staging:iio:ad7887: Rework regulator handling

Rework the regulator handling of the ad7887 driver to match more closely what we
do for other drivers. Only request the regulator if a external reference is
used, but treat it as an error if requesting the regulator fails. Also remove
the possibility to specify the reference voltage via platform data and always
use the regulator for this.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/adc/ad7887.h

@@ -30,8 +30,6 @@ enum ad7887_channels {
  */
 
 struct ad7887_platform_data {
-	/* External Vref voltage applied */
-	u16				vref_mv;
 	/*
 	 * AD7887:
 	 * In single channel mode en_dual = flase, AIN1/Vref pins assumes its
@@ -63,7 +61,6 @@ struct ad7887_state {
 	struct spi_device		*spi;
 	const struct ad7887_chip_info	*chip_info;
 	struct regulator		*reg;
-	u16				int_vref_mv;
 	struct spi_transfer		xfer[4];
 	struct spi_message		msg[3];
 	struct spi_message		*ring_msg;

drivers/staging/iio/adc/ad7887_core.c

@@ -39,7 +39,6 @@ static int ad7887_read_raw(struct iio_dev *indio_dev,
 {
 	int ret;
 	struct ad7887_state *st = iio_priv(indio_dev);
-	unsigned int scale_uv;
 
 	switch (m) {
 	case IIO_CHAN_INFO_RAW:
@@ -56,11 +55,18 @@ static int ad7887_read_raw(struct iio_dev *indio_dev,
 			RES_MASK(st->chip_info->channel[0].scan_type.realbits);
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
-		scale_uv = (st->int_vref_mv * 1000)
-			>> st->chip_info->channel[0].scan_type.realbits;
-		*val =  scale_uv/1000;
-		*val2 = (scale_uv%1000)*1000;
-		return IIO_VAL_INT_PLUS_MICRO;
+		if (st->reg) {
+			*val = regulator_get_voltage(st->reg);
+			if (*val < 0)
+				return *val;
+			*val /= 1000;
+		} else {
+			*val = st->chip_info->int_vref_mv;
+		}
+
+		*val2 = st->chip_info->channel[0].scan_type.realbits;
+
+		return IIO_VAL_FRACTIONAL_LOG2;
 	}
 	return -EINVAL;
 }
@@ -105,21 +111,24 @@ static int __devinit ad7887_probe(struct spi_device *spi)
 {
 	struct ad7887_platform_data *pdata = spi->dev.platform_data;
 	struct ad7887_state *st;
-	int ret, voltage_uv = 0;
 	struct iio_dev *indio_dev = iio_device_alloc(sizeof(*st));
+	int ret;
 
 	if (indio_dev == NULL)
 		return -ENOMEM;
 
 	st = iio_priv(indio_dev);
 
-	st->reg = regulator_get(&spi->dev, "vcc");
-	if (!IS_ERR(st->reg)) {
+	if (!pdata || !pdata->use_onchip_ref) {
+		st->reg = regulator_get(&spi->dev, "vref");
+		if (IS_ERR(st->reg)) {
+			ret = PTR_ERR(st->reg);
+			goto error_free;
+		}
+
 		ret = regulator_enable(st->reg);
 		if (ret)
 			goto error_put_reg;
-
-		voltage_uv = regulator_get_voltage(st->reg);
 	}
 
 	st->chip_info =
@@ -176,23 +185,9 @@ static int __devinit ad7887_probe(struct spi_device *spi)
 		spi_message_init(&st->msg[AD7887_CH1]);
 		spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);
 
-		if (pdata && pdata->vref_mv)
-			st->int_vref_mv = pdata->vref_mv;
-		else if (voltage_uv)
-			st->int_vref_mv = voltage_uv / 1000;
-		else
-			dev_warn(&spi->dev, "reference voltage unspecified\n");
-
 		indio_dev->channels = st->chip_info->channel;
 		indio_dev->num_channels = 3;
 	} else {
-		if (pdata && pdata->vref_mv)
-			st->int_vref_mv = pdata->vref_mv;
-		else if (pdata && pdata->use_onchip_ref)
-			st->int_vref_mv = st->chip_info->int_vref_mv;
-		else
-			dev_warn(&spi->dev, "reference voltage unspecified\n");
-
 		indio_dev->channels = &st->chip_info->channel[1];
 		indio_dev->num_channels = 2;
 	}
@@ -209,11 +204,12 @@ static int __devinit ad7887_probe(struct spi_device *spi)
 error_unregister_ring:
 	ad7887_ring_cleanup(indio_dev);
 error_disable_reg:
-	if (!IS_ERR(st->reg))
+	if (st->reg)
 		regulator_disable(st->reg);
 error_put_reg:
-	if (!IS_ERR(st->reg))
+	if (st->reg)
 		regulator_put(st->reg);
+error_free:
 	iio_device_free(indio_dev);
 
 	return ret;
@@ -226,7 +222,7 @@ static int __devexit ad7887_remove(struct spi_device *spi)
 
 	iio_device_unregister(indio_dev);
 	ad7887_ring_cleanup(indio_dev);
-	if (!IS_ERR(st->reg)) {
+	if (st->reg) {
 		regulator_disable(st->reg);
 		regulator_put(st->reg);
 	}