RE: [PATCH 5/6] soc: aspeed: Add eSPI driver

[ChiaWei Wang]

Hi Rob,

> -----Original Message-----
> From: Rob Herring <robh@xxxxxxxxxx>
> Sent: Wednesday, January 6, 2021 11:32 PM
> To: ChiaWei Wang <chiawei_wang@xxxxxxxxxxxxxx>
> Subject: Re: [PATCH 5/6] soc: aspeed: Add eSPI driver
> 
> On Wed, Jan 06, 2021 at 01:59:38PM +0800, Chia-Wei, Wang wrote:
> > The Aspeed eSPI controller is slave device to communicate with the
> > master through the Enhanced Serial Peripheral Interface (eSPI).
> > All of the four eSPI channels, namely peripheral, virtual wire,
> > out-of-band, and flash are supported.
> >
> > Signed-off-by: Chia-Wei, Wang <chiawei_wang@xxxxxxxxxxxxxx>
> > ---
> >  drivers/soc/aspeed/Kconfig                  |  49 ++
> >  drivers/soc/aspeed/Makefile                 |   5 +
> >  drivers/soc/aspeed/aspeed-espi-ctrl.c       | 197 ++++++
> >  drivers/soc/aspeed/aspeed-espi-flash.c      | 490 ++++++++++++++
> >  drivers/soc/aspeed/aspeed-espi-oob.c        | 706
> ++++++++++++++++++++
> >  drivers/soc/aspeed/aspeed-espi-peripheral.c | 613 +++++++++++++++++
> >  drivers/soc/aspeed/aspeed-espi-vw.c         | 211 ++++++
> >  include/uapi/linux/aspeed-espi.h            | 160 +++++
> >  8 files changed, 2431 insertions(+)
> >  create mode 100644 drivers/soc/aspeed/aspeed-espi-ctrl.c
> >  create mode 100644 drivers/soc/aspeed/aspeed-espi-flash.c
> >  create mode 100644 drivers/soc/aspeed/aspeed-espi-oob.c
> >  create mode 100644 drivers/soc/aspeed/aspeed-espi-peripheral.c
> >  create mode 100644 drivers/soc/aspeed/aspeed-espi-vw.c
> 
> drivers/spi/ is the correct location for a SPI controller.
> 
> >  create mode 100644 include/uapi/linux/aspeed-espi.h
> 
> This userspace interface is not going to be accepted upstream.
> 
> I'd suggest you look at similar SPI flash capable SPI controller drivers upstream
> and model your driver after them. This looks like it needs major reworking.
> 
eSPI resues the timing and electrical specification of SPI but runs completely different protocol.
Only the flash channel is related to SPI and the other 3 channels are for EC/BMC/SIO.
Therefore, an eSPI driver might not fit into the SPI model.

Chiawei