spidev.h 4.9 KB

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  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. #ifndef SPIDEV_H
  22. #define SPIDEV_H
  23. #include <linux/types.h>
  24. /* User space versions of kernel symbols for SPI clocking modes,
  25. * matching <linux/spi/spi.h>
  26. */
  27. #define SPI_CPHA 0x01
  28. #define SPI_CPOL 0x02
  29. #define SPI_MODE_0 (0|0)
  30. #define SPI_MODE_1 (0|SPI_CPHA)
  31. #define SPI_MODE_2 (SPI_CPOL|0)
  32. #define SPI_MODE_3 (SPI_CPOL|SPI_CPHA)
  33. #define SPI_CS_HIGH 0x04
  34. #define SPI_LSB_FIRST 0x08
  35. #define SPI_3WIRE 0x10
  36. #define SPI_LOOP 0x20
  37. #define SPI_NO_CS 0x40
  38. #define SPI_READY 0x80
  39. #define SPI_TX_DUAL 0x100
  40. #define SPI_TX_QUAD 0x200
  41. #define SPI_RX_DUAL 0x400
  42. #define SPI_RX_QUAD 0x800
  43. /*---------------------------------------------------------------------------*/
  44. /* IOCTL commands */
  45. #define SPI_IOC_MAGIC 'k'
  46. /**
  47. * struct spi_ioc_transfer - describes a single SPI transfer
  48. * @tx_buf: Holds pointer to userspace buffer with transmit data, or null.
  49. * If no data is provided, zeroes are shifted out.
  50. * @rx_buf: Holds pointer to userspace buffer for receive data, or null.
  51. * @len: Length of tx and rx buffers, in bytes.
  52. * @speed_hz: Temporary override of the device's bitrate.
  53. * @bits_per_word: Temporary override of the device's wordsize.
  54. * @delay_usecs: If nonzero, how long to delay after the last bit transfer
  55. * before optionally deselecting the device before the next transfer.
  56. * @cs_change: True to deselect device before starting the next transfer.
  57. *
  58. * This structure is mapped directly to the kernel spi_transfer structure;
  59. * the fields have the same meanings, except of course that the pointers
  60. * are in a different address space (and may be of different sizes in some
  61. * cases, such as 32-bit i386 userspace over a 64-bit x86_64 kernel).
  62. * Zero-initialize the structure, including currently unused fields, to
  63. * accommodate potential future updates.
  64. *
  65. * SPI_IOC_MESSAGE gives userspace the equivalent of kernel spi_sync().
  66. * Pass it an array of related transfers, they'll execute together.
  67. * Each transfer may be half duplex (either direction) or full duplex.
  68. *
  69. * struct spi_ioc_transfer mesg[4];
  70. * ...
  71. * status = ioctl(fd, SPI_IOC_MESSAGE(4), mesg);
  72. *
  73. * So for example one transfer might send a nine bit command (right aligned
  74. * in a 16-bit word), the next could read a block of 8-bit data before
  75. * terminating that command by temporarily deselecting the chip; the next
  76. * could send a different nine bit command (re-selecting the chip), and the
  77. * last transfer might write some register values.
  78. */
  79. struct spi_ioc_transfer {
  80. __u64 tx_buf;
  81. __u64 rx_buf;
  82. __u32 len;
  83. __u32 speed_hz;
  84. __u16 delay_usecs;
  85. __u8 bits_per_word;
  86. __u8 cs_change;
  87. __u8 tx_nbits;
  88. __u8 rx_nbits;
  89. __u16 pad;
  90. /* If the contents of 'struct spi_ioc_transfer' ever change
  91. * incompatibly, then the ioctl number (currently 0) must change;
  92. * ioctls with constant size fields get a bit more in the way of
  93. * error checking than ones (like this) where that field varies.
  94. *
  95. * NOTE: struct layout is the same in 64bit and 32bit userspace.
  96. */
  97. };
  98. /* not all platforms use <asm-generic/ioctl.h> or _IOC_TYPECHECK() ... */
  99. #define SPI_MSGSIZE(N) \
  100. ((((N)*(sizeof (struct spi_ioc_transfer))) < (1 << 13)) \
  101. ? ((N)*(sizeof (struct spi_ioc_transfer))) : 0)
  102. #define SPI_IOC_MESSAGE(N) _IOW(SPI_IOC_MAGIC, 0, char[SPI_MSGSIZE(N)])
  103. /* Read / Write of SPI mode (SPI_MODE_0..SPI_MODE_3) (limited to 8 bits) */
  104. #define SPI_IOC_RD_MODE _IOR(SPI_IOC_MAGIC, 1, __u8)
  105. #define SPI_IOC_WR_MODE _IOW(SPI_IOC_MAGIC, 1, __u8)
  106. /* Read / Write SPI bit justification */
  107. #define SPI_IOC_RD_LSB_FIRST _IOR(SPI_IOC_MAGIC, 2, __u8)
  108. #define SPI_IOC_WR_LSB_FIRST _IOW(SPI_IOC_MAGIC, 2, __u8)
  109. /* Read / Write SPI device word length (1..N) */
  110. #define SPI_IOC_RD_BITS_PER_WORD _IOR(SPI_IOC_MAGIC, 3, __u8)
  111. #define SPI_IOC_WR_BITS_PER_WORD _IOW(SPI_IOC_MAGIC, 3, __u8)
  112. /* Read / Write SPI device default max speed hz */
  113. #define SPI_IOC_RD_MAX_SPEED_HZ _IOR(SPI_IOC_MAGIC, 4, __u32)
  114. #define SPI_IOC_WR_MAX_SPEED_HZ _IOW(SPI_IOC_MAGIC, 4, __u32)
  115. /* Read / Write of the SPI mode field */
  116. #define SPI_IOC_RD_MODE32 _IOR(SPI_IOC_MAGIC, 5, __u32)
  117. #define SPI_IOC_WR_MODE32 _IOW(SPI_IOC_MAGIC, 5, __u32)
  118. #endif /* SPIDEV_H */