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Subject[PATCH 13/15] drivers/char: Use DIV_ROUND_CLOSEST
From: Julia Lawall <julia@diku.dk>

The kernel.h macro DIV_ROUND_CLOSEST performs the computation (x + d/2)/d
but is perhaps more readable.

The semantic patch that makes this change is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@haskernel@
@@

#include <linux/kernel.h>

@depends on haskernel@
expression x,__divisor;
@@

- (((x) + ((__divisor) / 2)) / (__divisor))
+ DIV_ROUND_CLOSEST(x,__divisor)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---
drivers/char/mmtimer.c | 5 +++--
drivers/char/riscom8.c | 12 ++++++------
2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c
index 918711a..e33acb8 100644
--- a/drivers/char/mmtimer.c
+++ b/drivers/char/mmtimer.c
@@ -788,8 +788,9 @@ static int __init mmtimer_init(void)
goto out1;
}

- mmtimer_femtoperiod = ((unsigned long)1E15 + sn_rtc_cycles_per_second /
- 2) / sn_rtc_cycles_per_second;
+ mmtimer_femtoperiod =
+ DIV_ROUND_CLOSEST((unsigned long)1E15,
+ sn_rtc_cycles_per_second);

if (request_irq(SGI_MMTIMER_VECTOR, mmtimer_interrupt, IRQF_PERCPU, MMTIMER_NAME, NULL)) {
printk(KERN_WARNING "%s: unable to allocate interrupt.",
diff --git a/drivers/char/riscom8.c b/drivers/char/riscom8.c
index 171711a..7f1bb27 100644
--- a/drivers/char/riscom8.c
+++ b/drivers/char/riscom8.c
@@ -665,8 +665,8 @@ static void rc_change_speed(struct riscom_board *bp, struct riscom_port *port)
*/

/* Set baud rate for port */
- tmp = (((RC_OSCFREQ + baud/2) / baud +
- CD180_TPC/2) / CD180_TPC);
+ tmp = DIV_ROUND_CLOSEST(DIV_ROUND_CLOSEST(RC_OSCFREQ, baud),
+ CD180_TPC);

rc_out(bp, CD180_RBPRH, (tmp >> 8) & 0xff);
rc_out(bp, CD180_TBPRH, (tmp >> 8) & 0xff);
@@ -676,12 +676,12 @@ static void rc_change_speed(struct riscom_board *bp, struct riscom_port *port)
baud = (baud + 5) / 10; /* Estimated CPS */

/* Two timer ticks seems enough to wakeup something like SLIP driver */
- tmp = ((baud + HZ/2) / HZ) * 2 - CD180_NFIFO;
+ tmp = DIV_ROUND_CLOSEST(baud, HZ) * 2 - CD180_NFIFO;
port->wakeup_chars = (tmp < 0) ? 0 : ((tmp >= SERIAL_XMIT_SIZE) ?
SERIAL_XMIT_SIZE - 1 : tmp);

/* Receiver timeout will be transmission time for 1.5 chars */
- tmp = (RISCOM_TPS + RISCOM_TPS/2 + baud/2) / baud;
+ tmp = DIV_ROUND_CLOSEST(RISCOM_TPS + RISCOM_TPS / 2, baud);
tmp = (tmp > 0xff) ? 0xff : tmp;
rc_out(bp, CD180_RTPR, tmp);

@@ -1184,7 +1184,7 @@ static int rc_set_serial_info(struct riscom_port *port,
if ((tmp.irq != bp->irq) ||
(tmp.port != bp->base) ||
(tmp.type != PORT_CIRRUS) ||
- (tmp.baud_base != (RC_OSCFREQ + CD180_TPC/2) / CD180_TPC) ||
+ (tmp.baud_base != DIV_ROUND_CLOSEST(RC_OSCFREQ, CD180_TPC)) ||
(tmp.custom_divisor != 0) ||
(tmp.xmit_fifo_size != CD180_NFIFO) ||
(tmp.flags & ~RISCOM_LEGAL_FLAGS))
@@ -1230,7 +1230,7 @@ static int rc_get_serial_info(struct riscom_port *port,
tmp.port = bp->base;
tmp.irq = bp->irq;
tmp.flags = port->port.flags;
- tmp.baud_base = (RC_OSCFREQ + CD180_TPC/2) / CD180_TPC;
+ tmp.baud_base = DIV_ROUND_CLOSEST(RC_OSCFREQ, CD180_TPC);
tmp.close_delay = port->port.close_delay * HZ/100;
tmp.closing_wait = port->port.closing_wait * HZ/100;
tmp.xmit_fifo_size = CD180_NFIFO;

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