From mboxrd@z Thu Jan 1 00:00:00 1970 From: Krzysztof Kozlowski Subject: Re: [PATCH-v2 2/2] regulator: 88pm800: Add support for configuration of dual phase on BUCK1 Date: Thu, 06 Aug 2015 15:06:21 +0900 Message-ID: <55C2F95D.3060608@samsung.com> References: <1437495782-15767-1-git-send-email-vaibhav.hiremath@linaro.org> <1437495782-15767-3-git-send-email-vaibhav.hiremath@linaro.org> <55C1CD47.3060400@linaro.org> <55C2A340.6020809@samsung.com> <55C2F8CC.1010308@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <55C2F8CC.1010308@linaro.org> Sender: linux-kernel-owner@vger.kernel.org To: Vaibhav Hiremath Cc: linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, robh+dt@kernel.org, broonie@kernel.org, lee.jones@linaro.org List-Id: devicetree@vger.kernel.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 >>>> : >>>>> 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 >>>>> --- >>>>> 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