diff options
| author | Josh Poimboeuf <jpoimboe@kernel.org> | 2025-04-01 12:28:59 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-04-25 10:45:20 +0200 |
| commit | 8ddbec73ea2598d8414e8f7103241b55cf877010 (patch) | |
| tree | 058d932590ef4613deb4e3a2f73ec40e93311628 | |
| parent | a0171967abdde8ccbf62473481291fdc894b0953 (diff) | |
pwm: mediatek: Prevent divide-by-zero in pwm_mediatek_config()
[ Upstream commit 7ca59947b5fcf94e7ea4029d1bd0f7c41500a161 ]
With CONFIG_COMPILE_TEST && !CONFIG_HAVE_CLK, pwm_mediatek_config() has a
divide-by-zero in the following line:
do_div(resolution, clk_get_rate(pc->clk_pwms[pwm->hwpwm]));
due to the fact that the !CONFIG_HAVE_CLK version of clk_get_rate()
returns zero.
This is presumably just a theoretical problem: COMPILE_TEST overrides
the dependency on RALINK which would select COMMON_CLK. Regardless it's
a good idea to check for the error explicitly to avoid divide-by-zero.
Fixes the following warning:
drivers/pwm/pwm-mediatek.o: warning: objtool: .text: unexpected end of section
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Link: https://lore.kernel.org/r/fb56444939325cc173e752ba199abd7aeae3bf12.1742852847.git.jpoimboe@kernel.org
[ukleinek: s/CONFIG_CLK/CONFIG_HAVE_CLK/]
Fixes: caf065f8fd58 ("pwm: Add MediaTek PWM support")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://lore.kernel.org/r/9e78a0796acba3435553ed7db1c7965dcffa6215.1743501688.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/pwm/pwm-mediatek.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c index 6adb0ed01906..6b1a75b6bd12 100644 --- a/drivers/pwm/pwm-mediatek.c +++ b/drivers/pwm/pwm-mediatek.c @@ -124,21 +124,25 @@ static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm, struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip); u32 clkdiv = 0, cnt_period, cnt_duty, reg_width = PWMDWIDTH, reg_thres = PWMTHRES; + unsigned long clk_rate; u64 resolution; int ret; ret = pwm_mediatek_clk_enable(chip, pwm); - if (ret < 0) return ret; + clk_rate = clk_get_rate(pc->clk_pwms[pwm->hwpwm]); + if (!clk_rate) + return -EINVAL; + /* Make sure we use the bus clock and not the 26MHz clock */ if (pc->soc->has_ck_26m_sel) writel(0, pc->regs + PWM_CK_26M_SEL); /* Using resolution in picosecond gets accuracy higher */ resolution = (u64)NSEC_PER_SEC * 1000; - do_div(resolution, clk_get_rate(pc->clk_pwms[pwm->hwpwm])); + do_div(resolution, clk_rate); cnt_period = DIV_ROUND_CLOSEST_ULL((u64)period_ns * 1000, resolution); while (cnt_period > 8191) { |