From 002d561f89c3a61ee17d38070e48ea4eb1243732 Mon Sep 17 00:00:00 2001 From: David Lechner Date: Fri, 23 Jan 2026 14:37:26 -0600 Subject: spi: support controllers with multiple data lanes Add support for SPI controllers with multiple physical SPI data lanes. (A data lane in this context means lines connected to a serializer, so a controller with two data lanes would have two serializers in a single controller). This is common in the type of controller that can be used with parallel flash memories, but can be used for general purpose SPI as well. To indicate support, a controller just needs to set ctlr->num_data_lanes to something greater than 1. Peripherals indicate which lane they are connected to via device tree (ACPI support can be added if needed). The spi-{tx,rx}-bus-width DT properties can now be arrays. The length of the array indicates the number of data lanes, and each element indicates the bus width of that lane. For now, we restrict all lanes to have the same bus width to keep things simple. Support for an optional controller lane mapping property is also implemented. Signed-off-by: David Lechner Link: https://patch.msgid.link/20260123-spi-add-multi-bus-support-v6-3-12af183c06eb@baylibre.com Signed-off-by: Mark Brown --- include/linux/spi/spi.h | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'include') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index cb2c2df31089..9fc5a9c012e2 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -23,6 +23,9 @@ /* Max no. of CS supported per spi device */ #define SPI_DEVICE_CS_CNT_MAX 4 +/* Max no. of data lanes supported per spi device */ +#define SPI_DEVICE_DATA_LANE_CNT_MAX 8 + struct dma_chan; struct software_node; struct ptp_system_timestamp; @@ -174,6 +177,10 @@ extern void spi_transfer_cs_change_delay_exec(struct spi_message *msg, * @cs_index_mask: Bit mask of the active chipselect(s) in the chipselect array * @cs_gpiod: Array of GPIO descriptors of the corresponding chipselect lines * (optional, NULL when not using a GPIO line) + * @tx_lane_map: Map of peripheral lanes (index) to controller lanes (value). + * @num_tx_lanes: Number of transmit lanes wired up. + * @rx_lane_map: Map of peripheral lanes (index) to controller lanes (value). + * @num_rx_lanes: Number of receive lanes wired up. * * A @spi_device is used to interchange data between an SPI target device * (usually a discrete chip) and CPU memory. @@ -242,6 +249,12 @@ struct spi_device { struct gpio_desc *cs_gpiod[SPI_DEVICE_CS_CNT_MAX]; /* Chip select gpio desc */ + /* Multi-lane SPI controller support. */ + u8 tx_lane_map[SPI_DEVICE_DATA_LANE_CNT_MAX]; + u8 num_tx_lanes; + u8 rx_lane_map[SPI_DEVICE_DATA_LANE_CNT_MAX]; + u8 num_rx_lanes; + /* * Likely need more hooks for more protocol options affecting how * the controller talks to each chip, like: @@ -401,6 +414,7 @@ extern struct spi_device *spi_new_ancillary_device(struct spi_device *spi, u8 ch * SPI targets, and are numbered from zero to num_chipselects. * each target has a chipselect signal, but it's common that not * every chipselect is connected to a target. + * @num_data_lanes: Number of data lanes supported by this controller. Default is 1. * @dma_alignment: SPI controller constraint on DMA buffers alignment. * @mode_bits: flags understood by this controller driver * @buswidth_override_bits: flags to override for this controller driver @@ -576,6 +590,14 @@ struct spi_controller { */ u16 num_chipselect; + /* + * Some specialized SPI controllers can have more than one physical + * data lane interface per controller (each having it's own serializer). + * This specifies the number of data lanes in that case. Other + * controllers do not need to set this (defaults to 1). + */ + u16 num_data_lanes; + /* Some SPI controllers pose alignment requirements on DMAable * buffers; let protocol drivers know about these requirements. */ -- cgit v1.2.3 From 5621a7bc851658ea2f8e015060f8bb5d27739b06 Mon Sep 17 00:00:00 2001 From: David Lechner Date: Fri, 23 Jan 2026 14:37:27 -0600 Subject: spi: add multi_lane_mode field to struct spi_transfer MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a new multi_lane_mode field to struct spi_transfer to allow peripherals that support multiple SPI lanes to be used with a single SPI controller. This requires both the peripheral and the controller to have multiple serializers connected to separate data lanes. It could also be used with a single controller and multiple peripherals that are functioning as a single logical device (similar to parallel memories). Acked-by: Nuno Sá Acked-by: Marcelo Schmitt Reviewed-by: Jonathan Cameron Signed-off-by: David Lechner Link: https://patch.msgid.link/20260123-spi-add-multi-bus-support-v6-4-12af183c06eb@baylibre.com Signed-off-by: Mark Brown --- include/linux/spi/spi.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 9fc5a9c012e2..39681f7e063b 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -981,6 +981,8 @@ struct spi_res { * (SPI_NBITS_SINGLE) is used. * @rx_nbits: number of bits used for reading. If 0 the default * (SPI_NBITS_SINGLE) is used. + * @multi_lane_mode: How to serialize data on multiple lanes. One of the + * SPI_MULTI_LANE_MODE_* values. * @len: size of rx and tx buffers (in bytes) * @speed_hz: Select a speed other than the device default for this * transfer. If 0 the default (from @spi_device) is used. @@ -1117,6 +1119,12 @@ struct spi_transfer { unsigned cs_change:1; unsigned tx_nbits:4; unsigned rx_nbits:4; + +#define SPI_MULTI_LANE_MODE_SINGLE 0 /* only use single lane */ +#define SPI_MULTI_LANE_MODE_STRIPE 1 /* one data word per lane */ +#define SPI_MULTI_LANE_MODE_MIRROR 2 /* same word sent on all lanes */ + unsigned multi_lane_mode: 2; + unsigned timestamped:1; bool dtr_mode; #define SPI_NBITS_SINGLE 0x01 /* 1-bit transfer */ -- cgit v1.2.3