Fix I2CScan invalid JSON

Fix I2CScan invalid JSON error message (#3925)

sonoff/_changelog.ino

@@ -1,6 +1,7 @@
 /* 6.2.1.9 20180928
  * Add Apparent Power and Reactive Power to Energy Monitoring devices (#251)
  * Add RF Receiver control to module MagicHome to be used on Arilux LC10 (#3792)
+ * Fix I2CScan invalid JSON error message (#3925)
  *
  * 6.2.1.8 20180926
  * Change status JSON message providing more switch and retain information

sonoff/sonoff_template.h

@@ -855,35 +855,19 @@ const mytmplt kModules[MAXMODULE] PROGMEM = {
      0, 0, 0, 0, 0, 0, // Flash connection
      0, 0, 0, 0, 0
   },
-/*
-  { "MagicHome",       // Magic Home (aka Flux-light) (ESP8266)
-                       // https://www.aliexpress.com/item/Magic-Home-Mini-RGB-RGBW-Wifi-Controller-For-Led-Strip-Panel-light-Timing-Function-16million-colors/32686853650.html
-     0,
-     GPIO_USER,        // GPIO01 Serial RXD and Optional sensor
-     GPIO_LED1_INV,    // GPIO02 Blue onboard LED
-     GPIO_USER,        // GPIO03 Serial TXD and Optional sensor
-     GPIO_USER,        // GPIO04 IR receiver (optional)
-     GPIO_PWM2,        // GPIO05 RGB LED Green
-     0, 0, 0, 0, 0, 0, // Flash connection
-     GPIO_PWM3,        // GPIO12 RGB LED Blue
-     GPIO_USER,        // GPIO13 RGBW LED White (optional - set to PWM4 for Cold White or Warm White)
-     GPIO_PWM1,        // GPIO14 RGB LED Red
-     0, 0, 0
-  },
-*/
   { "MagicHome",       // Magic Home (aka Flux-light) (ESP8266) and Arilux LC10 (ESP8285)
                        // https://www.aliexpress.com/item/Magic-Home-Mini-RGB-RGBW-Wifi-Controller-For-Led-Strip-Panel-light-Timing-Function-16million-colors/32686853650.html
      0,
      GPIO_USER,        // GPIO01 Serial RXD and Optional sensor
      GPIO_LED1_INV,    // GPIO02 Blue onboard LED
      GPIO_USER,        // GPIO03 Serial TXD and Optional sensor
-     GPIO_ARIRFRCV,    // GPIO04 IR or RF receiver (optional)
+     GPIO_ARIRFRCV,    // GPIO04 IR or RF receiver (optional) (Arilux LC10)
      GPIO_PWM2,        // GPIO05 RGB LED Green
      0, 0, 0, 0, 0, 0, // Flash connection
      GPIO_PWM3,        // GPIO12 RGB LED Blue
      GPIO_USER,        // GPIO13 RGBW LED White (optional - set to PWM4 for Cold White or Warm White as used on Arilux LC10)
      GPIO_PWM1,        // GPIO14 RGB LED Red
-     GPIO_LED2_INV,    // GPIO15 RF receiver control
+     GPIO_LED2_INV,    // GPIO15 RF receiver control (Arilux LC10)
      0, 0
   },
   { "Luani HVIO",      // ESP8266_HVIO
@@ -1089,6 +1073,20 @@ const mytmplt kModules[MAXMODULE] PROGMEM = {
 /*
   Optionals
 
+  { "MagicHome",       // Magic Home (aka Flux-light) (ESP8266)
+                       // https://www.aliexpress.com/item/Magic-Home-Mini-RGB-RGBW-Wifi-Controller-For-Led-Strip-Panel-light-Timing-Function-16million-colors/32686853650.html
+     0,
+     GPIO_USER,        // GPIO01 Serial RXD and Optional sensor
+     GPIO_LED1_INV,    // GPIO02 Blue onboard LED
+     GPIO_USER,        // GPIO03 Serial TXD and Optional sensor
+     GPIO_USER,        // GPIO04 IR receiver (optional)
+     GPIO_PWM2,        // GPIO05 RGB LED Green
+     0, 0, 0, 0, 0, 0, // Flash connection
+     GPIO_PWM3,        // GPIO12 RGB LED Blue
+     GPIO_USER,        // GPIO13 RGBW LED White (optional - set to PWM4 for Cold White or Warm White)
+     GPIO_PWM1,        // GPIO14 RGB LED Red
+     0, 0, 0
+  },
   { "Arilux LC10",     // Arilux LC10 (ESP8285), RGBW + RF
                        // https://github.com/arendst/Sonoff-Tasmota/wiki/MagicHome-with-ESP8285
                        // https://www.aliexpress.com/item/DC5-24V-Wireless-WIFI-LED-RGB-Controller-RGBW-Controller-IR-RF-Remote-Control-IOS-Android-for/32827253255.html

sonoff/support.ino

@@ -1775,27 +1775,35 @@ int8_t I2cWriteBuffer(uint8_t addr, uint8_t reg, uint8_t *reg_data, uint16_t len
 
 void I2cScan(char *devs, unsigned int devs_len)
 {
-  byte error;
+  // Return error codes defined in twi.h and core_esp8266_si2c.c
-  byte address;
+  // I2C_OK                      0
+  // I2C_SCL_HELD_LOW            1 = SCL held low by another device, no procedure available to recover
+  // I2C_SCL_HELD_LOW_AFTER_READ 2 = I2C bus error. SCL held low beyond slave clock stretch time
+  // I2C_SDA_HELD_LOW            3 = I2C bus error. SDA line held low by slave/another_master after n bits
+  // I2C_SDA_HELD_LOW_AFTER_INIT 4 = line busy. SDA again held low by another device. 2nd master?
+
+  byte error = 0;
+  byte address = 0;
   byte any = 0;
-  char tstr[10];
 
   snprintf_P(devs, devs_len, PSTR("{\"" D_CMND_I2CSCAN "\":\"" D_JSON_I2CSCAN_DEVICES_FOUND_AT));
   for (address = 1; address <= 127; address++) {
     Wire.beginTransmission(address);
     error = Wire.endTransmission();
     if (0 == error) {
-      snprintf_P(tstr, sizeof(tstr), PSTR(" 0x%2x"), address);
-      strncat(devs, tstr, devs_len);
       any = 1;
+      snprintf_P(devs, devs_len, PSTR("%s 0x%02x"), devs, address);
     }
-    else if (4 == error) {
+    else if (error != 2) {  // Seems to happen anyway using this scan
-      snprintf_P(devs, devs_len, PSTR("{\"" D_CMND_I2CSCAN "\":\"" D_JSON_I2CSCAN_UNKNOWN_ERROR_AT " 0x%2x\"}"), address);
+      any = 2;
+      snprintf_P(devs, devs_len, PSTR("{\"" D_CMND_I2CSCAN "\":\"Error %d at 0x%02x"), error, address);
+      break;
     }
   }
   if (any) {
     strncat(devs, "\"}", devs_len);
-  } else {
+  }
+  else {
     snprintf_P(devs, devs_len, PSTR("{\"" D_CMND_I2CSCAN "\":\"" D_JSON_I2CSCAN_NO_DEVICES_FOUND "\"}"));
   }
 }