Hi Anil,
On 11/06/2012 06:07 AM, AnilKumar, Chimata wrote:
> On Mon, Nov 05, 2012 at 22:13:25, Cousson, Benoit wrote:
>> Hi Anil / Colin,
>>
>> On 11/05/2012 10:42 AM, AnilKumar Ch wrote:
>>> From: Colin Foe-Parker <colin.foeparker@xxxxxxxxxxx>
>>>
>>> Add system power off control to rtc driver which is the in-charge
>>> of controlling the BeagleBone system power. The power_off routine
>>> can be hooked up to "pm_power_off" system call.
>>>
>>> System power off sequence:-
>>> * Set PMIC STATUS_OFF when PMIC_POWER_EN is pulled low
>>> * Enable PMIC_POWER_EN in rtc module
>>> * Set rtc ALARM2 time
>>> * Enable ALARM2 interrupt
>>>
>>> Added while (1); after the above steps to make sure that no other
>>> process acquire cpu. Otherwise we might see an unexpected behaviour
>>> because we are shutting down all the power rails of SoC except RTC.
>>>
>>> Signed-off-by: Colin Foe-Parker <colin.foeparker@xxxxxxxxxxx>
>>> [anilkumar@xxxxxx: move poweroff additions to rtc driver]
>>> Signed-off-by: AnilKumar Ch <anilkumar@xxxxxx>
>>> ---
>>> Documentation/devicetree/bindings/rtc/rtc-omap.txt | 5 ++
>>> drivers/rtc/rtc-omap.c | 79 +++++++++++++++++++-
>>> 2 files changed, 83 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/rtc/rtc-omap.txt b/Documentation/devicetree/bindings/rtc/rtc-omap.txt
>>> index b47aa41..8d9f4f9 100644
>>> --- a/Documentation/devicetree/bindings/rtc/rtc-omap.txt
>>> +++ b/Documentation/devicetree/bindings/rtc/rtc-omap.txt
>>> @@ -6,6 +6,10 @@ Required properties:
>>> - interrupts: rtc timer, alarm interrupts in order
>>> - interrupt-parent: phandle for the interrupt controller
>>>
>>> +Optional properties:
>>> +- ti,system-power-controller: Telling whether or not rtc is controlling
>>> + the system power.
>>
>> I don't know how it is connected at board level, but I'm not sure the
>> binding is the proper one.
>
> Hi Benoit,
> ________________________________
> | ______ _______ |
> | | | | | |
> | |RTC | | | |
> | |PMIC | Line | | |
> | |PWR_EN|=======>|PWR_EN | |
> | |______| |_______| |
> | AM335x SoC TPS65217 |
> | |
> |________________________________|
> BeagleBone
>
> This is how RTC PMIC_PWR_EN is connected to PWR_EN of TPS65217 PMIC. Only when
> RTC pull low in PMIC_PWR_EN then PMIC will go to power off state provided TPS65217
> status should be changed to STATUS_OFF.
>
> ALARM2 event should be trigger to configure PMIC_PWR_EN properly then the "Line"
> driven low so that PMIC will go to shutdown mode.
Thanks for the nice diagram :-)
I'm wondering if we cannot abuse the gpio binding to describe that
connection instead of creating two custom attributes (PMIC + RTC).
Ideally we should do that without having to change the RTC to use the
gpiolib at all.
rtc: rtc@44e3e000 {
compatible = "ti,da830-rtc";
reg = <0x44e3e000 0x1000>;
interrupts = <75, 76>;
ti,hwmods = "rtc";
/* expose the PWR_EN functionality of this RTC*/
gpio-controller;
#gpio-cells = <0>; /* assuming we can use 0 ??? */
};
...
tps: tps@24 {
compatible = "ti,tps65217";
/*
* Enable the power enable feature from
* the input line if that attribute is there.
*/
gpio-power-en = <&rtc>; /* PWR_EN */
...
}
Any thought?
Regards,
Benoit
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