[PATCH v3 1/2] staging: iio: ad7606: replace range/range_available with corresponding scale

From: Eva Rachel Retuya
Date: Sat Dec 10 2016 - 21:48:43 EST


Eliminate the non-standard attributes in_voltage_range and
in_voltage_range_available. Implement in_voltage_scale_available in place
of these attributes and update the SCALE accordingly. The array
scale_avail is introduced to hold the available scale values.

Signed-off-by: Eva Rachel Retuya <eraretuya@xxxxxxxxx>
---
Change in v3:
* Change incorrect type of 'scale' from unsigned int to unsigned long long

Changes in v2:
* Update commit message to reflect changes.
* Introduce scale_avail[] array to hold the available scales.
* Rewrite read_raw's SCALE to make use of the scale_avail[].
* Provide write_raw and write_raw_get_fmt for implementing SCALE.
* Populate the scale_avail[] with values in probe().

drivers/staging/iio/adc/ad7606.c | 100 ++++++++++++++++++++++++---------------
drivers/staging/iio/adc/ad7606.h | 1 +
2 files changed, 62 insertions(+), 39 deletions(-)

diff --git a/drivers/staging/iio/adc/ad7606.c b/drivers/staging/iio/adc/ad7606.c
index 4531908..b878664 100644
--- a/drivers/staging/iio/adc/ad7606.c
+++ b/drivers/staging/iio/adc/ad7606.c
@@ -151,9 +151,9 @@ static int ad7606_read_raw(struct iio_dev *indio_dev,
*val = (short)ret;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
- *val = st->range * 2;
- *val2 = st->chip_info->channels[0].scan_type.realbits;
- return IIO_VAL_FRACTIONAL_LOG2;
+ *val = st->scale_avail[st->range][0];
+ *val2 = st->scale_avail[st->range][1];
+ return IIO_VAL_INT_PLUS_NANO;
case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
*val = st->oversampling;
return IIO_VAL_INT;
@@ -161,42 +161,24 @@ static int ad7606_read_raw(struct iio_dev *indio_dev,
return -EINVAL;
}

-static ssize_t ad7606_show_range(struct device *dev,
- struct device_attribute *attr, char *buf)
+static ssize_t in_voltage_scale_available_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad7606_state *st = iio_priv(indio_dev);
+ int i, len = 0;

- return sprintf(buf, "%u\n", st->range);
-}
-
-static ssize_t ad7606_store_range(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t count)
-{
- struct iio_dev *indio_dev = dev_to_iio_dev(dev);
- struct ad7606_state *st = iio_priv(indio_dev);
- unsigned long lval;
- int ret;
-
- ret = kstrtoul(buf, 10, &lval);
- if (ret)
- return ret;
-
- if (!(lval == 5000 || lval == 10000))
- return -EINVAL;
+ for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++)
+ len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%09u ",
+ st->scale_avail[i][0], st->scale_avail[i][1]);

- mutex_lock(&indio_dev->mlock);
- gpiod_set_value(st->gpio_range, lval == 10000);
- st->range = lval;
- mutex_unlock(&indio_dev->mlock);
+ buf[len - 1] = '\n';

- return count;
+ return len;
}

-static IIO_DEVICE_ATTR(in_voltage_range, S_IRUGO | S_IWUSR,
- ad7606_show_range, ad7606_store_range, 0);
-static IIO_CONST_ATTR(in_voltage_range_available, "5000 10000");
+static IIO_DEVICE_ATTR_RO(in_voltage_scale_available, 0);

static int ad7606_oversampling_get_index(unsigned int val)
{
@@ -218,9 +200,23 @@ static int ad7606_write_raw(struct iio_dev *indio_dev,
{
struct ad7606_state *st = iio_priv(indio_dev);
int values[3];
- int ret;
+ int ret, i;

switch (mask) {
+ case IIO_CHAN_INFO_SCALE:
+ ret = -EINVAL;
+ mutex_lock(&indio_dev->mlock);
+ for (i = 0; i < ARRAY_SIZE(st->scale_avail); i++)
+ if (val2 == st->scale_avail[i][1]) {
+ gpiod_set_value(st->gpio_range, i);
+ st->range = i;
+
+ ret = 0;
+ break;
+ }
+ mutex_unlock(&indio_dev->mlock);
+
+ return ret;
case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
if (val2)
return -EINVAL;
@@ -244,11 +240,22 @@ static int ad7606_write_raw(struct iio_dev *indio_dev,
}
}

+static int ad7606_write_raw_get_fmt(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ long mask)
+{
+ switch (mask) {
+ case IIO_CHAN_INFO_SCALE:
+ return IIO_VAL_INT_PLUS_NANO;
+ default:
+ return -EINVAL;
+ }
+}
+
static IIO_CONST_ATTR(oversampling_ratio_available, "1 2 4 8 16 32 64");

static struct attribute *ad7606_attributes_os_and_range[] = {
- &iio_dev_attr_in_voltage_range.dev_attr.attr,
- &iio_const_attr_in_voltage_range_available.dev_attr.attr,
+ &iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
&iio_const_attr_oversampling_ratio_available.dev_attr.attr,
NULL,
};
@@ -267,8 +274,7 @@ static const struct attribute_group ad7606_attribute_group_os = {
};

static struct attribute *ad7606_attributes_range[] = {
- &iio_dev_attr_in_voltage_range.dev_attr.attr,
- &iio_const_attr_in_voltage_range_available.dev_attr.attr,
+ &iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
NULL,
};

@@ -384,6 +390,7 @@ static const struct iio_info ad7606_info_os_and_range = {
.driver_module = THIS_MODULE,
.read_raw = &ad7606_read_raw,
.write_raw = &ad7606_write_raw,
+ .write_raw_get_fmt = &ad7606_write_raw_get_fmt,
.attrs = &ad7606_attribute_group_os_and_range,
};

@@ -397,6 +404,8 @@ static const struct iio_info ad7606_info_os = {
static const struct iio_info ad7606_info_range = {
.driver_module = THIS_MODULE,
.read_raw = &ad7606_read_raw,
+ .write_raw = &ad7606_write_raw,
+ .write_raw_get_fmt = &ad7606_write_raw_get_fmt,
.attrs = &ad7606_attribute_group_range,
};

@@ -405,7 +414,9 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
const struct ad7606_bus_ops *bops)
{
struct ad7606_state *st;
- int ret;
+ unsigned int range;
+ unsigned long long scale;
+ int ret, i, j;
struct iio_dev *indio_dev;

indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
@@ -417,8 +428,19 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
st->dev = dev;
st->bops = bops;
st->base_address = base_address;
- st->range = 5000;
+ /* tied to logic low, analog input range is +/- 5V */
+ st->range = 0;
st->oversampling = 1;
+ /* Populate the scales, 2.5/2**16 then 5/2**16 */
+ range = 5000;
+ for (i = 0, j = 1; i < ARRAY_SIZE(st->scale_avail); i++, j--) {
+ scale = ((u64)range * 100000000) >>
+ ad7606_channels[1].scan_type.realbits;
+ scale >>= j;
+
+ st->scale_avail[i][1] = do_div(scale, 100000000) * 10;
+ st->scale_avail[i][0] = scale;
+ }
INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);

st->reg = devm_regulator_get(dev, "avcc");
@@ -525,7 +547,7 @@ static int ad7606_resume(struct device *dev)
struct ad7606_state *st = iio_priv(indio_dev);

if (st->gpio_standby) {
- gpiod_set_value(st->gpio_range, st->range == 10000);
+ gpiod_set_value(st->gpio_range, st->range);
gpiod_set_value(st->gpio_standby, 1);
ad7606_reset(st);
}
diff --git a/drivers/staging/iio/adc/ad7606.h b/drivers/staging/iio/adc/ad7606.h
index 746f955..671c456 100644
--- a/drivers/staging/iio/adc/ad7606.h
+++ b/drivers/staging/iio/adc/ad7606.h
@@ -34,6 +34,7 @@ struct ad7606_state {
const struct ad7606_bus_ops *bops;
unsigned int range;
unsigned int oversampling;
+ unsigned int scale_avail[2][2];
bool done;
void __iomem *base_address;

--
2.7.4