source: rtems/bsps/arm/raspberrypi/include/bsp/i2c.h @ d8de6b9

5
Last change on this file since d8de6b9 was 2afb22b, checked in by Chris Johns <chrisj@…>, on 12/23/17 at 07:18:56

Remove make preinstall

A speciality of the RTEMS build system was the make preinstall step. It
copied header files from arbitrary locations into the build tree. The
header files were included via the -Bsome/build/tree/path GCC command
line option.

This has at least seven problems:

  • The make preinstall step itself needs time and disk space.
  • Errors in header files show up in the build tree copy. This makes it hard for editors to open the right file to fix the error.
  • There is no clear relationship between source and build tree header files. This makes an audit of the build process difficult.
  • The visibility of all header files in the build tree makes it difficult to enforce API barriers. For example it is discouraged to use BSP-specifics in the cpukit.
  • An introduction of a new build system is difficult.
  • Include paths specified by the -B option are system headers. This may suppress warnings.
  • The parallel build had sporadic failures on some hosts.

This patch removes the make preinstall step. All installed header
files are moved to dedicated include directories in the source tree.
Let @RTEMS_CPU@ be the target architecture, e.g. arm, powerpc, sparc,
etc. Let @RTEMS_BSP_FAMILIY@ be a BSP family base directory, e.g.
erc32, imx, qoriq, etc.

The new cpukit include directories are:

  • cpukit/include
  • cpukit/score/cpu/@RTEMS_CPU@/include
  • cpukit/libnetworking

The new BSP include directories are:

  • bsps/include
  • bsps/@RTEMS_CPU@/include
  • bsps/@RTEMS_CPU@/@RTEMS_BSP_FAMILIY@/include

There are build tree include directories for generated files.

The include directory order favours the most general header file, e.g.
it is not possible to override general header files via the include path
order.

The "bootstrap -p" option was removed. The new "bootstrap -H" option
should be used to regenerate the "headers.am" files.

Update #3254.
  • Property mode set to 100644
File size: 1.9 KB
Line 
1/**
2 * @file i2c.h
3 *
4 * @ingroup raspberrypi_i2c
5 *
6 * @brief Raspberry Pi specific I2C definitions.
7 */
8
9/*
10 *  Copyright (c) 2014-2015 Andre Marques <andre.lousa.marques at gmail.com>
11 *
12 *  The license and distribution terms for this file may be
13 *  found in the file LICENSE in this distribution or at
14 *  http://www.rtems.org/license/LICENSE.
15 */
16
17#ifndef LIBBSP_ARM_RASPBERRYPI_I2C_H
18#define LIBBSP_ARM_RASPBERRYPI_I2C_H
19
20#include <dev/i2c/i2c.h>
21
22#ifdef __cplusplus
23extern "C" {
24#endif /* __cplusplus */
25
26/**
27 * @name I2C constants.
28 *
29 * @{
30 */
31
32/**
33 * @brief BSC controller core clock rate in Hz.
34 *
35 * This is set to 150 MHz as per the BCM2835 datasheet.
36 */
37#define BSC_CORE_CLK_HZ 150000000
38
39/**
40 * @brief Default bus clock.
41 *
42 * This sets the bus with a 100 kHz clock speed.
43 */
44#define DEFAULT_BUS_CLOCK 100000
45
46/** @} */
47
48/**
49 * @name  I2C directives.
50 *
51 * @{
52 */
53
54/**
55 * @brief Setups the Raspberry Pi GPIO header to activate the BSC I2C bus.
56 */
57extern void rpi_i2c_init(void);
58
59/**
60 * @brief Registers the Raspberry Pi BSC I2C bus with the
61 *        Linux I2C User-Space API.
62 *
63 * @param[in] bus_path Path to the bus device file.
64 * @param[in] bus_clock Bus clock in Hz.
65 *
66 * @retval 0 Bus registered successfully.
67 * @retval <0 Could not register the bus. The return value is a negative
68 *            errno code.
69 */
70extern int rpi_i2c_register_bus(
71  const char *bus_path,
72  uint32_t bus_clock
73);
74
75/**
76 * @brief Setups the Raspberry Pi BSC I2C bus (located on the GPIO header)
77 *        on the "/dev/i2c" device file, using the default bus clock.
78 *
79 * @retval 0 Bus configured and registered successfully.
80 * @retval <0 See @see rpi_i2c_register_bus().
81 */
82static inline int rpi_setup_i2c_bus(void)
83{
84  rpi_i2c_init();
85
86  return rpi_i2c_register_bus("/dev/i2c", DEFAULT_BUS_CLOCK);
87}
88
89/** @} */
90
91#ifdef __cplusplus
92}
93#endif /* __cplusplus */
94
95#endif /* LIBBSP_ARM_RASPBERRYPI_I2C_H */
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