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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

/* 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

/*---------------------------------------------------------------------------*/

/* 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

 * accomodate 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 */