[U-Boot] [UBOOT PATCH 1/2] spi: zynqmp_qspi: Add support for ZynqMP qspi driver

[Siva Durga Prasad Paladugu]

Hi Jagan,

> -----Original Message-----
> From: Jagan Teki [mailto:jagannadh.teki at gmail.com]
> Sent: Wednesday, November 01, 2017 2:54 PM
> To: Siva Durga Prasad Paladugu <sivadur at xilinx.com>
> Cc: u-boot at lists.denx.de; Liam Beguin <liambeguin at gmail.com>
> Subject: Re: [UBOOT PATCH 1/2] spi: zynqmp_qspi: Add support for
> ZynqMP qspi driver
> 
> On Tue, Oct 31, 2017 at 6:33 PM, Siva Durga Prasad Paladugu
> <sivadur at xilinx.com> wrote:
> > Hi Jagan,
> >
> >> -----Original Message-----
> >> From: Jagan Teki [mailto:jagannadh.teki at gmail.com]
> >> Sent: Tuesday, October 31, 2017 3:01 PM
> >> To: Siva Durga Prasad Paladugu <sivadur at xilinx.com>
> >> Cc: u-boot at lists.denx.de; Liam Beguin <liambeguin at gmail.com>
> >> Subject: Re: [UBOOT PATCH 1/2] spi: zynqmp_qspi: Add support for
> >> ZynqMP qspi driver
> >>
> >> On Tue, Oct 31, 2017 at 2:50 PM, Siva Durga Prasad Paladugu
> >> <sivadur at xilinx.com> wrote:
> >> > Hi Jagan,
> >> >
> >> >> -----Original Message-----
> >> >> From: Jagan Teki [mailto:jagannadh.teki at gmail.com]
> >> >> Sent: Tuesday, October 31, 2017 2:40 PM
> >> >> To: Siva Durga Prasad Paladugu <sivadur at xilinx.com>
> >> >> Cc: u-boot at lists.denx.de; Liam Beguin <liambeguin at gmail.com>;
> Siva
> >> >> Durga Prasad Paladugu <sivadur at xilinx.com>
> >> >> Subject: Re: [UBOOT PATCH 1/2] spi: zynqmp_qspi: Add support for
> >> >> ZynqMP qspi driver
> >> >>
> >> >> On Tue, Oct 24, 2017 at 3:33 PM, Siva Durga Prasad Paladugu
> >> >> <siva.durga.paladugu at xilinx.com> wrote:
> >> >> > This patch adds qspi driver support for ZynqMP SoC. This driver
> >> >> > is responsible for communicating with qspi flash devices.
> >> >>
> >> >> Legacy question, what is your approach for dual memory setup? Did
> >> >> you write another flash driver?
> >> > No
> >> >
> >> >>
> >> >> I see this driver use dual flash slave 'option' which doesn't live
> >> >> on spi side anymore. better to have a discussion on approach and
> >> >> will
> >> review further.
> >> >
> >> > I can see that spi_flash.c(driver/mtd/spi/spi_flash.c) has the
> >> > option for
> >> dual flash under CONFIG_SF_DUAL_FLASH.
> >> > I thought of using the same. Isn't it takes care of dual flash case?
> >> > Please let me know if you any further thoughts on how it has to be
> >> handled.
> >>
> >> Dual flash case should take for generic spi drivers, if you strictly
> >> want your controller to handle flash device rather !flashes then we
> >> need to write the driver at flash side. ie why I asked as first question.
> >
> > Does this mean that drivers that are present in drivers/spi/ should
> > work for both flashes and !flashes. And the drivers that only targets
> > flash devices should be in different place and doesn’t use Dual flash
> functionality under CONFIG_SF_DUAL_FLASH? Or it can still use this.
> 
> Sorry, you understand it reverse or may be I'm not clear.
> 
> drivers at drivers/spi can handle only generic slaves which includes spi-flash
> and some spi-flash(spi-nor) controllers which only deals with spi-flash
> slaves which can be part of drivers/mtd/spi. Since your driver is categorized
> as spi-nor controller(in above notes from you) it's better to write driver at
> drivers/mtd/spi side.

No, the controller is meant to handle other slaves as well along with spi-nor. 
Also for now, we are targeting single spi flash. So, keeping the driver here
should just be fine. Please let me know if you need any further info.

Thanks,
Siva.
> 
> Hope it clear.
> 
> thanks!
> --
> Jagan Teki
> Free Software Engineer | www.openedev.com U-Boot, Linux | Upstream
> Maintainer Hyderabad, India.