From: "Uwe Kleine-König" <ukleinek@kernel.org>
To: Thierry Reding <thierry.reding@kernel.org>,
Jonathan Hunter <jonathanh@nvidia.com>,
Mikko Perttunen <mperttunen@nvidia.com>
Cc: linux-pwm@vger.kernel.org, linux-tegra@vger.kernel.org,
linux-kernel@vger.kernel.org, Sashiko <sashiko-bot@kernel.org>
Subject: Re: [PATCH v2] pwm: tegra: Fix value discarding for duty and period
Date: Fri, 30 Oct 2026 11:04:20 +0100 [thread overview]
Message-ID: <auRrUs-eGyJxrlXd@monoceros> (raw)
In-Reply-To: <20261020133938.191013-2-u.kleine-koenig@baylibre.com>
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Hello,
On Tue, Oct 20, 2026 at 03:39:38PM +0200, Uwe Kleine-König wrote:
> tegra_pwm_config() is called with u64 values passed for duty_ns and
> period_ns in tegra_pwm_apply(). Make these parameters u64 instead of int
> to not lose the upper bits for bigger values. If such a discard happens
> the values that are written to hardware become wrong, or (if the
> discarded period value becomes 0) a division by zero happens.
>
> Adapt the math functions accordingly to not let the now potentially
> bigger values result in overflows. While touching these, also limit the
> scope of the required_clk_rate variable.
>
> Reported-by: Sashiko <sashiko-bot@kernel.org>
> Link: https://sashiko.dev/#/bug/linux-5c5b97d6-4da6-4d06-9dc7-957419dcd832
> Fixes: fd3ddd4355c0 ("pwm: tegra: Implement .apply() callback")
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
pushed to
https://git.kernel.org/pub/scm/linux/kernel/git/ukleinek/linux.git pwm/for-nexxt
which I will rebase to v7.4-rc1 once that's available and then put in
my for-next branch as 7.5 material.
Best regards
Uwe
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prev parent reply other threads:[~2026-10-30 10:04 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-20 13:39 [PATCH v2] pwm: tegra: Fix value discarding for duty and period Uwe Kleine-König
2026-10-27 6:54 ` Karl Mehltretter
2026-10-30 5:54 ` Mikko Perttunen
2026-10-30 10:04 ` Uwe Kleine-König [this message]
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