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: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Reviewed-by: Johan Hovold <johan@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

3 files changed, 46 insertions, 0 deletions

diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index 1bef39828ca7..3c573a8caa80 100644
--- a/drivers/tty/serdev/core.c
+++ b/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;
diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c
index 247788a16f0b..1bdf2959ac5c 100644
--- a/drivers/tty/serdev/serdev-ttyport.c
+++ b/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,
diff --git a/include/linux/serdev.h b/include/linux/serdev.h
index d609e6dc5bad..a73d87b483b4 100644
--- a/include/linux/serdev.h
+++ b/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
  */