iio: dac: cio-dac: Utilize iomap interface

This driver doesn't need to access I/O ports directly via inb()/outb()
and friends. This patch abstracts such access by calling ioport_map()
to enable the use of more typical ioread8()/iowrite8() I/O memory
accessor calls.
Suggested-by: David Laight <David.Laight@ACULAB.COM>
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/c973ce9a326131552caf762381edf8e90be43cc5.1652201921.git.william.gray@linaro.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/dac/cio-dac.c

@@ -41,7 +41,7 @@ MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
  */
 struct cio_dac_iio {
 	int chan_out_states[CIO_DAC_NUM_CHAN];
-	unsigned int base;
+	void __iomem *base;
 };
 
 static int cio_dac_read_raw(struct iio_dev *indio_dev,
@@ -71,7 +71,7 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev,
 		return -EINVAL;
 
 	priv->chan_out_states[chan->channel] = val;
-	outw(val, priv->base + chan_addr_offset);
+	iowrite16(val, priv->base + chan_addr_offset);
 
 	return 0;
 }
@@ -105,18 +105,20 @@ static int cio_dac_probe(struct device *dev, unsigned int id)
 		return -EBUSY;
 	}
 
+	priv = iio_priv(indio_dev);
+	priv->base = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
+	if (!priv->base)
+		return -ENOMEM;
+
 	indio_dev->info = &cio_dac_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = cio_dac_channels;
 	indio_dev->num_channels = CIO_DAC_NUM_CHAN;
 	indio_dev->name = dev_name(dev);
 
-	priv = iio_priv(indio_dev);
-	priv->base = base[id];
-
 	/* initialize DAC outputs to 0V */
 	for (i = 0; i < 32; i += 2)
-		outw(0, base[id] + i);
+		iowrite16(0, priv->base + i);
 
 	return devm_iio_device_register(dev, indio_dev);
 }