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2024-07-29spi: Enable controllers to extend the SPI protocol with MOSI idle configurationMarcelo Schmitt
The behavior of an SPI controller data output line (SDO or MOSI or COPI (Controller Output Peripheral Input) for disambiguation) is usually not specified when the controller is not clocking out data on SCLK edges. However, there do exist SPI peripherals that require specific MOSI line state when data is not being clocked out of the controller. Conventional SPI controllers may set the MOSI line on SCLK edges then bring it low when no data is going out or leave the line the state of the last transfer bit. More elaborated controllers are capable to set the MOSI idle state according to different configurable levels and thus are more suitable for interfacing with demanding peripherals. Add SPI mode bits to allow peripherals to request explicit MOSI idle state when needed. When supporting a particular MOSI idle configuration, the data output line state is expected to remain at the configured level when the controller is not clocking out data. When a device that needs a specific MOSI idle state is identified, its driver should request the MOSI idle configuration by setting the proper SPI mode bit. Acked-by: Nuno Sa <nuno.sa@analog.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-by: David Lechner <dlechner@baylibre.com> Tested-by: David Lechner <dlechner@baylibre.com> Signed-off-by: Marcelo Schmitt <marcelo.schmitt@analog.com> Link: https://patch.msgid.link/9802160b5e5baed7f83ee43ac819cb757a19be55.1720810545.git.marcelo.schmitt@analog.com Signed-off-by: Mark Brown <broonie@kernel.org>
2024-04-02spi: docs: drop driver owner initializationKrzysztof Kozlowski
Core in spi_register_driver() already sets the .owner, so driver does not need to. Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> Link: https://msgid.link/r/20240328203927.156184-1-krzysztof.kozlowski@linaro.org Signed-off-by: Mark Brown <broonie@kernel.org>
2024-03-25spi: remove struct spi_message::is_dma_mappedDavid Lechner
There are no more users of the deprecated is_dma_mapped in struct spi_message so it can be removed. References in documentation and comments are also removed. A few similar checks if xfer->tx_dma or xfer->rx_dma are not NULL are also removed since these are now guaranteed to be NULL because they were previously set only if is_dma_mapped was true. Signed-off-by: David Lechner <dlechner@baylibre.com> Link: https://msgid.link/r/20240325-spi-remove-is_dma_mapped-v2-1-d08d62b61f1c@baylibre.com Signed-off-by: Mark Brown <broonie@kernel.org>
2024-02-19spi: spi-summary.rst: fix underline lengthRandy Dunlap
The change to use "target" requires an underline to be extended by one more character to fix a documentation build warning: Documentation/spi/spi-summary.rst:274: WARNING: Title underline too short. Declare target Devices ^^^^^^^^^^^^^^^^^^^^^ Fixes: hash ("spi: Update the "master/slave" terminology in documentation") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Dhruva Gole <d-gole@ti.com> Cc: Mark Brown <broonie@kernel.org> Cc: linux-spi@vger.kernel.org Reviewed-by: Dhruva Gole <d-gole@ti.com> Link: https://msgid.link/r/20240216051637.10920-1-rdunlap@infradead.org Signed-off-by: Mark Brown <broonie@kernel.org>
2024-02-15spi: Update the "master/slave" terminology in documentationDhruva Gole
Update the master/slave terminology wherever possible to adopt usage of the controller/host/target. Some parts have been left untouched because they were sysfs entries and will probably end up being inaccurate if simply replaced here. Signed-off-by: Dhruva Gole <d-gole@ti.com> Link: https://msgid.link/r/20240215085404.1711976-1-d-gole@ti.com Signed-off-by: Mark Brown <broonie@kernel.org>
2024-02-08Documentation: spi: Update documentation for renaming "master" to "controller"Uwe Kleine-König
In commit 8caab75fd2c2 ("spi: Generalize SPI "master" to "controller"") some functions and struct members were renamed. Adapt the documentation accordingly. Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/3d643e22cacff12d3918ad5224baa1d01813d03b.1707324794.git.u.kleine-koenig@pengutronix.de Signed-off-by: Mark Brown <broonie@kernel.org>
2023-03-14spi: docs: adjust summary to CONFIG_SYSFS_DEPRECATED removalLukas Bulwahn
With commit 721da5cee9d4 ("driver core: remove CONFIG_SYSFS_DEPRECATED and CONFIG_SYSFS_DEPRECATED_V2"), ./scripts/checkkconfigsymbols.py indicated an unresolved reference to the config SYSFS_DEPRECATED in the SPI summary documentation. Simply, delete the sentence referring to the removed config there. Also update the documentation, as these sys/class entries should always be symlinks, as the commit message of the commit above suggests. Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/20230314075609.5232-1-lukas.bulwahn@gmail.com Signed-off-by: Mark Brown <broonie@kernel.org>
2023-01-27spi: correct spellingRandy Dunlap
Correct spelling problems for Documentation/spi/ as reported by codespell. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lore.kernel.org/r/20230127064005.1558-28-rdunlap@infradead.org Signed-off-by: Mark Brown <broonie@kernel.org>
2021-10-07spi: Remove unused function spi_busnum_to_master()Uwe Kleine-König
The last user is gone since commit 2962db71c703 ("staging/fbtft: Remove fbtft_device") in 2019. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20211007121415.2401638-3-u.kleine-koenig@pengutronix.de Signed-off-by: Mark Brown <broonie@kernel.org>
2021-03-12spi: docs: update info about 'delay_usecs'Alexandru Ardelean
The 'delay_usecs' field is no longer present on the spi_transfer struct. This change updates the doc to mention the usage of the (relatively) new 'delay' field. Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com> Link: https://lore.kernel.org/r/20210308145502.1075689-11-aardelean@deviqon.com Signed-off-by: Mark Brown <broonie@kernel.org>
2019-07-31spi: docs: convert to ReST and add it to the kABI booksetMauro Carvalho Chehab
While there's one file there with briefily describes the uAPI, the documentation was written just like most subsystems: focused on kernel developers. So, add it together with driver-api books. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio Signed-off-by: Jonathan Corbet <corbet@lwn.net>