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spi: Adding a new configuration bit for the frame format

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So TI will no longer be the only frame format available, though it will
still be the default one. It will be possible to select the Motorola
frame format when relevant.

Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>
This commit is contained in:
Tomasz Bursztyka 2021-11-02 10:38:47 +01:00 • committed by Carles Cufí
commit bc1124cf86
1 changed files with 17 additions and 1 deletions
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18
include/drivers/spi.h
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@ -117,6 +117,22 @@ extern "C" {
#define SPI_CS_ACTIVE_HIGH BIT(14)
/** @} */
/**
* @name SPI Frame Format
* @{
*
* 2 frame formats are exposed: Motorola and TI.
* The main difference is the behavior of the CS line. In Motorala it stays
* active the whole transfer. In TI, it's active only one serial clock period
* prior to actually make the transfer, it is thus inactive during the transfer,
* which ends when the clocks ends as well.
* By default, as it is the most commonly used, the Motorola frame format
* will prevail.
*/
#define SPI_FRAME_FORMAT_MOTOROLA (0U << 15)
#define SPI_FRAME_FORMAT_TI (1U << 15)
/** @} */
/**
* @name SPI MISO lines (if @kconfig{CONFIG_SPI_EXTENDED_MODES} is enabled)
* @{
@ -248,7 +264,7 @@ struct spi_cs_control {
* cs_hold [ 12 ] - Hold on the CS line if possible.
* lock_on [ 13 ] - Keep resource locked for the caller.
* cs_active_high [ 14 ] - Active high CS logic.
* reserved [ 15 ] - reserved for future use.
* format [ 15 ] - Motorola or TI frame format (optional).
* if @kconfig{CONFIG_SPI_EXTENDED_MODES} is defined:
* lines [ 16 : 17 ] - MISO lines: Single/Dual/Quad/Octal.
* reserved [ 18 : 31 ] - reserved for future use.