diff --git a/drivers/iio/adc/stx104.c b/drivers/iio/adc/stx104.c
index 55bd2dc514e9..7552351bfed9 100644
--- a/drivers/iio/adc/stx104.c
+++ b/drivers/iio/adc/stx104.c
@@ -51,7 +51,7 @@ MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
  */
 struct stx104_iio {
 	unsigned int chan_out_states[STX104_NUM_OUT_CHAN];
-	unsigned int base;
+	void __iomem *base;
 };
 
 /**
@@ -64,7 +64,7 @@ struct stx104_iio {
 struct stx104_gpio {
 	struct gpio_chip chip;
 	spinlock_t lock;
-	unsigned int base;
+	void __iomem *base;
 	unsigned int out_state;
 };
 
@@ -79,7 +79,7 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
 	switch (mask) {
 	case IIO_CHAN_INFO_HARDWAREGAIN:
 		/* get gain configuration */
-		adc_config = inb(priv->base + 11);
+		adc_config = ioread8(priv->base + 11);
 		gain = adc_config & 0x3;
 
 		*val = 1 << gain;
@@ -91,24 +91,24 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
 		}
 
 		/* select ADC channel */
-		outb(chan->channel | (chan->channel << 4), priv->base + 2);
+		iowrite8(chan->channel | (chan->channel << 4), priv->base + 2);
 
 		/* trigger ADC sample capture and wait for completion */
-		outb(0, priv->base);
-		while (inb(priv->base + 8) & BIT(7));
+		iowrite8(0, priv->base);
+		while (ioread8(priv->base + 8) & BIT(7));
 
-		*val = inw(priv->base);
+		*val = ioread16(priv->base);
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_OFFSET:
 		/* get ADC bipolar/unipolar configuration */
-		adc_config = inb(priv->base + 11);
+		adc_config = ioread8(priv->base + 11);
 		adbu = !(adc_config & BIT(2));
 
 		*val = -32768 * adbu;
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
 		/* get ADC bipolar/unipolar and gain configuration */
-		adc_config = inb(priv->base + 11);
+		adc_config = ioread8(priv->base + 11);
 		adbu = !(adc_config & BIT(2));
 		gain = adc_config & 0x3;
 
@@ -130,16 +130,16 @@ static int stx104_write_raw(struct iio_dev *indio_dev,
 		/* Only four gain states (x1, x2, x4, x8) */
 		switch (val) {
 		case 1:
-			outb(0, priv->base + 11);
+			iowrite8(0, priv->base + 11);
 			break;
 		case 2:
-			outb(1, priv->base + 11);
+			iowrite8(1, priv->base + 11);
 			break;
 		case 4:
-			outb(2, priv->base + 11);
+			iowrite8(2, priv->base + 11);
 			break;
 		case 8:
-			outb(3, priv->base + 11);
+			iowrite8(3, priv->base + 11);
 			break;
 		default:
 			return -EINVAL;
@@ -153,7 +153,7 @@ static int stx104_write_raw(struct iio_dev *indio_dev,
 				return -EINVAL;
 
 			priv->chan_out_states[chan->channel] = val;
-			outw(val, priv->base + 4 + 2 * chan->channel);
+			iowrite16(val, priv->base + 4 + 2 * chan->channel);
 
 			return 0;
 		}
@@ -222,7 +222,7 @@ static int stx104_gpio_get(struct gpio_chip *chip, unsigned int offset)
 	if (offset >= 4)
 		return -EINVAL;
 
-	return !!(inb(stx104gpio->base) & BIT(offset));
+	return !!(ioread8(stx104gpio->base) & BIT(offset));
 }
 
 static int stx104_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
@@ -230,7 +230,7 @@ static int stx104_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
 {
 	struct stx104_gpio *const stx104gpio = gpiochip_get_data(chip);
 
-	*bits = inb(stx104gpio->base);
+	*bits = ioread8(stx104gpio->base);
 
 	return 0;
 }
@@ -252,7 +252,7 @@ static void stx104_gpio_set(struct gpio_chip *chip, unsigned int offset,
 	else
 		stx104gpio->out_state &= ~mask;
 
-	outb(stx104gpio->out_state, stx104gpio->base);
+	iowrite8(stx104gpio->out_state, stx104gpio->base);
 
 	spin_unlock_irqrestore(&stx104gpio->lock, flags);
 }
@@ -279,7 +279,7 @@ static void stx104_gpio_set_multiple(struct gpio_chip *chip,
 
 	stx104gpio->out_state &= ~*mask;
 	stx104gpio->out_state |= *mask & *bits;
-	outb(stx104gpio->out_state, stx104gpio->base);
+	iowrite8(stx104gpio->out_state, stx104gpio->base);
 
 	spin_unlock_irqrestore(&stx104gpio->lock, flags);
 }
@@ -306,11 +306,16 @@ static int stx104_probe(struct device *dev, unsigned int id)
 		return -EBUSY;
 	}
 
+	priv = iio_priv(indio_dev);
+	priv->base = devm_ioport_map(dev, base[id], STX104_EXTENT);
+	if (!priv->base)
+		return -ENOMEM;
+
 	indio_dev->info = &stx104_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
 	/* determine if differential inputs */
-	if (inb(base[id] + 8) & BIT(5)) {
+	if (ioread8(priv->base + 8) & BIT(5)) {
 		indio_dev->num_channels = ARRAY_SIZE(stx104_channels_diff);
 		indio_dev->channels = stx104_channels_diff;
 	} else {
@@ -320,18 +325,15 @@ static int stx104_probe(struct device *dev, unsigned int id)
 
 	indio_dev->name = dev_name(dev);
 
-	priv = iio_priv(indio_dev);
-	priv->base = base[id];
-
 	/* configure device for software trigger operation */
-	outb(0, base[id] + 9);
+	iowrite8(0, priv->base + 9);
 
 	/* initialize gain setting to x1 */
-	outb(0, base[id] + 11);
+	iowrite8(0, priv->base + 11);
 
 	/* initialize DAC output to 0V */
-	outw(0, base[id] + 4);
-	outw(0, base[id] + 6);
+	iowrite16(0, priv->base + 4);
+	iowrite16(0, priv->base + 6);
 
 	stx104gpio->chip.label = dev_name(dev);
 	stx104gpio->chip.parent = dev;
@@ -346,7 +348,7 @@ static int stx104_probe(struct device *dev, unsigned int id)
 	stx104gpio->chip.get_multiple = stx104_gpio_get_multiple;
 	stx104gpio->chip.set = stx104_gpio_set;
 	stx104gpio->chip.set_multiple = stx104_gpio_set_multiple;
-	stx104gpio->base = base[id] + 3;
+	stx104gpio->base = priv->base + 3;
 	stx104gpio->out_state = 0x0;
 
 	spin_lock_init(&stx104gpio->lock);