[0/4] spi: differentiate between unsupported and invalid requests

Message

Miquel Raynal May 22, 2024, 2:52 p.m. UTC

Hello Mark,

I am working on spi-nand continuous read support, which lead me to check
what spi controllers were capable of.

From a caller (and reviewer) point of view, distinguishing between error
cases has been proven useful, especially between two conditions:
- the request is totally unsupported and will never work
- the request is typically out of range somehow but a subsequent call
  with corrected parameters might work

So while I was statically reading the various drivers, I attempted to
clarify these situations and thought it might be nice to have this
upstream as well.

As ENOTSUPP is not a SUSV4 code and previous series have already been
merged to reduce its use, I also converted these few cases to EOPNOTSUP
instead, but if anybody doesn't like these changes, it can be dropped.

The series can be squashed if you prefer, I don't mind.

Cheers,
Miquèl

Miquel Raynal (4):
  spi: dw: differentiate between unsupported and invalid requests
  spi: mxic: differentiate between unsupported and invalid requests
  spi: rpc-if: differentiate between unsupported and invalid requests
  spi: wpcm-fiu: differentiate between unsupported and invalid requests

 drivers/spi/spi-dw-bt1.c   | 10 ++++++----
 drivers/spi/spi-mxic.c     |  2 +-
 drivers/spi/spi-rpc-if.c   | 12 ++++++------
 drivers/spi/spi-wpcm-fiu.c |  6 +++---
 4 files changed, 16 insertions(+), 14 deletions(-)