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SubjectRe: [PATCH 0/5] mtd: rawnand: qcom: Add support for QSPI nand
On 2020-10-28 15:18, Miquel Raynal wrote:
> Hello,
>
> Md Sadre Alam <mdalam@codeaurora.org> wrote on Sat, 10 Oct 2020
> 11:01:37 +0530:
>
>> QPIC 2.0 supports Serial NAND support in addition to all features and
>> commands in QPIC 1.0 for parallel NAND. Parallel and Serial NAND
>> cannot
>> operate simultaneously. QSPI nand devices will connect to QPIC
>> IO_MACRO
>> block of QPIC controller. There is a separate IO_MACRO clock for
>> IO_MACRO
>> block. Default IO_MACRO block divide the input clock by 4. so if
>> IO_MACRO
>> input clock is 320MHz then on bus it will be 80MHz, so QSPI nand
>> device
>> should also support this frequency.
>>
>> QPIC provides 4 data pins to QSPI nand. In standard SPI mode (x1 mode)
>> data
>> transfer will occur on only 2 pins one pin for Serial data in and one
>> for
>> serial data out. In QUAD SPI mode (x4 mode) data transfer will occur
>> at all
>> the four data lines. QPIC controller supports command for x1 mode and
>> x4 mode.
>>
>> Md Sadre Alam (5):
>> dt-bindings: qcom_nandc: IPQ5018 QPIC NAND documentation
>> mtd: rawnand: qcom: Add initial support for qspi nand
>> mtd: rawnand: qcom: Read QPIC version
>> mtd: rawnand: qcom: Enable support for erase,read & write for serial
>> nand.
>> mtd: rawnand: qcom: Add support for serial training.
>>
>> .../devicetree/bindings/mtd/qcom_nandc.txt | 3 +
>> drivers/mtd/nand/raw/nand_ids.c | 13 +
>> drivers/mtd/nand/raw/qcom_nandc.c | 502
>> ++++++++++++++++++++-
>> 3 files changed, 494 insertions(+), 24 deletions(-)
>>
>
> I'm sorry but this series clearly breaks the current layering. I cannot
> authorize SPI-NAND code to fall into the raw NAND subsystem.
>

I am agree with you, we should not add SPI-NAND changes inside
raw NAND subsystem.

> As both typologies cannot be used at the same time, I guess you should
> have another driver handling this feature under the spi/ subsystem +
> a few declarations in the SPI-NAND devices list.
>

Initially I was started writing separate driver under SPI-NAND subsystem
then I
realized that more than 85% of raw/qcom_nand.c code getting duplicated.

That's why I have added this SPI-NAND change in raw/qcom_nand.c since
more than 85% of code will be reused.

If I will add this change inside SPI-NAND subsystem then much of
raw/qcom_nand.c code will get duplicated. Would it be ok ?

> Thanks,
> Miquèl

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