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authorUwe Kleine-König <u.kleine-koenig@pengutronix.de>2020-04-16 10:02:45 +0200
committerThierry Reding <thierry.reding@gmail.com>2020-06-02 15:50:52 +0200
commitaef1a3799b5cb3ba4841f6034497b179646ccc70 (patch)
tree144592a7fec04b95bedbe61ab9dc9938b4134ef6 /drivers/pwm
parentcad0f2960675261584c14e8f0026cd67c60f4864 (diff)
pwm: imx27: Fix rounding behavior
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>
Diffstat (limited to 'drivers/pwm')
-rw-r--r--drivers/pwm/pwm-imx27.c20
1 files 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;
/*