linux-kernel - [PATCH 4/8] USB: serial: kobil

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Message-ID: <20251022152640.24212-5-johan@kernel.org>
Date: Wed, 22 Oct 2025 17:26:36 +0200
From: Johan Hovold <johan@...nel.org>
To: Johan Hovold <johan@...nel.org>
Cc: linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 4/8] USB: serial: kobil_sct: clean up tiocmset()

Clean up the tiocmset() implementation by simplifying the flag check,
dropping some dev_dbg(), logging errors using dev_err() and using a
common control message call for both DTR and RTS to make the existing
logic easier to follow.

Note that the modem control lines are currently only manipulated in this
function, which therefore does not require any locking.

Signed-off-by: Johan Hovold <johan@...nel.org>
---
 drivers/usb/serial/kobil_sct.c | 61 +++++++++++++++-------------------
 1 file changed, 26 insertions(+), 35 deletions(-)

diff --git a/drivers/usb/serial/kobil_sct.c b/drivers/usb/serial/kobil_sct.c
index 96ea571c436a..b8169783f6f0 100644
--- a/drivers/usb/serial/kobil_sct.c
+++ b/drivers/usb/serial/kobil_sct.c
@@ -418,11 +418,10 @@ static int kobil_tiocmset(struct tty_struct *tty,
 	struct usb_serial_port *port = tty->driver_data;
 	struct device *dev = &port->dev;
 	struct kobil_private *priv;
-	int result = 0;
-	int dtr = 0;
-	int rts = 0;
+	int dtr, rts;
+	int result;
+	u16 val = 0;
 
-	/* FIXME: locking ? */
 	priv = usb_get_serial_port_data(port);
 	if (priv->device_type == KOBIL_USBTWIN_PRODUCT_ID
 		|| priv->device_type == KOBIL_KAAN_SIM_PRODUCT_ID) {
@@ -430,46 +429,38 @@ static int kobil_tiocmset(struct tty_struct *tty,
 		return -EINVAL;
 	}
 
-	if (set & TIOCM_RTS)
-		rts = 1;
-	if (set & TIOCM_DTR)
-		dtr = 1;
-	if (clear & TIOCM_RTS)
-		rts = 1;
-	if (clear & TIOCM_DTR)
-		dtr = 1;
+	dtr = (set | clear) & TIOCM_DTR;
+	rts = (set | clear) & TIOCM_RTS;
 
 	if (dtr && priv->device_type == KOBIL_ADAPTER_B_PRODUCT_ID) {
 		if (set & TIOCM_DTR)
-			dev_dbg(dev, "%s - Setting DTR\n", __func__);
+			val = SUSBCR_SSL_SETDTR;
 		else
-			dev_dbg(dev, "%s - Clearing DTR\n", __func__);
-		result = usb_control_msg(port->serial->dev,
-			  usb_sndctrlpipe(port->serial->dev, 0),
-			  SUSBCRequest_SetStatusLinesOrQueues,
-			  USB_TYPE_VENDOR | USB_RECIP_ENDPOINT | USB_DIR_OUT,
-			  ((set & TIOCM_DTR) ? SUSBCR_SSL_SETDTR : SUSBCR_SSL_CLRDTR),
-			  0,
-			  NULL,
-			  0,
-			  KOBIL_TIMEOUT);
+			val = SUSBCR_SSL_CLRDTR;
 	} else if (rts) {
 		if (set & TIOCM_RTS)
-			dev_dbg(dev, "%s - Setting RTS\n", __func__);
+			val = SUSBCR_SSL_SETRTS;
 		else
-			dev_dbg(dev, "%s - Clearing RTS\n", __func__);
+			val = SUSBCR_SSL_CLRRTS;
+	}
+
+	if (val) {
 		result = usb_control_msg(port->serial->dev,
-			usb_sndctrlpipe(port->serial->dev, 0),
-			SUSBCRequest_SetStatusLinesOrQueues,
-			USB_TYPE_VENDOR | USB_RECIP_ENDPOINT | USB_DIR_OUT,
-			((set & TIOCM_RTS) ? SUSBCR_SSL_SETRTS : SUSBCR_SSL_CLRRTS),
-			0,
-			NULL,
-			0,
-			KOBIL_TIMEOUT);
+				usb_sndctrlpipe(port->serial->dev, 0),
+				SUSBCRequest_SetStatusLinesOrQueues,
+				USB_TYPE_VENDOR | USB_RECIP_ENDPOINT | USB_DIR_OUT,
+				val,
+				0,
+				NULL,
+				0,
+				KOBIL_TIMEOUT);
+		if (result < 0) {
+			dev_err(dev, "failed to set status lines: %d\n", result);
+			return result;
+		}
 	}
-	dev_dbg(dev, "%s - Send set_status_line URB returns: %i\n", __func__, result);
-	return (result < 0) ? result : 0;
+
+	return 0;
 }
 
 static void kobil_set_termios(struct tty_struct *tty,
-- 
2.49.1