Re: [PATCH 0/6] spi: add multi-CS and per-transfer lane mask support

[Nuno Sá]

On Tue, Jul 14, 2026 at 02:55:31AM -0300, Jonathan Santos wrote:
> This series introduces two SPI subsystem features: per-transfer chipselect
> masks and multi-CS device support. Together they address the multi-device
> setup described in [1] and the limitation noted in [2], where no SPI
> controller completely handles logical chip selects beyond the first one.
> 
> The first part of the set addresses multi-CS support. Some SPI controllers
> can assert multiple chip selects simultaneously, but the existing code
> hardcoded CS index 0 in both spi_set_cs() and of_spi_parse_dt(),
> preventing this from working.
> 
> The second part addresses dynamic lane selection for STRIPE mode. In
> SPI_MULTI_LANE_MODE_STRIPE, all available lanes are currently always
> active. Some peripherals need to select a different subset of rx/tx lanes
> per transfer. New fields are added to the spi_transfer struct to allow
> drivers to specify which lanes to use for each transfer. The documentation
> is also updated to describe this new behavior.
> 
> [1]: https://lore.kernel.org/linux-iio/af0EGv172ZMl%2F6N5@xxxxxxxxxxxxxxxxxxxxxxxxxx/T/#t
> [2]: https://lore.kernel.org/all/20250915183725.219473-1-jonas.gorski@xxxxxxxxx/
> 
> Jonathan Santos (6):
>   spi: support simultaneous assertion of multiple CS
>   spi: add per-transfer CS mask
>   spi: spi-engine-ex: Add support for multi-CS devices
>   spi: Documentation: multiple-data-lanes: describe rx and tx lane mask
>   spi: add rx and tx lane mask to spi_transfer struct
>   spi: axi-spi-engine: add support for dynamic multi-lane selection

It would be nice to include an actual user for this in the series.

- Nuno Sá

> 
>  Documentation/spi/multiple-data-lanes.rst |  30 ++++++
>  drivers/spi/spi-axi-spi-engine.c          | 106 +++++++++++++++++-----
>  drivers/spi/spi.c                         |  97 +++++++++++++++++---
>  include/linux/spi/spi.h                   |  12 +++
>  4 files changed, 206 insertions(+), 39 deletions(-)
> 
> 
> base-commit: 093239070573637ad2b4cb56abc9c4c7ee109294
> -- 
> 2.34.1
>