From mboxrd@z Thu Jan  1 00:00:00 1970
From: arnd@arndb.de (Arnd Bergmann)
Date: Tue, 17 Jul 2012 16:53:45 +0000
Subject: [PATCH V2 6/7] ARM: SPEAr13xx: Add auxdata for Ethernet
 controller.
In-Reply-To: <500537C2.1030501@st.com>
References: <cover.1342171151.git.vipulkumar.samar@st.com>
 <CAOh2x==ob+N26pJdc1DC8DfOomus1robkj=8DeyVE_ve_L-bAA@mail.gmail.com>
 <500537C2.1030501@st.com>
Message-ID: <201207171653.45688.arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tuesday 17 July 2012, deepaksi wrote:
> I do differ on the point over here. I do believe that the code for now 
> should be left as into mutually
> exclusive sections.
> As you said, without DT, the platform data would exist without any 
> problem, Thats fine
> 
> But with DT also, as of now since the DT is still evolving we should not 
> merge the data and keep it at
> two places. The reasons being.
> The stmmac driver is being used by multiple platforms, lets say within 
> spear we have different variants
> requiring different configurations and dividing those configurations at 
> two different places will require larger
> maintenance.

I don't think that the STMMAC_PLATFORM part is used by any other
platform in the mainline kernel, so we are definitely free to
rip out (parts of) the platform_data and replace them with DT
properties.
There is also no platform defining plat_stmmacenet_data
yet, which means that the code is completely untested at
the moment.

Don't worry about any out-of-tree platforms, they can keep
their out of tree patches to add back the platform data if
they don't want to move to DT booting.

Since all the data you are adding to spear1340.c is constant
anyway, I suppose that means this data is specific to
the spear1340 soc, not to a particular board or configuration.
I would suggest you add a preset like

static const struct of_device_id stmmac_dt_ids[] = {
        { .compatible = "st,spear600-gmac", .data = &spear600_data},
        { .compatible = "st,spear1340-gmac", .data = &spear1340_data}
};

that contains all the soc-specific data. You can probably make
that "const" and just kill off the platform_data path in the
driver.

> Any more changes in driver that has dependency on the 
> platform data will require updates,
> and more such conflicts will arrive related to maintenance.
> 
> Lets keep the platform data as a part of AUXDATA for now, till the tree 
> evolves fully specifically if DT is being
> used.

SPEAr is already fully using DT for everything except DMA channels.
Please don't add any more such exceptions.

	Arnd