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From: Andrew Lunn <andrew@lunn.ch>
To: Lucas Stach <l.stach@pengutronix.de>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Mike Turquette <mturquette@linaro.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Jason Cooper <jason@lakedaemon.net>, Andrew Lunn <andrew@lunn.ch>,
	Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
	Gregory Clement <gregory.clement@free-electrons.com>,
	"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	Tawfik Bayouk <tawfik@marvell.com>,
	Nadav Haklai <nadavh@marvell.com>,
	Lior Amsalem <alior@marvell.com>,
	Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Subject: Re: [PATCH 2/8] cpufreq: add driver for Armada XP
Date: Fri, 4 Jul 2014 16:15:41 +0200	[thread overview]
Message-ID: <20140704141541.GE7773@lunn.ch> (raw)
In-Reply-To: <1404481934.4634.2.camel@weser.hi.pengutronix.de>

On Fri, Jul 04, 2014 at 03:52:14PM +0200, Lucas Stach wrote:
> Am Freitag, den 04.07.2014, 13:12 +0200 schrieb Thomas Petazzoni:
> [...]
> > This doesn't work very well with the idea of having the OPP table
> > statically encoded in to the Device Tree. Options are:
> > 
> >  - Improve the cpufreq-cpu0 driver so that the OPP table can be passed
> >    through platform_data, and therefore built dynamically by the
> >    platform code and passed when registering the cpufreq
> >    platform_device.
> > 
> >  - Dynamically build/update the OPP table in the Device Tree.
> 
> This sounds like the right thing to do. Ideally your bootloader would do
> this for you, so you don't have to encode those properties statically at
> all.
> 
> Barebox already has facilities to fixup any loaded device tree. Have a
> look at of_register_fixup() there.

We are talking about legacy devices here, which have been in the field
for years. There is very little chance of a boot loader
upgrade. Appended DT is the norm for these devices, and modifying the
DT would have to happen in kernel.

   Andrew

WARNING: multiple messages have this Message-ID (diff)
From: andrew@lunn.ch (Andrew Lunn)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/8] cpufreq: add driver for Armada XP
Date: Fri, 4 Jul 2014 16:15:41 +0200	[thread overview]
Message-ID: <20140704141541.GE7773@lunn.ch> (raw)
In-Reply-To: <1404481934.4634.2.camel@weser.hi.pengutronix.de>

On Fri, Jul 04, 2014 at 03:52:14PM +0200, Lucas Stach wrote:
> Am Freitag, den 04.07.2014, 13:12 +0200 schrieb Thomas Petazzoni:
> [...]
> > This doesn't work very well with the idea of having the OPP table
> > statically encoded in to the Device Tree. Options are:
> > 
> >  - Improve the cpufreq-cpu0 driver so that the OPP table can be passed
> >    through platform_data, and therefore built dynamically by the
> >    platform code and passed when registering the cpufreq
> >    platform_device.
> > 
> >  - Dynamically build/update the OPP table in the Device Tree.
> 
> This sounds like the right thing to do. Ideally your bootloader would do
> this for you, so you don't have to encode those properties statically at
> all.
> 
> Barebox already has facilities to fixup any loaded device tree. Have a
> look at of_register_fixup() there.

We are talking about legacy devices here, which have been in the field
for years. There is very little chance of a boot loader
upgrade. Appended DT is the norm for these devices, and modifying the
DT would have to happen in kernel.

   Andrew

  reply	other threads:[~2014-07-04 14:20 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-04  9:44 [PATCH 0/8] cpufreq support for Marvell Armada XP Thomas Petazzoni
2014-07-04  9:44 ` Thomas Petazzoni
2014-07-04  9:44 ` [PATCH 1/8] clk: add an APPLY_RATE_CHANGE notifier event during clk_set_rate() Thomas Petazzoni
2014-07-04  9:44   ` Thomas Petazzoni
2014-07-04  9:44 ` [PATCH 2/8] cpufreq: add driver for Armada XP Thomas Petazzoni
2014-07-04  9:44   ` Thomas Petazzoni
2014-07-04  9:55   ` Viresh Kumar
2014-07-04  9:55     ` Viresh Kumar
2014-07-04 11:12     ` Thomas Petazzoni
2014-07-04 11:12       ` Thomas Petazzoni
2014-07-04 13:25       ` Andrew Lunn
2014-07-04 13:25         ` Andrew Lunn
2014-07-04 13:52       ` Lucas Stach
2014-07-04 13:52         ` Lucas Stach
2014-07-04 14:15         ` Andrew Lunn [this message]
2014-07-04 14:15           ` Andrew Lunn
2014-07-04 16:12           ` Viresh Kumar
2014-07-04 16:12             ` Viresh Kumar
2014-07-16 14:02     ` Thomas Petazzoni
2014-07-16 14:02       ` Thomas Petazzoni
2014-07-16 15:25       ` Viresh Kumar
2014-07-16 15:25         ` Viresh Kumar
2014-07-16 15:28         ` Thomas Petazzoni
2014-07-16 15:28           ` Thomas Petazzoni
2014-07-16 15:32           ` Viresh Kumar
2014-07-16 15:32             ` Viresh Kumar
2014-07-16 15:47             ` Thomas Petazzoni
2014-07-16 15:47               ` Thomas Petazzoni
2014-07-16 16:03               ` Viresh Kumar
2014-07-16 16:03                 ` Viresh Kumar
2014-07-04  9:44 ` [PATCH 3/8] clk: mvebu: extend clk-cpu for dynamic frequency scaling Thomas Petazzoni
2014-07-04  9:44   ` Thomas Petazzoni
2014-07-04  9:44 ` [PATCH 4/8] ARM: mvebu: ensure CPU clocks are enabled Thomas Petazzoni
2014-07-04  9:44   ` Thomas Petazzoni
2014-07-04  9:45 ` [PATCH 5/8] ARM: mvebu: extend PMSU code to support dynamic frequency scaling Thomas Petazzoni
2014-07-04  9:45   ` Thomas Petazzoni
2014-07-04  9:45 ` [PATCH 6/8] ARM: mvebu: update Armada XP DT for " Thomas Petazzoni
2014-07-04  9:45   ` Thomas Petazzoni
2014-07-04  9:45 ` [PATCH 7/8] ARM: mvebu: allow enabling of cpufreq on Armada XP Thomas Petazzoni
2014-07-04  9:45   ` Thomas Petazzoni
2014-07-04  9:45 ` [PATCH 8/8] ARM: mvebu: update mvebu_v7_defconfig with cpufreq support Thomas Petazzoni
2014-07-04  9:45   ` Thomas Petazzoni

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