iio: pressure-core: st: Allow for number of channels to vary

At the moment the number of channels specified is dictated by the first
sensor supported by the driver. As we add support for more sensors this
is likely to vary. Instead of using the ARRAY_SIZE() of the LPS331AP's
channel specifier we'll use a new adaptable 'struct st_sensors' element
instead.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Denis Ciocca <denis.ciocca@st.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/pressure/st_pressure_core.c

@@ -107,6 +107,7 @@ static const struct st_sensors st_press_sensors[] = {
 			[0] = LPS331AP_PRESS_DEV_NAME,
 		},
 		.ch = (struct iio_chan_spec *)st_press_lps331ap_channels,
+		.num_ch = ARRAY_SIZE(st_press_lps331ap_channels),
 		.odr = {
 			.addr = ST_PRESS_LPS331AP_ODR_ADDR,
 			.mask = ST_PRESS_LPS331AP_ODR_MASK,
@@ -245,7 +246,7 @@ int st_press_common_probe(struct iio_dev *indio_dev,
 	pdata->num_data_channels = ST_PRESS_NUMBER_DATA_CHANNELS;
 	pdata->multiread_bit = pdata->sensor->multi_read_bit;
 	indio_dev->channels = pdata->sensor->ch;
-	indio_dev->num_channels = ARRAY_SIZE(st_press_lps331ap_channels);
+	indio_dev->num_channels = pdata->sensor->num_ch;
 
 	if (pdata->sensor->fs.addr != 0)
 		pdata->current_fullscale = (struct st_sensor_fullscale_avl *)

include/linux/iio/common/st_sensors.h

@@ -184,6 +184,7 @@ struct st_sensors {
 	u8 wai;
 	char sensors_supported[ST_SENSORS_MAX_4WAI][ST_SENSORS_MAX_NAME];
 	struct iio_chan_spec *ch;
+	int num_ch;
 	struct st_sensor_odr odr;
 	struct st_sensor_power pw;
 	struct st_sensor_axis enable_axis;