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From: Andres Salomon <dilinger@queued.net>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Samuel Ortiz <sameo@linux.intel.com>,
	Russell King <linux@arm.linux.org.uk>,
	Mark Brown <broonie@opensource.wolfsonmicro.com>,
	linux-kernel@vger.kernel.org, Richard Purdie <rpurdie@rpsys.net>,
	Sascha Hauer <kernel@pengutronix.de>,
	linux-arm-kernel@lists.infradead.org,
	Liam Girdwood <lrg@slimlogic.co.uk>
Subject: Re: [PATCH 15/19] mc13xxx: mfd_cell is now implicitly available to drivers
Date: Fri, 4 Feb 2011 02:16:41 -0800	[thread overview]
Message-ID: <20110204021641.4f7fc66a@queued.net> (raw)
In-Reply-To: <20110204093458.GH30452@pengutronix.de>

On Fri, 4 Feb 2011 10:34:58 +0100
Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote:

> Hello Andres,
> 
> On Wed, Feb 02, 2011 at 08:20:15PM -0800, Andres Salomon wrote:
> > 
> > No need to explicitly set the cell's platform_data/data_size.
> > 
> > In this case, move the various platform_data pointers
> > to driver_data.  All of the clients which make use of it
> > are also changed.
> > 
> > Mfd-core makes a copy of platform_data, but driver_data keeps a
> > pointer to the original data.  Because each cell's platform_data
> > previously pointed to a local (stack) variable, the various ARM
> > mach types that set the pdata are updated to keep the memory around.
> I didn't get this even after reading it 5 times.  You wrote in the
> subject that drivers now have access to mfd_cell.  I don't see where
> e.g. drivers/leds/leds-mc13783.c uses that?!  Does this depend on some
> mfd-changes I don't see and this is just a first step?
> 
> After reading the changes I think I understood:
> 
>  - You made things that were passed as platform_data before available
>    via driver_data.

Right.  And as someone pointed out, this doesn't really work as well as
I'd hoped, so I'll have to refine my approach.  Ideally, something
simpler..


>  - Because platform_data is copied and driver_data is not at register
>    time, the data being platform_data cannot be __initdata or stack
>    local anymore, so this needs fixing.
> 
> In sum this results in .data becoming bigger (which is bad).
> 
> And I think this patch has a conceptual problem, too.  In my opionion
> platform_data is the point to hand over platform specific data to a
> driver.  driver_data is something that is private to the driver and
> has to be considered opaque for the platform.  The driver was sort of
> OK before ...


I'll be sending updated patches once I've reworked things.

  parent reply	other threads:[~2011-02-04 10:16 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-03  3:54 [RFC] [PATCH 0/19] mfd sharing support Andres Salomon
2011-02-03  3:55 ` [PATCH 01/19] mfd-core: unconditionally add mfd_cell to every platform_device Andres Salomon
2011-02-03  3:58 ` [PATCH 02/19] jz4740: mfd_cell is now implicitly available to drivers Andres Salomon
2011-02-03  8:09   ` Jean Delvare
2011-02-03  4:01 ` [PATCH 03/19] ab3550: " Andres Salomon
2011-02-04  8:20   ` Mattias Wallin
2011-02-03  4:03 ` [PATCH 04/19] ab3100: " Andres Salomon
2011-02-03 12:52   ` Linus Walleij
2011-02-03  4:04 ` [PATCH 05/19] asic3: " Andres Salomon
2011-02-03  4:05 ` [PATCH 06/19] htc-pasic3: " Andres Salomon
2011-02-03  4:08 ` [PATCH 07/19] timberdale: " Andres Salomon
2011-03-31 23:05   ` Grant Likely
2011-04-01 11:20     ` Samuel Ortiz
2011-04-01 17:47       ` Andres Salomon
2011-04-01 17:56         ` Grant Likely
2011-04-01 18:00           ` Grant Likely
2011-04-01 23:52           ` Samuel Ortiz
2011-04-01 23:58             ` Grant Likely
2011-04-02  0:10               ` Andres Salomon
2011-04-04 10:03               ` Samuel Ortiz
2011-04-05  3:04                 ` Grant Likely
2011-04-06 15:23                   ` Samuel Ortiz
2011-04-06 15:58                     ` Greg KH
2011-04-06 17:05                       ` Samuel Ortiz
2011-04-06 17:16                         ` Ben Hutchings
2011-04-06 17:51                           ` Samuel Ortiz
2011-04-06 18:07                             ` Ben Hutchings
2011-04-06 17:56                         ` Greg KH
2011-04-06 18:25                           ` Andres Salomon
2011-04-06 18:38                             ` Greg KH
2011-04-07  8:04                               ` Grant Likely
2011-04-06 18:47                           ` Samuel Ortiz
2011-04-06 18:59                             ` Felipe Balbi
2011-04-06 22:09                               ` Greg KH
2011-04-07  8:09                                 ` Felipe Balbi
2011-04-07 13:40                               ` Samuel Ortiz
2011-04-07 14:35                                 ` Grant Likely
2011-04-07 15:03                                   ` Samuel Ortiz
2011-04-07 18:06                                     ` Grant Likely
2011-04-07 16:24                   ` Grant Likely
2011-04-01 18:26         ` Samuel Ortiz
2011-02-03  4:09 ` [PATCH 08/19] t7166xb: " Andres Salomon
2011-02-03  4:11 ` [PATCH 09/19] wl1273: " Andres Salomon
2011-02-03  4:12 ` [PATCH 10/19] sh_mobile_sdhi: " Andres Salomon
2011-02-03  4:13 ` [PATCH 11/19] tc6393xb: " Andres Salomon
2011-02-03  4:15 ` [PATCH 12/19] twl4030: " Andres Salomon
2011-02-03  6:05   ` Dmitry Torokhov
2011-02-03  6:39     ` Andres Salomon
2011-02-03  6:53       ` Dmitry Torokhov
2011-02-03  7:03         ` Andres Salomon
2011-02-03  9:31           ` Mark Brown
2011-02-05  2:39             ` Andres Salomon
2011-02-05  3:25               ` Andres Salomon
2011-02-03 12:23           ` Peter Ujfalusi
2011-02-04 10:41           ` Uwe Kleine-König
2011-02-03  4:16 ` [PATCH 13/19] tc6387xb: " Andres Salomon
2011-02-03  4:17 ` [PATCH 14/19] janz: " Andres Salomon
2011-02-03  4:20 ` [PATCH 15/19] mc13xxx: " Andres Salomon
2011-02-04  9:34   ` Uwe Kleine-König
2011-02-04 10:13     ` Uwe Kleine-König
2011-02-04 10:16     ` Andres Salomon [this message]
2011-02-03  4:21 ` [PATCH 16/19] mfd-core: drop platform_data/data_size from core mfd_cell struct Andres Salomon
2011-02-03  4:22 ` [PATCH 17/19] mfd-core: add refcounting support to mfd_cells Andres Salomon
2011-02-03  4:23 ` [PATCH 18/19] mfd-core: add platform_device sharing support for mfd Andres Salomon
2011-02-03  4:26 ` [PATCH 19/19] cs5535-mfd: add sharing for acpi/pms cells Andres Salomon

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