Re: [PATCH v3 4/9] of: mtd: add documentation for the ONFI NAND timing mode property

[Boris BREZILLON <b.brezillon.dev@gmail.com>]

Le 12/03/2014 19:27, Warner Losh a écrit :
> On Mar 12, 2014, at 12:07 PM, Boris BREZILLON <b.brezillon.dev@gmail.com> wrote:
>
>> Add documentation for the ONFI NAND timing mode property.
> I don’t see a Toggle/JEDEC mode timing property. Will that be defined for Toshiba, Samsung
> and San Disk flash? Or will this be limited to Micron, Intel and Hynix (the only ones
> supporting ONFI)?

There is currently no Toggle/JEDEC timing mode support, and I don't know 
what these
timing modes describe.
But I guess they can be converted to standard timings described in 
nand_sdr_timings
struct (or in your case in the future nand_ddr_timings struct).

Could you check that the timings described by these modes use the same 
naming convention
as those defined in the ONFI specification 
(www.onfi.org/~/media/ONFI/specs/onfi_3_1_spec.pdf
  chapter 4.15.4) ?

If this is the case, we can define a new DT property and new converters.

Best Regards,

Boris

> Warner
>
>
>> Signed-off-by: Boris BREZILLON <b.brezillon.dev@gmail.com>
>> ---
>> Documentation/devicetree/bindings/mtd/nand.txt |    8 ++++++++
>> 1 file changed, 8 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/mtd/nand.txt b/Documentation/devicetree/bindings/mtd/nand.txt
>> index b53f92e..2046027 100644
>> --- a/Documentation/devicetree/bindings/mtd/nand.txt
>> +++ b/Documentation/devicetree/bindings/mtd/nand.txt
>> @@ -19,3 +19,11 @@ errors per {size} bytes".
>> The interpretation of these parameters is implementation-defined, so not all
>> implementations must support all possible combinations. However, implementations
>> are encouraged to further specify the value(s) they support.
>> +
>> +- onfi,nand-timing-mode: an integer encoding the supported ONFI timing modes of
>> +  the NAND chip. Each supported mode is represented as a bit position (i.e. :
>> +  mode 0 and 1 => (1 << 0) | (1 << 1) = 0x3).
>> +  This is only used when the chip does not support the ONFI standard.
>> +  The last bit set represent the closest mode fulfilling the NAND chip timings.
>> +  For a full description of the different timing modes see this document:
>> +  www.onfi.org/~/media/ONFI/specs/onfi_3_1_spec.pdf
>> -- 
>> 1.7.9.5
>>
>> --
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