diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c
index 53ea353409ce..f3b622f00047 100644
--- a/drivers/tty/serial/8250/8250_fintek.c
+++ b/drivers/tty/serial/8250/8250_fintek.c
@@ -40,6 +40,16 @@
 #define IRQ_LEVEL_LOW	0
 #define IRQ_EDGE_HIGH	BIT(5)
 
+/*
+ * F81216H clock source register, the value and mask is the same with F81866,
+ * but it's on F0h.
+ *
+ * Clock speeds for UART (register F0h)
+ * 00: 1.8432MHz.
+ * 01: 18.432MHz.
+ * 10: 24MHz.
+ * 11: 14.769MHz.
+ */
 #define RS485  0xF0
 #define RTS_INVERT BIT(5)
 #define RS485_URA BIT(4)
@@ -293,11 +303,28 @@ void fintek_8250_set_termios(struct uart_port *port, struct ktermios *termios,
 	struct fintek_8250 *pdata = port->private_data;
 	unsigned int baud = tty_termios_baud_rate(termios);
 	int i;
+	u8 reg;
 	static u32 baudrate_table[] = {115200, 921600, 1152000, 1500000};
 	static u8 clock_table[] = { F81866_UART_CLK_1_8432MHZ,
 			F81866_UART_CLK_14_769MHZ, F81866_UART_CLK_18_432MHZ,
 			F81866_UART_CLK_24MHZ };
 
+	switch (pdata->pid) {
+	case CHIP_ID_F81216H:
+		reg = RS485;
+		break;
+	case CHIP_ID_F81866:
+		reg = F81866_UART_CLK;
+		break;
+	default:
+		/* Don't change clocksource with unknown PID */
+		dev_warn(port->dev,
+			"%s: pid: %x Not support. use default set_termios.\n",
+			__func__, pdata->pid);
+		serial8250_do_set_termios(port, termios, old);
+		return;
+	}
+
 	for (i = 0; i < ARRAY_SIZE(baudrate_table); ++i) {
 		if (baud > baudrate_table[i] || baudrate_table[i] % baud != 0)
 			continue;
@@ -311,8 +338,8 @@ void fintek_8250_set_termios(struct uart_port *port, struct ktermios *termios,
 		port->uartclk = baudrate_table[i] * 16;
 
 		sio_write_reg(pdata, LDN, pdata->index);
-		sio_write_mask_reg(pdata, F81866_UART_CLK,
-				F81866_UART_CLK_MASK, clock_table[i]);
+		sio_write_mask_reg(pdata, reg, F81866_UART_CLK_MASK,
+				clock_table[i]);
 
 		fintek_8250_exit_key(pdata->base_port);
 		break;
@@ -331,6 +358,7 @@ static void fintek_8250_set_termios_handler(struct uart_8250_port *uart)
 	struct fintek_8250 *pdata = uart->port.private_data;
 
 	switch (pdata->pid) {
+	case CHIP_ID_F81216H:
 	case CHIP_ID_F81866:
 		uart->port.set_termios = fintek_8250_set_termios;
 		break;