linux-kernel - Re: [PATCH V3 2/2] phy: qcom-qmp-ufs: Add regulator loads for SM8650 and SM8750

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Message-ID: <9a38ec05-f7ab-4241-ba47-0d514b79e808@quicinc.com>
Date: Thu, 21 Aug 2025 21:32:35 +0530
From: Nitin Rawat <quic_nitirawa@...cinc.com>
To: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
CC: <vkoul@...nel.org>, <kishon@...nel.org>, <mani@...nel.org>,
        <andersson@...nel.org>, <konradybcio@...nel.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-phy@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V3 2/2] phy: qcom-qmp-ufs: Add regulator loads for SM8650
 and SM8750



On 8/20/2025 5:24 PM, Dmitry Baryshkov wrote:
> On Wed, Aug 20, 2025 at 12:07:57PM +0530, Nitin Rawat wrote:
>>
>>
>> On 8/20/2025 6:19 AM, Dmitry Baryshkov wrote:
>>> On Wed, Aug 20, 2025 at 03:58:26AM +0530, Nitin Rawat wrote:
>>>> Add regulator load voting support for SM8650 and SM8750 platforms by
>>>> introducing dedicated regulator bulk data arrays with their load
>>>> values.
>>>>
>>>> The load requirements are:
>>>> - SM8650: vdda-phy (205mA), vdda-pll (17.5mA)
>>>> - SM8750: vdda-phy (213mA), vdda-pll (18.3mA)
>>>>
>>>> This ensures stable operation and proper power management for these
>>>> platforms where regulators are shared between the QMP USB PHY and
>>>> other IP blocks by setting appropriate regulator load currents during PHY
>>>> operations.
>>>>
>>>> Configurations without specific load requirements will continue to work
>>>> unchanged, as init_load_uA remains zero-initialized when .init_load_uA
>>>> is not provided.
>>>
>>> Can we please get configuration for the rest of the platforms?
>>
>> Hi Dmitry,
>>
>> If you're okay with it, can I merge the configuration for the remaining
>> platforms in the next patch series after I complete testing on all remaining
>> platforms.
> 
> You don't need to test, finding MSM8996 or 98 might be troublesome. Just
> fill in the values from the hardware documentation.

Hi Dmitry,

While implementing changes for all remaining platform, I noticed that 
the "regulator-allow-set-load" property is defined only for SM8750 and 
SM8850 within the PMIC PHY and PLL device tree nodes which means that 
even if the UFS PHY driver is updated to vote for this configuration on 
other platforms, it will have no impact.

Should I still proceed with applying the change across all platform, or 
limit it to just the SM8750 and SM8850 drivers? What’s your recommendation?

===========================================================================
// Device tree:
vreg_l1j_0p91: ldo1 {
     regulator-name = "vreg_l1j_0p91";
     regulator-min-microvolt = <880000>;
     regulator-max-microvolt = <920000>;
     regulator-initial-mode = <RPMH_REGULATOR_MODE_HPM>;
     regulator-allow-set-load;
     regulator-allowed-modes = <RPMH_REGULATOR_MODE_LPM 
RPMH_REGULATOR_MODE_HPM>;
};

===========================================================================
drivers/regulator/of_regulator.c


if (of_property_read_bool(np, "regulator-allow-set-load"))
		constraints->valid_ops_mask |= REGULATOR_CHANGE_DRMS;

===========================================================================
//drivers/regulator/core.c
static int drms_uA_update(struct regulator_dev *rdev)
{
     ...
     if (!regulator_ops_is_valid(rdev, REGULATOR_CHANGE_DRMS)) {
         rdev_dbg(rdev, "DRMS operation not allowed\n");
         return 0;
     }
     ...
}


Regards,
Nitin




>