[U-Boot] [PATCH v2] dm: implement a cfi flash uclass

Thomas Chou thomas at wytron.com.tw
Sun Oct 11 15:29:34 CEST 2015


Hi Bin,

On 10/11/2015 08:43 PM, Bin Meng wrote:
> The spi-flash is converted to driver model, which is good, as there
> are spi flashes from different vendors which have different op codes
> thus need different drivers to handle. But for cfi-flash, almost every
> cfi-flash we see in the market conforms to the same CFI spec, thus we
> only need one driver (drivers/mtd/cfi_flash.c) to work with all these
> flashes, right? Unless I am missing something recently, eg: some
> vendors started to created flashes which are not 100% compatible with
> the CFI spec? If this is the only single driver, I don't see the need
> to create a special driver model uclass for it. Just an open
> discussion. I am not saying we should, or we should not :)

I had the same question myself. But I found that there are several 
uclasses which has only one driver. No worries. :)

>> It is not just base address. There is device binding with compatible ids.
>> There will be resources allocation, too. Please don't limit your imagination
>> by my poor coding skill.
>
> All there can be obtained from device tree. Being a non-DM driver does
> not prevent you from using device tree.

It is true. Yet using driver model does have some advantages over 
non-DM. It is more unified and dynamic. So I chose the DM way when I 
have to add device tree binding. You may find my patch quite trivial. 
Thanks to the DM framework.

Best regards,
Thomas



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