wrote:
>>>
>>>> When a battery is connected to a beaglebone black, how does the
>>>> software know to issue a shutdown when power is no longer coming in ? More
>>>> specifically I'm interested in which file / script performs this action,
>>>> and what mechanism triggers this behavior.
>>>>
>>>> My intentions are to modify / customize what actually happens when
>>>> power to the board is battery only.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> For more options, visit http://beagleboard.org/discuss
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>>>
>>>
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