Re: [RFC PATCH 1/5] mtd: cfi_cmdset_0002: Add support for polling status register

[Sergei Shtylyov]

On 02/19/2019 09:36 AM, Vignesh R (by way of Boris Brezillon <bbrezillon@xxxxxxxxxx>) wrote:

> HyperFlash devices are compliant with CFI AMD/Fujitsu Extended Command
> Set(0x0002) for flash operations, therefore drivers/mtd/chips/cfi_cmdset_0002.c
> can be use as is. But these devices do not support DQ polling method of
> determining chip ready/good status. These flashes provide Status
> Register whose bits can be polled to know status of flash operation.
> 
> Cypress HyperFlash datasheet here[1], talks about CFI Amd/Fujitsu
> Extended Query version 1.5. Bit 0 of "Software Features supported" field
> of CFI Primary Vendor-Specific Extended Query table indicates
> presence/absence of status register and Bit 1 indicates whether or not
> DQ polling is supported. Using these bits, its possible to determine
> whether flash supports DQ polling or need to use Status Register.
> 
> Add support for polling status register to know device ready/status of
> erase/write operations when DQ polling is not supported.
> 
> [1] https://www.cypress.com/file/213346/download
> 
> Signed-off-by: Vignesh R <vigneshr@xxxxxx>

   Forgot about one thing: tags like S-o-b: need your full name,
cfr. Documentation/process/5.Posting.rst...

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MBR, Sergei