aboutsummaryrefslogtreecommitdiffstats
path: root/os/hal/src/spi.c
blob: 29e69a283ac37d9fa3b8f7f4f9a10fa3dd2cfc96 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT 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 3 of the License, or
    (at your option) any later version.

    ChibiOS/RT 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, see <http://www.gnu.org/licenses/>.
*/

/**
 * @file    spi.c
 * @brief   SPI Driver code.
 *
 * @addtogroup SPI
 * @{
 */

#include "ch.h"
#include "hal.h"

#if CH_HAL_USE_SPI || defined(__DOXYGEN__)

/*===========================================================================*/
/* Driver exported variables.                                                */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local variables.                                                   */
/*===========================================================================*/

/*===========================================================================*/
/* Driver local functions.                                                   */
/*===========================================================================*/

/*===========================================================================*/
/* Driver exported functions.                                                */
/*===========================================================================*/

/**
 * @brief   SPI Driver initialization.
 */
void spiInit(void) {

  spi_lld_init();
}

/**
 * @brief   Initializes the standard part of a @p SPIDriver structure.
 *
 * @param[in] spip      pointer to the @p SPIDriver object
 */
void spiObjectInit(SPIDriver *spip) {

  spip->spd_state = SPI_STOP;
#if CH_USE_MUTEXES
  chMtxInit(&spip->spd_mutex);
#elif CH_USE_SEMAPHORES
  chSemInit(&spip->spd_semaphore, 1);
#endif
  spip->spd_config = NULL;
}

/**
 * @brief   Configures and activates the SPI peripheral.
 *
 * @param[in] spip      pointer to the @p SPIDriver object
 * @param[in] config    pointer to the @p SPIConfig object
 */
void spiStart(SPIDriver *spip, const SPIConfig *config) {

  chDbgCheck((spip != NULL) && (config != NULL), "spiStart");

  chSysLock();
  chDbgAssert((spip->spd_state == SPI_STOP) || (spip->spd_state == SPI_READY),
              "spiStart(), #1",
              "invalid state");
  spip->spd_config = config;
  spi_lld_start(spip);
  spip->spd_state = SPI_READY;
  chSysUnlock();
}

/**
 * @brief Deactivates the SPI peripheral.
 *
 * @param[in] spip      pointer to the @p SPIDriver object
 */
void spiStop(SPIDriver *spip) {

  chDbgCheck(spip != NULL, "spiStop");

  chSysLock();
  chDbgAssert((spip->spd_state == SPI_STOP) || (spip->spd_state == SPI_READY),
              "spiStop(), #1",
              "invalid state");
  spi_lld_stop(spip);
  spip->spd_state = SPI_STOP;
  chSysUnlock();
}

/**
 * @brief   Asserts the slave select signal and prepares for transfers.
 *
 * @param[in] spip      pointer to the @p SPIDriver object
 */
void spiSelect(SPIDriver *spip) {

  chDbgCheck(spip != NULL, "spiSelect");

  chSysLock();
  chDbgAssert((spip->spd_state == SPI_READY) ||
              (spip->spd_state == SPI_ACTIVE),
              "spiSelect(), #1",
              "not idle");
  spi_lld_select(spip);
  spip->spd_state = SPI_ACTIVE;
  chSysUnlock();
}

/**
 * @brief   Deasserts the slave select signal.
 * @details The previously selected peripheral is unselected.
 *
 * @param[in] spip      pointer to the @p SPIDriver object
 */
void spiUnselect(SPIDriver *spip) {

  chDbgCheck(spip != NULL, "spiUnselect");

  chSysLock();
  chDbgAssert((spip->spd_state == SPI_READY) ||
              (spip->spd_state == SPI_ACTIVE),
              "spiUnselect(), #1",
              "not locked");
  spi_lld_unselect(spip);
  spip->spd_state = SPI_READY;
  chSysUnlock();
}

/**
 * @brief   Ignores data on the SPI bus.
 * @details This function transmits a series of idle words on the SPI bus and
 *          ignores the received data. This function can be invoked even
 *          when a slave select signal has not been yet asserted.
 *
 * @param[in] spip      pointer to the @p SPIDriver object
 * @param[in] n         number of words to be ignored
 */
void spiIgnore(SPIDriver *spip, size_t n) {

  chDbgCheck((spip != NULL) && (n > 0), "spiIgnore");
  chDbgAssert((spip->spd_state == SPI_READY) || (spip->spd_state == SPI_ACTIVE),
              "spiIgnore(), #1",
              "not active");

  spi_lld_ignore(spip, n);
}

/**
 * @brief   Exchanges data on the SPI bus.
 * @details This function performs a simultaneous transmit/receive operation.
 * @note    The buffers are organized as uint8_t arrays for data sizes below
 *          or equal to 8 bits else it is organized as uint16_t arrays.
 *
 * @param[in] spip      pointer to the @p SPIDriver object
 * @param[in] n         number of words to be exchanged
 * @param[in] txbuf     the pointer to the transmit buffer
 * @param[out] rxbuf    the pointer to the receive buffer
 */
void spiExchange(SPIDriver *spip, size_t n, const void *txbuf, void *rxbuf) {

  chDbgCheck((spip != NULL) && (n > 0) && (rxbuf != NULL) && (txbuf != NULL),
             "spiExchange");
  chDbgAssert(spip->spd_state == SPI_ACTIVE,
              "spiExchange(), #1",
              "not active");

  spi_lld_exchange(spip, n, txbuf, rxbuf);
}

/**
 * @brief   Sends data ever the SPI bus.
 * @note    The buffers are organized as uint8_t arrays for data sizes below
 *          or equal to 8 bits else it is organized as uint16_t arrays.
 *
 * @param[in] spip      pointer to the @p SPIDriver object
 * @param[in] n         number of words to send
 * @param[in] txbuf     the pointer to the transmit buffer
 */
void spiSend(SPIDriver *spip, size_t n, const void *txbuf) {

  chDbgCheck((spip != NULL) && (n > 0) && (txbuf != NULL),
             "spiSend");
  chDbgAssert(spip->spd_state == SPI_ACTIVE,
              "spiSend(), #1",
              "not active");

  spi_lld_send(spip, n, txbuf);
}

/**
 * @brief   Receives data from the SPI bus.
 * @note    The buffers are organized as uint8_t arrays for data sizes below
 *          or equal to 8 bits else it is organized as uint16_t arrays.
 *
 * @param[in] spip      pointer to the @p SPIDriver object
 * @param[in] n         number of words to receive
 * @param[out] rxbuf    the pointer to the receive buffer
 */
void spiReceive(SPIDriver *spip, size_t n, void *rxbuf) {

  chDbgCheck((spip != NULL) && (n > 0) && (rxbuf != NULL),
             "spiReceive");
  chDbgAssert(spip->spd_state == SPI_ACTIVE,
              "spiReceive(), #1",
              "not active");

  spi_lld_receive(spip, n, rxbuf);
}

#if SPI_USE_MUTUAL_EXCLUSION || defined(__DOXYGEN__)
/**
 * @brief   Gains exclusive access to the SPI bus.
 * @details This function tries to gain ownership to the SPI bus, if the bus
 *          is already being used then the invoking thread is queued.
 * @note    This function is only available when the @p SPI_USE_MUTUAL_EXCLUSION
 *          option is set to @p TRUE.
 *
 * @param[in] spip      pointer to the @p SPIDriver object
 *
 */
void spiAcquireBus(SPIDriver *spip) {

  chDbgCheck(spip != NULL, "spiAcquireBus");

#if CH_USE_MUTEXES
  chMtxLock(&spip->spd_mutex);
#elif CH_USE_SEMAPHORES
  chSemWait(&spip->spd_semaphore);
#endif
}

/**
 * @brief   Releases exclusive access to the SPI bus.
 * @note    This function is only available when the @p SPI_USE_MUTUAL_EXCLUSION
 *          option is set to @p TRUE.
 *
 * @param[in] spip      pointer to the @p SPIDriver object
 */
void spiReleaseBus(SPIDriver *spip) {

  chDbgCheck(spip != NULL, "spiReleaseBus");

#if CH_USE_MUTEXES
  (void)spip;
  chMtxUnlock();
#elif CH_USE_SEMAPHORES
  chSemSignal(&spip->spd_semaphore);
#endif
}
#endif /* SPI_USE_MUTUAL_EXCLUSION */

#endif /* CH_HAL_USE_SPI */

/** @} */