Re: [PATCH 1/2] OMAP: features: export symbol omap3_features

[Nishanth Menon <nm@ti.com>]

Paul Walmsley had written, on 09/24/2010 12:17 PM, the following:
> On Fri, 24 Sep 2010, Paul Walmsley wrote:
> 
>> On Fri, 24 Sep 2010, Nishanth Menon wrote:
>>
>>> The intent of omap_has_featureX() is to ensure that the drivers dont do
>>> cpu_is_omap123(). Now if we had OMAP dma driver which has DMA chaining - what
>>> options do we have DMA driver?
>>>
>>> a) we introduce it based on cpu_is_omap123() -> bad bad nightmare for
>>> maintenance
>>> b) we introduce it based on module h/w block(TI internal terminology "IP
>>> block") revision -> unfortunately no luck in some of the h/w blocks.
>>> c) we use if (omap_has_dma_chaining())
>> d) you pass in errata/feature flags via a platform_data struct, like 
>> McBSP, McSPI, MMC, MUSB, I2C, etc. already do on OMAP.  On OMAP1, which 
>> doesn't have hwmod support, you set your platform_data in your OMAP1 
>> integration code.  On OMAP2+ (which has hwmod support), you define your 
>> errata/feature flags and any other integration data that you need to pass 
>> via the struct omap_hwmod.dev_attr field, then pass that data via struct 
>> platform_data in the OMAP2+ integration code.
> 
> Just to clarify something that may be unclear: there's no problem with 
> calling cpu_is_omapXXXX(), or any other OMAP core-specific function, from 
> the OMAP<->driver integration code, living in arch/arm/*omap*.  The 
> results of those functions can then be passed through platform_data.  But 
> there is a problem with calling OMAP core-specific functions directly from 
> the driver code itself, since driver code should be completely 
> platform-independent -- e.g., the same DMA controller could exist on OMAP, 
> DaVinci, etc.
> 
yep. your comment makes sense now. thanks for clarifying. NAK from me as 
well.

-- 
Regards,
Nishanth Menon