VisionFive2 Linux kernel

StarFive Tech Linux Kernel for VisionFive (JH7110) boards (mirror)

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author: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> 2021-01-15 08:32:39 +0100 committer: Thierry Reding <thierry.reding@gmail.com> 2021-02-22 15:18:36 +0100 commit: 72d6b2459dbd539c1369149e501fdc3dc8ddef16 parent: 11be938ae003c1cf157f0e80d5c9ad29a0f4c34c
Commit Summary:
pwm: iqs620a: Fix overflow and optimize calculations
Diffstat:
1 file changed, 5 insertions, 3 deletions
diff --git a/drivers/pwm/pwm-iqs620a.c b/drivers/pwm/pwm-iqs620a.c
index 5ede8255926e..14b18fb4f527 100644
--- a/drivers/pwm/pwm-iqs620a.c
+++ b/drivers/pwm/pwm-iqs620a.c
@@ -46,7 +46,8 @@ static int iqs620_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 {
 	struct iqs620_pwm_private *iqs620_pwm;
 	struct iqs62x_core *iqs62x;
-	u64 duty_scale;
+	unsigned int duty_cycle;
+	unsigned int duty_scale;
 	int ret;
 
 	if (state->polarity != PWM_POLARITY_NORMAL)
@@ -70,7 +71,8 @@ static int iqs620_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	 * For lower duty cycles (e.g. 0), the PWM output is simply disabled to
 	 * allow an external pull-down resistor to hold the GPIO3/LTX pin low.
 	 */
-	duty_scale = div_u64(state->duty_cycle * 256, IQS620_PWM_PERIOD_NS);
+	duty_cycle = min_t(u64, state->duty_cycle, IQS620_PWM_PERIOD_NS);
+	duty_scale = duty_cycle * 256 / IQS620_PWM_PERIOD_NS;
 
 	mutex_lock(&iqs620_pwm->lock);
 
@@ -82,7 +84,7 @@ static int iqs620_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	}
 
 	if (duty_scale) {
-		u8 duty_val = min_t(u64, duty_scale - 1, 0xff);
+		u8 duty_val = duty_scale - 1;
 
 		ret = regmap_write(iqs62x->regmap, IQS620_PWM_DUTY_CYCLE,
 				   duty_val);