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Message-ID: <53480bd1-0b6f-053c-b1fd-b04de7b49096@linaro.org>
Date:   Mon, 15 May 2023 15:39:50 +0000
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Subject: Re: [PATCH] leds: qcom-lpg: Fix PWM period limits
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To:     Bjorn Andersson <andersson@kernel.org>
Cc:     Bjorn Andersson <quic_bjorande@quicinc.com>,
        Pavel Machek <pavel@ucw.cz>, Lee Jones <lee@kernel.org>,
        Anjelique Melendez <quic_amelende@quicinc.com>,
        =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= <u.kleine-koenig@pengutronix.de>,
        Luca Weiss <luca@z3ntu.xyz>, linux-leds@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org
References: <20230512165524.3367443-1-quic_bjorande@quicinc.com>
 <cab829ec-5763-1352-618a-adad8c01227d@linaro.org>
 <20230515022041.4i2w36vubzggpdt6@ripper>
From:   Caleb Connolly <caleb.connolly@linaro.org>
In-Reply-To: <20230515022041.4i2w36vubzggpdt6@ripper>
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On 15/05/2023 02:20, Bjorn Andersson wrote:
> On Sat, May 13, 2023 at 10:09:49AM +0000, Caleb Connolly wrote:
>>
>>
>> On 12/05/2023 16:55, Bjorn Andersson wrote:
>>> The introduction of high resolution PWM support moved the parenthesis of
>>> the divisions in the calculation of min and max period. The result in
>>> both divisions is in most cases truncation to 0, which limits the period
>>> to the range of [0, 0].
>>
>> Huh, TIL C gives multiplication and division the same precedence when
>> deciding order of operations.
> 
> There where no explicit parenthesis in the original implementation. So
> I guess it would be more correct to state that parenthesis was
> introduced around part of the expression?

It might be clearer just to say the div64_u64 changed the order of
operations.
> 
> Let me know if you think the wording matters and you would prefer me to
> rewrite it.

Yeah, that would be appreciated

Thanks
> 
> Regards,
> Bjorn
> 
-- 
Kind Regards,
Caleb (they/them)