drivers/l3g4200d: Acquire exclusive access to I2C bus

drivers/l3g4200d/l3g4200d.c

@@ -14,12 +14,14 @@
  * @brief       Device driver implementation for the L3G4200D gyroscope
  *
  * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ * @author      Peter Kietzmann <peter.kietzmann@haw-hamburg.de>
  *
  * @}
  */
 
 #include <stdint.h>
 
+#include "mutex.h"
 #include "l3g4200d.h"
 #include "l3g4200d-regs.h"
 #include "periph/i2c.h"
@@ -38,10 +40,15 @@ int l3g4200d_init(l3g4200d_t *dev, i2c_t i2c, uint8_t address,
 {
     char tmp;
 
+    /* Acquire exclusive access to the bus. */
+    i2c_acquire(dev->i2c);
     /* initialize the I2C bus */
     if (i2c_init_master(i2c, I2C_SPEED) < 0) {
+        /* Release the bus for other threads. */
+        i2c_release(dev->i2c);
         return -1;
     }
+    i2c_release(dev->i2c);
 
     /* write device descriptor */
     dev->i2c = i2c;
@@ -67,13 +74,17 @@ int l3g4200d_init(l3g4200d_t *dev, i2c_t i2c, uint8_t address,
 
     /* configure CTRL_REG1 */
     tmp = ((mode & 0xf) << L3G4200D_CTRL1_MODE_POS) | L3G4200D_CTRL1_ALLON;
+    i2c_acquire(dev->i2c);
     if (i2c_write_reg(dev->i2c, dev->addr, L3G4200D_REG_CTRL1, tmp) != 1) {
+        i2c_release(dev->i2c);
         return -1;
     }
     tmp = ((scale & 0x3) << L3G4200D_CTRL4_FS_POS) | L3G4200D_CTRL4_BDU;
     if (i2c_write_reg(dev->i2c, dev->addr, L3G4200D_REG_CTRL4, tmp) != 1) {
+        i2c_release(dev->i2c);
         return -1;
     }
+    i2c_release(dev->i2c);
     return 0;
 }
 
@@ -82,8 +93,10 @@ int l3g4200d_read(l3g4200d_t *dev, l3g4200d_data_t *data)
     char tmp[6];
     int16_t res;
 
+    i2c_acquire(dev->i2c);
     /* get acceleration in x direction */
     i2c_read_regs(dev->i2c, dev->addr, L3G4200D_REG_OUT_X_L | L3G4200D_AUTOINC, tmp, 6);
+    i2c_release(dev->i2c);
 
     /* parse and normalize data into result vector */
     res = (tmp[1] << 8) | tmp[0];
@@ -100,14 +113,18 @@ int l3g4200d_enable(l3g4200d_t *dev)
     char tmp;
     int res;
 
+    i2c_acquire(dev->i2c);
     res = i2c_read_reg(dev->i2c, dev->addr, L3G4200D_REG_CTRL1, &tmp);
     if (res < 1) {
+        i2c_release(dev->i2c);
         return res;
     }
     tmp |= L3G4200D_CTRL1_PD;
     if (i2c_write_reg(dev->i2c, dev->addr, L3G4200D_REG_CTRL1, tmp) != 1) {
+        i2c_release(dev->i2c);
         return -1;
     }
+    i2c_release(dev->i2c);
     return 0;
 }
 
@@ -116,13 +133,17 @@ int l3g4200d_disable(l3g4200d_t *dev)
     char tmp;
     int res;
 
+    i2c_acquire(dev->i2c);
     res = i2c_read_reg(dev->i2c, dev->addr, L3G4200D_REG_CTRL1, &tmp);
     if (res < 1) {
+        i2c_release(dev->i2c);
         return res;
     }
     tmp &= ~L3G4200D_CTRL1_PD;
     if (i2c_write_reg(dev->i2c, dev->addr, L3G4200D_REG_CTRL1, tmp) != 1) {
+        i2c_release(dev->i2c);
         return -1;
     }
+    i2c_release(dev->i2c);
     return 0;
 }