Bug fixes and improved interrupt support for mcp23x17 driver

drivers/ioexpander/Kconfig

@@ -78,6 +78,13 @@ config MCP23X17_INT_ENABLE
 	---help---
 		Enable driver interrupt functionality
 
+config MCP23X17_INT_MIRROR
+	bool "Enable MCP23x17 Interrupt Mirror"
+	default n
+	select MCP23X17_INT_ENABLE
+	---help---
+		Enable driver interrupt mirror functionality
+
 config MCP23X17_INT_NCALLBACKS
 	int "Max number of interrupt callbacks"
 	default 4

drivers/ioexpander/mcp23x17.c

@@ -312,6 +312,7 @@ static int mcp23x17_direction(FAR struct ioexpander_dev_s *dev, uint8_t pin,
   int ret;
 
   if (direction != IOEXPANDER_DIRECTION_IN &&
+      direction != IOEXPANDER_DIRECTION_IN_PULLUP &&
       direction != IOEXPANDER_DIRECTION_OUT)
     {
       return -EINVAL;
@@ -326,7 +327,17 @@ static int mcp23x17_direction(FAR struct ioexpander_dev_s *dev, uint8_t pin,
     }
 
   ret = mcp23x17_setbit(priv, MCP23X17_IODIRA, pin,
-                        (direction == IOEXPANDER_DIRECTION_IN));
+                        (direction == IOEXPANDER_DIRECTION_IN) ||
+                        (direction == IOEXPANDER_DIRECTION_IN_PULLUP));
+  if (ret < 0)
+    {
+      nxmutex_unlock(&priv->lock);
+      return ret;
+    }
+
+  ret = mcp23x17_setbit(priv, MCP23X17_GPPUA, pin,
+                        (direction == IOEXPANDER_DIRECTION_IN_PULLUP));
+
   nxmutex_unlock(&priv->lock);
   return ret;
 }
@@ -746,6 +757,8 @@ static FAR void *mcp23x17_attach(FAR struct ioexpander_dev_s *dev,
 {
   FAR struct mcp23x17_dev_s *priv = (FAR struct mcp23x17_dev_s *)dev;
   FAR void *handle = NULL;
+  uint8_t addr = MCP23X17_GPINTENA;
+  uint8_t buf[3];
   int i;
   int ret;
 
@@ -754,7 +767,25 @@ static FAR void *mcp23x17_attach(FAR struct ioexpander_dev_s *dev,
   ret = nxmutex_lock(&priv->lock);
   if (ret < 0)
     {
-      return ret;
+      return NULL;
+    }
+
+  ret = mcp23x17_writeread(priv, &addr, 1, &buf[1], 2);
+  if (ret < 0)
+    {
+      nxmutex_unlock(&priv->lock);
+      return NULL;
+    }
+
+  buf[0] = addr;
+  buf[1] |= (uint8_t)(pinset & 0x00ff);
+  buf[2] |= (uint8_t)((pinset & 0xff00) >> 8);
+
+  ret = mcp23x17_write(priv, buf, 3);
+  if (ret < 0)
+    {
+      nxmutex_unlock(&priv->lock);
+      return NULL;
     }
 
   /* Find and available in entry in the callback table */
@@ -806,7 +837,7 @@ static int mcp23x17_detach(FAR struct ioexpander_dev_s *dev,
   DEBUGASSERT(priv != NULL && cb != NULL);
   DEBUGASSERT((uintptr_t)cb >= (uintptr_t)&priv->cb[0] &&
               (uintptr_t)cb <=
-              (uintptr_t)&priv->cb[CONFIG_TCA64XX_INT_NCALLBACKS - 1]);
+              (uintptr_t)&priv->cb[CONFIG_MCP23X17_INT_NCALLBACKS - 1]);
   UNUSED(priv);
 
   cb->pinset = 0;
@@ -827,26 +858,20 @@ static int mcp23x17_detach(FAR struct ioexpander_dev_s *dev,
 static void mcp23x17_irqworker(void *arg)
 {
   FAR struct mcp23x17_dev_s *priv = (FAR struct mcp23x17_dev_s *)arg;
-  uint8_t addr = MCP23X17_GPIOA;
+  uint8_t addr = MCP23X17_INTFA;
   uint8_t buf[2];
   ioe_pinset_t pinset;
   int ret;
   int i;
 
-  /* Read inputs */
+  /* Read interrupt flags */
 
   ret = mcp23x17_writeread(priv, &addr, 1, buf, 2);
   if (ret == OK)
     {
-#ifdef CONFIG_MCP23X17_SHADOW_MODE
-      /* Don't forget to update the shadow registers at this point */
-
-      priv->sreg[addr]     = buf[0];
-      priv->sreg[addr + 1] = buf[1];
-#endif
       /* Create a 16-bit pinset */
 
-      pinset = ((unsigned int)buf[0] << 8) | buf[1];
+      pinset = ((unsigned int)buf[1] << 8) | buf[0];
 
       /* Perform pin interrupt callbacks */
 
@@ -870,6 +895,19 @@ static void mcp23x17_irqworker(void *arg)
                 }
             }
         }
+
+      /* Read GPIOs to clear interrupt condition */
+
+      addr = MCP23X17_INTCAPA;
+
+      mcp23x17_writeread(priv, &addr, 1, buf, 2);
+
+#ifdef CONFIG_MCP23X17_SHADOW_MODE
+      /* Don't forget to update the shadow registers at this point */
+
+      priv->sreg[addr]     = buf[0];
+      priv->sreg[addr + 1] = buf[1];
+#endif
     }
 
   /* Re-enable interrupts */
@@ -934,6 +972,9 @@ FAR struct ioexpander_dev_s *mcp23x17_initialize(
                               FAR struct mcp23x17_config_s *config)
 {
   FAR struct mcp23x17_dev_s *priv;
+#ifdef CONFIG_MCP23X17_INT_MIRROR
+  uint8_t buf[3];
+#endif
 
   DEBUGASSERT(i2cdev != NULL && config != NULL);
 
@@ -967,6 +1008,14 @@ FAR struct ioexpander_dev_s *mcp23x17_initialize(
   priv->config  = config;
 
 #ifdef CONFIG_MCP23X17_INT_ENABLE
+
+#ifdef CONFIG_MCP23X17_INT_MIRROR
+  buf[0] = MCP23X17_IOCON;
+  buf[1] = 0x40;
+  buf[2] = 0x40;
+  mcp23x17_write(priv, buf, 3);
+#endif
+
   priv->config->attach(priv->config, mcp23x17_interrupt, priv);
   priv->config->enable(priv->config, TRUE);
 #endif

drivers/ioexpander/mcp23x17.h

@@ -152,6 +152,10 @@ struct mcp23x17_dev_s
   struct ioexpander_dev_s dev;          /* Nested structure to allow casting
                                          * as public gpio expander.
                                          */
+#ifdef CONFIG_MCP23X17_MULTIPLE
+  FAR struct mcp23x17_dev_s *flink;     /* Supports a singly linked list of drivers */
+#endif
+
   FAR struct mcp23x17_config_s *config; /* Board configuration data */
   FAR struct i2c_master_s *i2c;         /* Saved I2C driver instance */
   mutex_t lock;                         /* Mutual exclusion */