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References: <20220802175755.6530-1-sudip.mukherjee@sifive.com>
 <20220802175755.6530-5-sudip.mukherjee@sifive.com> <Yul3aNP8yoBf5QWu@sirena.org.uk>
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From:   Sudip Mukherjee <sudip.mukherjee@sifive.com>
Date:   Wed, 3 Aug 2022 18:35:06 +0100
Message-ID: <CAHyZL-f73MGxmOGZ_-082BXZs5uxtRXtXiVr39DK+__LHTjTUQ@mail.gmail.com>
Subject: Re: [PATCH 04/11] spi: dw: use TMOD_RO to read in enhanced spi modes
To:     Mark Brown <broonie@kernel.org>
Cc:     Serge Semin <fancer.lancer@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Greentime Hu <greentime.hu@sifive.com>,
        Jude Onyenegecha <jude.onyenegecha@sifive.com>,
        William Salmon <william.salmon@sifive.com>,
        Adnan Chowdhury <adnan.chowdhury@sifive.com>,
        Ben Dooks <ben.dooks@sifive.com>, linux-spi@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jeegar Lakhani <jeegar.lakhani@sifive.com>
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Hi Mark,

On Tue, Aug 2, 2022 at 8:13 PM Mark Brown <broonie@kernel.org> wrote:
>
> On Tue, Aug 02, 2022 at 06:57:48PM +0100, Sudip Mukherjee wrote:
> > When we are using the enhanced spi modes we can not use EEPROM Read.
> > The Synopsys datasheet mentions EEPROM Read is not applicable in
> > enhanced SPI modes. We will need to use Receive only mode.
> >
> > Signed-off-by: Sudip Mukherjee <sudip.mukherjee@sifive.com>
> > ---
> >  drivers/spi/spi-dw-core.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
> > index 8c84a2e991b5..8e624620864f 100644
> > --- a/drivers/spi/spi-dw-core.c
> > +++ b/drivers/spi/spi-dw-core.c
> > @@ -727,7 +727,10 @@ static int dw_spi_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
> >       cfg.dfs = 8;
> >       cfg.freq = clamp(mem->spi->max_speed_hz, 0U, dws->max_mem_freq);
> >       if (op->data.dir == SPI_MEM_DATA_IN) {
> > -             cfg.tmode = DW_SPI_CTRLR0_TMOD_EPROMREAD;
> > +             if (enhanced_spi)
> > +                     cfg.tmode = DW_SPI_CTRLR0_TMOD_RO;
> > +             else
> > +                     cfg.tmode = DW_SPI_CTRLR0_TMOD_EPROMREAD;
>
> This is fixing the previous commit...

This was not actually meant to be a fixup patch. I intentionally made
it separate so that "enhanced_spi" is introduced in the previous
patch,
and then modified the tmode read protocol in this patch based on
enhanced_spi. But I can merge it with the previous patch like you have
suggested.

--
Regards
Sudip