On Sat, Mar 4, 2017 at 5:58 AM, Sebastian Reichel [off-list ref] wrote:

Add function to enable/disable RTS line.

Signed-off-by: Sebastian Reichel <redacted>
---

+static void ttyport_set_rts(struct serdev_controller *ctrl, bool enable)
+{
+       struct serport *serport = serdev_controller_get_drvdata(ctrl);
+       struct tty_struct *tty = serport->tty;
+       int status = tty->driver->ops->tiocmget(tty);
+       unsigned int set = 0;
+       unsigned int clear = 0;
+
+       if (enable) {
+               set |= (TIOCM_OUT2 | TIOCM_RTS);
+               clear = ~set;
+               set &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
+                      TIOCM_OUT2 | TIOCM_LOOP;
+               clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
+                        TIOCM_OUT2 | TIOCM_LOOP;
+               status = tty->driver->ops->tiocmset(tty, set, clear);
+       } else {
+               set &= ~(TIOCM_OUT2 | TIOCM_RTS);
+               clear = ~set;
+               set &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
+                      TIOCM_OUT2 | TIOCM_LOOP;
+               clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
+                        TIOCM_OUT2 | TIOCM_LOOP;
+               status = tty->driver->ops->tiocmset(tty, set, clear);

The logic here can be greatly simplified. Here's a patch to the
original version that I came up with, but haven't tested:

diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index de20a438a78a..0e35663c5d04 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c

@@ -264,8 +264,8 @@ void hci_uart_set_flow_control(struct hci_uart

*hu, bool enable)
        struct tty_struct *tty = hu->tty;
        struct ktermios ktermios;
        int status;
-       unsigned int set = 0;
-       unsigned int clear = 0;
+       unsigned int set;
+       unsigned int clear = TIOCM_DTR | TIOCM_OUT1 | TIOCM_LOOP;

        if (enable) {
                /* Disable hardware flow control */

@@ -280,25 +280,15 @@ void hci_uart_set_flow_control(struct hci_uart

*hu, bool enable)
                status = tty->driver->ops->tiocmget(tty);
                BT_DBG("Current tiocm 0x%x", status);

-               set &= ~(TIOCM_OUT2 | TIOCM_RTS);
-               clear = ~set;
-               set &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
-                      TIOCM_OUT2 | TIOCM_LOOP;
-               clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
-                        TIOCM_OUT2 | TIOCM_LOOP;
-               status = tty->driver->ops->tiocmset(tty, set, clear);
+               clear |= TIOCM_RTS | TIOCM_OUT2;
+               status = tty->driver->ops->tiocmset(tty, 0, clear);
                BT_DBG("Clearing RTS: %s", status ? "failed" : "success");
        } else {
                /* Set RTS to allow the device to send again */
                status = tty->driver->ops->tiocmget(tty);
                BT_DBG("Current tiocm 0x%x", status);

-               set |= (TIOCM_OUT2 | TIOCM_RTS);
-               clear = ~set;
-               set &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
-                      TIOCM_OUT2 | TIOCM_LOOP;
-               clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
-                        TIOCM_OUT2 | TIOCM_LOOP;
+               set = TIOCM_OUT2 | TIOCM_RTS;
                status = tty->driver->ops->tiocmset(tty, set, clear);
                BT_DBG("Setting RTS: %s", status ? "failed" : "success");