From: Nylon Chen <nylon.chen@sifive.com>
To: "Uwe Kleine-König" <ukleinek@kernel.org>,
devicetree@vger.kernel.org, linux-pwm@vger.kernel.org,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Cc: conor@kernel.org, robh@kernel.org, krzk+dt@kernel.org,
paul.walmsley@sifive.com, palmer@dabbelt.com,
aou@eecs.berkeley.edu, samuel.holland@sifive.com,
Nylon Chen <nylon.chen@sifive.com>, Zong Li <zong.li@sifive.com>
Subject: [PATCH v14 3/5] pwm: sifive: Fix the error in the idempotent test within the pwm_apply_state_debug function
Date: Fri, 9 May 2025 17:52:32 +0800 [thread overview]
Message-ID: <20250509095234.643890-4-nylon.chen@sifive.com> (raw)
In-Reply-To: <20250509095234.643890-1-nylon.chen@sifive.com>
Round the result to the nearest whole number. This ensures that real_period
is always a reasonable integer that is not lower than the actual value.
e.g.
$ echo 110 > /sys/devices/platform/led-controller-1/leds/d12/brightness
$ .apply is not idempotent (ena=1 pol=0 1739692/4032985) -> (ena=1 pol=0
1739630/4032985)
Co-developed-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Zong Li <zong.li@sifive.com>
Signed-off-by: Nylon Chen <nylon.chen@sifive.com>
---
drivers/pwm/pwm-sifive.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c
index bb9146267bc5..6259f8500f71 100644
--- a/drivers/pwm/pwm-sifive.c
+++ b/drivers/pwm/pwm-sifive.c
@@ -101,7 +101,7 @@ static void pwm_sifive_update_clock(struct pwm_sifive_ddata *ddata,
/* As scale <= 15 the shift operation cannot overflow. */
num = (unsigned long long)NSEC_PER_SEC << (PWM_SIFIVE_CMPWIDTH + scale);
- ddata->real_period = div64_ul(num, rate);
+ ddata->real_period = DIV_ROUND_UP_ULL(num, rate);
dev_dbg(ddata->parent,
"New real_period = %u ns\n", ddata->real_period);
}
--
2.34.1
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next prev parent reply other threads:[~2025-05-09 10:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-09 9:52 [PATCH v14 0/5] Change PWM-controlled LED pin active mode and algorithm Nylon Chen
2025-05-09 9:52 ` [PATCH v14 1/5] riscv: dts: sifive: unleashed/unmatched: Remove PWM controlled LED's active-low properties Nylon Chen
2025-05-09 9:52 ` [PATCH v14 2/5] pwm: sifive: change the PWM algorithm Nylon Chen
2025-05-09 9:52 ` Nylon Chen [this message]
2025-05-09 9:52 ` [PATCH v14 4/5] pwm: sifive: Fix rounding issues in apply and get_state functions Nylon Chen
2025-05-09 9:52 ` [PATCH v14 5/5] pwm: sifive: clarify inverted compare logic in comments Nylon Chen
2025-05-28 10:21 ` [PATCH v14 0/5] Change PWM-controlled LED pin active mode and algorithm Uwe Kleine-König
2025-05-28 11:25 ` Conor Dooley
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