tmakin/tegra-linux-noble
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

pwm: meson: Use mul_u64_u64_div_u64() for frequency calculating

Browse Source 
BugLink: https://bugs.launchpad.net/bugs/2071621

[ 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: 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>
Signed-off-by: Manuel Diewald <manuel.diewald@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
This commit is contained in:
George Stark
2024-04-25 20:12:53 +03:00
committed by Stefan Bader
parent f01fa3c6d4
commit 53b8c0fc88
1 changed files with 2 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/pwm/pwm-meson.c
+2 -2
View File
@@ -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);