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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>,
	eric.y.miao@gmail.com, Haojian Zhuang <haojian.zhuang@gmail.com>,
	linux@arm.linux.org.uk, Grant Likely <grant.likely@secretlab.ca>,
	sodaville@linutronix.de, linux-arm-kernel@lists.infradead.org,
	Dirk Brandewie <dirk.brandewie@gmail.com>,
	spi-devel-general@lists.sourceforge.net, tglx@linutronix.de,
	drwyrm@gmail.com
Subject: Re: [PATCH 1/9] spi/pxa2xx: don't use subys initcall for driver init
Date: Wed, 24 Nov 2010 16:39:05 +0100	[thread overview]
Message-ID: <4CED3199.2040700@linutronix.de> (raw)
In-Reply-To: <20101124141623.GH24970@rakim.wolfsonmicro.main>

Mark Brown wrote:
> On Wed, Nov 24, 2010 at 03:09:25PM +0100, Sebastian Andrzej Siewior wrote:
> 
>> I've been pointed out to this commit but I don't understand _why_.
>> The part I don't get is "so it can be used with cpufreq". Is it
>> refered to a driver or the subsystem as it?
> 
> We need the regulators for the CPU rails to start before the cpufreq
> driver starts so cpufreq can talk to them, and since the regulators may
> be SPI attached this means we also need the SPI controller to start
> before cpufreq.  cpufreq starts at vanilla init time.

After digging through the code I think I've found it. pxa_cpu_init()
registers a cpufreq client. cpufreq calls init and pxa then
regulator_get() to get the regulator and I guess this is the problem.
So I would suggest to defer pxa_cpu_init() via late_initcall().

The other way around will force you to hack the init code for various
drivers to make it work.

Sebastian

WARNING: multiple messages have this Message-ID (diff)
From: bigeasy@linutronix.de (Sebastian Andrzej Siewior)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/9] spi/pxa2xx: don't use subys initcall for driver init
Date: Wed, 24 Nov 2010 16:39:05 +0100	[thread overview]
Message-ID: <4CED3199.2040700@linutronix.de> (raw)
In-Reply-To: <20101124141623.GH24970@rakim.wolfsonmicro.main>

Mark Brown wrote:
> On Wed, Nov 24, 2010 at 03:09:25PM +0100, Sebastian Andrzej Siewior wrote:
> 
>> I've been pointed out to this commit but I don't understand _why_.
>> The part I don't get is "so it can be used with cpufreq". Is it
>> refered to a driver or the subsystem as it?
> 
> We need the regulators for the CPU rails to start before the cpufreq
> driver starts so cpufreq can talk to them, and since the regulators may
> be SPI attached this means we also need the SPI controller to start
> before cpufreq.  cpufreq starts at vanilla init time.

After digging through the code I think I've found it. pxa_cpu_init()
registers a cpufreq client. cpufreq calls init and pxa then
regulator_get() to get the regulator and I guess this is the problem.
So I would suggest to defer pxa_cpu_init() via late_initcall().

The other way around will force you to hack the init code for various
drivers to make it work.

Sebastian

  parent reply	other threads:[~2010-11-24 15:39 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-24 11:13 SPI support for Sodaville Sebastian Andrzej Siewior
2010-11-24 11:13 ` Sebastian Andrzej Siewior
     [not found] ` <1290597207-29838-1-git-send-email-bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2010-11-24 11:13   ` [PATCH 1/9] spi/pxa2xx: don't use subys initcall for driver init Sebastian Andrzej Siewior
2010-11-24 11:13     ` Sebastian Andrzej Siewior
2010-11-24 13:18     ` Antonio Ospite
2010-11-24 13:18       ` Antonio Ospite
     [not found]     ` <1290597207-29838-2-git-send-email-bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2010-11-24 13:54       ` Haojian Zhuang
2010-11-24 13:54         ` Haojian Zhuang
     [not found]         ` <AANLkTin4vh85XRkEd7YocCmKngViR_qZDe7z1b4JXyd--JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-11-24 14:09           ` Sebastian Andrzej Siewior
2010-11-24 14:09             ` Sebastian Andrzej Siewior
     [not found]             ` <4CED1C95.8070300-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2010-11-24 14:14               ` Haojian Zhuang
2010-11-24 14:14                 ` Haojian Zhuang
2010-11-24 14:16               ` Mark Brown
2010-11-24 14:16                 ` Mark Brown
     [not found]                 ` <20101124141623.GH24970-HF5t3jzXg/6ND3a5+9QAFujbO/Zr0HzV@public.gmane.org>
2010-11-24 15:30                   ` Grant Likely
2010-11-24 15:30                     ` Grant Likely
     [not found]                     ` <AANLkTikC+XW7JtJO77vQL99=d9FKpO2tLtkCuxE57j7o-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-11-24 15:43                       ` Mark Brown
2010-11-24 15:43                         ` Mark Brown
2010-11-24 15:39                 ` Sebastian Andrzej Siewior [this message]
2010-11-24 15:39                   ` Sebastian Andrzej Siewior
     [not found]                   ` <4CED3199.2040700-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2010-11-25 23:54                     ` Russell King - ARM Linux
2010-11-25 23:54                       ` Russell King - ARM Linux
     [not found]                       ` <20101125235415.GA9310-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2010-11-26  1:14                         ` Grant Likely
2010-11-26  1:14                           ` Grant Likely
     [not found]                           ` <AANLkTi=tbiYCvTKH_wDDE0QuFpoBMnw-ZjF826VupnRA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-11-26  9:08                             ` Russell King - ARM Linux
2010-11-26  9:08                               ` Russell King - ARM Linux
2010-11-26 10:50                         ` [sodaville] " Sebastian Andrzej Siewior
2010-11-26 10:50                           ` Sebastian Andrzej Siewior
2010-11-26 11:06                           ` Russell King - ARM Linux
2010-11-26 11:06                             ` Russell King - ARM Linux
     [not found]                             ` <20101126110605.GI9310-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2010-11-26 13:29                               ` Sebastian Andrzej Siewior
2010-11-26 13:29                                 ` Sebastian Andrzej Siewior
2010-11-24 11:13   ` [PATCH 2/9] spi/pxa2xx: add support for shared IRQ handler Sebastian Andrzej Siewior
2010-11-24 11:13     ` Sebastian Andrzej Siewior
2010-11-24 11:13   ` [PATCH 3/9] spi/pxa2xx: Use define for SSSR_TFL_MASK instead of plain numbers Sebastian Andrzej Siewior
2010-11-24 11:13     ` Sebastian Andrzej Siewior
2010-11-24 11:13   ` [PATCH 4/9] arm/pxa2xx: reorgazine SSP and SPI header files Sebastian Andrzej Siewior
2010-11-24 11:13     ` Sebastian Andrzej Siewior
     [not found]     ` <1290597207-29838-5-git-send-email-bigeasy-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
2010-11-24 14:03       ` Haojian Zhuang
2010-11-24 14:03         ` Haojian Zhuang
     [not found]         ` <AANLkTinBFQZkuH4haeQAZQv8p0WZN5uh4xJj53sjUGTt-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-11-24 14:13           ` Sebastian Andrzej Siewior
2010-11-24 14:13             ` Sebastian Andrzej Siewior
2010-11-24 11:13   ` [PATCH 5/9] spi/pxa2xx: Add CE4100 support Sebastian Andrzej Siewior
2010-11-24 11:13     ` Sebastian Andrzej Siewior
2010-11-24 11:13   ` [PATCH 6/9] spi/pxa2xx: Consider CE4100's FIFO depth Sebastian Andrzej Siewior
2010-11-24 11:13     ` Sebastian Andrzej Siewior
2010-11-24 11:13   ` [PATCH 7/9] spi/pxa2xx: Add chipselect support for Sodaville Sebastian Andrzej Siewior
2010-11-24 11:13     ` Sebastian Andrzej Siewior
2010-11-24 11:13   ` [PATCH 8/9] spi/pxa2xx: Modify RX-Tresh instead of busy-loop for the remaining RX bytes Sebastian Andrzej Siewior
2010-11-24 11:13     ` Sebastian Andrzej Siewior
2010-11-24 11:13   ` [PATCH 9/9] spi/pxa2xx: pass of_node to spi device and set a parent device Sebastian Andrzej Siewior
2010-11-24 11:13     ` Sebastian Andrzej Siewior

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