diff options
| author | Uwe Kleine-König <u.kleine-koenig@pengutronix.de> | 2021-03-08 10:16:29 +0100 |
|---|---|---|
| committer | Uwe Kleine-König <u.kleine-koenig@pengutronix.de> | 2021-03-17 11:48:23 +0100 |
| commit | 5bef4efc448a7f280139af49d71503ffe050c45f (patch) | |
| tree | 13090c2a9ffef89db2f00bc8caaeb8376e445b74 | |
| parent | 9e346ba4a937b4633ceee2bb046117ab4e20a541 (diff) | |
| download | linux-pwm-next.tar.gz linux-pwm-next.tar.xz | |
pwm: Soften potential loss of precision in compat codepwm-next
The legacy callback .config() only uses int for period and duty_cycle
while the corresponding values in struct pwm_state are u64. To prevent
that a value bigger than INT_MAX is discarded to a very small value,
explicitly check for big values and pass INT_MAX instead of discarding.
Acked-by: Guru Das Srinagesh <gurus@codeaurora.org>
Link: https://lore.kernel.org/r/20210315080050.2337075-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
| -rw-r--r-- | drivers/pwm/core.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 4b3779d58c5a..b1adf3bb8508 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -605,9 +605,18 @@ int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state) if (state->period != pwm->state.period || state->duty_cycle != pwm->state.duty_cycle) { + int duty_cycle, period; + + /* + * The legacy callbacks use only (signed!) int for + * period and duty_cycle compared to u64 in struct + * pwm_state. So clamp the values to INT_MAX. + */ + period = min(state->period, (u64)INT_MAX); + duty_cycle = min(state->duty_cycle, (u64)INT_MAX); + err = chip->ops->config(pwm->chip, pwm, - state->duty_cycle, - state->period); + duty_cycle, period); if (err) return err; |