power: supply: ab8500_fg: Convert to IIO ADC

This switches the AB8500 fuel gauge driver to using
the standard IIO ADC channel lookup and conversion routines.

Acked-by: Sebastian Reichel <[e-mail]>
Acked-by: Jonathan Cameron <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/power/supply/ab8500_fg.c

···
 #include <linux/mfd/abx500.h>
 #include <linux/mfd/abx500/ab8500.h>
 #include <linux/mfd/abx500/ab8500-bm.h>
-#include <linux/mfd/abx500/ab8500-gpadc.h>
+#include <linux/iio/consumer.h>
 #include <linux/kernel.h>
 
 #define MILLI_TO_MICRO			1000
···
  * @bat_cap:		Structure for battery capacity specific parameters
  * @avg_cap:		Average capacity filter
  * @parent:		Pointer to the struct ab8500
- * @gpadc:		Pointer to the struct gpadc
+ * @main_bat_v:		ADC channel for the main battery voltage
  * @bm:           	Platform specific battery management information
  * @fg_psy:		Structure that holds the FG specific battery properties
  * @fg_wq:		Work queue for running the FG algorithm
···
 	struct ab8500_fg_battery_capacity bat_cap;
 	struct ab8500_fg_avg_cap avg_cap;
 	struct ab8500 *parent;
-	struct ab8500_gpadc *gpadc;
+	struct iio_channel *main_bat_v;
 	struct abx500_bm_data *bm;
 	struct power_supply *fg_psy;
 	struct workqueue_struct *fg_wq;
···
  */
 static int ab8500_fg_bat_voltage(struct ab8500_fg *di)
 {
-	int vbat;
+	int vbat, ret;
 	static int prev;
 
-	vbat = ab8500_gpadc_convert(di->gpadc, MAIN_BAT_V);
-	if (vbat < 0) {
+	ret = iio_read_channel_processed(di->main_bat_v, &vbat);
+	if (ret < 0) {
 		dev_err(di->dev,
-			"%s gpadc conversion failed, using previous value\n",
+			"%s ADC conversion failed, using previous value\n",
 			__func__);
 		return prev;
 	}
···
 	/* get parent data */
 	di->dev = &pdev->dev;
 	di->parent = dev_get_drvdata(pdev->dev.parent);
-	di->gpadc = ab8500_gpadc_get("ab8500-gpadc.0");
+
+	di->main_bat_v = devm_iio_channel_get(&pdev->dev, "main_bat_v");
+	if (IS_ERR(di->main_bat_v)) {
+		if (PTR_ERR(di->main_bat_v) == -ENODEV)
+			return -EPROBE_DEFER;
+		dev_err(&pdev->dev, "failed to get main battery ADC channel\n");
+		return PTR_ERR(di->main_bat_v);
+	}
 
 	psy_cfg.supplied_to = supply_interface;
 	psy_cfg.num_supplicants = ARRAY_SIZE(supply_interface);