linux-kernel - [PATCH v4 3/3] USB: serial: cp210x: Cleaned up CRTSCTS flag code.

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Message-Id: <1462323155-27549-1-git-send-email-konstantin.shkolnyy@gmail.com>
Date:	Tue,  3 May 2016 19:52:35 -0500
From:	Konstantin Shkolnyy <konstantin.shkolnyy@...il.com>
To:	johan@...nel.org
Cc:	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	Konstantin Shkolnyy <konstantin.shkolnyy@...il.com>
Subject: [PATCH v4 3/3] USB: serial: cp210x: Cleaned up CRTSCTS flag code.

The CRTSCTS flag code cleared (and inconsistently) bits unrelated to
CRTSCTS functionality. It was also harder than necessary to read.

Signed-off-by: Konstantin Shkolnyy <konstantin.shkolnyy@...il.com>
---
v4:
Same series of patches, fixed names and defines by feedback.
v3:
Regenerated the patches correctly against the latest usb-next branch.
v2
Improved CRTSCTS fix by feedback. Dropped get_termios error handling fix.

 drivers/usb/serial/cp210x.c | 32 ++++++++++----------------------
 1 file changed, 10 insertions(+), 22 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 9857d0c..2d43716 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -995,34 +995,22 @@ static void cp210x_set_termios(struct tty_struct *tty,
 		dev_dbg(dev, "%s - read ulControlHandshake=0x%08x, ulFlowReplace=0x%08x\n",
 			__func__, ctl_hs, flow_repl);
 
+		ctl_hs &= ~CP210X_SERIAL_DSR_HANDSHAKE;
+		ctl_hs &= ~CP210X_SERIAL_DCD_HANDSHAKE;
+		ctl_hs &= ~CP210X_SERIAL_DSR_SENSITIVITY;
+		ctl_hs &= ~CP210X_SERIAL_DTR_MASK;
+		ctl_hs |= CP210X_SERIAL_DTR_SHIFT(CP210X_SERIAL_DTR_ACTIVE);
 		if (cflag & CRTSCTS) {
-			ctl_hs &= ~(CP210X_SERIAL_DTR_MASK |
-					CP210X_SERIAL_CTS_HANDSHAKE |
-					CP210X_SERIAL_DSR_HANDSHAKE |
-					CP210X_SERIAL_DCD_HANDSHAKE |
-					CP210X_SERIAL_DSR_SENSITIVITY);
-			ctl_hs |= CP210X_SERIAL_DTR_SHIFT(
-					CP210X_SERIAL_DTR_ACTIVE);
 			ctl_hs |= CP210X_SERIAL_CTS_HANDSHAKE;
-			/*
-			 * FIXME: Why clear bits unrelated to flow control.
-			 * Why clear CP210X_SERIAL_XOFF_CONTINUE which is
-			 * never set
-			 */
-			flow_repl = 0;
+
+			flow_repl &= ~CP210X_SERIAL_RTS_MASK;
 			flow_repl |= CP210X_SERIAL_RTS_SHIFT(
 					CP210X_SERIAL_RTS_FLOW_CTL);
 			dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);
 		} else {
-			ctl_hs &= ~(CP210X_SERIAL_DTR_MASK |
-					CP210X_SERIAL_CTS_HANDSHAKE |
-					CP210X_SERIAL_DSR_HANDSHAKE |
-					CP210X_SERIAL_DCD_HANDSHAKE |
-					CP210X_SERIAL_DSR_SENSITIVITY);
-			ctl_hs |= CP210X_SERIAL_DTR_SHIFT(
-					CP210X_SERIAL_DTR_ACTIVE;
-			/* FIXME: Why clear bits unrelated to flow control */
-			((u8)flow_repl) = 0;
+			ctl_hs &= ~CP210X_SERIAL_CTS_HANDSHAKE;
+
+			flow_repl &= ~CP210X_SERIAL_RTS_MASK;
 			flow_repl |= CP210X_SERIAL_RTS_SHIFT(
 					CP210X_SERIAL_RTS_ACTIVE);
 			dev_dbg(dev, "%s - flow control = NONE\n", __func__);
-- 
1.8.4.5