linux-kernel - Re: [PATCH] phy: qcom-snps-femto-v2: Add load and voltage setting for LDO's used

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Date: Tue, 7 May 2024 13:43:13 +0200
From: Konrad Dybcio <konrad.dybcio@...aro.org>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
 Udipto Goswami <quic_ugoswami@...cinc.com>
Cc: Bjorn Andersson <andersson@...nel.org>, Vinod Koul <vkoul@...nel.org>,
 Kishon Vijay Abraham I <kishon@...nel.org>, linux-arm-msm@...r.kernel.org,
 linux-phy@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] phy: qcom-snps-femto-v2: Add load and voltage setting for
 LDO's used



On 5/2/24 15:12, Dmitry Baryshkov wrote:
> On Thu, 2 May 2024 at 15:33, Udipto Goswami <quic_ugoswami@...cinc.com> wrote:
>>
>> The Femto phy depends on 0.88/ 1.8/ 3.3V regulators for its operation.
>> If one of the regulators is not voted to the required minimum voltage
>> for phy to operate, then High speed mode of operation will fail.
>>
>> On certain targets like (qcm6490_rb3gen2) where the minimum voltage
>> of the regulator is lower than the operating voltage of the phy.
>> If not voted properly, the phy supply would be limited to the min value
>> of the LDO thereby rendering the phy non-operational.
>>
>> The current implementation of the regulators in the Femto PHY is not
>> setting the load and voltage for each LDO. The appropriate voltages and
>> loads required for the PHY to operate should be set.
> 
> Please move min/max voltages to the DTS. There is no need to set them
> from the driver.
> 
> Also, is there any reason why you can't use `regulator-initial-mode =
> <RPMH_REGULATOR_MODE_HPM>;` like other boards do?

The point is to aggregate the values and switch to HPM if a threshold is
crossed (or stay in LPM otherwise)

Konrad