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From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Liu Ying <victor.liu@nxp.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Heiko Stuebner <heiko@sntech.de>,
	Elaine Zhang <zhangqing@rock-chips.com>,
	Stephen Boyd <sboyd@kernel.org>,
	linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org,
	Michael Turquette <mturquette@baylibre.com>,
	NXP Linux Team <linux-imx@nxp.com>, Jacky Bai <ping.bai@nxp.com>
Subject: Re: [PATCH v2 2/3] clk: fractional-divider: Introduce NO_PRESCALER flag
Date: Thu, 22 Jul 2021 12:38:15 +0300	[thread overview]
Message-ID: <CAHp75Vdm8nO-zT0vyKcB1hOXkR7_2RY-2P_fnkjV5BCc+uoqXQ@mail.gmail.com> (raw)
In-Reply-To: <9117e5212a3b743ca541918ec2b701c159ac752c.camel@nxp.com>

On Thu, Jul 22, 2021 at 12:33 PM Liu Ying <victor.liu@nxp.com> wrote:
> On Fri, 2021-07-16 at 16:34 +0300, Andy Shevchenko wrote:
> > The newly introduced flag, when set, makes the flow to skip
> > the assumption that the caller will use an additional 2^scale
> > prescaler to get the desired clock rate.
>
> As I mentioned in v1 comment, it seems to be good to decouple the
> prescaler knowledge from this common fractional divider clk driver.
> This way, we'll make it simpler and easier to maintain. Also, then, the
> NO_PRESCALER flag is not needed at all.  However, it seems that two
> Intel drivers which use the frational divider drivers will be affected
> and rate negotiation logics need to be implemented for them.  Please
> consider if it's doable or not.

The current driver works for the certain hardware without this change.
If you think it's better, submit a proposal we will discuss.

> If we ultimately keep the prescaler knowledge here, please consider to
> add the NO_PRESCALER flag for i.MX7ulp as it hasn't the prescaler IIUC.

You mean there is a code which is currently using this driver w/o
taking into account this prescaller flavour? Can you, please, point
out, I'll definitely update it. Thanks for the catch!

-- 
With Best Regards,
Andy Shevchenko

WARNING: multiple messages have this Message-ID (diff)
From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Liu Ying <victor.liu@nxp.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Heiko Stuebner <heiko@sntech.de>,
	 Elaine Zhang <zhangqing@rock-chips.com>,
	Stephen Boyd <sboyd@kernel.org>,
	 linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org,
	 linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org,
	 Michael Turquette <mturquette@baylibre.com>,
	NXP Linux Team <linux-imx@nxp.com>, Jacky Bai <ping.bai@nxp.com>
Subject: Re: [PATCH v2 2/3] clk: fractional-divider: Introduce NO_PRESCALER flag
Date: Thu, 22 Jul 2021 12:38:15 +0300	[thread overview]
Message-ID: <CAHp75Vdm8nO-zT0vyKcB1hOXkR7_2RY-2P_fnkjV5BCc+uoqXQ@mail.gmail.com> (raw)
In-Reply-To: <9117e5212a3b743ca541918ec2b701c159ac752c.camel@nxp.com>

On Thu, Jul 22, 2021 at 12:33 PM Liu Ying <victor.liu@nxp.com> wrote:
> On Fri, 2021-07-16 at 16:34 +0300, Andy Shevchenko wrote:
> > The newly introduced flag, when set, makes the flow to skip
> > the assumption that the caller will use an additional 2^scale
> > prescaler to get the desired clock rate.
>
> As I mentioned in v1 comment, it seems to be good to decouple the
> prescaler knowledge from this common fractional divider clk driver.
> This way, we'll make it simpler and easier to maintain. Also, then, the
> NO_PRESCALER flag is not needed at all.  However, it seems that two
> Intel drivers which use the frational divider drivers will be affected
> and rate negotiation logics need to be implemented for them.  Please
> consider if it's doable or not.

The current driver works for the certain hardware without this change.
If you think it's better, submit a proposal we will discuss.

> If we ultimately keep the prescaler knowledge here, please consider to
> add the NO_PRESCALER flag for i.MX7ulp as it hasn't the prescaler IIUC.

You mean there is a code which is currently using this driver w/o
taking into account this prescaller flavour? Can you, please, point
out, I'll definitely update it. Thanks for the catch!

-- 
With Best Regards,
Andy Shevchenko

_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

WARNING: multiple messages have this Message-ID (diff)
From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Liu Ying <victor.liu@nxp.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Heiko Stuebner <heiko@sntech.de>,
	 Elaine Zhang <zhangqing@rock-chips.com>,
	Stephen Boyd <sboyd@kernel.org>,
	 linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org,
	 linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org,
	 Michael Turquette <mturquette@baylibre.com>,
	NXP Linux Team <linux-imx@nxp.com>, Jacky Bai <ping.bai@nxp.com>
Subject: Re: [PATCH v2 2/3] clk: fractional-divider: Introduce NO_PRESCALER flag
Date: Thu, 22 Jul 2021 12:38:15 +0300	[thread overview]
Message-ID: <CAHp75Vdm8nO-zT0vyKcB1hOXkR7_2RY-2P_fnkjV5BCc+uoqXQ@mail.gmail.com> (raw)
In-Reply-To: <9117e5212a3b743ca541918ec2b701c159ac752c.camel@nxp.com>

On Thu, Jul 22, 2021 at 12:33 PM Liu Ying <victor.liu@nxp.com> wrote:
> On Fri, 2021-07-16 at 16:34 +0300, Andy Shevchenko wrote:
> > The newly introduced flag, when set, makes the flow to skip
> > the assumption that the caller will use an additional 2^scale
> > prescaler to get the desired clock rate.
>
> As I mentioned in v1 comment, it seems to be good to decouple the
> prescaler knowledge from this common fractional divider clk driver.
> This way, we'll make it simpler and easier to maintain. Also, then, the
> NO_PRESCALER flag is not needed at all.  However, it seems that two
> Intel drivers which use the frational divider drivers will be affected
> and rate negotiation logics need to be implemented for them.  Please
> consider if it's doable or not.

The current driver works for the certain hardware without this change.
If you think it's better, submit a proposal we will discuss.

> If we ultimately keep the prescaler knowledge here, please consider to
> add the NO_PRESCALER flag for i.MX7ulp as it hasn't the prescaler IIUC.

You mean there is a code which is currently using this driver w/o
taking into account this prescaller flavour? Can you, please, point
out, I'll definitely update it. Thanks for the catch!

-- 
With Best Regards,
Andy Shevchenko

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-07-22  9:39 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-16 13:34 [PATCH v2 1/3] clk: fractional-divider: Export approximation algo to the CCF users Andy Shevchenko
2021-07-16 13:34 ` Andy Shevchenko
2021-07-16 13:34 ` Andy Shevchenko
2021-07-16 13:34 ` [PATCH v2 2/3] clk: fractional-divider: Introduce NO_PRESCALER flag Andy Shevchenko
2021-07-16 13:34   ` Andy Shevchenko
2021-07-16 13:34   ` Andy Shevchenko
2021-07-22  9:29   ` Liu Ying
2021-07-22  9:29     ` Liu Ying
2021-07-22  9:29     ` Liu Ying
2021-07-22  9:38     ` Andy Shevchenko [this message]
2021-07-22  9:38       ` Andy Shevchenko
2021-07-22  9:38       ` Andy Shevchenko
2021-07-22  9:43       ` Liu Ying
2021-07-22  9:43         ` Liu Ying
2021-07-22  9:43         ` Liu Ying
2021-07-22 15:42         ` Andy Shevchenko
2021-07-22 15:42           ` Andy Shevchenko
2021-07-22 15:42           ` Andy Shevchenko
2021-07-16 13:34 ` [PATCH v2 3/3] clk: fractional-divider: Document the arithmetics used behind the code Andy Shevchenko
2021-07-16 13:34   ` Andy Shevchenko
2021-07-16 13:34   ` Andy Shevchenko
2021-07-17 12:19 ` [PATCH v2 1/3] clk: fractional-divider: Export approximation algo to the CCF users Heiko Stübner
2021-07-17 12:19   ` Heiko Stübner
2021-07-17 12:19   ` Heiko Stübner

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