pwm: stm32: Change prototype of helper that detects npwm to prepare further changes

When the stm32 pwm driver is converted to pwmchip_alloc(), the number of
available PWM lines must be known before the driver private data can be
allocated. So rework the helper function that determines this number to
not take the driver private data struct as input parameter.

Link: https://lore.kernel.org/r/13d4d3e90a9ee1bcd04674dfdc16f242615b8320.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-stm32.c

@@ -606,7 +606,7 @@ static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
 	priv->have_complementary_output = (ccer != 0);
 }
 
-static unsigned int stm32_pwm_detect_channels(struct stm32_pwm *priv,
+static unsigned int stm32_pwm_detect_channels(struct regmap *regmap,
 					      unsigned int *num_enabled)
 {
 	u32 ccer, ccer_backup;
@@ -615,10 +615,10 @@ static unsigned int stm32_pwm_detect_channels(struct stm32_pwm *priv,
 	 * If channels enable bits don't exist writing 1 will have no
 	 * effect so we can detect and count them.
 	 */
-	regmap_read(priv->regmap, TIM_CCER, &ccer_backup);
-	regmap_set_bits(priv->regmap, TIM_CCER, TIM_CCER_CCXE);
-	regmap_read(priv->regmap, TIM_CCER, &ccer);
-	regmap_write(priv->regmap, TIM_CCER, ccer_backup);
+	regmap_read(regmap, TIM_CCER, &ccer_backup);
+	regmap_set_bits(regmap, TIM_CCER, TIM_CCER_CCXE);
+	regmap_read(regmap, TIM_CCER, &ccer);
+	regmap_write(regmap, TIM_CCER, ccer_backup);
 
 	*num_enabled = hweight32(ccer_backup & TIM_CCER_CCXE);
 
@@ -657,7 +657,7 @@ static int stm32_pwm_probe(struct platform_device *pdev)
 
 	chip->dev = dev;
 	chip->ops = &stm32pwm_ops;
-	chip->npwm = stm32_pwm_detect_channels(priv, &num_enabled);
+	chip->npwm = stm32_pwm_detect_channels(ddata->regmap, &num_enabled);
 
 	/* Initialize clock refcount to number of enabled PWM channels. */
 	for (i = 0; i < num_enabled; i++)