serdev: add method to set parity

Adds serdev_device_set_parity() and an implementation for ttyport.
The interface uses an enum with the values SERIAL_PARITY_NONE,
SERIAL_PARITY_EVEN and SERIAL_PARITY_ODD.
Signed-off-by: NUlrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: NSebastian Reichel <sebastian.reichel@collabora.co.uk>
Reviewed-by: NJohan Hovold <johan@kernel.org>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>

drivers/tty/serdev/core.c

@@ -225,6 +225,18 @@ void serdev_device_set_flow_control(struct serdev_device *serdev, bool enable)
 }
 EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
 
+int serdev_device_set_parity(struct serdev_device *serdev,
+			     enum serdev_parity parity)
+{
+	struct serdev_controller *ctrl = serdev->ctrl;
+
+	if (!ctrl || !ctrl->ops->set_parity)
+		return -ENOTSUPP;
+
+	return ctrl->ops->set_parity(ctrl, parity);
+}
+EXPORT_SYMBOL_GPL(serdev_device_set_parity);
+
 void serdev_device_wait_until_sent(struct serdev_device *serdev, long timeout)
 {
 	struct serdev_controller *ctrl = serdev->ctrl;

drivers/tty/serdev/serdev-ttyport.c

@@ -190,6 +190,29 @@ static void ttyport_set_flow_control(struct serdev_controller *ctrl, bool enable
 	tty_set_termios(tty, &ktermios);
 }
 
+static int ttyport_set_parity(struct serdev_controller *ctrl,
+			      enum serdev_parity parity)
+{
+	struct serport *serport = serdev_controller_get_drvdata(ctrl);
+	struct tty_struct *tty = serport->tty;
+	struct ktermios ktermios = tty->termios;
+
+	ktermios.c_cflag &= ~(PARENB | PARODD | CMSPAR);
+	if (parity != SERDEV_PARITY_NONE) {
+		ktermios.c_cflag |= PARENB;
+		if (parity == SERDEV_PARITY_ODD)
+			ktermios.c_cflag |= PARODD;
+	}
+
+	tty_set_termios(tty, &ktermios);
+
+	if ((tty->termios.c_cflag & (PARENB | PARODD | CMSPAR)) !=
+	    (ktermios.c_cflag & (PARENB | PARODD | CMSPAR)))
+		return -EINVAL;
+
+	return 0;
+}
+
 static void ttyport_wait_until_sent(struct serdev_controller *ctrl, long timeout)
 {
 	struct serport *serport = serdev_controller_get_drvdata(ctrl);
@@ -227,6 +250,7 @@ static const struct serdev_controller_ops ctrl_ops = {
 	.open = ttyport_open,
 	.close = ttyport_close,
 	.set_flow_control = ttyport_set_flow_control,
+	.set_parity = ttyport_set_parity,
 	.set_baudrate = ttyport_set_baudrate,
 	.wait_until_sent = ttyport_wait_until_sent,
 	.get_tiocm = ttyport_get_tiocm,

include/linux/serdev.h

@@ -76,6 +76,12 @@ static inline struct serdev_device_driver *to_serdev_device_driver(struct device
 	return container_of(d, struct serdev_device_driver, driver);
 }
 
+enum serdev_parity {
+	SERDEV_PARITY_NONE,
+	SERDEV_PARITY_EVEN,
+	SERDEV_PARITY_ODD,
+};
+
 /*
  * serdev controller structures
  */
@@ -86,6 +92,7 @@ struct serdev_controller_ops {
 	int (*open)(struct serdev_controller *);
 	void (*close)(struct serdev_controller *);
 	void (*set_flow_control)(struct serdev_controller *, bool);
+	int (*set_parity)(struct serdev_controller *, enum serdev_parity);
 	unsigned int (*set_baudrate)(struct serdev_controller *, unsigned int);
 	void (*wait_until_sent)(struct serdev_controller *, long);
 	int (*get_tiocm)(struct serdev_controller *);
@@ -298,6 +305,9 @@ static inline int serdev_device_set_rts(struct serdev_device *serdev, bool enabl
 		return serdev_device_set_tiocm(serdev, 0, TIOCM_RTS);
 }
 
+int serdev_device_set_parity(struct serdev_device *serdev,
+			     enum serdev_parity parity);
+
 /*
  * serdev hooks into TTY core
  */