Re: [PATCH v2 0/6] spi: Add Renesas SPIBSC controller

[Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>]

On 12/16/2019 11:31 PM, Sergei Shtylyov wrote:

[...]
>> My understanding is that HyperFlash uses standard CFI commands, so all 
> 
>    The CFI command set driver needed some changes too (e.g. using the status
> register to determine if a command is done).
> 
>> we need to do is register a CFI device in the driver, just like we 
>> register a serial flash device.
> 
>> (I guess I could go look at the sample code for our RTOS package and find out)
>>
>>>> library that you are proposing have a very different API than just
>>>> 'send bytes' and 'receive bytes'?
>>>
>>>    There's "prepare" and "transfer" APIs and also "direct map read" API.
> 
>   The 1st one prepares the values to be written in either SPI mode or direct
> read mode registers. Then you can call "transfer" or "direct mao read" which
> would write out the register values into either set...
> 
>> I wonder what is the value of the "direct map read" (other than XIP in 
>> RZ/A systems). If you really want to directly access the flash (no 
>> buffering though the MTD layer), you need to register as a mtd-rom device, 
>> and then you don't really need an API at all.
> 
>   I'd leave this question to Boris, else I never complete this msg. :-) 

   Didn't really summon him, doing that now... :-)

>> Chris

MBR, Sergei