linux-kernel - Re: [PATCH v6 4/6] mfd: tps65219: Add driver for TI TPS65219 PMIC

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Date:   Thu, 10 Nov 2022 08:12:40 +0100
From:   jerome Neanne <jneanne@...libre.com>
To:     Andrew Davis <afd@...com>, Kevin Hilman <khilman@...libre.com>,
        Nishanth Menon <nm@...com>
Cc:     Lee Jones <lee@...nel.org>, lgirdwood@...il.com,
        broonie@...nel.org, robh+dt@...nel.org, kristo@...nel.org,
        dmitry.torokhov@...il.com, krzysztof.kozlowski+dt@...aro.org,
        catalin.marinas@....com, will@...nel.org, tony@...mide.com,
        vigneshr@...com, bjorn.andersson@...aro.org, shawnguo@...nel.org,
        geert+renesas@...der.be, dmitry.baryshkov@...aro.org,
        marcel.ziswiler@...adex.com, vkoul@...nel.org,
        biju.das.jz@...renesas.com, arnd@...db.de, jeff@...undy.com,
        narmstrong@...libre.com, msp@...libre.com, j-keerthy@...com,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-input@...r.kernel.org,
        linux-omap@...r.kernel.org
Subject: Re: [PATCH v6 4/6] mfd: tps65219: Add driver for TI TPS65219 PMIC



On 09/11/2022 22:59, Andrew Davis wrote:
> On 11/7/22 3:14 PM, Kevin Hilman wrote:
>> Nishanth Menon <nm@...com> writes:
>>
>>> On 13:58-20221104, jerome Neanne wrote:
>>>>
>>> [...]
>>>
>>>>
>>>>>
>>>>> Can you try an compile with W=1 please.
>>>> This raise one warning on mfd:
>>>> drivers/mfd/tps65219.c:28:12: warning: ‘tps65219_soft_shutdown’ 
>>>> defined but
>>>> not used [-Wunused-function]
>>>>     28 | static int tps65219_soft_shutdown(struct tps65219 *tps)
>>>>        |            ^~~~~~~~~~~~~~~~~~~~~~
>>>> soft_shutdown has been validated and is used in TI baseline even if not
>>>> hooked in upstream version further to this review:
>>>> https://lore.kernel.org/lkml/20220825150224.826258-5-msp@baylibre.com/
>>>>
>>>> It was a TI requirement to implement it...
>>>> Let me know if you want me to remove this function or if we can keep 
>>>> it like
>>>> this.
>>>
>>> There are platforms without psci, correct? I think the comment was to
>>> drop the force override with system-power-controller property,
>>>
>>> if (!pm_power_off) {
>>>     tps65219_i2c_client = client;
>>>     pm_power_off = &tps65219_pm_power_off;
>>> }
>>>
>>> Could still be valid for such platforms, no? I do see that the
>>> capability that the PMIC has - which is software shutdown is a valid
>>> feature that we support in many different PMIC drivers. Is'nt the job of
>>> the driver to introduce the functionality in a manner that is
>>> appropriate to the OS framework?
>>
>> Yeah, I think Nishanth is right here.
>>
>> We should probably keep the `if (!pm_power_off)` part so the PMIC will
>> be used if PSCI is not, but it also allows an easy way to test/use the 
>> PMIC
>> shutdown functionality downstream if needed.
>>
> 
> Then should be using the sys-off handler API[0] so it doesn't block PSCI
> which is also switching over[1].
> 
> Andrew
> 
> [0] https://lwn.net/Articles/894511/
> [1] https://www.spinics.net/lists/arm-kernel/msg1024127.html
Can we go for upstream with v7 without tps65219_soft_shutdown. Then if 
everyone agrees with Andrew proposal, I'll submit a separate patch which 
adds implementation of tps65219_soft_shutdown support through sys-off 
handler.

So that we are not blocking upstream in case further 
discussions/alignment are required.

Jerome