Hello Biju, On Fri, Dec 08, 2023 at 10:34:55AM +0000, Biju Das wrote: > > -----Original Message----- > > From: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> > > Sent: Thursday, December 7, 2023 9:42 PM > > Subject: Re: [PATCH v17 3/4] pwm: Add support for RZ/G2L GPT > > > > Hello Biju, > > > > On Thu, Dec 07, 2023 at 06:26:44PM +0000, Biju Das wrote: > > > ######[ 304.213944] pwm-rzg2l-gpt 10048000.pwm: .apply is not > > > idempotent (ena=1 pol=0 5500000000000/43980352512000) -> (ena=1 pol=0 > > > 5500000000000/43980239923200) > > > High setting## > > > [ 304.230854] pwm-rzg2l-gpt 10048000.pwm: .apply is not idempotent > > > (ena=1 pol=0 23980465100800/43980352512000) -> (ena=1 pol=0 > > > 23980465100800/43980239923200) > > > > Have you tried to understand that? What is the clk rate when this happens? > > You're not suggesting that mul_u64_u64_div_u64 is wrong, are you? > > mul_u64_u64_div_u64() works for certain values. But for very high > values we are losing precision and is giving unexpected values. Can you reduce the problem to a bogus result of mul_u64_u64_div_u64()? I'd be very surprised if the problem was mul_u64_u64_div_u64() and not how it's used in your pwm driver. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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