[PATCH 23/24] mtd: spinand: winbond: Add comment about naming

[Tudor Ambarus]

On 12/18/24 9:33 AM, Miquel Raynal wrote:
> On 18/12/2024 at 08:14:36 GMT, Tudor Ambarus <tudor.ambarus at linaro.org> wrote:
> 
>> On 12/13/24 12:25 PM, Miquel Raynal wrote:
>>> On 11/11/2024 at 14:38:53 GMT, Tudor Ambarus <tudor.ambarus at linaro.org> wrote:
>>>
>>>> On 10/25/24 5:15 PM, Miquel Raynal wrote:
>>>>> Make the link between the core macros and the datasheet.
>>>>>
>>>>> Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
>>>>> ---
>>>>>  drivers/mtd/nand/spi/winbond.c | 5 +++++
>>>>>  1 file changed, 5 insertions(+)
>>>>>
>>>>> diff --git a/drivers/mtd/nand/spi/winbond.c b/drivers/mtd/nand/spi/winbond.c
>>>>> index 686e872fe0ff..9e2562805d23 100644
>>>>> --- a/drivers/mtd/nand/spi/winbond.c
>>>>> +++ b/drivers/mtd/nand/spi/winbond.c
>>>>> @@ -18,6 +18,11 @@
>>>>>  
>>>>>  #define W25N04KV_STATUS_ECC_5_8_BITFLIPS	(3 << 4)
>>>>>  
>>>>> +/*
>>>>> + * "X2" in the core is equivalent to "dual output" in the datasheets,
>>>>> + * "X4" in the core is equivalent to "quad output" in the datasheets.
>>>>> + */
>>>>
>>>> doesn't help great for an outsider like me. Is quad referring to cmd,
>>>> addr or data? Or maybe of all? I need to read the code anyway.
>>>
>>> I also don't like these terms. IIRC "output" is referring to the data cycles,
>>> otherwise it means address (dummy) and data cycles.
>>>
>>> In single, dual or quad mode the naming is unclear but "okay". But octal
>>> DDR modes can require the opcode to be sent in octal mode as well, which
>>> is new. If we support that, I'll take care of using a more
>>> understandable naming for all macros like Xy-Xy-Xy, X being the
>>> buswidth, y being S (sdr) or D (ddr) and the three members being
>>
>> 8d-8d-8d is common and covered by few standards, yes.
>>
>>> Command-Address-Data. I might even be tempted to include dummy cycles as
>>> well, because it is important to be clear if eg. in octal mode "1" means
>>> "1 cycle" or "8 cycles".
>> I find the info about dummy cycles useful. I wonder if such terminology
>> is already specified in a standard. If not, maybe we can put the dummy
>> cycles after the mode, in parenthesis? I would refrain custom terminology.
> 
> I see you concern, but would you mind giving an example of what you have
> in mind?
> 

on a second thought, the number of dummy cycles can vary depending on
frequency, so better to stick just to the
	Xy-Xy-Xy, X = {1,2,4,8}, y = {S, D} terminology.