staging: iio: resolver: ad2s1210: remove config attribute

This removes the config register sysfs attribute.

Writing to the config register directly can be dangerous and userspace
should not need to have to know the register layout. This register
can still be accessed though debugfs if needed.

We can add new attributes to set specific flags in the config register
in the future if needed (e.g. `enable_hysterisis` and
`phase_lock_range`).
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20230929-ad2s1210-mainline-v3-12-fa4364281745@baylibre.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/staging/iio/resolver/ad2s1210.c

@@ -273,50 +273,6 @@ static ssize_t ad2s1210_store_fexcit(struct device *dev,
 	return ret < 0 ? ret : len;
 }
 
-static ssize_t ad2s1210_show_control(struct device *dev,
-				     struct device_attribute *attr,
-				     char *buf)
-{
-	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
-	unsigned int value;
-	int ret;
-
-	mutex_lock(&st->lock);
-	ret = regmap_read(st->regmap, AD2S1210_REG_CONTROL, &value);
-	mutex_unlock(&st->lock);
-	return ret < 0 ? ret : sprintf(buf, "0x%x\n", value);
-}
-
-static ssize_t ad2s1210_store_control(struct device *dev,
-				      struct device_attribute *attr,
-				      const char *buf, size_t len)
-{
-	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
-	unsigned char udata;
-	unsigned char data;
-	int ret;
-
-	ret = kstrtou8(buf, 16, &udata);
-	if (ret)
-		return -EINVAL;
-
-	mutex_lock(&st->lock);
-	data = udata & ~AD2S1210_ADDRESS_DATA;
-	ret = regmap_write(st->regmap, AD2S1210_REG_CONTROL, data);
-	if (ret < 0)
-		goto error_ret;
-
-	st->resolution =
-		ad2s1210_resolution_value[data & AD2S1210_SET_RES];
-	ad2s1210_set_resolution_pin(st);
-	ret = len;
-	st->hysteresis = !!(data & AD2S1210_ENABLE_HYSTERESIS);
-
-error_ret:
-	mutex_unlock(&st->lock);
-	return ret;
-}
-
 static ssize_t ad2s1210_show_resolution(struct device *dev,
 					struct device_attribute *attr,
 					char *buf)
@@ -523,8 +479,6 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev,
 
 static IIO_DEVICE_ATTR(fexcit, 0644,
 		       ad2s1210_show_fexcit,	ad2s1210_store_fexcit, 0);
-static IIO_DEVICE_ATTR(control, 0644,
-		       ad2s1210_show_control, ad2s1210_store_control, 0);
 static IIO_DEVICE_ATTR(bits, 0644,
 		       ad2s1210_show_resolution, ad2s1210_store_resolution, 0);
 static IIO_DEVICE_ATTR(fault, 0644,
@@ -570,7 +524,6 @@ static const struct iio_chan_spec ad2s1210_channels[] = {
 
 static struct attribute *ad2s1210_attributes[] = {
 	&iio_dev_attr_fexcit.dev_attr.attr,
-	&iio_dev_attr_control.dev_attr.attr,
 	&iio_dev_attr_bits.dev_attr.attr,
 	&iio_dev_attr_fault.dev_attr.attr,
 	&iio_dev_attr_los_thrd.dev_attr.attr,