mirror_ubuntu-kernels/include/uapi/linux/spi/spi.h
Boerge Struempfel a45baa079e
spi: add SPI_MOSI_IDLE_LOW mode bit
Some spi controller switch the mosi line to high, whenever they are
idle. This may not be desired in all use cases. For example neopixel
leds can get confused and flicker due to misinterpreting the idle state.
Therefore, we introduce a new spi-mode bit, with which the idle behaviour
can be overwritten on a per device basis.

Signed-off-by: Boerge Struempfel <boerge.struempfel@gmail.com>
Link: https://lore.kernel.org/r/20230530141641.1155691-2-boerge.struempfel@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2023-05-30 15:20:08 +01:00

44 lines
1.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
#ifndef _UAPI_SPI_H
#define _UAPI_SPI_H
#include <linux/const.h>
#define SPI_CPHA _BITUL(0) /* clock phase */
#define SPI_CPOL _BITUL(1) /* clock polarity */
#define SPI_MODE_0 (0|0) /* (original MicroWire) */
#define SPI_MODE_1 (0|SPI_CPHA)
#define SPI_MODE_2 (SPI_CPOL|0)
#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
#define SPI_MODE_X_MASK (SPI_CPOL|SPI_CPHA)
#define SPI_CS_HIGH _BITUL(2) /* chipselect active high? */
#define SPI_LSB_FIRST _BITUL(3) /* per-word bits-on-wire */
#define SPI_3WIRE _BITUL(4) /* SI/SO signals shared */
#define SPI_LOOP _BITUL(5) /* loopback mode */
#define SPI_NO_CS _BITUL(6) /* 1 dev/bus, no chipselect */
#define SPI_READY _BITUL(7) /* slave pulls low to pause */
#define SPI_TX_DUAL _BITUL(8) /* transmit with 2 wires */
#define SPI_TX_QUAD _BITUL(9) /* transmit with 4 wires */
#define SPI_RX_DUAL _BITUL(10) /* receive with 2 wires */
#define SPI_RX_QUAD _BITUL(11) /* receive with 4 wires */
#define SPI_CS_WORD _BITUL(12) /* toggle cs after each word */
#define SPI_TX_OCTAL _BITUL(13) /* transmit with 8 wires */
#define SPI_RX_OCTAL _BITUL(14) /* receive with 8 wires */
#define SPI_3WIRE_HIZ _BITUL(15) /* high impedance turnaround */
#define SPI_RX_CPHA_FLIP _BITUL(16) /* flip CPHA on Rx only xfer */
#define SPI_MOSI_IDLE_LOW _BITUL(17) /* leave mosi line low when idle */
/*
* All the bits defined above should be covered by SPI_MODE_USER_MASK.
* The SPI_MODE_USER_MASK has the SPI_MODE_KERNEL_MASK counterpart in
* 'include/linux/spi/spi.h'. The bits defined here are from bit 0 upwards
* while in SPI_MODE_KERNEL_MASK they are from the other end downwards.
* These bits must not overlap. A static assert check should make sure of that.
* If adding extra bits, make sure to increase the bit index below as well.
*/
#define SPI_MODE_USER_MASK (_BITUL(18) - 1)
#endif /* _UAPI_SPI_H */