iio: adc: stx104: Implement and utilize register structures

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

Tested-by: Fred Eckert <Frede@cmslaser.com>
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Link: https://lore.kernel.org/r/8cb91d5b53e57b066120e42ea07000d6c7ef5543.1657213745.git.william.gray@linaro.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/stx104.c b/drivers/iio/adc/stx104.c
index 7552351bfed9ec06bbe0f719af0f81ac6a58eafd..48a91a95e597b306a3bd194d7f26d90c10b6fc58 100644 (file)
--- a/drivers/iio/adc/stx104.c
+++ b/drivers/iio/adc/stx104.c
@@ -16,6 +16,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/spinlock.h>
+#include <linux/types.h>
 
 #define STX104_OUT_CHAN(chan) {                                \
        .type = IIO_VOLTAGE,                            \
@@ -44,14 +45,36 @@ static unsigned int num_stx104;
 module_param_hw_array(base, uint, ioport, &num_stx104, 0);
 MODULE_PARM_DESC(base, "Apex Embedded Systems STX104 base addresses");
 
+/**
+ * struct stx104_reg - device register structure
+ * @ssr_ad:    Software Strobe Register and ADC Data
+ * @achan:     ADC Channel
+ * @dio:       Digital I/O
+ * @dac:       DAC Channels
+ * @cir_asr:   Clear Interrupts and ADC Status
+ * @acr:       ADC Control
+ * @pccr_fsh:  Pacer Clock Control and FIFO Status MSB
+ * @acfg:      ADC Configuration
+ */
+struct stx104_reg {
+       u16 ssr_ad;
+       u8 achan;
+       u8 dio;
+       u16 dac[2];
+       u8 cir_asr;
+       u8 acr;
+       u8 pccr_fsh;
+       u8 acfg;
+};
+
 /**
  * struct stx104_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 stx104_iio {
        unsigned int chan_out_states[STX104_NUM_OUT_CHAN];
-       void __iomem *base;
+       struct stx104_reg __iomem *reg;
 };
 
 /**
@@ -64,7 +87,7 @@ struct stx104_iio {
 struct stx104_gpio {
        struct gpio_chip chip;
        spinlock_t lock;
-       void __iomem *base;
+       u8 __iomem *base;
        unsigned int out_state;
 };
 
@@ -72,6 +95,7 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
        struct iio_chan_spec const *chan, int *val, int *val2, long mask)
 {
        struct stx104_iio *const priv = iio_priv(indio_dev);
+       struct stx104_reg __iomem *const reg = priv->reg;
        unsigned int adc_config;
        int adbu;
        int gain;
@@ -79,7 +103,7 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
        switch (mask) {
        case IIO_CHAN_INFO_HARDWAREGAIN:
                /* get gain configuration */
-               adc_config = ioread8(priv->base + 11);
+               adc_config = ioread8(&reg->acfg);
                gain = adc_config & 0x3;
 
                *val = 1 << gain;
@@ -91,24 +115,26 @@ static int stx104_read_raw(struct iio_dev *indio_dev,
                }
 
                /* select ADC channel */
-               iowrite8(chan->channel | (chan->channel << 4), priv->base + 2);
+               iowrite8(chan->channel | (chan->channel << 4), &reg->achan);
 
-               /* trigger ADC sample capture and wait for completion */
-               iowrite8(0, priv->base);
-               while (ioread8(priv->base + 8) & BIT(7));
+               /* trigger ADC sample capture by writing to the 8-bit
+                * Software Strobe Register and wait for completion
+                */
+               iowrite8(0, &reg->ssr_ad);
+               while (ioread8(&reg->cir_asr) & BIT(7));
 
-               *val = ioread16(priv->base);
+               *val = ioread16(&reg->ssr_ad);
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_OFFSET:
                /* get ADC bipolar/unipolar configuration */
-               adc_config = ioread8(priv->base + 11);
+               adc_config = ioread8(&reg->acfg);
                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 = ioread8(priv->base + 11);
+               adc_config = ioread8(&reg->acfg);
                adbu = !(adc_config & BIT(2));
                gain = adc_config & 0x3;
 
@@ -130,16 +156,16 @@ static int stx104_write_raw(struct iio_dev *indio_dev,
                /* Only four gain states (x1, x2, x4, x8) */
                switch (val) {
                case 1:
-                       iowrite8(0, priv->base + 11);
+                       iowrite8(0, &priv->reg->acfg);
                        break;
                case 2:
-                       iowrite8(1, priv->base + 11);
+                       iowrite8(1, &priv->reg->acfg);
                        break;
                case 4:
-                       iowrite8(2, priv->base + 11);
+                       iowrite8(2, &priv->reg->acfg);
                        break;
                case 8:
-                       iowrite8(3, priv->base + 11);
+                       iowrite8(3, &priv->reg->acfg);
                        break;
                default:
                        return -EINVAL;
@@ -153,7 +179,7 @@ static int stx104_write_raw(struct iio_dev *indio_dev,
                                return -EINVAL;
 
                        priv->chan_out_states[chan->channel] = val;
-                       iowrite16(val, priv->base + 4 + 2 * chan->channel);
+                       iowrite16(val, &priv->reg->dac[chan->channel]);
 
                        return 0;
                }
@@ -307,15 +333,15 @@ static int stx104_probe(struct device *dev, unsigned int id)
        }
 
        priv = iio_priv(indio_dev);
-       priv->base = devm_ioport_map(dev, base[id], STX104_EXTENT);
-       if (!priv->base)
+       priv->reg = devm_ioport_map(dev, base[id], STX104_EXTENT);
+       if (!priv->reg)
                return -ENOMEM;
 
        indio_dev->info = &stx104_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
 
        /* determine if differential inputs */
-       if (ioread8(priv->base + 8) & BIT(5)) {
+       if (ioread8(&priv->reg->cir_asr) & BIT(5)) {
                indio_dev->num_channels = ARRAY_SIZE(stx104_channels_diff);
                indio_dev->channels = stx104_channels_diff;
        } else {
@@ -326,14 +352,14 @@ static int stx104_probe(struct device *dev, unsigned int id)
        indio_dev->name = dev_name(dev);
 
        /* configure device for software trigger operation */
-       iowrite8(0, priv->base + 9);
+       iowrite8(0, &priv->reg->acr);
 
        /* initialize gain setting to x1 */
-       iowrite8(0, priv->base + 11);
+       iowrite8(0, &priv->reg->acfg);
 
        /* initialize DAC output to 0V */
-       iowrite16(0, priv->base + 4);
-       iowrite16(0, priv->base + 6);
+       iowrite16(0, &priv->reg->dac[0]);
+       iowrite16(0, &priv->reg->dac[1]);
 
        stx104gpio->chip.label = dev_name(dev);
        stx104gpio->chip.parent = dev;
@@ -348,7 +374,7 @@ 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 = priv->base + 3;
+       stx104gpio->base = &priv->reg->dio;
        stx104gpio->out_state = 0x0;
 
        spin_lock_init(&stx104gpio->lock);