iio:adc:twl6030: Enable measurements of VUSB, VBAT and others

Some inputs need to be wired up to produce proper measurements,
without this change only near zero values are reported.
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Fixes: 1696f364 ("iio: twl6030-gpadc: TWL6030, TWL6032 GPADC driver")
Link: https://lore.kernel.org/r/20221201181635.3522962-1-andreas@kemnade.info
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/twl6030-gpadc.c

@@ -57,6 +57,18 @@
 #define TWL6030_GPADCS				BIT(1)
 #define TWL6030_GPADCR				BIT(0)
 
+#define USB_VBUS_CTRL_SET			0x04
+#define USB_ID_CTRL_SET				0x06
+
+#define TWL6030_MISC1				0xE4
+#define VBUS_MEAS				0x01
+#define ID_MEAS					0x01
+
+#define VAC_MEAS                0x04
+#define VBAT_MEAS               0x02
+#define BB_MEAS                 0x01
+
+
 /**
  * struct twl6030_chnl_calib - channel calibration
  * @gain:		slope coefficient for ideal curve
@@ -927,6 +939,26 @@ static int twl6030_gpadc_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	ret = twl_i2c_write_u8(TWL_MODULE_USB, VBUS_MEAS, USB_VBUS_CTRL_SET);
+	if (ret < 0) {
+		dev_err(dev, "failed to wire up inputs\n");
+		return ret;
+	}
+
+	ret = twl_i2c_write_u8(TWL_MODULE_USB, ID_MEAS, USB_ID_CTRL_SET);
+	if (ret < 0) {
+		dev_err(dev, "failed to wire up inputs\n");
+		return ret;
+	}
+
+	ret = twl_i2c_write_u8(TWL6030_MODULE_ID0,
+				VBAT_MEAS | BB_MEAS | BB_MEAS,
+				TWL6030_MISC1);
+	if (ret < 0) {
+		dev_err(dev, "failed to wire up inputs\n");
+		return ret;
+	}
+
 	indio_dev->name = DRIVER_NAME;
 	indio_dev->info = &twl6030_gpadc_iio_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;