1 files changed, 56 insertions, 0 deletions
diff --git a/mpm/lib/spi/spidev.h b/mpm/lib/spi/spidev.h
new file mode 100644
index 000000000..30ea9ecc5
--- /dev/null
+++ b/mpm/lib/spi/spidev.h
@@ -0,0 +1,56 @@
+//
+// Copyright 2017 Ettus Research (National Instruments)
+//
+// This program 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.
+//
+// This program 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/>.
+//
+
+#include <stdint.h>
+
+/*! Initialize a spidev interface
+ *
+ * \param fd Return value of the file descriptor
+ * \param device Path of spidev device, e.g. "/dev/spidev0.0"
+ * \param mode SPI mode. See linux/spi/spidev.h
+ * \param speed_hz The *maximum* SPI speed in Hz
+ * \param bits_per_word Just set it to 8.
+ * \param delay_us Delay between writes in microseconds
+ *
+ * \returns 0 if all is good, or an error code otherwise
+ */
+int init_spi(int *fd, const char *device,
+    const uint32_t mode,
+    const uint32_t speed_hz,
+    const uint8_t bits_per_word,
+    const uint16_t delay_us
+);
+
+/*! Do a SPI transaction over spidev
+ *
+ * \param tx Buffer of data to be written
+ * \param rx Must match tx buffer length; result will be written here
+ * \param len Total number of bytes in this transaction
+ * \param speed_hz Speed of this transaction in Hz
+ * \param bits_per_word 8, dude
+ * \param delay_us Delay between transfers
+ *
+ * Assumption: spidev was configured properly beforehand.
+ *
+ * \returns 0 if all is golden
+ */
+int transfer(
+        int fd,
+        uint8_t *tx, uint8_t *rx, uint32_t len,
+        uint32_t speed_hz, uint8_t bits_per_word, uint16_t delay_us
+);
+