linux-kernel - Re: [PATCH v3 0/2] firmware: exynos-acpm: allow use during system shutdown

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Message-ID: <48c082ffbb6eaa75eacbf3c7cbf0e4caec441bfc.camel@linaro.org>
Date: Tue, 25 Mar 2025 10:15:16 +0000
From: André Draszik <andre.draszik@...aro.org>
To: Tudor Ambarus <tudor.ambarus@...aro.org>, Krzysztof Kozlowski
	 <krzk@...nel.org>, Alim Akhtar <alim.akhtar@...sung.com>
Cc: Peter Griffin <peter.griffin@...aro.org>, Will McVicker
	 <willmcvicker@...gle.com>, kernel-team@...roid.com, 
	linux-kernel@...r.kernel.org, linux-samsung-soc@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3 0/2] firmware: exynos-acpm: allow use during system
 shutdown

On Tue, 2025-03-25 at 09:46 +0000, André Draszik wrote:
> One user of this ACPM driver is a PMIC driver that needs to communicate
> with the PMIC during late system shutdown [1] and at that time we are
> not allowed to sleep anymore.
> 
> This series address this by switching the code to using udelay() in the
> specific case of system shutdown. This approach was inspired by I2C's
> i2c_in_atomic_xfer_mode(), which has to deal with a similar corner
> case.

Looks like I forgot to update the paragraph here. As of v3, we
now use udelay() unconditionally, instead of the fragile approach
inspired by I2C, as suggested by Krzysztof.

A.

> 
> Link: https://lore.kernel.org/all/20250323-s2mpg10-v1-29-d08943702707@linaro.org/ [1]
> 
> Signed-off-by: André Draszik <andre.draszik@...aro.org>
> ---
> Changes in v3:
> - switch to unconditional udelay() (Krzysztof)
> - Link to v2: https://lore.kernel.org/r/20250324-acpm-atomic-v2-0-7d87746e1765@linaro.org
> 
> Changes in v2:
> - add missing ktime.h include
> - switch to ktime_before() instead of !ktime_after()
> - add link to user requiring this change to cover letter
> - collect Tudor's Rb
> - Link to v1: https://lore.kernel.org/r/20250321-acpm-atomic-v1-0-fb887bde7e61@linaro.org
> 
> ---
> André Draszik (2):
>       firmware: exynos-acpm: use ktime APIs for timeout detection
>       firmware: exynos-acpm: allow use during system shutdown
> 
>  drivers/firmware/samsung/exynos-acpm.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> ---
> base-commit: 9388ec571cb1adba59d1cded2300eeb11827679c
> change-id: 20250321-acpm-atomic-033775b051ef
> 
> Best regards,