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path: root/drivers/hwmon/pwm-fan.c
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Diffstat (limited to 'drivers/hwmon/pwm-fan.c')
-rw-r--r--drivers/hwmon/pwm-fan.c16
1 files changed, 9 insertions, 7 deletions
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index bdba2143021a..1f63807c0399 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -54,16 +54,18 @@ static irqreturn_t pulse_handler(int irq, void *dev_id)
static void sample_timer(struct timer_list *t)
{
struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer);
+ unsigned int delta = ktime_ms_delta(ktime_get(), ctx->sample_start);
int pulses;
- u64 tmp;
- pulses = atomic_read(&ctx->pulses);
- atomic_sub(pulses, &ctx->pulses);
- tmp = (u64)pulses * ktime_ms_delta(ktime_get(), ctx->sample_start) * 60;
- do_div(tmp, ctx->pulses_per_revolution * 1000);
- ctx->rpm = tmp;
+ if (delta) {
+ pulses = atomic_read(&ctx->pulses);
+ atomic_sub(pulses, &ctx->pulses);
+ ctx->rpm = (unsigned int)(pulses * 1000 * 60) /
+ (ctx->pulses_per_revolution * delta);
+
+ ctx->sample_start = ktime_get();
+ }
- ctx->sample_start = ktime_get();
mod_timer(&ctx->rpm_timer, jiffies + HZ);
}