diff --git a/drivers/timers/mcp794xx.c b/drivers/timers/mcp794xx.c
index 54953a0c73..2734c87f5a 100644
--- a/drivers/timers/mcp794xx.c
+++ b/drivers/timers/mcp794xx.c
@@ -77,6 +77,7 @@ struct mcp794xx_dev_s
 {
   FAR struct i2c_master_s *i2c;  /* Contained reference to the I2C bus driver. */
   uint8_t addr;                  /* The I2C device address. */
+  bool coarse_trim;              /* Coarse trim mode */
 };
 
 /****************************************************************************
@@ -182,6 +183,105 @@ static int rtc_bcd2bin(uint8_t value)
  * Public Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: mcp794xx_rtc_set_trim
+ *
+ * Description:
+ *   Sets the digital trimming to correct for inaccuracies of clock source.
+ *   Digital trimming consists of the MCP794XX periodically adding or
+ *   subtracting clock cycles, resulting in small adjustments in the internal
+ *   timing.
+ *
+ * Input Parameters:
+ *   trim_val    - Calculated trimming value, refer to MCP794XX reference
+ *                 manual.
+ *   rtc_slow    - True indicates RTC is behind real clock, false otherwise.
+ *                 This has to be set to ensure correct trimming direction.
+ *   coarse_mode - MCP794XX allows coarse mode that trims every second
+ *                 instead of every minute.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno on failure
+ *
+ ****************************************************************************/
+
+int mcp794xx_rtc_set_trim(uint8_t trim_val, bool rtc_slow, bool coarse_mode)
+{
+  struct i2c_msg_s msg[2];
+  uint8_t buffer[2];
+  uint8_t address;
+  uint8_t ctrl;
+  int ret;
+
+  if (g_mcp794xx.coarse_trim != coarse_mode)
+    {
+      address = MCP794XX_REG_CONTROL;
+      msg[0].frequency = CONFIG_MCP794XX_I2C_FREQUENCY;
+      msg[0].addr      = g_mcp794xx.addr;
+      msg[0].flags     = I2C_M_NOSTOP;
+      msg[0].buffer    = &address;
+      msg[0].length    = 1;
+
+      msg[1].frequency = CONFIG_MCP794XX_I2C_FREQUENCY;
+      msg[1].addr      = g_mcp794xx.addr;
+      msg[1].flags     = I2C_M_READ;
+      msg[1].buffer    = &ctrl;
+      msg[1].length    = 1;
+
+      ret = I2C_TRANSFER(g_mcp794xx.i2c, msg, 2);
+      if (ret < 0)
+        {
+          rtcerr("ERROR: I2C_TRANSFER failed: %d\n", ret);
+          return ret;
+        }
+
+      ctrl &= ~MCP794XX_CONTROL_CRSTRIM;
+      if (coarse_mode)
+        {
+          ctrl |= MCP794XX_CONTROL_CRSTRIM;
+        }
+
+      buffer[0] = MCP794XX_REG_CONTROL;
+      buffer[1] = ctrl;
+      msg[0].frequency = CONFIG_MCP794XX_I2C_FREQUENCY;
+      msg[0].addr      = g_mcp794xx.addr;
+      msg[0].flags     = 0;
+      msg[0].buffer    = buffer;
+      msg[0].length    = 2;
+
+      ret = I2C_TRANSFER(g_mcp794xx.i2c, msg, 1);
+      if (ret < 0)
+        {
+          rtcerr("ERROR: I2C_TRANSFER failed: %d\n", ret);
+          return ret;
+        }
+
+      g_mcp794xx.coarse_trim = coarse_mode;
+    }
+
+  buffer[0] = MCP794XX_REG_OSCTRIM;
+  buffer[1] = trim_val & 0x7;
+  if (rtc_slow)
+    {
+      buffer[1] |= MCP794XX_OSCTRIM_SIGN;
+    }
+
+  msg[0].frequency = CONFIG_MCP794XX_I2C_FREQUENCY;
+  msg[0].addr      = g_mcp794xx.addr;
+  msg[0].flags     = 0;
+  msg[0].buffer    = buffer;
+  msg[0].length    = 2;
+
+  ret = I2C_TRANSFER(g_mcp794xx.i2c, msg, 1);
+  if (ret < 0)
+    {
+      rtcerr("ERROR: I2C_TRANSFER failed: %d\n", ret);
+      return ret;
+    }
+
+  return OK;
+}
+
 /****************************************************************************
  * Name: mcp794xx_rtc_initialize
  *
@@ -211,9 +311,10 @@ int mcp794xx_rtc_initialize(FAR struct i2c_master_s *i2c, uint8_t addr)
 {
   /* Remember the i2c device and claim that the RTC is enabled */
 
-  g_mcp794xx.i2c  = i2c;
-  g_mcp794xx.addr = addr;
-  g_rtc_enabled   = true;
+  g_mcp794xx.i2c         = i2c;
+  g_mcp794xx.addr        = addr;
+  g_mcp794xx.coarse_trim = false;
+  g_rtc_enabled          = true;
   return OK;
 }
 
diff --git a/include/nuttx/timers/mcp794xx.h b/include/nuttx/timers/mcp794xx.h
index 7b8abf1f9b..d75c63356c 100644
--- a/include/nuttx/timers/mcp794xx.h
+++ b/include/nuttx/timers/mcp794xx.h
@@ -41,6 +41,30 @@ extern "C"
 #define EXTERN extern
 #endif
 
+/****************************************************************************
+ * Name: mcp794xx_rtc_set_trim
+ *
+ * Description:
+ *   Sets the digital trimming to correct for inaccuracies of clock source.
+ *   Digital trimming consists of the MCP794XX periodically adding or
+ *   subtracting clock cycles, resulting in small adjustments in the internal
+ *   timing.
+ *
+ * Input Parameters:
+ *   trim_val    - Calculated trimming value, refer to MCP794XX reference
+ *                 manual.
+ *   rtc_slow    - True indicates RTC is behind real clock, false otherwise.
+ *                 This has to be set to ensure correct trimming direction.
+ *   coarse_mode - MCP794XX allows coarse mode that trims every second
+ *                 instead of every minute.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; a negated errno on failure
+ *
+ ****************************************************************************/
+
+int mcp794xx_rtc_set_trim(uint8_t trim_val, bool rtc_slow, bool coarse_mode);
+
 /****************************************************************************
  * Name: mcp794xx_rtc_initialize
  *