This series is adding support for SPI controllers and peripherals that
have multiple SPI data lanes (data lanes being independent sets of
SDI/SDO lines, each with their own serializer/deserializer).

This series covers this specific use case:

+--------------+    +---------+
| SPI          |    | SPI     |
| Controller   |    | ADC     |
|              |    |         |
|          CS0 |--->| CS      |
|         SCLK |--->| SCLK    |
|          SDO |--->| SDI     |
|         SDI0 |<---| SDOA    |
|         SDI1 |<---| SDOB    |
|         SDI2 |<---| SDOC    |
|         SDI3 |<---| SDOD    |
+--------------+     +--------+

The ADC is a simultaneous sampling ADC that can convert 4 samples at the
same time. It has 4 data output lines (SDOA-D) that each contain the
data of one of the 4 channels. So it requires a SPI controller with 4
separate deserializers in order to receive all of the information at the
same time.

This should also work for the use case in [1] as well. (Some of the
patches in this series were already submitted there). In that case the
SPI controller is used kind of like it is two separate SPI controllers,
each with its own chip select, clock, and data lines.

[1]: https://lore.kernel.org/linux-spi/20250616220054.3968946-1-sean.anderson@linux.dev/

The DT bindings are a fairly straight-forward mapping of which pins on
the peripheral are connected to which pins on the controller. The SPI
core code parses this and makes the information available to drivers.
When a peripheral driver sees that multiple data lanes are wired up, it
can chose to use them when sending messages.

The SPI message API is a bit higher-level than just specifying the
number of data lines for a SPI transfer though. I did some research on
other SPI controllers that have this feature. They tend to be the kind
meant for connecting to two flash memory chips at the same time but can
be used more generically as well. They generally have the option to
either use one lane at a time (Sean's use case), or can mirror the same
data on multiple lanes (no users of this yet) or can perform striping
of a single data FIFO/DMA stream to/from the two lanes (our use case).

For now, the API assumes that if you want to do mirror/striping, then
you want to use all available data lanes. Otherwise, it just uses the
first data lane for "normal" SPI transfers.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---
Maintainer coordination:

Jonathan has requested an immutable branch from the SPI tree containing
the SPI patches from this series (all but the last two patches) so that
he can pick up the IIO patches.

Given the timing in the release cycle, if the SPI bits make it into the
next merge window, then an immutable branch won't be necessary and we
will pick up the IIO patches after -rc1.

Changes in v6:
- Addressed several review comments in the "spi: support controllers
  with multiple data lanes" patch.
- Fixed some typos in the documentation patch.
- Link to v5: https://lore.kernel.org/r/20260112-spi-add-multi-bus-support-v5-0-295f4f09f6ba@baylibre.com

Changes in v5:
- Fixed up affected dt-bindings for a new SPI controller that was added
  recently.
- Made some clarification and fixes in the documentation in several
  places.
- Fixed parsing of mapping properties.
- Link to v4: https://lore.kernel.org/r/20251219-spi-add-multi-bus-support-v4-0-145dc5204cd8@baylibre.com

Changes in v4:
- New patch to change spi-{rx,tx}-bus-width to array. This will cover
  most use cases.
- Split data-lanes property into spi-{rx,tx}-lane-map. These properties
  are now only needed for special cases instead of being the primary
  property for multi-lane support.
- Didn't pick up Rob's acks since all DT bindings are significantly changed.
- Rework other code to accommodate the above changes.
- New documentation patch.
- Link to v3: https://lore.kernel.org/r/20251201-spi-add-multi-bus-support-v3-0-34e05791de83@baylibre.com

Changes in v3:
- Use existing data-lanes devicetree property name instead of creating a
  new one.
- Renamed "buses" to "lanes" everywhere to match the devicetree property
  name.
- Clarified bindings description about how to specify data lanes.
- Link to v2: https://lore.kernel.org/r/20251107-spi-add-multi-bus-support-v2-0-8a92693314d9@baylibre.com

Changes in v2:
- Renamed devicetree property spi-buses to spi-data-buses. (Driver code
  was already using spi->data_buses, so it matches).
- Fixed a small bug in the AXI ADC driver changes.
- Moved one line of code in the ADC driver changes.
- Link to v1: https://lore.kernel.org/r/20251014-spi-add-multi-bus-support-v1-0-2098c12d6f5f@baylibre.com

---
David Lechner (9):
      spi: dt-bindings: change spi-{rx,tx}-bus-width to arrays
      spi: dt-bindings: add spi-{tx,rx}-lane-map properties
      spi: support controllers with multiple data lanes
      spi: add multi_lane_mode field to struct spi_transfer
      spi: Documentation: add page on multi-lane support
      spi: dt-bindings: adi,axi-spi-engine: add multi-lane support
      spi: axi-spi-engine: support SPI_MULTI_LANE_MODE_STRIPE
      dt-bindings: iio: adc: adi,ad7380: add spi-rx-bus-width property
      iio: adc: ad7380: add support for multiple SPI lanes

 .../bindings/display/panel/sitronix,st7789v.yaml   |   5 +-
 .../devicetree/bindings/iio/adc/adi,ad4030.yaml    |  42 +++-
 .../devicetree/bindings/iio/adc/adi,ad4695.yaml    |   5 +-
 .../devicetree/bindings/iio/adc/adi,ad7380.yaml    |  23 +++
 .../bindings/spi/adi,axi-spi-engine.yaml           |  15 ++
 .../bindings/spi/allwinner,sun4i-a10-spi.yaml      |   6 +-
 .../bindings/spi/allwinner,sun6i-a31-spi.yaml      |   6 +-
 .../bindings/spi/andestech,ae350-spi.yaml          |   6 +-
 .../bindings/spi/nvidia,tegra210-quad.yaml         |   6 +-
 .../bindings/spi/spi-peripheral-props.yaml         |  40 +++-
 Documentation/spi/index.rst                        |   1 +
 Documentation/spi/multiple-data-lanes.rst          | 217 +++++++++++++++++++++
 drivers/iio/adc/ad7380.c                           |  51 +++--
 drivers/spi/spi-axi-spi-engine.c                   | 145 +++++++++++++-
 drivers/spi/spi.c                                  | 144 +++++++++++++-
 include/linux/spi/spi.h                            |  30 +++
 16 files changed, 702 insertions(+), 40 deletions(-)
---
base-commit: a0c666c25aeefd16f4b088c6549a6fb6b65a8a1d
change-id: 20250815-spi-add-multi-bus-support-1b35d05c54f6

Best regards,
-- 
David Lechner <dlechner@baylibre.com>

On Fri, Jan 23, 2026 at 02:37:23PM -0600, David Lechner wrote:
> This series is adding support for SPI controllers and peripherals that
> have multiple SPI data lanes (data lanes being independent sets of
> SDI/SDO lines, each with their own serializer/deserializer).

The following changes since commit 8f0b4cce4481fb22653697cced8d0d04027cb1e8:

  Linux 6.19-rc1 (2025-12-14 16:05:07 +1200)

are available in the Git repository at:

  https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git tags/spi-multi-lane

for you to fetch changes up to 0ec5ed7c95d1ba6a74491928ff38abb351dbed36:

  spi: axi-spi-engine: support SPI_MULTI_LANE_MODE_STRIPE (2026-02-02 12:12:47 +0000)

----------------------------------------------------------------
spi: Add multi-lane support

This series is adding support for SPI controllers and peripherals that
have multiple SPI data lanes (data lanes being independent sets of
SDI/SDO lines, each with their own serializer/deserializer).

----------------------------------------------------------------
CL Wang (1):
      spi: dt-bindings: Add support for ATCSPI200 SPI controller

David Lechner (7):
      spi: dt-bindings: change spi-{rx,tx}-bus-width to arrays
      spi: dt-bindings: add spi-{tx,rx}-lane-map properties
      spi: support controllers with multiple data lanes
      spi: add multi_lane_mode field to struct spi_transfer
      spi: Documentation: add page on multi-lane support
      spi: dt-bindings: adi,axi-spi-engine: add multi-lane support
      spi: axi-spi-engine: support SPI_MULTI_LANE_MODE_STRIPE

 .../bindings/display/panel/sitronix,st7789v.yaml   |   5 +-
 .../devicetree/bindings/iio/adc/adi,ad4030.yaml    |  42 +++-
 .../devicetree/bindings/iio/adc/adi,ad4695.yaml    |   5 +-
 .../bindings/spi/adi,axi-spi-engine.yaml           |  15 ++
 .../bindings/spi/allwinner,sun4i-a10-spi.yaml      |   6 +-
 .../bindings/spi/allwinner,sun6i-a31-spi.yaml      |   6 +-
 .../bindings/spi/andestech,ae350-spi.yaml          |  87 +++++++++
 .../bindings/spi/nvidia,tegra210-quad.yaml         |   6 +-
 .../bindings/spi/spi-peripheral-props.yaml         |  40 +++-
 Documentation/spi/index.rst                        |   1 +
 Documentation/spi/multiple-data-lanes.rst          | 217 +++++++++++++++++++++
 drivers/spi/spi-axi-spi-engine.c                   | 145 +++++++++++++-
 drivers/spi/spi.c                                  | 144 +++++++++++++-
 include/linux/spi/spi.h                            |  30 +++
 14 files changed, 724 insertions(+), 25 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/spi/andestech,ae350-spi.yaml
 create mode 100644 Documentation/spi/multiple-data-lanes.rst

On Mon, 2 Feb 2026 23:22:59 +0000
Mark Brown <broonie@kernel.org> wrote:

> On Fri, Jan 23, 2026 at 02:37:23PM -0600, David Lechner wrote:
> > This series is adding support for SPI controllers and peripherals that
> > have multiple SPI data lanes (data lanes being independent sets of
> > SDI/SDO lines, each with their own serializer/deserializer).  
> 
> The following changes since commit 8f0b4cce4481fb22653697cced8d0d04027cb1e8:
> 
>   Linux 6.19-rc1 (2025-12-14 16:05:07 +1200)
> 
> are available in the Git repository at:
> 
>   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git tags/spi-multi-lane

Thanks. Given timing, I plan to hold the last two patches until next cycle.
I'll pick them up nice and early though so they'll be in next shortly after
rc1.

Thanks,

Jonathan

> 
> for you to fetch changes up to 0ec5ed7c95d1ba6a74491928ff38abb351dbed36:
> 
>   spi: axi-spi-engine: support SPI_MULTI_LANE_MODE_STRIPE (2026-02-02 12:12:47 +0000)
> 
> ----------------------------------------------------------------
> spi: Add multi-lane support
> 
> This series is adding support for SPI controllers and peripherals that
> have multiple SPI data lanes (data lanes being independent sets of
> SDI/SDO lines, each with their own serializer/deserializer).
> 
> ----------------------------------------------------------------
> CL Wang (1):
>       spi: dt-bindings: Add support for ATCSPI200 SPI controller
> 
> David Lechner (7):
>       spi: dt-bindings: change spi-{rx,tx}-bus-width to arrays
>       spi: dt-bindings: add spi-{tx,rx}-lane-map properties
>       spi: support controllers with multiple data lanes
>       spi: add multi_lane_mode field to struct spi_transfer
>       spi: Documentation: add page on multi-lane support
>       spi: dt-bindings: adi,axi-spi-engine: add multi-lane support
>       spi: axi-spi-engine: support SPI_MULTI_LANE_MODE_STRIPE
> 
>  .../bindings/display/panel/sitronix,st7789v.yaml   |   5 +-
>  .../devicetree/bindings/iio/adc/adi,ad4030.yaml    |  42 +++-
>  .../devicetree/bindings/iio/adc/adi,ad4695.yaml    |   5 +-
>  .../bindings/spi/adi,axi-spi-engine.yaml           |  15 ++
>  .../bindings/spi/allwinner,sun4i-a10-spi.yaml      |   6 +-
>  .../bindings/spi/allwinner,sun6i-a31-spi.yaml      |   6 +-
>  .../bindings/spi/andestech,ae350-spi.yaml          |  87 +++++++++
>  .../bindings/spi/nvidia,tegra210-quad.yaml         |   6 +-
>  .../bindings/spi/spi-peripheral-props.yaml         |  40 +++-
>  Documentation/spi/index.rst                        |   1 +
>  Documentation/spi/multiple-data-lanes.rst          | 217 +++++++++++++++++++++
>  drivers/spi/spi-axi-spi-engine.c                   | 145 +++++++++++++-
>  drivers/spi/spi.c                                  | 144 +++++++++++++-
>  include/linux/spi/spi.h                            |  30 +++
>  14 files changed, 724 insertions(+), 25 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/spi/andestech,ae350-spi.yaml
>  create mode 100644 Documentation/spi/multiple-data-lanes.rst
>

On Fri, 23 Jan 2026 14:37:23 -0600, David Lechner wrote:
> This series is adding support for SPI controllers and peripherals that
> have multiple SPI data lanes (data lanes being independent sets of
> SDI/SDO lines, each with their own serializer/deserializer).
> 
> This series covers this specific use case:
> 
> +--------------+    +---------+
> | SPI          |    | SPI     |
> | Controller   |    | ADC     |
> |              |    |         |
> |          CS0 |--->| CS      |
> |         SCLK |--->| SCLK    |
> |          SDO |--->| SDI     |
> |         SDI0 |<---| SDOA    |
> |         SDI1 |<---| SDOB    |
> |         SDI2 |<---| SDOC    |
> |         SDI3 |<---| SDOD    |
> +--------------+     +--------+
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git for-next

Thanks!

[1/9] spi: dt-bindings: change spi-{rx,tx}-bus-width to arrays
      commit: 37bb4033e48b8a0ddee66fd77f9e12a9a930681b
[2/9] spi: dt-bindings: add spi-{tx,rx}-lane-map properties
      commit: 31eab8425110b933dd7c818809cb4ffa3b2c6d82
[3/9] spi: support controllers with multiple data lanes
      commit: 002d561f89c3a61ee17d38070e48ea4eb1243732
[4/9] spi: add multi_lane_mode field to struct spi_transfer
      commit: 5621a7bc851658ea2f8e015060f8bb5d27739b06
[5/9] spi: Documentation: add page on multi-lane support
      commit: 05c3bd745bb065223201824f0044455558541bdc
[6/9] spi: dt-bindings: adi,axi-spi-engine: add multi-lane support
      commit: 2e706f86a5aa94702694774efb7d8b151c6d724f
[7/9] spi: axi-spi-engine: support SPI_MULTI_LANE_MODE_STRIPE
      commit: 0ec5ed7c95d1ba6a74491928ff38abb351dbed36

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark