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From: dillon min <dillon.minfei@gmail.com>
To: Mark Brown <broonie@kernel.org>
Cc: "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
	<devicetree@vger.kernel.org>, Dave Airlie <airlied@linux.ie>,
	Michael Turquette <mturquette@baylibre.com>,
	linux-clk <linux-clk@vger.kernel.org>,
	linux-kernel@vger.kernel.org,
	"open list:DRM PANEL DRIVERS" <dri-devel@lists.freedesktop.org>,
	linux-spi@vger.kernel.org, Stephen Boyd <sboyd@kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	thierry.reding@gmail.com,
	Maxime Coquelin <mcoquelin.stm32@gmail.com>,
	Sam Ravnborg <sam@ravnborg.org>,
	linux-stm32@st-md-mailman.stormreply.com,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Alexandre Torgue <alexandre.torgue@st.com>
Subject: Re: [PATCH v4 3/8] spi: stm32: Add 'SPI_SIMPLEX_RX', 'SPI_3WIRE_RX' support for stm32f4
Date: Fri, 22 May 2020 23:59:25 +0800
Message-ID: <CAL9mu0JZ4Qy+m2oF9TSTRqA_mM0J89huCt3t_Gs7qHa=3LxhBw@mail.gmail.com> (raw)
In-Reply-To: <CAL9mu0LAnT+AfjpGs0O-MD2HYrpnQRmrj6qXtJQrJi9kbQLPUw@mail.gmail.com>

On Fri, May 22, 2020 at 10:57 PM dillon min <dillon.minfei@gmail.com> wrote:
>
> hi Mark,
>
> Thanks for reviewing.
>
> On Fri, May 22, 2020 at 7:36 PM Mark Brown <broonie@kernel.org> wrote:
> >
> > On Mon, May 18, 2020 at 07:09:20PM +0800, dillon.minfei@gmail.com wrote:
> >
> > > 2, use stm32 spi's "In full-duplex (BIDIMODE=0 and RXONLY=0)", as tx_buf is
> > > null, we must add dummy data sent out before read data.
> > > so, add stm32f4_spi_tx_dummy() to handle this situation.
> >
> > There are flags SPI_CONTROLLER_MUST_TX and SPI_CONTROLLER_MUST_RX flags
> > that the driver can set if it needs to, no need to open code this in the
> > driver.
>
> Yes, after check SPI_CONTROLLER_MUST_TX in drivers/spi/spi.c , it's
> indeed to meet
> this situation,  i will try it and sumbmit a new patch.
>
> thanks.
>
> best regards
>
> Dillon

Hi Mark,

There might be a conflict with 'SPI_CONTROLLER_MUST_TX' and 'SPI_3WIRE' mode,
i need to know the SPI_3WIRE direction,  currently i get this
information from 'struct spi_device'
and 'struct spi_transfer'
if ((spi_device->mode & SPI_3WIRE) && (spi_transfer->tx_buf == NULL)
&& (spi_transfer->rx_buf != NULL))
    this is a SPI_3WIRE_RX transfer
if ((spi_device->mode & SPI_3WIRE) && (spi_transfer->tx_buf != NULL)
&& (spi_transfer->rx_buf == NULL))
    this is a SPI_3WIRE_TX transfer

but, after spi-core create a dummy tx_buf or rx_buf, then i can't get
the correct spi_3wire direction.
actually, this dummy tx_buf is useless for SPI_3WIRE. it's has meaning
for SPI_SIMPLE_RX mode,
simulate SPI_FULL_DUMPLEX

how do you think?

thanks

best regards

Dillon
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  reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-18 11:09 [PATCH v4 0/8] Enable ili9341 and l3gd20 on stm32f429-disco dillon.minfei
2020-05-18 11:09 ` [PATCH v4 1/8] ARM: dts: stm32: Add dma config for spi5 dillon.minfei
2020-05-18 11:09 ` [PATCH v4 2/8] ARM: dts: stm32: enable l3gd20 on stm32429-disco board dillon.minfei
2020-05-18 11:09 ` [PATCH v4 3/8] spi: stm32: Add 'SPI_SIMPLEX_RX', 'SPI_3WIRE_RX' support for stm32f4 dillon.minfei
2020-05-22 11:36   ` Mark Brown
2020-05-22 14:57     ` dillon min
2020-05-22 15:59       ` dillon min [this message]
2020-05-22 16:29         ` Mark Brown
2020-05-23  1:35           ` dillon min
2020-05-25 11:43             ` Mark Brown
2020-05-18 11:09 ` [PATCH v4 4/8] ARM: dts: stm32: Add pin map for ltdc on stm32f429-disco board dillon.minfei
2020-05-18 11:09 ` [PATCH v4 5/8] dt-bindings: display: panel: Add ilitek ili9341 panel bindings dillon.minfei
2020-05-28 20:49   ` Rob Herring
2020-05-18 11:09 ` [PATCH v4 6/8] ARM: dts: stm32: enable ltdc binding with ili9341 on stm32429-disco board dillon.minfei
2020-05-18 11:09 ` [PATCH v4 7/8] clk: stm32: Fix stm32f429's ltdc driver hang in set clock rate dillon.minfei
2020-05-18 11:09 ` [PATCH v4 8/8] drm/panel: Add ilitek ili9341 panel driver dillon.minfei

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