serial: 8250: Add MSR/MCR TIOCM conversion wrapper functions

This patch adds wrapper functions to convert MSR <-> TIOCM and also
MCR <-> TIOCM. These functions are used now in serial8250_do_set_mctrl()
and serial8250_do_get_mctrl().
Signed-off-by: Stefan Roese <sr@denx.de>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Yegor Yefremov <yegorslists@googlemail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Giulio Benetti <giulio.benetti@micronovasrl.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250.h

@@ -157,6 +157,60 @@ void serial8250_rpm_put_tx(struct uart_8250_port *p);
 int serial8250_em485_init(struct uart_8250_port *p);
 void serial8250_em485_destroy(struct uart_8250_port *p);
 
+/* MCR <-> TIOCM conversion */
+static inline int serial8250_TIOCM_to_MCR(int tiocm)
+{
+	int mcr = 0;
+
+	if (tiocm & TIOCM_RTS)
+		mcr |= UART_MCR_RTS;
+	if (tiocm & TIOCM_DTR)
+		mcr |= UART_MCR_DTR;
+	if (tiocm & TIOCM_OUT1)
+		mcr |= UART_MCR_OUT1;
+	if (tiocm & TIOCM_OUT2)
+		mcr |= UART_MCR_OUT2;
+	if (tiocm & TIOCM_LOOP)
+		mcr |= UART_MCR_LOOP;
+
+	return mcr;
+}
+
+static inline int serial8250_MCR_to_TIOCM(int mcr)
+{
+	int tiocm = 0;
+
+	if (mcr & UART_MCR_RTS)
+		tiocm |= TIOCM_RTS;
+	if (mcr & UART_MCR_DTR)
+		tiocm |= TIOCM_DTR;
+	if (mcr & UART_MCR_OUT1)
+		tiocm |= TIOCM_OUT1;
+	if (mcr & UART_MCR_OUT2)
+		tiocm |= TIOCM_OUT2;
+	if (mcr & UART_MCR_LOOP)
+		tiocm |= TIOCM_LOOP;
+
+	return tiocm;
+}
+
+/* MSR <-> TIOCM conversion */
+static inline int serial8250_MSR_to_TIOCM(int msr)
+{
+	int tiocm = 0;
+
+	if (msr & UART_MSR_DCD)
+		tiocm |= TIOCM_CAR;
+	if (msr & UART_MSR_RI)
+		tiocm |= TIOCM_RNG;
+	if (msr & UART_MSR_DSR)
+		tiocm |= TIOCM_DSR;
+	if (msr & UART_MSR_CTS)
+		tiocm |= TIOCM_CTS;
+
+	return tiocm;
+}
+
 static inline void serial8250_out_MCR(struct uart_8250_port *up, int value)
 {
 	serial_out(up, UART_MCR, value);

drivers/tty/serial/8250/8250_port.c

@@ -1939,22 +1939,12 @@ unsigned int serial8250_do_get_mctrl(struct uart_port *port)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 	unsigned int status;
-	unsigned int ret;
 
 	serial8250_rpm_get(up);
 	status = serial8250_modem_status(up);
 	serial8250_rpm_put(up);
 
-	ret = 0;
-	if (status & UART_MSR_DCD)
-		ret |= TIOCM_CAR;
-	if (status & UART_MSR_RI)
-		ret |= TIOCM_RNG;
-	if (status & UART_MSR_DSR)
-		ret |= TIOCM_DSR;
-	if (status & UART_MSR_CTS)
-		ret |= TIOCM_CTS;
-	return ret;
+	return serial8250_MSR_to_TIOCM(status);
 }
 EXPORT_SYMBOL_GPL(serial8250_do_get_mctrl);
 
@@ -1968,18 +1958,9 @@ static unsigned int serial8250_get_mctrl(struct uart_port *port)
 void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
-	unsigned char mcr = 0;
+	unsigned char mcr;
 
-	if (mctrl & TIOCM_RTS)
-		mcr |= UART_MCR_RTS;
-	if (mctrl & TIOCM_DTR)
-		mcr |= UART_MCR_DTR;
-	if (mctrl & TIOCM_OUT1)
-		mcr |= UART_MCR_OUT1;
-	if (mctrl & TIOCM_OUT2)
-		mcr |= UART_MCR_OUT2;
-	if (mctrl & TIOCM_LOOP)
-		mcr |= UART_MCR_LOOP;
+	mcr = serial8250_TIOCM_to_MCR(mctrl);
 
 	mcr = (mcr & up->mcr_mask) | up->mcr_force | up->mcr;