[PATCH] adding ROM chips to device tree
Vitaly Wool
vwool at ru.mvista.com
Fri Nov 3 00:45:56 EST 2006
Josh Boyer wrote:
> On Thu, 2006-11-02 at 14:55 +0300, Vitaly Wool wrote:
>
>> In fact, currently this description can handle only flash devices mapped into memory in a linear way.
>> For NAND flashes we'll need a whole lot different description but let's solve problems as they arise
>> since I'm not aware of any ppc board w/ NAND chip yet :)
>>
>
> Um... all of the 440EP and 440EPx boards have NAND. And those have
> been around for a while...
>
>
Okay, that's nice to know. As you might have noticed, I'm a huge fan of
NAND flashes :)
>> +
>> + Required properties:
>> +
>> + - device_type : has to be "rom"
>>
>
> Why "rom" instead of "NOR"?
>
Hmm, it corresponds to Sergei's version. The latter had this as "mtd"
but following the thread I preferred to give it a more generic name.
However, thinking of it now, I realize that "NOR" is probably better
since we'll have to define another set of properties for NAND (which
will be of type "NAND" then) :)
>
>> + - compatible : Should be the name of the MTD driver. Currently, this is
>> + most likely to be "physmap".
>> + - reg : Offset and length of the register set for the device.
>>
>
> reg doesn't really describe a register set here. It's the overall
> memory space for flash.
>
Absolutely. Basically the description was just taken from Sergei's patch
with minimal modifications :)
>
>> +
>> + Recommended properties :
>> +
>> + - bank-width : Width of the flash data bus in bytes. Must be specified
>> + for the NOR flashes.
>>
>
> This is a required property, not a recommended one.
>
Yea, better have it in a separate section.
Thanks,
Vitaly
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