From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: linux-pwm@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org,
Thierry Reding <thierry.reding@gmail.com>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Greentime Hu <greentime.hu@sifive.com>,
jarkko.nikula@linux.intel.com
Subject: Re: [PATCH v9 4/6] pwm: dwc: use clock rate in hz to avoid rounding issues
Date: Mon, 11 Sep 2023 21:47:51 +0200 [thread overview]
Message-ID: <20230911194751.mohdwipo74ccgail@pengutronix.de> (raw)
In-Reply-To: <d45c3d25-13ca-474f-a3e3-c295d3cea866@codethink.co.uk>
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Hello Ben,
On Mon, Sep 11, 2023 at 08:33:02AM +0100, Ben Dooks wrote:
> On 07/09/2023 22:34, Uwe Kleine-König wrote:
> > > + duty *= NSEC_PER_SEC;
> > > + period *= NSEC_PER_SEC;
> >
> > A comment that/why this cannot overflow would be nice. (I didn't check,
> > maybe it can?)
>
> I /think/ that as long as NSEC_PER_SEC 2^32 then this shouldn't
> overflow.
I guess NSEC_PER_SEC won't change in the near future :-)
double checking and writing the result down in a comment would be
appreciated.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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next prev parent reply other threads:[~2023-09-11 20:49 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-07 16:12 [PATCH v9 0/6] designware pwm driver updates Ben Dooks
2023-09-07 16:12 ` [PATCH v9 1/6] pwm: dwc: split pci out of core driver Ben Dooks
2023-09-07 21:15 ` Uwe Kleine-König
2023-09-07 16:12 ` [PATCH v9 2/6] pwm: dwc: make timer clock configurable Ben Dooks
2023-09-07 16:12 ` [PATCH v9 3/6] pwm: dwc: add PWM bit unset in get_state call Ben Dooks
2023-09-22 17:35 ` Uwe Kleine-König
2023-09-25 7:02 ` Ben Dooks
2023-09-07 16:12 ` [PATCH v9 4/6] pwm: dwc: use clock rate in hz to avoid rounding issues Ben Dooks
2023-09-07 21:34 ` Uwe Kleine-König
2023-09-11 7:33 ` Ben Dooks
2023-09-11 19:47 ` Uwe Kleine-König [this message]
2023-09-07 16:12 ` [PATCH v9 5/6] pwm: dwc: round rate divisions up Ben Dooks
2023-09-07 21:36 ` Uwe Kleine-König
2023-09-07 16:12 ` [PATCH v9 6/6] pwm: dwc: add of/platform support Ben Dooks
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