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Message-ID: <4038b408-838d-4804-8866-cc8471749daa@quicinc.com>
Date:   Tue, 28 Nov 2023 18:03:49 +0800
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Subject: Re: [PATCH v5 09/10] phy: qualcomm: phy-qcom-qmp-ufs: Add High Speed
 Gear 5 support for SM8550
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To:     <neil.armstrong@linaro.org>, <bvanassche@acm.org>,
        <mani@kernel.org>, <adrian.hunter@intel.com>, <beanhuo@micron.com>,
        <avri.altman@wdc.com>, <junwoo80.lee@samsung.com>,
        <martin.petersen@oracle.com>
CC:     <linux-scsi@vger.kernel.org>, <linux-arm-msm@vger.kernel.org>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Vinod Koul <vkoul@kernel.org>,
        Kishon Vijay Abraham I <kishon@kernel.org>,
        "open list:GENERIC PHY FRAMEWORK" <linux-phy@lists.infradead.org>,
        open list <linux-kernel@vger.kernel.org>
References: <1700729190-17268-1-git-send-email-quic_cang@quicinc.com>
 <1700729190-17268-10-git-send-email-quic_cang@quicinc.com>
 <0d8fe915-4d53-414b-b145-231fe913474d@linaro.org>
From:   Can Guo <quic_cang@quicinc.com>
In-Reply-To: <0d8fe915-4d53-414b-b145-231fe913474d@linaro.org>
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Hi Neil,

On 11/28/2023 5:59 PM, neil.armstrong@linaro.org wrote:
> Hi,
> 
> On 23/11/2023 09:46, Can Guo wrote:
>> On SM8550, two sets of UFS PHY settings are provided, one set is to 
>> support
>> HS-G5, another set is to support HS-G4 and lower gears. The two sets 
>> of PHY
>> settings are programming different values to different registers, mixing
>> the two sets and/or overwriting one set with another set is definitely 
>> not
>> blessed by UFS PHY designers.
>>
>> To add HS-G5 support for SM8550, split the two sets of PHY settings into
>> their dedicated overlay tables, only the common parts of the two sets of
>> PHY settings are left in the .tbls.
>>
>> Consider we are going to add even higher gear support in future, to avoid
>> adding more tables with different names, rename the .tbls_hs_g4 and 
>> make it
>> an array, a size of 2 is enough as of now.
>>
>> In this case, .tbls alone is not a complete set of PHY settings, so 
>> either
>> tbls_hs_overlay[0] or tbls_hs_overlay[1] must be applied on top of the
>> .tbls to become a complete set of PHY settings.
>>
>> Signed-off-by: Can Guo <quic_cang@quicinc.com>
> 
> Since Vinod has already merged SM8650 UFS PHY support, I'm afraid this
> serie will break UFS if the SM8650 UFS tables aren't updated aswell.
> 
> Could you confirm if this will be the case ?

Because this change modifies data struct, it would be caught during 
compiliation stage even if this change applies cleanly, hence it won't 
break UFS.

Thanks,
Can Guo.

> 
> Thanks,
> Neil
> 
>