[PATCH 2/2] iio: dac: cio-dac: Implement and utilize register structures

William Breathitt Gray
2022-06-06T14:16:51Z

Reduce magic numbers and improve code readability by implementing and
utilizing named register data structures.

Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
---
drivers/iio/dac/cio-dac.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/drivers/iio/dac/cio-dac.c b/drivers/iio/dac/cio-dac.c
index 8080984dcb03..7860450ceaf3 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

@@ -34,14 +35,22 @@ static unsigned int num_cio_dac;
module_param_hw_array(base, uint, ioport, &num_cio_dac, 0);
MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");

+/**
+ * struct cio_dac_reg - device register structure
+ * @da: D/A data
+ */
+struct cio_dac_reg {
+ u16 da[CIO_DAC_NUM_CHAN];
+};
+
/**
* struct cio_dac_iio - IIO device private data structure
* @chan_out_states: channels' output states
- * @base: base port address of the IIO device
+ * @reg: I/O address offset for the device registers
*/
struct cio_dac_iio {
int chan_out_states[CIO_DAC_NUM_CHAN];
- void __iomem *base;
+ struct cio_dac_reg __iomem *reg;
};

static int cio_dac_read_raw(struct iio_dev *indio_dev,
@@ -61,7 +70,6 @@ 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 +79,7 @@ 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->reg->da + chan->channel);

return 0;
}
@@ -106,8 +114,8 @@ static int cio_dac_probe(struct device *dev, unsigned int id)
}

priv = iio_priv(indio_dev);
- priv->base = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
- if (!priv->base)
+ priv->reg = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
+ if (!priv->reg)
return -ENOMEM;

indio_dev->info = &cio_dac_info;
@@ -117,8 +125,8 @@ 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)
- iowrite16(0, priv->base + i);
+ for (i = 0; i < CIO_DAC_NUM_CHAN; i++)
+ iowrite16(0, priv->reg->da + i);

return devm_iio_device_register(dev, indio_dev);
}
--
2.36.1