arch: cxd56xx: Improve i2c reset function

During I2C communication between non-Spresense devices is performed,
the I2C bus may freeze after initialization of the Spresense I2C.
As a workaround, add clock gating process and disable GPIO input
to the I2C reset function.

Signed-off-by: SPRESENSE <[email protected]>

arch/arm/src/cxd56xx/cxd56_i2c.c

@@ -723,6 +723,10 @@ static int cxd56_i2c_reset(struct i2c_master_s *dev)
 
   nxmutex_lock(&priv->lock);
 
+  /* Disable clock gating (clock enable) */
+
+  cxd56_i2c_clock_gate_disable(priv->port);
+
   /* Use GPIO configuration to un-wedge the bus */
 
   cxd56_i2c_pincontrol(priv->port, false);
@@ -794,6 +798,11 @@ static int cxd56_i2c_reset(struct i2c_master_s *dev)
       up_udelay(10);
     }
 
+  /* Disable input of SCL and SDA pins */
+
+  cxd56_gpio_config(scl_gpio, false);
+  cxd56_gpio_config(sda_gpio, false);
+
   /* Generate a start followed by a stop to reset slave
    * state machines.
    */
@@ -820,6 +829,10 @@ static int cxd56_i2c_reset(struct i2c_master_s *dev)
 
   cxd56_i2c_pincontrol(priv->port, true);
 
+  /* Enable clock gating (clock disable) */
+
+  cxd56_i2c_clock_gate_enable(priv->port);
+
   /* Release the port for re-use by other clients */
 
   nxmutex_unlock(&priv->lock);