pwm: stm32: Use hweight32 in stm32_pwm_detect_channels

Use hweight32() to count the CCxE bits in stm32_pwm_detect_channels().
Since the return value is assigned to chip.npwm, change it to unsigned
int as well.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-stm32.c

@@ -563,10 +563,9 @@ static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
 	priv->have_complementary_output = (ccer != 0);
 }
 
-static int stm32_pwm_detect_channels(struct stm32_pwm *priv)
+static unsigned int stm32_pwm_detect_channels(struct stm32_pwm *priv)
 {
 	u32 ccer;
-	int npwm = 0;
 
 	/*
 	 * If channels enable bits don't exist writing 1 will have no
@@ -576,19 +575,7 @@ static int stm32_pwm_detect_channels(struct stm32_pwm *priv)
 	regmap_read(priv->regmap, TIM_CCER, &ccer);
 	regmap_clear_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE);
 
-	if (ccer & TIM_CCER_CC1E)
-		npwm++;
-
-	if (ccer & TIM_CCER_CC2E)
-		npwm++;
-
-	if (ccer & TIM_CCER_CC3E)
-		npwm++;
-
-	if (ccer & TIM_CCER_CC4E)
-		npwm++;
-
-	return npwm;
+	return hweight32(ccer & TIM_CCER_CCXE);
 }
 
 static int stm32_pwm_probe(struct platform_device *pdev)