Re: [PATCH v2 0/3] Add multi mode support for omap-mcspi

[Louis Chauvet]

Hello Mark,

Given how far we already are in the current cycle I suppose this series 
will only be considered after -rc1, will you want me to re-send or will 
it stay on your stack? I know some maintainers prefer contributors to 
re-send and others don't, so let met know what suits best your workflow.

Thanks!
Louis

Le 23/02/24 - 10:32, Louis Chauvet a écrit :
> This series adds the support for the omap-mcspi multi mode which allows
> sending SPI messages with a shorter delay between CS and the message.
> 
> One drawback of the multi-mode is that the CS is raised between each word, 
> so it can only be used with messages containing 1 word transfers and 
> asking for cs_change. Few devices, like FPGAs, may easily workaround this 
> limitation.
> 
> The first patch removes the current implementation, which is working, but 
> don't comply with what is asked in the spi transfer (The CS is raised by 
> the hardware regardless of cs_change state). No drivers or board file use this 
> implementation upstream.
> 
> The second patch adds the implementation of the multi-mode, which complies 
> with what is asked in the SPI message.
> 
> The third patch is the suggested optimization for using MULTI mode in more 
> situations.
> 
> Signed-off-by: Louis Chauvet <louis.chauvet@xxxxxxxxxxx>
> ---
> Changes in v2:
> - Updated the commit line for the first patch to use the correct format;
> - Updated the commit message for the second patch, adding precision on how
>   the controler works;
> - Added the suggestion from Mark Brown to merge multiple transfers word 
>   into one when applicable;
> - Link to v1: https://lore.kernel.org/r/20240126-spi-omap2-mcspi-multi-mode-v1-0-d143d33f0fe0@xxxxxxxxxxx
> 
> ---
> Louis Chauvet (3):
>       spi: spi-omap2-mcspi.c: revert "Toggle CS after each word"
>       spi: omap2-mcspi: Add support for MULTI-mode
>       spi: omap2-mcpsi: Enable MULTI-mode in more situations
> 
>  drivers/spi/spi-omap2-mcspi.c                 | 96 +++++++++++++++++++++------
>  include/linux/platform_data/spi-omap2-mcspi.h |  3 -
>  2 files changed, 75 insertions(+), 24 deletions(-)
> ---
> base-commit: 41bccc98fb7931d63d03f326a746ac4d429c1dd3
> change-id: 20240126-spi-omap2-mcspi-multi-mode-e62f68b78ad3
> 
> Best regards,
> -- 
> Louis Chauvet <louis.chauvet@xxxxxxxxxxx>
> 
> 

-- 
Louis Chauvet, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com