AT91SAM7 SPI driver contributed by Alexander.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@2049 35acf78f-673a-0410-8e92-d51de3d6d3f4

1 files changed, 226 insertions, 0 deletions

diff --git a/os/hal/platforms/AT91SAM7/spi_lld.c b/os/hal/platforms/AT91SAM7/spi_lld.c
new file mode 100644
index 000000000..2353b76cb
--- /dev/null
+++ b/os/hal/platforms/AT91SAM7/spi_lld.c
@@ -0,0 +1,226 @@
+/*

+    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 AT91SAM7/spi_lld.c

+ * @brief AT91SAM7 low level SPI driver code.

+ * @addtogroup AT91SAM7_SPI

+ * @{

+ */

+

+#include "ch.h"

+#include "hal.h"

+

+#if CH_HAL_USE_SPI || defined(__DOXYGEN__)

+

+/*===========================================================================*/

+/* Driver exported variables.                                                */

+/*===========================================================================*/

+

+#if USE_AT91SAM7_SPI || defined(__DOXYGEN__)

+/** @brief SPI driver identifier.*/

+SPIDriver SPID;

+#endif

+

+/*===========================================================================*/

+/* Driver local variables.                                                   */

+/*===========================================================================*/

+

+/*===========================================================================*/

+/* Driver local functions.                                                   */

+/*===========================================================================*/

+

+/**

+ * @brief Synchronous SPI transfer.

+ *

+ * @param[in] n         number of bytes to be exchanged

+ *

+ * @param[in] txbuf     the pointer to the transmit buffer or @p NULL

+ * @param[out] rxbuf    the pointer to the receive buffer or @p NULL

+ */

+void rw8(size_t n, const uint8_t *txbuf, uint8_t *rxbuf) {

+  size_t ntx = n;

+

+  while (n > 0) {

+    uint32_t sr = AT91C_BASE_SPI->SPI_SR;

+    if (sr & AT91C_SPI_RDRF) {

+      uint8_t w = AT91C_BASE_SPI->SPI_RDR;

+      if (rxbuf != NULL)

+        *rxbuf++ = w;

+      n--;

+      continue; /* Priority over transmission. */

+    }

+    if ((ntx > 0) && (sr & AT91C_SPI_TDRE)) {

+      if (txbuf != NULL)

+        AT91C_BASE_SPI->SPI_TDR = *txbuf++;

+      else

+        AT91C_BASE_SPI->SPI_TDR = 0xFF;

+      ntx--;

+    }

+  }

+}

+

+/*===========================================================================*/

+/* Driver interrupt handlers.                                                */

+/*===========================================================================*/

+

+/*===========================================================================*/

+/* Driver exported functions.                                                */

+/*===========================================================================*/

+

+/**

+ * @brief Low level SPI driver initialization.

+ */

+void spi_lld_init(void) {

+

+#if USE_AT91SAM7_SPI

+  spiObjectInit(&SPID);

+#endif

+}

+

+/**

+ * @brief Configures and activates the SPI peripheral.

+ *

+ * @param[in] spip      pointer to the @p SPIDriver object

+ */

+void spi_lld_start(SPIDriver *spip) {

+

+  if (spip->spd_state == SPI_STOP) {

+    /* disable general-purpose I/O for SPI pins */

+    AT91C_BASE_PIOA->PIO_PDR = SPI_MISO | SPI_MOSI | SPI_SCK;

+    /* select perepheral A for SPI pins*/

+    AT91C_BASE_PIOA->PIO_ASR = SPI_MISO | SPI_MOSI | SPI_SCK;

+    /* Clock activation.*/

+    AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_SPI);

+  }

+  /* software reset must be written twice (errata for revision B parts) */

+  AT91C_BASE_SPI->SPI_CR = AT91C_SPI_SWRST;

+  AT91C_BASE_SPI->SPI_CR = AT91C_SPI_SWRST;

+  /* Configuration.*/

+  AT91C_BASE_SPI->SPI_MR = spip->spd_config->spc_mr;

+  AT91C_BASE_SPI->SPI_CSR[MMC_CSR_NUM] = spip->spd_config->spc_csr;

+  /* Enable SPI */

+  AT91C_BASE_SPI->SPI_CR = AT91C_SPI_SPIEN;

+}

+

+/**

+ * @brief Deactivates the SPI peripheral.

+ *

+ * @param[in] spip      pointer to the @p SPIDriver object

+ */

+void spi_lld_stop(SPIDriver *spip) {

+

+  if (spip->spd_state != SPI_STOP) {

+    /* disable SPI */

+    AT91C_BASE_SPI->SPI_CR = AT91C_SPI_SPIDIS;

+    /* disable clocks to SPI perepheral */

+    AT91C_BASE_PMC->PMC_PCDR = (1 << AT91C_ID_SPI);

+  }

+}

+

+/**

+ * @brief Asserts the slave select signal and prepares for transfers.

+ *

+ * @param[in] spip      pointer to the @p SPIDriver object

+ */

+void spi_lld_select(SPIDriver *spip) {

+

+  palClearPad(spip->spd_config->spc_ssport, spip->spd_config->spc_sspad);

+}

+

+/**

+ * @brief Deasserts the slave select signal.

+ * @details The previously selected peripheral is unselected.

+ *

+ * @param[in] spip      pointer to the @p SPIDriver object

+ */

+void spi_lld_unselect(SPIDriver *spip) {

+

+  palSetPad(spip->spd_config->spc_ssport, spip->spd_config->spc_sspad);

+}

+

+/**

+ * @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 spi_lld_ignore(SPIDriver *spip, size_t n) {

+

+  (void)spip;

+  rw8(n, NULL, NULL);

+}

+

+/**

+ * @brief Exchanges data on the SPI bus.

+ * @details This function performs a simultaneous transmit/receive operation.

+ *

+ * @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

+ *

+ * @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.

+ */

+void spi_lld_exchange(SPIDriver *spip, size_t n,

+                      const void *txbuf, void *rxbuf) {

+

+  (void)spip;

+  rw8(n, txbuf, rxbuf);

+}

+

+/**

+ * @brief Sends data over the SPI bus.

+ *

+ * @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

+ *

+ * @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.

+ */

+void spi_lld_send(SPIDriver *spip, size_t n, const void *txbuf) {

+

+  (void)spip;

+  rw8(n, txbuf, NULL);

+}

+

+/**

+ * @brief Receives data from the SPI bus.

+ *

+ * @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

+ *

+ * @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.

+ */

+void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf) {

+

+  (void)spip;

+  rw8(n, NULL, rxbuf);

+}

+

+#endif /* CH_HAL_USE_SPI */

+

+/** @} */