mpm: Add i2c APIs for simple transfers

1 files changed, 84 insertions, 0 deletions

diff --git a/mpm/lib/i2c/i2cdev.c b/mpm/lib/i2c/i2cdev.c
new file mode 100644
index 000000000..2ced96870
--- /dev/null
+++ b/mpm/lib/i2c/i2cdev.c
@@ -0,0 +1,84 @@
+//
+// Copyright 2018 Ettus Research, a National Instruments Company
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+
+#include "i2cdev.h"
+#include <fcntl.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <linux/i2c.h>
+#include <linux/i2c-dev.h>
+#include <stdio.h>
+
+int i2cdev_open(int *fd, const char *device, const unsigned int timeout_ms)
+{
+    if (!fd)
+    {
+        fprintf(stderr, "%s: was passed a null pointer\n",
+            __func__);
+        return -EINVAL;
+    }
+
+    *fd = open(device, O_RDWR);
+    if (*fd < 0) {
+        fprintf(stderr, "%s: Failed to open device. %s\n",
+            __func__, strerror(*fd));
+        return *fd;
+    }
+
+    if (ioctl(*fd, I2C_TIMEOUT, timeout_ms) < 0)
+    {
+        int err = errno;
+        fprintf(stderr, "%s: Failed to set timeout. %s\n",
+            __func__, strerror(err));
+        return err;
+    }
+
+    return 0;
+}
+
+int i2cdev_transfer(int fd, uint16_t addr, int ten_bit_addr,
+                    uint8_t *tx, size_t tx_len,
+                    uint8_t *rx, size_t rx_len)
+{
+    int err;
+    struct i2c_msg msgs[2];
+    int num_msgs = 0;
+    struct i2c_rdwr_ioctl_data i2c_data = {
+        .msgs = msgs,
+    };
+
+    if (tx && tx_len > 0) {
+        msgs[num_msgs].addr = addr;
+        msgs[num_msgs].buf = tx;
+        msgs[num_msgs].len = tx_len;
+        msgs[num_msgs].flags = ten_bit_addr ? I2C_M_TEN : 0;
+        num_msgs++;
+    }
+
+    if (rx && rx_len > 0) {
+        msgs[num_msgs].addr = addr;
+        msgs[num_msgs].buf = rx;
+        msgs[num_msgs].len = rx_len;
+        msgs[num_msgs].flags = ten_bit_addr ? I2C_M_TEN : 0;
+        msgs[num_msgs].flags |= I2C_M_RD;
+        num_msgs++;
+    }
+
+    i2c_data.nmsgs = num_msgs;
+    if (num_msgs <= 0)
+        return -EINVAL;
+
+    err = ioctl(fd, I2C_RDWR, &i2c_data);
+    if (err < 0) {
+        fprintf(stderr, "%s: Failed I2C_RDWR: %d\n", __func__, err);
+        perror("ioctl: \n");
+        return err;
+    }
+
+    return 0;
+}
+