linux-kernel - Re: [PATCH v6 2/4] pwm: Add support for RZ/V2M PWM driver

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Message-ID: <vovrjoymovpjzz2myx73ns4zvbqyfw6twzvjhuyruogmcqvj4y@g2at4kznmqxh>
Date: Sat, 10 Feb 2024 18:26:55 +0100
From: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
To: Fabrizio Castro <fabrizio.castro.jz@...esas.com>
Cc: Philipp Zabel <p.zabel@...gutronix.de>, 
	Geert Uytterhoeven <geert+renesas@...der.be>, Biju Das <biju.das.jz@...renesas.com>, 
	Magnus Damm <magnus.damm@...il.com>, linux-kernel@...r.kernel.org, linux-pwm@...r.kernel.org, 
	linux-renesas-soc@...r.kernel.org
Subject: Re: [PATCH v6 2/4] pwm: Add support for RZ/V2M PWM driver

Hello Fabrizio,

On Thu, Feb 08, 2024 at 11:24:09PM +0000, Fabrizio Castro wrote:
> +static inline u64 rzv2m_pwm_mul_u64_u64_div_u64_roundup(u64 a, u64 b, u64 c)
> +{
> +	u64 ab = a * b;

This might overflow.

> +	return ab / c + (ab % c ? 1 : 0);

This division triggered the kernel build bot error. If you want to
divide a u64, you must not use /.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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