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

[Siva Durga Prasad Paladugu]

Hi Jagan,

Ping!!


Thanks,
Siva
> -----Original Message-----
> From: Siva Durga Prasad Paladugu
> Sent: Thursday, November 23, 2017 1:01 PM
> To: Jagan Teki <jagannadh.teki at gmail.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
> 
> 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.