[PATCH 1/3] clocksource: timer-dm: Check prescaler value

Ladislav Michl
2018-01-17T21:47:14Z

Invalid value silently disables use of the prescaler.
Use -1 explicitely for that purpose and error out on
invalid value.

Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
---
drivers/clocksource/timer-dm.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clocksource/timer-dm.c b/drivers/clocksource/timer-dm.c
index 60db1734ea3b..324ec93d3dd2 100644
--- a/drivers/clocksource/timer-dm.c
+++ b/drivers/clocksource/timer-dm.c
@@ -663,13 +663,13 @@ int omap_dm_timer_set_prescaler(struct omap_dm_timer *timer, int prescaler)
{
u32 l;

- if (unlikely(!timer))
+ if (unlikely(!timer) || prescaler < -1 || prescaler > 7)
return -EINVAL;

omap_dm_timer_enable(timer);
l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG);
l &= ~(OMAP_TIMER_CTRL_PRE | (0x07 << 2));
- if (prescaler >= 0x00 && prescaler <= 0x07) {
+ if (prescaler >= 0) {
l |= OMAP_TIMER_CTRL_PRE;
l |= prescaler << 2;
}