Re: [PATCH v3 4/6] spi: spi-axi-spi-engine: Add support for MOSI idle configuration

Nuno Sá
2024-06-06T06:47:44Z

On Wed, 2024-06-05 at 12:03 -0500, David Lechner wrote:
> On 6/4/24 5:43 PM, Marcelo Schmitt wrote:
> > Implement MOSI idle low and MOSI idle high to better support peripherals
> > that request specific MOSI behavior.
> >
> > Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com>
> > ---
> >  drivers/spi/spi-axi-spi-engine.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/spi/spi-axi-spi-engine.c b/drivers/spi/spi-axi-spi-
> > engine.c
> > index 0aa31d745734..549f03069d0e 100644
> > --- a/drivers/spi/spi-axi-spi-engine.c
> > +++ b/drivers/spi/spi-axi-spi-engine.c
> > @@ -41,6 +41,7 @@
> >  #define SPI_ENGINE_CONFIG_CPHA BIT(0)
> >  #define SPI_ENGINE_CONFIG_CPOL BIT(1)
> >  #define SPI_ENGINE_CONFIG_3WIRE BIT(2)
> > +#define SPI_ENGINE_CONFIG_SDO_IDLE BIT(3)
> >
> >  #define SPI_ENGINE_INST_TRANSFER 0x0
> >  #define SPI_ENGINE_INST_ASSERT 0x1
> > @@ -132,6 +133,10 @@ static unsigned int spi_engine_get_config(struct
> > spi_device *spi)
> >   config |= SPI_ENGINE_CONFIG_CPHA;
> >   if (spi->mode & SPI_3WIRE)
> >   config |= SPI_ENGINE_CONFIG_3WIRE;
> > + if (spi->mode & SPI_MOSI_IDLE_HIGH)
> > + config |= SPI_ENGINE_CONFIG_SDO_IDLE;
> > + if (spi->mode & SPI_MOSI_IDLE_LOW)
> > + config &= ~SPI_ENGINE_CONFIG_SDO_IDLE;
> >
> >   return config;
> >  }
> > @@ -645,7 +650,8 @@ static int spi_engine_probe(struct platform_device
> > *pdev)
> >   return ret;
> >
> >   host->dev.of_node = pdev->dev.of_node;
> > - host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_3WIRE;
> > + host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_3WIRE |
> > SPI_MOSI_IDLE_LOW
> > +   | SPI_MOSI_IDLE_HIGH;
> >   host->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 32);
> >   host->max_speed_hz = clk_get_rate(spi_engine->ref_clk) / 2;
> >   host->transfer_one_message = spi_engine_transfer_one_message;
>
> I think we need a version check instead of setting the flags unconditionally
> here since older versions of the AXI SPI Engine won't support this feature.

Oh, was not aware of that... Then, we definitely need to do that. Marcelo, only
add my r-b tag with the version change in place.

- Nuno Sá