Power Supply Fixes for 7.3 cycle

* power-supply core
   - prevent unregistering a power supply while a callback runs
  * power-supply drivers
   - generic-adc-battery: Fix temperature IIO channel conversion
   - ds2780: Fix ds2780_get_capacity() returning raw value
   - max17042_battery: Fix vmin assigned instead of vmax in DT parsing
   - Fix maintenance charge table kernel-doc
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Merge tag 'for-v7.3-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply

Pull power supply fixes from Sebastian Reichel:
 "power-supply core:
   - prevent unregistering a power supply while a callback runs

  power-supply drivers:
   - generic-adc-battery: Fix temperature IIO channel conversion
   - ds2780: Fix ds2780_get_capacity() returning raw value
   - max17042_battery: Fix vmin assigned instead of vmax in DT parsing
   - Fix maintenance charge table kernel-doc"

* tag 'for-v7.3-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-power-supply:
  power: supply: core: prevent unregistering a power supply while a callback runs
  power: supply: generic-adc-battery: Fix temperature IIO channel conversion
  power: supply: ds2780: Fix ds2780_get_capacity() returning raw value
  power: supply: Fix maintenance charge table kernel-doc
  power: supply: max17042_battery: Fix vmin assigned instead of vmax in DT parsing

drivers/power/supply/ds2780_battery.c

@@ -304,7 +304,7 @@ static int ds2780_get_capacity(struct ds2780_device_info *dev_info,
 		return ret;
 
 	*capacity = raw;
-	return raw;
+	return 0;
 }
 
 static int ds2780_get_status(struct ds2780_device_info *dev_info, int *status)

drivers/power/supply/generic-adc-battery.c

@@ -90,12 +90,17 @@ static int gab_read_channel(struct gab *adc_bat, enum gab_chan_type channel,
 	int ret;
 
 	ret = iio_read_channel_processed(adc_bat->channel[channel], result);
-	if (ret < 0)
+	if (ret < 0) {
 		dev_err(&adc_bat->psy->dev, "read channel error: %d\n", ret);
+		return ret;
+	}
+
+	if (channel == GAB_TEMP)
+		*result /= 100; /* Convert from milli- to deci-degree */
 	else
 		*result *= 1000;
 
-	return ret;
+	return 0;
 }
 
 static int gab_get_property(struct power_supply *psy,

drivers/power/supply/max17042_battery.c

@@ -1233,7 +1233,7 @@ static int max17042_parse_dt(struct max17042_chip *chip)
 	if (of_property_read_u32(np, "maxim,over-volt", &prop))
 		chip->vmax = INT_MAX;
 	else
-		chip->vmin = prop;
+		chip->vmax = prop;
 
 	return 0;
 }

drivers/power/supply/power_supply_core.c

@@ -1530,6 +1530,19 @@ void power_supply_external_power_changed(struct power_supply *psy)
 			!psy->desc->external_power_changed)
 		return;
 
+	/*
+	 * Keep power_supply_unregister() from returning, and thus from letting
+	 * the driver's data be freed, while the callback is running. The
+	 * ->removing check has to happen under the lock: on its own, just like
+	 * the use_cnt check above, it only tells us the supply was still there
+	 * when we looked, not that it still is by the time the callback
+	 * dereferences its driver data.
+	 */
+	guard(rwsem_read)(&psy->epc_sem);
+
+	if (psy->removing)
+		return;
+
 	psy->desc->external_power_changed(psy);
 }
 EXPORT_SYMBOL_GPL(power_supply_external_power_changed);
@@ -1774,6 +1787,7 @@ __power_supply_register(struct device *parent,
 	}
 
 	spin_lock_init(&psy->changed_lock);
+	init_rwsem(&psy->epc_sem);
 	init_rwsem(&psy->extensions_sem);
 	INIT_LIST_HEAD(&psy->extensions);
 
@@ -1914,7 +1928,17 @@ EXPORT_SYMBOL_GPL(devm_power_supply_register);
 void power_supply_unregister(struct power_supply *psy)
 {
 	WARN_ON(atomic_dec_return(&psy->use_cnt));
-	psy->removing = true;
+
+	/*
+	 * Publish ->removing so that no new ->external_power_changed() call can
+	 * start, and wait via semaphore for one that is already running: it may
+	 * be a supplier's changed_work, which cancel_work_sync() below does not
+	 * cover, and it may still dereference driver data that the caller is
+	 * about to free.
+	 */
+	scoped_guard(rwsem_write, &psy->epc_sem)
+		psy->removing = true;
+
 	cancel_work_sync(&psy->changed_work);
 	cancel_delayed_work_sync(&psy->deferred_register_work);
 	sysfs_remove_link(&psy->dev.kobj, "powers");

include/linux/power_supply.h

@@ -351,6 +351,16 @@ struct power_supply {
 	bool removing;
 	atomic_t use_cnt;
 	struct power_supply_battery_info *battery_info;
+	/*
+	 * Held for read while ->external_power_changed() runs, and for write by
+	 * power_supply_unregister() when it publishes @removing, so that it
+	 * waits for an in-flight callback to finish. Without this a driver's
+	 * data, typically devm-allocated on its own device, can be freed while
+	 * the callback is still using it.
+	 * Must not be shared with extensions_sem: callbacks may read their own
+	 * properties, which takes that one for read.
+	 */
+	struct rw_semaphore epc_sem;
 	struct rw_semaphore extensions_sem; /* protects "extensions" */
 	struct list_head extensions;
 #ifdef CONFIG_THERMAL
@@ -414,9 +424,9 @@ struct power_supply_vbat_ri_table {
  * @charge_voltage_max_uv: maintenance charging voltage that is usually a bit
  *   lower than the constant_charge_voltage_max_uv. We can apply this settings
  *   charge_current_max_ua until we get back up to this voltage.
- * @safety_timer_minutes: maintenance charging safety timer, with an expiry
- *   time in minutes. We will only use maintenance charging in this setting
- *   for a certain amount of time, then we will first move to the next
+ * @charge_safety_timer_minutes: maintenance charging safety timer, with an
+ *   expiry time in minutes. We will only use maintenance charging in this
+ *   setting for a certain amount of time, then we will first move to the next
  *   maintenance charge current and voltage pair in respective array and wait
  *   for the next safety timer timeout, or, if we reached the last maintencance
  *   charging setting, disable charging until we reach