linux-kernel - [PATCH 4/5] USB: serial: cp210x: Prepared get

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <1458603505-26952-1-git-send-email-konstantin.shkolnyy@gmail.com>
Date:	Mon, 21 Mar 2016 18:38:25 -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 4/5] USB: serial: cp210x: Prepared get_termios() for adding error handling

Replaced several register write calls with one, to simplify adding error
handling.

Signed-off-by: Konstantin Shkolnyy <konstantin.shkolnyy@...il.com>
---
 drivers/usb/serial/cp210x.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index b2321a7..58cffc9 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -692,6 +692,7 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
 	unsigned int cflag;
 	u8 modem_ctl[16];
 	u32 baud;
+	u16 old_bits;
 	u16 bits;
 
 	cp210x_read_u32_reg(port, CP210X_GET_BAUDRATE, &baud);
@@ -702,6 +703,7 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
 	cflag = *cflagp;
 
 	cp210x_get_line_ctl(port, &bits);
+	old_bits = bits;
 	cflag &= ~CSIZE;
 	switch (bits & BITS_DATA_MASK) {
 	case BITS_DATA_5:
@@ -725,14 +727,12 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
 		cflag |= CS8;
 		bits &= ~BITS_DATA_MASK;
 		bits |= BITS_DATA_8;
-		cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
 		break;
 	default:
 		dev_dbg(dev, "%s - Unknown number of data bits, using 8\n", __func__);
 		cflag |= CS8;
 		bits &= ~BITS_DATA_MASK;
 		bits |= BITS_DATA_8;
-		cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
 		break;
 	}
 
@@ -763,7 +763,6 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
 		dev_dbg(dev, "%s - Unknown parity mode, disabling parity\n", __func__);
 		cflag &= ~PARENB;
 		bits &= ~BITS_PARITY_MASK;
-		cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
 		break;
 	}
 
@@ -775,7 +774,6 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
 	case BITS_STOP_1_5:
 		dev_dbg(dev, "%s - stop bits = 1.5 (not supported, using 1 stop bit)\n", __func__);
 		bits &= ~BITS_STOP_MASK;
-		cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
 		break;
 	case BITS_STOP_2:
 		dev_dbg(dev, "%s - stop bits = 2\n", __func__);
@@ -784,10 +782,12 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
 	default:
 		dev_dbg(dev, "%s - Unknown number of stop bits, using 1 stop bit\n", __func__);
 		bits &= ~BITS_STOP_MASK;
-		cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
 		break;
 	}
 
+	if (bits != old_bits)
+		cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
+
 	cp210x_read_reg_block(port, CP210X_GET_FLOW, modem_ctl,
 			sizeof(modem_ctl));
 	if (modem_ctl[0] & 0x08) { /* if SERIAL_CTS_HANDSHAKE */
-- 
1.8.4.5