5.4-stable review patch. If anyone has any objections, please let me know.
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From: Josh Poimboeuf jpoimboe@kernel.org
[ 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/fb56444939325cc173e752ba199abd7aeae3bf12.174285284... [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/9e78a0796acba3435553ed7db1c7965dcffa6215.174350168... Signed-off-by: Uwe Kleine-König ukleinek@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pwm/pwm-mediatek.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/pwm/pwm-mediatek.c b/drivers/pwm/pwm-mediatek.c index 2bece32e62dad..b2a2e1f501682 100644 --- a/drivers/pwm/pwm-mediatek.c +++ b/drivers/pwm/pwm-mediatek.c @@ -125,21 +125,25 @@ 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) {