[PATCH 1/7] iio:common:st_sensors: add st_sensors_get_settings_index() helper function

[Denis Ciocca <denis.ciocca@st.com>]

Extract from st_sensors_check_device_support() function the code that
is used to get the specific settings for a device. This will be used
by each driver to configure the multi-read bit at the beginning of the
probes.

Signed-off-by: Denis Ciocca <denis.ciocca@st.com>
---
 .../iio/common/st_sensors/st_sensors_core.c   | 45 ++++++++++++++-----
 include/linux/iio/common/st_sensors.h         |  4 ++
 2 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c b/drivers/iio/common/st_sensors/st_sensors_core.c
index 8b22dc241482..243b2097c57e 100644
--- a/drivers/iio/common/st_sensors/st_sensors_core.c
+++ b/drivers/iio/common/st_sensors/st_sensors_core.c
@@ -633,28 +633,49 @@ static int st_sensors_init_interface_mode(struct iio_dev *indio_dev,
 	return 0;
 }
 
-int st_sensors_check_device_support(struct iio_dev *indio_dev,
-			int num_sensors_list,
-			const struct st_sensor_settings *sensor_settings)
+/*
+ * st_sensors_get_settings_index() - get index of sensor settings
+ *				     for a specific device.
+ * @name: device name buffer reference.
+ * @list: sensor settings list.
+ * @list_length: length of sensor settings list.
+ */
+int st_sensors_get_settings_index(const char *name,
+				  const struct st_sensor_settings *list,
+				  const int list_length)
 {
-	int i, n, err = 0;
-	u8 wai;
-	struct st_sensor_data *sdata = iio_priv(indio_dev);
+	int i, n;
 
-	for (i = 0; i < num_sensors_list; i++) {
+	for (i = 0; i < list_length; i++) {
 		for (n = 0; n < ST_SENSORS_MAX_4WAI; n++) {
-			if (strcmp(indio_dev->name,
-				sensor_settings[i].sensors_supported[n]) == 0) {
+			if (strcmp(name, list[i].sensors_supported[n]) == 0) {
 				break;
 			}
 		}
 		if (n < ST_SENSORS_MAX_4WAI)
 			break;
 	}
-	if (i == num_sensors_list) {
-		dev_err(&indio_dev->dev, "device name %s not recognized.\n",
-							indio_dev->name);
+	if (i == list_length)
 		return -ENODEV;
+
+	return i;
+}
+EXPORT_SYMBOL(st_sensors_get_settings_index);
+
+int st_sensors_check_device_support(struct iio_dev *indio_dev,
+			int num_sensors_list,
+			const struct st_sensor_settings *sensor_settings)
+{
+	struct st_sensor_data *sdata = iio_priv(indio_dev);
+	int i, err = 0;
+	u8 wai;
+
+	i = st_sensors_get_settings_index(indio_dev->name,
+					  sensor_settings, num_sensors_list);
+	if (i < 0) {
+		dev_err(&indio_dev->dev, "device name %s not recognized.\n",
+			indio_dev->name);
+		return i;
 	}
 
 	err = st_sensors_init_interface_mode(indio_dev, &sensor_settings[i]);
diff --git a/include/linux/iio/common/st_sensors.h b/include/linux/iio/common/st_sensors.h
index 2948ac99e2da..17fbf3e9b013 100644
--- a/include/linux/iio/common/st_sensors.h
+++ b/include/linux/iio/common/st_sensors.h
@@ -334,6 +334,10 @@ int st_sensors_set_fullscale_by_gain(struct iio_dev *indio_dev, int scale);
 int st_sensors_read_info_raw(struct iio_dev *indio_dev,
 				struct iio_chan_spec const *ch, int *val);
 
+int st_sensors_get_settings_index(const char *name,
+				  const struct st_sensor_settings *list,
+				  const int list_length);
+
 int st_sensors_check_device_support(struct iio_dev *indio_dev,
 	int num_sensors_list, const struct st_sensor_settings *sensor_settings);
 
-- 
2.22.0