linux-kernel - Re: [PATCH v2 0/3] mfd: sprd-sc27xx: Move poweroff/reboot support to the parent MFD driver

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Message-ID: <6286c547-2710-4854-a58f-8f3aa1dfc91e@linux.alibaba.com>
Date: Wed, 19 Nov 2025 14:33:19 +0800
From: Baolin Wang <baolin.wang@...ux.alibaba.com>
To: Otto Pflüger <otto.pflueger@...cue.de>,
 Lee Jones <lee@...nel.org>, Orson Zhai <orsonzhai@...il.com>,
 Chunyan Zhang <zhang.lyra@...il.com>, Mark Brown <broonie@...nel.org>,
 Sebastian Reichel <sre@...nel.org>, Cixi Geng <cixi.geng@...ux.dev>
Cc: Rob Herring <robh@...nel.org>, linux-kernel@...r.kernel.org,
 linux-spi@...r.kernel.org, linux-pm@...r.kernel.org,
 Sebastian Reichel <sebastian.reichel@...labora.com>
Subject: Re: [PATCH v2 0/3] mfd: sprd-sc27xx: Move poweroff/reboot support to
 the parent MFD driver

CC Cixi.

On 2025/11/11 03:08, Otto Pflüger wrote:
> Registers for powering off the system are present in all SC27xx-series
> PMICs, although their locations vary between the specific PMIC models.
> On systems using these chips, the PMIC can always power off the system
> and is usually the only chip capable of doing this. Similarly, the PMICs
> (except for SC2731) contain a reset register that can always be used to
> restart the system.
> 
> There is an existing sc27xx-poweroff driver, but it currently only works
> on SC2731 and is not probed anywhere since it is missing an OF match
> table and is not instantiated by the MFD driver. Reboot for SC2731 is
> implemented in drivers/spi/spi-sprd-adi.c, which is not really an
> appropriate location for PMIC-specific code.
> 
> Since a separate device tree node for the poweroff support would not
> provide anything useful (see [1]) and passing platform-specific data
> between drivers is unnecessarily complex for such a simple feature,
> reimplement the poweroff functionality in the main MFD driver. While at
> it, add support for the newer SC2730 PMIC and its hardware reset
> register.
> 
> Reboot is special because it requires storing the reboot mode. Move the
> existing code for this from the SPI bus driver to the MFD driver.
> 
> [1]: https://lore.kernel.org/all/20251002025344.GA2958334-robh@kernel.org/
> 
> Signed-off-by: Otto Pflüger <otto.pflueger@...cue.de>
> ---

Overall, it looks reasonable to me, but I cannot test your patchset 
right now due to the lack of hardware. Cixi (who is from Unisoc), could 
you help test this patchset? Thanks.