hw/drivers/bme280: Fix writes to I2C

I2C writes when driver was enabled clear MSB of register
address.

This prevented any write to control registers.

Now registers MSB is cleared on write only for SPI.

Writing registers also requires single start condition.
Code was doing write with restart condtion that does not
seem to work correctly

Signed-off-by: Jerzy Kasenberg <jerzy.kasenberg@codecoup.pl>

hw/drivers/sensors/bme280/include/bme280/bme280.h

@@ -111,6 +111,7 @@ struct bme280 {
         struct bus_i2c_node i2c_node;
         struct bus_spi_node spi_node;
     };
+    bool node_is_spi;
 #else
     struct os_dev dev;
 #endif

hw/drivers/sensors/bme280/src/bme280.c

@@ -75,6 +75,14 @@ static const struct sensor_driver g_bme280_sensor_driver = {
     bme280_sensor_get_config
 };
 
+#if MYNEWT_VAL(BUS_DRIVER_PRESENT)
+static bool
+bme280_uses_spi(struct sensor_itf *itf)
+{
+    return ((struct bme280 *)(itf->si_dev))->node_is_spi;
+}
+#endif
+
 static int
 bme280_default_cfg(struct bme280_cfg *cfg)
 {
@@ -894,23 +902,28 @@ bme280_writelen(struct sensor_itf *itf, uint8_t addr, uint8_t *payload,
     int rc;
 
 #if MYNEWT_VAL(BUS_DRIVER_PRESENT)
+    uint8_t buf[4];
+
+    if (len > 3) {
+        return SYS_EINVAL;
+    }
+
     struct os_dev *dev = itf->si_dev;
 
     rc = bus_node_lock(dev, OS_TIMEOUT_NEVER);
     if (rc) {
         return SYS_EINVAL;
     }
 
-    addr &= ~BME280_SPI_READ_CMD_BIT;
-
-    rc = bus_node_write(dev, &addr, 1, OS_TIMEOUT_NEVER, BUS_F_NOSTOP);
-    if (rc) {
-        goto done;
+    if (bme280_uses_spi(itf)) {
+        addr &= ~BME280_SPI_READ_CMD_BIT;
     }
 
-    rc = bus_node_simple_write(dev, payload, len);
+    buf[0] = addr;
+    memcpy(buf + 1, payload, len);
+
+    rc = bus_node_simple_write(dev, buf, len + 1);
 
-done:
     (void)bus_node_unlock(dev);
 #else
     int i;