linux-kernel - [PATCH v2 2/2] iio: dac: cio-dac: Cleanup indexing for DAC writes

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Date:   Thu,  7 Jul 2022 13:21:25 -0400
From:   William Breathitt Gray <william.gray@...aro.org>
To:     jic23@...nel.org
Cc:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        William Breathitt Gray <william.gray@...aro.org>
Subject: [PATCH v2 2/2] iio: dac: cio-dac: Cleanup indexing for DAC writes

Simplify DAC write code by defining base member as u16 __iomem *; DAC
registers are 16-bit so this allows us to index each DAC channel
directly in a loop rather than calculating the offsets by multipling by
2 each time.

Signed-off-by: William Breathitt Gray <william.gray@...aro.org>
---
 drivers/iio/dac/cio-dac.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/dac/cio-dac.c b/drivers/iio/dac/cio-dac.c
index 8080984dcb03..791dd999cf29 100644
--- a/drivers/iio/dac/cio-dac.c
+++ b/drivers/iio/dac/cio-dac.c
@@ -16,6 +16,7 @@
 #include <linux/isa.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
+#include <linux/types.h>
 
 #define CIO_DAC_NUM_CHAN 16
 
@@ -37,11 +38,11 @@ MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
 /**
  * struct cio_dac_iio - IIO device private data structure
  * @chan_out_states:	channels' output states
- * @base:		base port address of the IIO device
+ * @base:		base memory address of the DAC device
  */
 struct cio_dac_iio {
 	int chan_out_states[CIO_DAC_NUM_CHAN];
-	void __iomem *base;
+	u16 __iomem *base;
 };
 
 static int cio_dac_read_raw(struct iio_dev *indio_dev,
@@ -61,7 +62,6 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev,
 	struct iio_chan_spec const *chan, int val, int val2, long mask)
 {
 	struct cio_dac_iio *const priv = iio_priv(indio_dev);
-	const unsigned int chan_addr_offset = 2 * chan->channel;
 
 	if (mask != IIO_CHAN_INFO_RAW)
 		return -EINVAL;
@@ -71,7 +71,7 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev,
 		return -EINVAL;
 
 	priv->chan_out_states[chan->channel] = val;
-	iowrite16(val, priv->base + chan_addr_offset);
+	iowrite16(val, priv->base + chan->channel);
 
 	return 0;
 }
@@ -117,7 +117,7 @@ static int cio_dac_probe(struct device *dev, unsigned int id)
 	indio_dev->name = dev_name(dev);
 
 	/* initialize DAC outputs to 0V */
-	for (i = 0; i < 32; i += 2)
+	for (i = 0; i < CIO_DAC_NUM_CHAN; i++)
 		iowrite16(0, priv->base + i);
 
 	return devm_iio_device_register(dev, indio_dev);
-- 
2.36.1