iio: adc: ti-adc12138: Simplify with devm_clk_get_enabled()

Driver is getting clock and almost immediately enabling it, with the
devm_request_irq() as the only relevant code executed between, thus the
probe path and cleanups can be simplified with devm_clk_get_enabled().

Move devm_request_irq() earlier, so the interrupt handler will be
registered before clock is enabled. This might be important in case
regulator supplies are enabled by other device driver and this device
raises interrupt immediately after clock sarts ticking.

The change does not reverse cleanup paths - first regulator will be
disabled, then clock and finally interrupt handler freed.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/adc/ti-adc12138.c

···
 struct adc12138 {
 	struct spi_device *spi;
 	unsigned int id;
-	/* conversion clock */
-	struct clk *cclk;
 	/* positive analog voltage reference */
 	struct regulator *vref_p;
 	/* negative analog voltage reference */
 	struct regulator *vref_n;
 	struct mutex lock;
 	struct completion complete;
-	/* The number of cclk periods for the S/H's acquisition time */
+	/* The number of conversion clock periods for the S/H's acquisition time */
 	unsigned int acquisition_time;
 	/*
 	 * Maximum size needed: 16x 2 bytes ADC data + 8 bytes timestamp.
···
 {
 	struct iio_dev *indio_dev;
 	struct adc12138 *adc;
+	struct clk *cclk;
 	int ret;
 
 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
···
 	if (ret)
 		adc->acquisition_time = 10;
 
-	adc->cclk = devm_clk_get(&spi->dev, NULL);
-	if (IS_ERR(adc->cclk))
-		return PTR_ERR(adc->cclk);
+	ret = devm_request_irq(&spi->dev, spi->irq, adc12138_eoc_handler,
+			       IRQF_TRIGGER_RISING, indio_dev->name, indio_dev);
+	if (ret)
+		return ret;
+
+	cclk = devm_clk_get_enabled(&spi->dev, NULL);
+	if (IS_ERR(cclk))
+		return PTR_ERR(cclk);
 
 	adc->vref_p = devm_regulator_get(&spi->dev, "vref-p");
 	if (IS_ERR(adc->vref_p))
···
 			return ret;
 	}
 
-	ret = devm_request_irq(&spi->dev, spi->irq, adc12138_eoc_handler,
-			       IRQF_TRIGGER_RISING, indio_dev->name, indio_dev);
-	if (ret)
-		return ret;
-
-	ret = clk_prepare_enable(adc->cclk);
-	if (ret)
-		return ret;
-
 	ret = regulator_enable(adc->vref_p);
 	if (ret)
-		goto err_clk_disable;
+		return ret;
 
 	if (!IS_ERR(adc->vref_n)) {
 		ret = regulator_enable(adc->vref_n);
···
 		regulator_disable(adc->vref_n);
 err_vref_p_disable:
 	regulator_disable(adc->vref_p);
-err_clk_disable:
-	clk_disable_unprepare(adc->cclk);
 
 	return ret;
 }
···
 	if (!IS_ERR(adc->vref_n))
 		regulator_disable(adc->vref_n);
 	regulator_disable(adc->vref_p);
-	clk_disable_unprepare(adc->cclk);
 }
 
 static const struct of_device_id adc12138_dt_ids[] = {