[U-Boot] [PATCH 6/7] mx35: Fix eSDHC clocks

[Stefano Babic <sbabic@denx.de>]

On 20/08/2012 14:34, Beno?t Th?baudeau wrote:
> Hi Stefano,
> 

Hi Beno?t,

>>> Even if the two controllers can have different clocks, this is not
>>> supported by the driver. In fact, in drivers/mmc/fsl_esdhc.c:
>>>
>>> int sdhc_clk = gd->sdhc_clk;
>>>
>>> The driver uses always the same clock, stored in the global
>>> structure.
>>> Before extending the code as in this patch, the driver should be
>>> modified to handle separate clocks. Currently the driver supports
>>> multiple controller, but they share the same clock or at least the
>>> same
>>> frequency.
>>
>> Indeed, I had seen that. I didn't know what to decide as to the
>> driver clocks,
>> so I made this change to select the correct clock if a single clock
>> or frequency
>> is used.
>>
>> If several clock frequencies are to be supported at once, what kind
>> of API would
>> you like? gd->sdhc_clk could be changed to an array, then the
>> corresponding
>> index could be passed to the init function through the fsl_esdhc_cfg
>> struct.
> 
> But there is also the issue of fsl_esdhc_mmc_init() that would need a new config
> just to pass this index. I don't like that. Any suggestion?

There is another issue. The driver is used by both ARM (i.MX) and
PowerPCs (PowerQuickIII, ...).

fsl_esdhc_mmc_init() is already the interface when one parameter is
enough. If we need more than one controller, we should already call
fsl_esdhc_initialize() with the cfg structure.

Then adding a field to the struct fsl_esdhc_cfg is maybe not too bad.
Instead of an index, we can add directly the frequency - reading the
driver this is all that the driver needs.

Best regards,
Stefano

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