On Sun, 2013-01-27 at 22:40 +0300, Dan Carpenter wrote:
> There is a kind of precedence problem here, but it doesn't affect how
> the code works because ->serial_signals is unsigned char.  We want to
> clear two flags here.
> 
> #define SerialSignal_RTS            0x20     /* Request to Send */
> #define SerialSignal_DTR            0x80     /* Data Terminal Ready */
> 
> Without the parenthesis then it does:
> 
>       info->serial_signals &= 0x5f;
> 
> With the parenthesis it does:
> 
>       info->serial_signals &= 0xffffff5f;
> 
> info->serial_signals is an unsigned char so the two statements are
> equivalent, but it's cleaner to add the parenthesis.  In other dtr_rts()
> functions the parenthesis are there so this makes it more consistent.


Wouldn't it be clearer still to use | instead of +

> diff --git a/drivers/char/pcmcia/synclink_cs.c 
> b/drivers/char/pcmcia/synclink_cs.c
[]
> @@ -2466,7 +2466,7 @@ static void dtr_rts(struct tty_port *port, int onoff)
>       if (onoff)
>               info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
>       else
> -             info->serial_signals &= ~SerialSignal_RTS + SerialSignal_DTR;
> +             info->serial_signals &= ~(SerialSignal_RTS + SerialSignal_DTR);

 drivers/tty/synclink.c    | 16 ++++++++--------
 drivers/tty/synclink_gt.c | 18 +++++++++---------
 drivers/tty/synclinkmp.c  | 18 +++++++++---------
 3 files changed, 26 insertions(+), 26 deletions(-)

diff --git a/drivers/tty/synclink.c b/drivers/tty/synclink.c
index 555fdc0..636ef3e 100644
--- a/drivers/tty/synclink.c
+++ b/drivers/tty/synclink.c
@@ -1850,7 +1850,7 @@ static void shutdown(struct mgsl_struct * info)
        usc_OutReg(info, PCR, (u16)((usc_InReg(info, PCR) | BIT13) | BIT12));
 
        if (!info->port.tty || info->port.tty->termios.c_cflag & HUPCL) {
-               info->serial_signals &= ~(SerialSignal_DTR + SerialSignal_RTS);
+               info->serial_signals &= ~(SerialSignal_DTR | SerialSignal_RTS);
                usc_set_serial_signals(info);
        }
 
@@ -1918,9 +1918,9 @@ static void mgsl_change_params(struct mgsl_struct *info)
        /* if B0 rate (hangup) specified then negate DTR and RTS */
        /* otherwise assert DTR and RTS */
        if (cflag & CBAUD)
-               info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
+               info->serial_signals |= SerialSignal_RTS | SerialSignal_DTR;
        else
-               info->serial_signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
+               info->serial_signals &= ~(SerialSignal_RTS | SerialSignal_DTR);
        
        /* byte size and parity */
        
@@ -3044,7 +3044,7 @@ static void mgsl_set_termios(struct tty_struct *tty, 
struct ktermios *old_termio
        /* Handle transition to B0 status */
        if (old_termios->c_cflag & CBAUD &&
            !(tty->termios.c_cflag & CBAUD)) {
-               info->serial_signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
+               info->serial_signals &= ~(SerialSignal_RTS | SerialSignal_DTR);
                spin_lock_irqsave(&info->irq_spinlock,flags);
                usc_set_serial_signals(info);
                spin_unlock_irqrestore(&info->irq_spinlock,flags);
@@ -3243,9 +3243,9 @@ static void dtr_rts(struct tty_port *port, int on)
 
        spin_lock_irqsave(&info->irq_spinlock,flags);
        if (on)
-               info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
+               info->serial_signals |= SerialSignal_RTS | SerialSignal_DTR;
        else
-               info->serial_signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
+               info->serial_signals &= ~(SerialSignal_RTS | SerialSignal_DTR);
        usc_set_serial_signals(info);
        spin_unlock_irqrestore(&info->irq_spinlock,flags);
 }
@@ -6240,7 +6240,7 @@ static void usc_get_serial_signals( struct mgsl_struct 
*info )
        u16 status;
 
        /* clear all serial signals except DTR and RTS */
-       info->serial_signals &= SerialSignal_DTR + SerialSignal_RTS;
+       info->serial_signals &= SerialSignal_DTR | SerialSignal_RTS;
 
        /* Read the Misc Interrupt status Register (MISR) to get */
        /* the V24 status signals. */
@@ -7780,7 +7780,7 @@ static int hdlcdev_open(struct net_device *dev)
        }
 
        /* assert DTR and RTS, apply hardware settings */
-       info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
+       info->serial_signals |= SerialSignal_RTS | SerialSignal_DTR;
        mgsl_program_hw(info);
 
        /* enable network layer transmit */
diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c
index ac8599a..a66539c 100644
--- a/drivers/tty/synclink_gt.c
+++ b/drivers/tty/synclink_gt.c
@@ -785,7 +785,7 @@ static void set_termios(struct tty_struct *tty, struct 
ktermios *old_termios)
        /* Handle transition to B0 status */
        if (old_termios->c_cflag & CBAUD &&
            !(tty->termios.c_cflag & CBAUD)) {
-               info->signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
+               info->signals &= ~(SerialSignal_RTS | SerialSignal_DTR);
                spin_lock_irqsave(&info->lock,flags);
                set_signals(info);
                spin_unlock_irqrestore(&info->lock,flags);
@@ -1561,7 +1561,7 @@ static int hdlcdev_open(struct net_device *dev)
        }
 
        /* assert DTR and RTS, apply hardware settings */
-       info->signals |= SerialSignal_RTS + SerialSignal_DTR;
+       info->signals |= SerialSignal_RTS | SerialSignal_DTR;
        program_hw(info);
 
        /* enable network layer transmit */
@@ -2488,7 +2488,7 @@ static void shutdown(struct slgt_info *info)
        slgt_irq_off(info, IRQ_ALL | IRQ_MASTER);
 
        if (!info->port.tty || info->port.tty->termios.c_cflag & HUPCL) {
-               info->signals &= ~(SerialSignal_DTR + SerialSignal_RTS);
+               info->signals &= ~(SerialSignal_DTR | SerialSignal_RTS);
                set_signals(info);
        }
 
@@ -2551,9 +2551,9 @@ static void change_params(struct slgt_info *info)
        /* if B0 rate (hangup) specified then negate DTR and RTS */
        /* otherwise assert DTR and RTS */
        if (cflag & CBAUD)
-               info->signals |= SerialSignal_RTS + SerialSignal_DTR;
+               info->signals |= SerialSignal_RTS | SerialSignal_DTR;
        else
-               info->signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
+               info->signals &= ~(SerialSignal_RTS | SerialSignal_DTR);
 
        /* byte size and parity */
 
@@ -3256,9 +3256,9 @@ static void dtr_rts(struct tty_port *port, int on)
 
        spin_lock_irqsave(&info->lock,flags);
        if (on)
-               info->signals |= SerialSignal_RTS + SerialSignal_DTR;
+               info->signals |= SerialSignal_RTS | SerialSignal_DTR;
        else
-               info->signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
+               info->signals &= ~(SerialSignal_RTS | SerialSignal_DTR);
        set_signals(info);
        spin_unlock_irqrestore(&info->lock,flags);
 }
@@ -4119,7 +4119,7 @@ static void reset_port(struct slgt_info *info)
        tx_stop(info);
        rx_stop(info);
 
-       info->signals &= ~(SerialSignal_DTR + SerialSignal_RTS);
+       info->signals &= ~(SerialSignal_DTR | SerialSignal_RTS);
        set_signals(info);
 
        slgt_irq_off(info, IRQ_ALL | IRQ_MASTER);
@@ -4547,7 +4547,7 @@ static void get_signals(struct slgt_info *info)
        unsigned short status = rd_reg16(info, SSR);
 
        /* clear all serial signals except DTR and RTS */
-       info->signals &= SerialSignal_DTR + SerialSignal_RTS;
+       info->signals &= SerialSignal_DTR | SerialSignal_RTS;
 
        if (status & BIT3)
                info->signals |= SerialSignal_DSR;
diff --git a/drivers/tty/synclinkmp.c b/drivers/tty/synclinkmp.c
index 5454025..620b1da 100644
--- a/drivers/tty/synclinkmp.c
+++ b/drivers/tty/synclinkmp.c
@@ -882,7 +882,7 @@ static void set_termios(struct tty_struct *tty, struct 
ktermios *old_termios)
        /* Handle transition to B0 status */
        if (old_termios->c_cflag & CBAUD &&
            !(tty->termios.c_cflag & CBAUD)) {
-               info->serial_signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
+               info->serial_signals &= ~(SerialSignal_RTS | SerialSignal_DTR);
                spin_lock_irqsave(&info->lock,flags);
                set_signals(info);
                spin_unlock_irqrestore(&info->lock,flags);
@@ -1677,7 +1677,7 @@ static int hdlcdev_open(struct net_device *dev)
        }
 
        /* assert DTR and RTS, apply hardware settings */
-       info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
+       info->serial_signals |= SerialSignal_RTS | SerialSignal_DTR;
        program_hw(info);
 
        /* enable network layer transmit */
@@ -2706,7 +2706,7 @@ static void shutdown(SLMP_INFO * info)
        reset_port(info);
 
        if (!info->port.tty || info->port.tty->termios.c_cflag & HUPCL) {
-               info->serial_signals &= ~(SerialSignal_DTR + SerialSignal_RTS);
+               info->serial_signals &= ~(SerialSignal_DTR | SerialSignal_RTS);
                set_signals(info);
        }
 
@@ -2771,9 +2771,9 @@ static void change_params(SLMP_INFO *info)
        /* if B0 rate (hangup) specified then negate DTR and RTS */
        /* otherwise assert DTR and RTS */
        if (cflag & CBAUD)
-               info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
+               info->serial_signals |= SerialSignal_RTS | SerialSignal_DTR;
        else
-               info->serial_signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
+               info->serial_signals &= ~(SerialSignal_RTS | SerialSignal_DTR);
 
        /* byte size and parity */
 
@@ -3272,9 +3272,9 @@ static void dtr_rts(struct tty_port *port, int on)
 
        spin_lock_irqsave(&info->lock,flags);
        if (on)
-               info->serial_signals |= SerialSignal_RTS + SerialSignal_DTR;
+               info->serial_signals |= SerialSignal_RTS | SerialSignal_DTR;
        else
-               info->serial_signals &= ~(SerialSignal_RTS + SerialSignal_DTR);
+               info->serial_signals &= ~(SerialSignal_RTS | SerialSignal_DTR);
        set_signals(info);
        spin_unlock_irqrestore(&info->lock,flags);
 }
@@ -4354,7 +4354,7 @@ static void reset_port(SLMP_INFO *info)
                tx_stop(info);
                rx_stop(info);
 
-               info->serial_signals &= ~(SerialSignal_DTR + SerialSignal_RTS);
+               info->serial_signals &= ~(SerialSignal_DTR | SerialSignal_RTS);
                set_signals(info);
 
                /* disable all port interrupts */
@@ -4751,7 +4751,7 @@ static void get_signals(SLMP_INFO *info)
        u16 testbit;
 
        /* clear all serial signals except DTR and RTS */
-       info->serial_signals &= SerialSignal_DTR + SerialSignal_RTS;
+       info->serial_signals &= SerialSignal_DTR | SerialSignal_RTS;
 
        /* set serial signal bits to reflect MISR */
 


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