linux-arm.git - Russell King's ARM Linux kernel tree

Age	Commit message (Collapse)	Author
2025-02-07	spi: offload: add support for hardware triggers	David Lechner
	Extend SPI offloading to support hardware triggers. This allows an arbitrary hardware trigger to be used to start a SPI transfer that was previously set up with spi_optimize_message(). A new struct spi_offload_trigger is introduced that can be used to configure any type of trigger. It has a type discriminator and a union to allow it to be extended in the future. Two trigger types are defined to start with. One is a trigger that indicates that the SPI peripheral is ready to read or write data. The other is a periodic trigger to repeat a SPI message at a fixed rate. There is also a spi_offload_hw_trigger_validate() function that works similar to clk_round_rate(). It basically asks the question of if we enabled the hardware trigger what would the actual parameters be. This can be used to test if the requested trigger type is actually supported by the hardware and for periodic triggers, it can be used to find the actual rate that the hardware is capable of. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Nuno Sa <nuno.sa@analog.com> Signed-off-by: David Lechner <dlechner@baylibre.com> Link: https://patch.msgid.link/20250207-dlech-mainline-spi-engine-offload-2-v8-2-e48a489be48c@baylibre.com Signed-off-by: Mark Brown <broonie@kernel.org>
2025-02-07	spi: add basic support for SPI offloading	David Lechner
	Add the basic infrastructure to support SPI offload providers and consumers. SPI offloading is a feature that allows the SPI controller to perform transfers without any CPU intervention. This is useful, e.g. for high-speed data acquisition. SPI controllers with offload support need to implement the get_offload and put_offload callbacks and can use the devm_spi_offload_alloc() to allocate offload instances. SPI peripheral drivers will call devm_spi_offload_get() to get a reference to the matching offload instance. This offload instance can then be attached to a SPI message to request offloading that message. It is expected that SPI controllers with offload support will check for the offload instance in the SPI message in the ctlr->optimize_message() callback and handle it accordingly. CONFIG_SPI_OFFLOAD is intended to be a select-only option. Both consumer and provider drivers should `select SPI_OFFLOAD` in their Kconfig to ensure that the SPI core is built with offload support. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: Nuno Sa <nuno.sa@analog.com> Signed-off-by: David Lechner <dlechner@baylibre.com> Link: https://patch.msgid.link/20250207-dlech-mainline-spi-engine-offload-2-v8-1-e48a489be48c@baylibre.com Signed-off-by: Mark Brown <broonie@kernel.org>