From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Sasha Levin" <sashal@kernel.org>,
linux-pwm@vger.kernel.org,
"Thierry Reding" <thierry.reding@gmail.com>,
linux-arm-kernel@lists.infradead.org,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Subject: [PATCH AUTOSEL 5.7 317/388] pwm: imx27: Fix rounding behavior
Date: Wed, 17 Jun 2020 21:06:54 -0400 [thread overview]
Message-ID: <20200618010805.600873-317-sashal@kernel.org> (raw)
In-Reply-To: <20200618010805.600873-1-sashal@kernel.org>
From: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[ Upstream commit aef1a3799b5cb3ba4841f6034497b179646ccc70 ]
To not trigger the warnings provided by CONFIG_PWM_DEBUG
- use up-rounding in .get_state()
- don't divide by the result of a division
- don't use the rounded counter value for the period length to calculate
the counter value for the duty cycle
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pwm/pwm-imx27.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/pwm/pwm-imx27.c b/drivers/pwm/pwm-imx27.c
index a6e40d4c485f..732a6f3701e8 100644
--- a/drivers/pwm/pwm-imx27.c
+++ b/drivers/pwm/pwm-imx27.c
@@ -150,13 +150,12 @@ static void pwm_imx27_get_state(struct pwm_chip *chip,
prescaler = MX3_PWMCR_PRESCALER_GET(val);
pwm_clk = clk_get_rate(imx->clk_per);
- pwm_clk = DIV_ROUND_CLOSEST_ULL(pwm_clk, prescaler);
val = readl(imx->mmio_base + MX3_PWMPR);
period = val >= MX3_PWMPR_MAX ? MX3_PWMPR_MAX : val;
/* PWMOUT (Hz) = PWMCLK / (PWMPR + 2) */
- tmp = NSEC_PER_SEC * (u64)(period + 2);
- state->period = DIV_ROUND_CLOSEST_ULL(tmp, pwm_clk);
+ tmp = NSEC_PER_SEC * (u64)(period + 2) * prescaler;
+ state->period = DIV_ROUND_UP_ULL(tmp, pwm_clk);
/*
* PWMSAR can be read only if PWM is enabled. If the PWM is disabled,
@@ -167,8 +166,8 @@ static void pwm_imx27_get_state(struct pwm_chip *chip,
else
val = imx->duty_cycle;
- tmp = NSEC_PER_SEC * (u64)(val);
- state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, pwm_clk);
+ tmp = NSEC_PER_SEC * (u64)(val) * prescaler;
+ state->duty_cycle = DIV_ROUND_UP_ULL(tmp, pwm_clk);
pwm_imx27_clk_disable_unprepare(imx);
}
@@ -220,22 +219,23 @@ static int pwm_imx27_apply(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_imx27_chip *imx = to_pwm_imx27_chip(chip);
struct pwm_state cstate;
unsigned long long c;
+ unsigned long long clkrate;
int ret;
u32 cr;
pwm_get_state(pwm, &cstate);
- c = clk_get_rate(imx->clk_per);
- c *= state->period;
+ clkrate = clk_get_rate(imx->clk_per);
+ c = clkrate * state->period;
- do_div(c, 1000000000);
+ do_div(c, NSEC_PER_SEC);
period_cycles = c;
prescale = period_cycles / 0x10000 + 1;
period_cycles /= prescale;
- c = (unsigned long long)period_cycles * state->duty_cycle;
- do_div(c, state->period);
+ c = clkrate * state->duty_cycle;
+ do_div(c, NSEC_PER_SEC * prescale);
duty_cycles = c;
/*
--
2.25.1
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next prev parent reply other threads:[~2020-06-18 1:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200618010805.600873-1-sashal@kernel.org>
2020-06-18 1:03 ` [PATCH AUTOSEL 5.7 087/388] pwm: img: Call pm_runtime_put() in pm_runtime_get_sync() failed case Sasha Levin
2020-06-18 1:06 ` Sasha Levin [this message]
2020-06-18 1:07 ` [PATCH AUTOSEL 5.7 333/388] pwm: Add missing "CONFIG_" prefix Sasha Levin
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