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spidev.h
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/* * include/linux/spi/spidev.h * * Copyright (C) 2006 SWAPP * Andrea Paterniani <a.paterniani@swapp-eng.it> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #ifndef SPIDEV_H #define SPIDEV_H #include <linux/types.h> /* User space versions of kernel symbols for SPI clocking modes, * matching <linux/spi/spi.h> */ #define SPI_CPHA 0x01 #define SPI_CPOL 0x02 #define SPI_MODE_0 (0|0) #define SPI_MODE_1 (0|SPI_CPHA) #define SPI_MODE_2 (SPI_CPOL|0) #define SPI_MODE_3 (SPI_CPOL|SPI_CPHA) #define SPI_CS_HIGH 0x04 #define SPI_LSB_FIRST 0x08 #define SPI_3WIRE 0x10 #define SPI_LOOP 0x20 #define SPI_NO_CS 0x40 #define SPI_READY 0x80 /*---------------------------------------------------------------------------*/ /* IOCTL commands */ #define SPI_IOC_MAGIC 'k' /** * struct spi_ioc_transfer - describes a single SPI transfer * @tx_buf: Holds pointer to userspace buffer with transmit data, or null. * If no data is provided, zeroes are shifted out. * @rx_buf: Holds pointer to userspace buffer for receive data, or null. * @len: Length of tx and rx buffers, in bytes. * @speed_hz: Temporary override of the device's bitrate. * @bits_per_word: Temporary override of the device's wordsize. * @delay_usecs: If nonzero, how long to delay after the last bit transfer * before optionally deselecting the device before the next transfer. * @cs_change: True to deselect device before starting the next transfer. * * This structure is mapped directly to the kernel spi_transfer structure; * the fields have the same meanings, except of course that the pointers * are in a different address space (and may be of different sizes in some * cases, such as 32-bit i386 userspace over a 64-bit x86_64 kernel). * Zero-initialize the structure, including currently unused fields, to * accommodate potential future updates. * * SPI_IOC_MESSAGE gives userspace the equivalent of kernel spi_sync(). * Pass it an array of related transfers, they'll execute together. * Each transfer may be half duplex (either direction) or full duplex. * * struct spi_ioc_transfer mesg[4]; * ... * status = ioctl(fd, SPI_IOC_MESSAGE(4), mesg); * * So for example one transfer might send a nine bit command (right aligned * in a 16-bit word), the next could read a block of 8-bit data before * terminating that command by temporarily deselecting the chip; the next * could send a different nine bit command (re-selecting the chip), and the * last transfer might write some register values. */ struct spi_ioc_transfer { __u64 tx_buf; __u64 rx_buf; __u32 len; __u32 speed_hz; __u16 delay_usecs; __u8 bits_per_word; __u8 cs_change; __u32 pad; /* If the contents of 'struct spi_ioc_transfer' ever change * incompatibly, then the ioctl number (currently 0) must change; * ioctls with constant size fields get a bit more in the way of * error checking than ones (like this) where that field varies. * * NOTE: struct layout is the same in 64bit and 32bit userspace. */ }; /* not all platforms use <asm-generic/ioctl.h> or _IOC_TYPECHECK() ... */ #define SPI_MSGSIZE(N) \ ((((N)*(sizeof (struct spi_ioc_transfer))) < (1 << _IOC_SIZEBITS)) \ ? ((N)*(sizeof (struct spi_ioc_transfer))) : 0) #define SPI_IOC_MESSAGE(N) _IOW(SPI_IOC_MAGIC, 0, char[SPI_MSGSIZE(N)]) /* Read / Write of SPI mode (SPI_MODE_0..SPI_MODE_3) */ #define SPI_IOC_RD_MODE _IOR(SPI_IOC_MAGIC, 1, __u8) #define SPI_IOC_WR_MODE _IOW(SPI_IOC_MAGIC, 1, __u8) /* Read / Write SPI bit justification */ #define SPI_IOC_RD_LSB_FIRST _IOR(SPI_IOC_MAGIC, 2, __u8) #define SPI_IOC_WR_LSB_FIRST _IOW(SPI_IOC_MAGIC, 2, __u8) /* Read / Write SPI device word length (1..N) */ #define SPI_IOC_RD_BITS_PER_WORD _IOR(SPI_IOC_MAGIC, 3, __u8) #define SPI_IOC_WR_BITS_PER_WORD _IOW(SPI_IOC_MAGIC, 3, __u8) /* Read / Write SPI device default max speed hz */ #define SPI_IOC_RD_MAX_SPEED_HZ _IOR(SPI_IOC_MAGIC, 4, __u32) #define SPI_IOC_WR_MAX_SPEED_HZ _IOW(SPI_IOC_MAGIC, 4, __u32) #endif /* SPIDEV_H */