From: George Stark Date: Thu, 25 Apr 2024 17:12:53 +0000 (+0300) Subject: pwm: meson: Use mul_u64_u64_div_u64() for frequency calculating X-Git-Tag: v6.8.12~229 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0aefb7a9c6eb5b919b3471c97139bd852729491d;p=thirdparty%2Fkernel%2Fstable.git pwm: meson: Use mul_u64_u64_div_u64() for frequency calculating [ Upstream commit 32c44e1fa921aebf8a5ef9f778534a30aab39313 ] 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: 329db102a26d ("pwm: meson: make full use of common clock framework") Suggested-by: Uwe Kleine-König Signed-off-by: George Stark Link: https://lore.kernel.org/r/20240425171253.2752877-4-gnstark@salutedevices.com Signed-off-by: Uwe Kleine-König Signed-off-by: Sasha Levin --- diff --git a/drivers/pwm/pwm-meson.c b/drivers/pwm/pwm-meson.c index 6fefa80af0a4c..52ac3277f4204 100644 --- a/drivers/pwm/pwm-meson.c +++ b/drivers/pwm/pwm-meson.c @@ -177,7 +177,7 @@ 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; @@ -192,7 +192,7 @@ 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);