[PATCHv4 1/3] serial: mctrl_gpio: implement mctrl_gpio_use_rtscts

[Richard Genoud <richard.genoud@gmail.com>]

This function returns true if CTS and RTS are used as GPIOs.
Some drivers (like atmel_serial) needs to know if the flow control is
handled by the controller or by GPIOs.

Signed-off-by: Richard Genoud <richard.genoud@gmail.com>
---
 drivers/tty/serial/serial_mctrl_gpio.c |  7 +++++++
 drivers/tty/serial/serial_mctrl_gpio.h | 10 ++++++++++
 2 files changed, 17 insertions(+)

diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c
index d2da6aa7f27d..38e6e784faa2 100644
--- a/drivers/tty/serial/serial_mctrl_gpio.c
+++ b/drivers/tty/serial/serial_mctrl_gpio.c
@@ -72,6 +72,13 @@ struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
 }
 EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
 
+bool mctrl_gpio_use_rtscts(struct mctrl_gpios *gpios)
+{
+	return mctrl_gpio_to_gpiod(gpios, UART_GPIO_CTS) &&
+		mctrl_gpio_to_gpiod(gpios, UART_GPIO_RTS);
+}
+EXPORT_SYMBOL_GPL(mctrl_gpio_use_rtscts);
+
 unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
 {
 	enum mctrl_gpio_idx i;
diff --git a/drivers/tty/serial/serial_mctrl_gpio.h b/drivers/tty/serial/serial_mctrl_gpio.h
index fa000bcff217..c34269733c62 100644
--- a/drivers/tty/serial/serial_mctrl_gpio.h
+++ b/drivers/tty/serial/serial_mctrl_gpio.h
@@ -101,6 +101,11 @@ void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios);
  */
 void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios);
 
+/*
+ * Return true if both CTS and RTS are used with GPIOs
+ */
+bool mctrl_gpio_use_rtscts(struct mctrl_gpios *gpios);
+
 #else /* GPIOLIB */
 
 static inline
@@ -152,6 +157,11 @@ static inline void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
 {
 }
 
+static inline bool mctrl_gpio_use_rtscts(struct mctrl_gpios *gpios)
+{
+	return false;
+}
+
 #endif /* GPIOLIB */
 
 #endif