From: Richard Cochran <richardcochran@gmail.com>
To: Yangbo Lu <yangbo.lu@nxp.com>
Cc: netdev@vger.kernel.org, madalin.bucur@nxp.com,
Rob Herring <robh+dt@kernel.org>, Shawn Guo <shawnguo@kernel.org>,
"David S . Miller" <davem@davemloft.net>,
devicetree@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] ptp_qoriq: convert to use module parameters for initialization
Date: Mon, 30 Jul 2018 07:30:43 -0700 [thread overview]
Message-ID: <20180730143043.qu66ttzwyjbw6si7@localhost> (raw)
In-Reply-To: <20180730100154.27906-3-yangbo.lu@nxp.com>
On Mon, Jul 30, 2018 at 06:01:54PM +0800, Yangbo Lu wrote:
> The ptp_qoriq driver initialized the 1588 timer with the
> configurations provided by the properties of device tree
> node. For example,
>
> fsl,tclk-period = <5>;
> fsl,tmr-prsc = <2>;
> fsl,tmr-add = <0xaaaaaaab>;
> fsl,tmr-fiper1 = <999999995>;
> fsl,tmr-fiper2 = <99990>;
> fsl,max-adj = <499999999>;
>
> These things actually were runtime configurations which
> were not proper to be put into dts.
That is debatable. While I agree that the dts isn't ideal for these,
still it is the lesser of two or more evils.
> This patch is to convert
> to use module parameters for 1588 timer initialization, and
> to support initial register values calculation.
It is hard for me to understand how using module parameters improves
the situation.
> If the parameters are not provided, the driver will calculate
> register values with a set of default parameters. With this
> patch, those dts properties are no longer needed for new
> platform to support 1588 timer, and many QorIQ DPAA platforms
> (some P series and T series platforms of PowerPC, and some
> LS series platforms of ARM64) could use this driver for their
> fman ptp timer with default module parameters. However, this
> patch didn't remove the dts method. Because there were still
> many old platforms using the dts method. We need to clean up
> their dts files, verify module parameters on them, and convert
> them to the new method gradually in case of breaking any
> function.
In addition, like it or not, because the dts is an ABI, you must
continue support of the dts values as a legacy option.
Thanks,
Richard
next prev parent reply other threads:[~2018-07-30 14:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-30 10:01 [PATCH 1/3] arm64: dts: fsl: add clocks property for fman ptp timer node Yangbo Lu
2018-07-30 10:01 ` [PATCH 2/3] powerpc/mpc85xx: " Yangbo Lu
2018-07-30 10:01 ` [PATCH 3/3] ptp_qoriq: convert to use module parameters for initialization Yangbo Lu
2018-07-30 14:30 ` Richard Cochran [this message]
2018-08-01 4:36 ` Y.b. Lu
2018-08-01 6:15 ` Richard Cochran
2018-08-01 10:10 ` Y.b. Lu
2018-07-30 16:25 ` David Miller
2018-08-01 4:38 ` Y.b. Lu
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