clocksource: timer-ti-dm: Check prescaler value

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>
Signed-off-by: Tony Lindgren <tony@atomide.com>
This commit is contained in:
Ladislav Michl 2018-02-23 11:15:01 +01:00 committed by Tony Lindgren
parent ad6e4b6fdc
commit 58a54f03e7

View File

@ -663,13 +663,13 @@ static int omap_dm_timer_set_prescaler(struct omap_dm_timer *timer,
{ {
u32 l; u32 l;
if (unlikely(!timer)) if (unlikely(!timer) || prescaler < -1 || prescaler > 7)
return -EINVAL; return -EINVAL;
omap_dm_timer_enable(timer); omap_dm_timer_enable(timer);
l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG); l = omap_dm_timer_read_reg(timer, OMAP_TIMER_CTRL_REG);
l &= ~(OMAP_TIMER_CTRL_PRE | (0x07 << 2)); l &= ~(OMAP_TIMER_CTRL_PRE | (0x07 << 2));
if (prescaler >= 0x00 && prescaler <= 0x07) { if (prescaler >= 0) {
l |= OMAP_TIMER_CTRL_PRE; l |= OMAP_TIMER_CTRL_PRE;
l |= prescaler << 2; l |= prescaler << 2;
} }