From: k.kozlowski@samsung•com (Krzysztof Kozlowski)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH-v2 2/2] regulator: 88pm800: Add support for configuration of dual phase on BUCK1
Date: Thu, 06 Aug 2015 15:06:21 +0900 [thread overview]
Message-ID: <55C2F95D.3060608@samsung.com> (raw)
In-Reply-To: <55C2F8CC.1010308@linaro.org>
On 06.08.2015 15:03, Vaibhav Hiremath wrote:
>
>
> On Thursday 06 August 2015 05:28 AM, Krzysztof Kozlowski wrote:
>> On 05.08.2015 17:45, Vaibhav Hiremath wrote:
>>>
>>>
>>> On Thursday 23 July 2015 10:21 AM, Krzysztof Kozlowski wrote:
>>>> 2015-07-22 1:23 GMT+09:00 Vaibhav Hiremath
>>>> <vaibhav.hiremath@linaro•org>:
>>>>> 88PM860 device supports dual phase mode on BUCK1 output.
>>>>> In normal usecase, BUCK1A and BUCK1B operates independently with 3A
>>>>> capacity. And they both can work as a dual phase providing 6A
>>>>> capacity.
>>>>>
>>>>> This patch updates the regulator driver to read the respective
>>>>> DT property and enable dual-phase mode on BUCK1.
>>>>>
>>>>> Note that, this is init time (one time) initialization.
>>>>>
>>>
>>> Sorry for delayed response, was on bed rest almost for week.
>>>
>>>>> Signed-off-by: Vaibhav Hiremath <vaibhav.hiremath@linaro•org>
>>>>> ---
>>>>> drivers/regulator/88pm800.c | 31 +++++++++++++++++++++++++++++++
>>>>> include/linux/mfd/88pm80x.h | 3 +++
>>>>> 2 files changed, 34 insertions(+)
>>>>
>>>> Don't you need to update the constraints also? I think the BUCK1
>>>> regulator has fixed constraint of 3 A:
>>>> PM800_BUCK(buck1, BUCK1, BUCK_ENA, 0, 3000000, buck1_volt_range,
>>>> 0x55),
>>>> and now it can handle 6 A.
>>>>
>>>
>>> Actually, BUCK1A and BUCK1B both combined together provide 6A capacity.
>>> And as discussed earlier, we need board change for this.
>>>
>>> I am quite not sure.
>>
>> AFAIU the regulator driver creates one BUCK1 regulator with constraints
>> 3 A. However after your change the regulator will handle up to 6 A.
>>
>> This means that constraints set by driver are wrong.
>>
>> Additionally I can't find BUCK1A and BUCK1B regulators. Driver provides
>> only BUCK1.
>>
>
> My patch does add BUCK1A and BUCK1B, please refer to the PATCH[4/5] of
> earlier series, which is accepted.
>
> https://patchwork.kernel.org/patch/6810461/
Indeed.
>
>
>>>
>>> Should I read the property and update the constraint runtime during
>>> probe?
>>
>> Driver should provide real constraints. Find the proper way to do this.
>>
>> The pm800_regulator_info[] array is not const so you can change it in
>> whatever way you want (although it should be const for existing driver
>> because regulator core accepts const and passing it to driver_data is
>> not necessary).
>>
>
>
> Probably that is the only way to handle this.
>
> how about,
>
> As you mentioned, pm800_regulator_info[] is not constant, so I can
> update the constraint before regulator_register() and also do not
> register BUCK1B, if dual phase is enabled.
>
> So in summary,
>
> if (dual phase is enabled)
> {
> Update constraint of BUCK1 to 6A
> and do not register BUCK1B
> } else {
> register both BUCK1A and BUCK1B with default constraint of 3A.
> }
This idea looks good to me.
Best regards,
Krzysztof
next prev parent reply other threads:[~2015-08-06 6:06 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-21 16:23 [PATCH-v2 0/2] regulator: 88pm800: Add dual phase mode support on BUCK1 Vaibhav Hiremath
2015-07-21 16:23 ` [PATCH-v2 1/2] mfd: devicetree: bindings: 88pm800: Add DT property for dual phase enable Vaibhav Hiremath
2015-07-23 15:53 ` Lee Jones
2015-08-05 8:49 ` Vaibhav Hiremath
2015-07-21 16:23 ` [PATCH-v2 2/2] regulator: 88pm800: Add support for configuration of dual phase on BUCK1 Vaibhav Hiremath
2015-07-23 4:51 ` Krzysztof Kozlowski
2015-08-05 8:45 ` Vaibhav Hiremath
2015-08-05 23:58 ` Krzysztof Kozlowski
2015-08-06 6:03 ` Vaibhav Hiremath
2015-08-06 6:06 ` Krzysztof Kozlowski [this message]
2015-07-23 15:54 ` Lee Jones
2015-08-05 8:47 ` Vaibhav Hiremath
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