From: Nylon Chen <nylon.chen@sifive.com>
To: "Conor Dooley" <conor@kernel.org>,
"Rob Herring" <robh@kernel.org>,
"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
"Paul Walmsley" <paul.walmsley@sifive.com>,
"Palmer Dabbelt" <palmer@dabbelt.com>,
"Albert Ou" <aou@eecs.berkeley.edu>,
"Samuel Holland" <samuel.holland@sifive.com>,
"Uwe Kleine-König" <ukleinek@kernel.org>
Cc: linux-riscv@lists.infradead.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org,
Nylon Chen <nylon.chen@sifive.com>, Zong Li <zong.li@sifive.com>
Subject: [PATCH v13 3/5] pwm: sifive: Fix the error in the idempotent test within the pwm_apply_state_debug function
Date: Wed, 23 Apr 2025 17:04:44 +0800 [thread overview]
Message-ID: <20250423090446.294846-4-nylon.chen@sifive.com> (raw)
In-Reply-To: <20250423090446.294846-1-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:[~2025-04-23 9:59 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-23 9:04 [PATCH v13 0/5] Change PWM-controlled LED pin active mode and algorithm Nylon Chen
2025-04-23 9:04 ` [PATCH v13 1/5] riscv: dts: sifive: unleashed/unmatched: Remove PWM controlled LED's active-low properties Nylon Chen
2025-04-23 9:04 ` [PATCH v13 2/5] pwm: sifive: change the PWM algorithm Nylon Chen
2025-04-23 9:04 ` Nylon Chen [this message]
2025-04-23 9:04 ` [PATCH v13 4/5] pwm: sifive: Fix rounding issues in apply and get_state functions Nylon Chen
2025-05-07 19:23 ` kernel test robot
2025-04-23 9:04 ` [PATCH v13 5/5] pwm: sifive: clarify inverted compare logic in comments Nylon Chen
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