pwm: meson: Use mul_u64_u64_div_u64() for frequency calculating

While calculating frequency for the given period u64 numbers are multiplied before division what can lead to overflow in theory so use secure mul_u64_u64_div_u64() which handles overflow correctly. Fixes: 329db10 ("pwm: meson: make full use of common clock framework") Suggested-by: Uwe Kleine-König <[email protected]> Signed-off-by: George Stark <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Uwe Kleine-König <[email protected]>
sched-ext · Apr 30, 2024 · 32c44e1 · 32c44e1
1 parent 3e55111
commit 32c44e1
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c
@@ -176,7 +176,7 @@ static int meson_pwm_calc(struct pwm_chip *chip, struct pwm_device *pwm,
 
 	dev_dbg(pwmchip_parent(chip), "fin_freq: %ld Hz\n", fin_freq);
 
-	cnt = div_u64(fin_freq * period, NSEC_PER_SEC);
+	cnt = mul_u64_u64_div_u64(fin_freq, period, NSEC_PER_SEC);
 	if (cnt > 0xffff) {
 		dev_err(pwmchip_parent(chip), "unable to get period cnt\n");
 		return -EINVAL;
@@ -191,7 +191,7 @@ static int meson_pwm_calc(struct pwm_chip *chip, struct pwm_device *pwm,
 		channel->hi = 0;
 		channel->lo = cnt;
 	} else {
-		duty_cnt = div_u64(fin_freq * duty, NSEC_PER_SEC);
+		duty_cnt = mul_u64_u64_div_u64(fin_freq, duty, NSEC_PER_SEC);
 
 		dev_dbg(pwmchip_parent(chip), "duty=%llu duty_cnt=%u\n", duty, duty_cnt);