analog: add comp enable/disable ioctl and STM32 support

arch/arm/src/common/stm32/Kconfig.comp

@@ -4,6 +4,12 @@
 
 # COMP supported only for M3M4 for now
 
+config STM32_COMP_INIT_DISABLED
+	bool "Do not enable the comparator at initialization"
+	default n
+	---help---
+		The comparator is kept disabled until ioctl() enable command.
+
 if STM32_HAVE_IP_COMP_M3M4_V2
 
 if STM32_COMP1

arch/arm/src/common/stm32/stm32_comp_m3m4_v2.c

@@ -764,6 +764,7 @@ static int comp_config(struct stm32_comp_s *priv)
 
   comp_putreg_csr(priv, regval);
 
+#ifndef CONFIG_STM32_COMP_INIT_DISABLED
   /* Enable Comparator */
 
   comp_enable(priv, true);
@@ -774,6 +775,7 @@ static int comp_config(struct stm32_comp_s *priv)
     {
       comp_lock_set(priv, true);
     }
+#endif
 
   return OK;
 }
@@ -918,8 +920,41 @@ static int comp_read(struct comp_dev_s *dev)
 #ifdef CONFIG_COMP
 static int comp_ioctl(struct comp_dev_s *dev, int cmd, unsigned long arg)
 {
-#warning "Missing logic"
-  return -ENOTTY;
+  FAR struct stm32_comp_s *priv = (FAR struct stm32_comp_s *)dev->ad_priv;
+  int ret = OK;
+
+  switch (cmd)
+    {
+      case ANIOC_COMP_ENABLE:
+        {
+          /* Enable comparator */
+
+          ret = comp_enable(priv, true);
+          if (ret == OK && priv->lock)
+            {
+              comp_lock_set(priv, true);
+            }
+
+          break;
+        }
+
+      case ANIOC_COMP_DISABLE:
+        {
+          /* Disable comparator */
+
+          ret = comp_enable(priv, false);
+          break;
+        }
+
+      default:
+        {
+          aerr("ERROR: Unknown cmd: %d\n", cmd);
+          ret = -ENOTTY;
+          break;
+        }
+    }
+
+  return ret;
 }
 #endif
 
@@ -954,57 +989,57 @@ struct comp_dev_s *stm32_compinitialize(int intf)
   switch (intf)
     {
 #ifdef CONFIG_STM32_COMP1
-    case 1:
-      ainfo("COMP1 selected\n");
-      dev = &g_comp1dev;
-      break;
+      case 1:
+        ainfo("COMP1 selected\n");
+        dev = &g_comp1dev;
+        break;
 #endif
 
 #ifdef CONFIG_STM32_COMP2
-    case 2:
-      ainfo("COMP2 selected\n");
-      dev = &g_comp2dev;
-      break;
+      case 2:
+        ainfo("COMP2 selected\n");
+        dev = &g_comp2dev;
+        break;
 #endif
 
 #ifdef CONFIG_STM32_COMP3
-    case 3:
-      ainfo("COMP3 selected\n");
-      dev = &g_comp3dev;
-      break;
+      case 3:
+        ainfo("COMP3 selected\n");
+        dev = &g_comp3dev;
+        break;
 #endif
 
 #ifdef CONFIG_STM32_COMP4
-    case 4:
-      ainfo("COMP4 selected\n");
-      dev = &g_comp4dev;
-      break;
+      case 4:
+        ainfo("COMP4 selected\n");
+        dev = &g_comp4dev;
+        break;
 #endif
 
 #ifdef CONFIG_STM32_COMP5
-    case 5:
-      ainfo("COMP5 selected\n");
-      dev = &g_comp5dev;
-      break;
+      case 5:
+        ainfo("COMP5 selected\n");
+        dev = &g_comp5dev;
+        break;
 #endif
 
 #ifdef CONFIG_STM32_COMP6
-    case 6:
-      ainfo("COMP6 selected\n");
-      dev = &g_comp6dev;
-      break;
+      case 6:
+        ainfo("COMP6 selected\n");
+        dev = &g_comp6dev;
+        break;
 #endif
 
 #ifdef CONFIG_STM32_COMP7
-    case 7:
-      ainfo("COMP7 selected\n");
-      dev = &g_comp7dev;
-      break;
+      case 7:
+        ainfo("COMP7 selected\n");
+        dev = &g_comp7dev;
+        break;
 #endif
 
-    default:
-      aerr("ERROR: No COMP interface defined\n");
-      return NULL;
+      default:
+        aerr("ERROR: No COMP interface defined\n");
+        return NULL;
     }
 
   /* Configure selected comparator */

boards/arm/stm32g4/nucleo-g431kb/configs/comp/defconfig

@@ -19,6 +19,7 @@ CONFIG_BUILTIN=y
 CONFIG_COMP=y
 CONFIG_DAC=y
 CONFIG_DEFAULT_SMALL=y
+CONFIG_EXAMPLES_COMP=y
 CONFIG_EXAMPLES_DAC=y
 CONFIG_EXAMPLES_DAC_DEVPATH="/dev/dac5"
 CONFIG_FILE_STREAM=y
@@ -37,6 +38,7 @@ CONFIG_STM32_COMP2=y
 CONFIG_STM32_COMP2_HYST=3
 CONFIG_STM32_COMP2_INM=4
 CONFIG_STM32_COMP2_OUT=y
+CONFIG_STM32_COMP_INIT_DISABLED=y
 CONFIG_STM32_DAC3=y
 CONFIG_STM32_DAC3CH2=y
 CONFIG_STM32_DAC3CH2_MODE=3

include/nuttx/analog/ioctl.h

@@ -86,8 +86,17 @@
                                                  * IN: None
                                                  * OUT: struct dac_info_s * */
 
+/* COMP */
+
+#define ANIOC_COMP_ENABLE       _ANIOC(0x000d)  /* Enable comparator
+                                                 * IN: None
+                                                 * OUT: None */
+#define ANIOC_COMP_DISABLE      _ANIOC(0x000e)  /* Disable comparator
+                                                 * IN: None
+                                                 * OUT: None */
+
 #define AN_FIRST          0x0001          /* First common command */
-#define AN_NCMDS          12              /* Number of common commands */
+#define AN_NCMDS          14              /* Number of common commands */
 
 /* User defined ioctl commands are also supported. These will be forwarded
  * by the upper-half driver to the lower-half driver via the ioctl()