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pwm: meson: Use mul_u64_u64_div_u64() for frequency calculating

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[ Upstream commit 32c44e1fa9 ]

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: 329db102a2 ("pwm: meson: make full use of common clock framework")
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: George Stark <gnstark@salutedevices.com>
Link: https://lore.kernel.org/r/20240425171253.2752877-4-gnstark@salutedevices.com
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
George Stark 2024-04-25 20:12:53 +03:00 committed by Greg Kroah-Hartman
parent 513202bfe4
commit 132fe6c1ee
1 changed files with 2 additions and 2 deletions
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4
drivers/pwm/pwm-meson.c
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@ -175,7 +175,7 @@ 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;
@ -190,7 +190,7 @@ 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);