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pwm: ipq: Prevent potential 32-bit integer overflow in hi_div calculation

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In ipq_pwm_get_state(), hi_div was calculated as:
  hi_div = hi_dur * (pre_div + 1);

hi_dur and (pre_div + 1) are both unsigned int (32-bit) values.
Evaluating their multiplication using 32-bit arithmetic before assigning to
the 64-bit u64 hi_div variable can overflow 32-bit unsigned math.

While effective_div explicitly uses (u64)(pwm_div + 1) * (pre_div + 1) to
prevent overflow, hi_div was missing the (u64) cast.

Fix this by casting hi_dur to (u64) before multiplication, matching the
precision used for effective_div.

Fixes: c436e3e9c2 ("pwm: Driver for qualcomm ipq6018 pwm block")
Signed-off-by: Surendra Singh Chouhan <kr494167@gmail.com>
Link: https://patch.msgid.link/20260724044854.33274-1-kr494167@gmail.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
This commit is contained in:
Surendra Singh Chouhan 2026-07-24 10:18:54 +05:30 committed by Uwe Kleine-König
parent 0de9b836a3
commit a662d944da
1 changed files with 1 additions and 1 deletions
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2
drivers/pwm/pwm-ipq.c
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@ -186,7 +186,7 @@ static int ipq_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
state->period = DIV64_U64_ROUND_UP(effective_div * NSEC_PER_SEC,
ipq_chip->clk_rate);
hi_div = hi_dur * (pre_div + 1);
hi_div = (u64)hi_dur * (pre_div + 1);
state->duty_cycle = DIV64_U64_ROUND_UP(hi_div * NSEC_PER_SEC,
ipq_chip->clk_rate);