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Message-ID: <680026.93151.qm@web29013.mail.ird.yahoo.com>
Date: Mon, 23 May 2011 15:27:18 +0100 (BST)
From: Paul Parsons <lost.distance@yahoo.com>
Subject: Re: [PATCH] mfd: Add ASIC3 PCMCIA/CF support
To: Samuel Ortiz <sameo@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, philipp.zabel@gmail.com, mad_soft@inbox.ru
In-Reply-To: <20110522221459.GQ18610@sortiz-mobl>
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Hi Samuel,

> Why is this driver linked to the pxa2 pcmcia driver ? Can't
> we make it just
> asic3 specific and enable it from the board asic3 platform
> data ?

This driver isn't the actual driver! This patch merely provides the platform_data for the asic3 pcmcia platform_device. This is then linked to the existing pxa2xx-pcmcia platform_driver, which is the actual driver.

In the case of pcmcia, the platform_data provides callbacks (struct pcmcia_low_level) rather than simple static data, and thus needs to reside in drivers/pcmcia where those callbacks are declared.

In the case of asic3, the pcmcia platform_device also needs to provide a parent link back to the asic3 platform_device because the callbacks need to access asic3 registers (in addition to GPIOs).

Thus either the pcmcia platform_data or the asic3 platform_device need to be made global if both are to be referenced by the pcmcia platform_device. I chose the former, simply because the pcmcia platform_device was already defined in arch/arm/mach-pxa/hx4700.c

Agreed this arrangement seems somewhat untidy. I am keen to hear if someone can improve upon it.

Paul
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