From: "qinjian[覃健]" <qinjian@cqplus1.com>
To: Stephen Boyd <sboyd@kernel.org>
Cc: "krzysztof.kozlowski@linaro.org" <krzysztof.kozlowski@linaro.org>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"mturquette@baylibre.com" <mturquette@baylibre.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"maz@kernel.org" <maz@kernel.org>,
"p.zabel@pengutronix.de" <p.zabel@pengutronix.de>,
"linux@armlinux.org.uk" <linux@armlinux.org.uk>,
"arnd@arndb.de" <arnd@arndb.de>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-clk@vger.kernel.org" <linux-clk@vger.kernel.org>
Subject: RE: [PATCH v15 05/10] clk: Add Sunplus SP7021 clock driver
Date: Thu, 19 May 2022 02:16:50 +0000 [thread overview]
Message-ID: <7fcb969a0d0740459a9ebc403aeb556f@cqplus1.com> (raw)
In-Reply-To: <20220518202049.6055BC385A9@smtp.kernel.org>
> > > > +
> > > > + df_quotient = df / m;
> > > > + df_remainder = ((df % m) * 1000) / m;
> > > > +
> > > > + if (freq > df_quotient) {
> > > > + df_quotient = freq - df_quotient - 1;
> > > > + df_remainder = 1000 - df_remainder;
> > >
> > > Where does 1000 come from?
> >
> > 1000 is come from "borrow 1" in last operation.
>
> It's scaling the value right? What is being scaled? Are we converting
> units to Hz from kHz?
Here just using integer replacement floating point operation, for example:
df = 13, m = 3
13 / 3 = 4.33333333
df_quotient = 4
df_remainder = 0.3333333 * 1000 (accurate to 3 decimal places) = 333
next prev parent reply other threads:[~2022-05-19 2:29 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-12 6:30 [PATCH v15 00/10] Add Sunplus SP7021 SoC Support Qin Jian
2022-05-12 6:30 ` [PATCH v15 01/10] dt-bindings: arm: sunplus: Add bindings for Sunplus SP7021 SoC boards Qin Jian
2022-05-16 18:29 ` Rob Herring
2022-05-12 6:30 ` [PATCH v15 02/10] dt-bindings: reset: Add bindings for SP7021 reset driver Qin Jian
2022-05-12 6:30 ` [PATCH v15 03/10] reset: Add Sunplus " Qin Jian
2022-05-12 6:30 ` [PATCH v15 04/10] dt-bindings: clock: Add bindings for SP7021 clock driver Qin Jian
2022-05-12 10:24 ` Krzysztof Kozlowski
2022-05-12 10:45 ` qinjian[覃健]
2022-05-12 10:54 ` Krzysztof Kozlowski
2022-05-13 3:22 ` qinjian[覃健]
2022-05-17 2:19 ` Stephen Boyd
2022-05-17 9:37 ` qinjian[覃健]
2022-05-12 6:31 ` [PATCH v15 05/10] clk: Add Sunplus " Qin Jian
2022-05-17 2:17 ` Stephen Boyd
2022-05-17 9:30 ` qinjian[覃健]
[not found] ` <20220518202049.6055BC385A9@smtp.kernel.org>
2022-05-19 2:16 ` qinjian[覃健] [this message]
2022-05-12 6:31 ` [PATCH v15 06/10] dt-bindings: interrupt-controller: Add bindings for SP7021 interrupt controller Qin Jian
2022-05-12 6:31 ` [PATCH v15 07/10] irqchip: Add Sunplus SP7021 interrupt controller driver Qin Jian
2022-05-12 6:31 ` [PATCH v15 08/10] ARM: sunplus: Add initial support for Sunplus SP7021 SoC Qin Jian
2022-05-12 6:31 ` [PATCH v15 09/10] ARM: sp7021_defconfig: Add Sunplus SP7021 defconfig Qin Jian
2022-05-13 11:27 ` Arnd Bergmann
2022-05-12 6:31 ` [PATCH v15 10/10] ARM: dts: Add Sunplus SP7021-Demo-V3 board device tree Qin Jian
2022-05-12 10:28 ` Krzysztof Kozlowski
2022-05-13 7:44 ` qinjian[覃健]
2022-05-13 8:10 ` Krzysztof Kozlowski
2022-05-13 9:47 ` qinjian[覃健]
2022-05-13 11:29 ` [PATCH v15 00/10] Add Sunplus SP7021 SoC Support Arnd Bergmann
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