tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * include/linux/spi/spidev.h
3 *
4 * Copyright (C) 2006 SWAPP
5 * Andrea Paterniani <a.paterniani@swapp-eng.it>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21
22#ifndef SPIDEV_H
23#define SPIDEV_H
24
25#include <linux/types.h>
26
27/* User space versions of kernel symbols for SPI clocking modes,
28 * matching <linux/spi/spi.h>
29 */
30
31#define SPI_CPHA 0x01
32#define SPI_CPOL 0x02
33
34#define SPI_MODE_0 (0|0)
35#define SPI_MODE_1 (0|SPI_CPHA)
36#define SPI_MODE_2 (SPI_CPOL|0)
37#define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
38
39#define SPI_CS_HIGH 0x04
40#define SPI_LSB_FIRST 0x08
41#define SPI_3WIRE 0x10
42#define SPI_LOOP 0x20
43
44/*---------------------------------------------------------------------------*/
45
46/* IOCTL commands */
47
48#define SPI_IOC_MAGIC 'k'
49
50/**
51 * struct spi_ioc_transfer - describes a single SPI transfer
52 * @tx_buf: Holds pointer to userspace buffer with transmit data, or null.
53 * If no data is provided, zeroes are shifted out.
54 * @rx_buf: Holds pointer to userspace buffer for receive data, or null.
55 * @len: Length of tx and rx buffers, in bytes.
56 * @speed_hz: Temporary override of the device's bitrate.
57 * @bits_per_word: Temporary override of the device's wordsize.
58 * @delay_usecs: If nonzero, how long to delay after the last bit transfer
59 * before optionally deselecting the device before the next transfer.
60 * @cs_change: True to deselect device before starting the next transfer.
61 *
62 * This structure is mapped directly to the kernel spi_transfer structure;
63 * the fields have the same meanings, except of course that the pointers
64 * are in a different address space (and may be of different sizes in some
65 * cases, such as 32-bit i386 userspace over a 64-bit x86_64 kernel).
66 * Zero-initialize the structure, including currently unused fields, to
67 * accomodate potential future updates.
68 *
69 * SPI_IOC_MESSAGE gives userspace the equivalent of kernel spi_sync().
70 * Pass it an array of related transfers, they'll execute together.
71 * Each transfer may be half duplex (either direction) or full duplex.
72 *
73 * struct spi_ioc_transfer mesg[4];
74 * ...
75 * status = ioctl(fd, SPI_IOC_MESSAGE(4), mesg);
76 *
77 * So for example one transfer might send a nine bit command (right aligned
78 * in a 16-bit word), the next could read a block of 8-bit data before
79 * terminating that command by temporarily deselecting the chip; the next
80 * could send a different nine bit command (re-selecting the chip), and the
81 * last transfer might write some register values.
82 */
83struct spi_ioc_transfer {
84 __u64 tx_buf;
85 __u64 rx_buf;
86
87 __u32 len;
88 __u32 speed_hz;
89
90 __u16 delay_usecs;
91 __u8 bits_per_word;
92 __u8 cs_change;
93 __u32 pad;
94
95 /* If the contents of 'struct spi_ioc_transfer' ever change
96 * incompatibly, then the ioctl number (currently 0) must change;
97 * ioctls with constant size fields get a bit more in the way of
98 * error checking than ones (like this) where that field varies.
99 *
100 * NOTE: struct layout is the same in 64bit and 32bit userspace.
101 */
102};
103
104/* not all platforms use <asm-generic/ioctl.h> or _IOC_TYPECHECK() ... */
105#define SPI_MSGSIZE(N) \
106 ((((N)*(sizeof (struct spi_ioc_transfer))) < (1 << _IOC_SIZEBITS)) \
107 ? ((N)*(sizeof (struct spi_ioc_transfer))) : 0)
108#define SPI_IOC_MESSAGE(N) _IOW(SPI_IOC_MAGIC, 0, char[SPI_MSGSIZE(N)])
109
110
111/* Read / Write of SPI mode (SPI_MODE_0..SPI_MODE_3) */
112#define SPI_IOC_RD_MODE _IOR(SPI_IOC_MAGIC, 1, __u8)
113#define SPI_IOC_WR_MODE _IOW(SPI_IOC_MAGIC, 1, __u8)
114
115/* Read / Write SPI bit justification */
116#define SPI_IOC_RD_LSB_FIRST _IOR(SPI_IOC_MAGIC, 2, __u8)
117#define SPI_IOC_WR_LSB_FIRST _IOW(SPI_IOC_MAGIC, 2, __u8)
118
119/* Read / Write SPI device word length (1..N) */
120#define SPI_IOC_RD_BITS_PER_WORD _IOR(SPI_IOC_MAGIC, 3, __u8)
121#define SPI_IOC_WR_BITS_PER_WORD _IOW(SPI_IOC_MAGIC, 3, __u8)
122
123/* Read / Write SPI device default max speed hz */
124#define SPI_IOC_RD_MAX_SPEED_HZ _IOR(SPI_IOC_MAGIC, 4, __u32)
125#define SPI_IOC_WR_MAX_SPEED_HZ _IOW(SPI_IOC_MAGIC, 4, __u32)
126
127
128
129#endif /* SPIDEV_H */