generic-adc-battery: Fix forever loop in gab_remove()

There is a forever loop calling iio_channel_release() because the
"chan < " part of the "chan < ARRAY_SIZE()" is missing.  This is in both
the error handling on probe and also in the remove function.

The other thing is that it's possible for some of the elements of the
adc_bat->channel[chan] array to be an ERR_PTR().  I've changed them to be
NULL instead.  We're still not allowed to pass NULLs to
iio_channel_release() so I've added a check.

Finally, I removed an unused "chan = ARRAY_SIZE(gab_chan_name);" statement
as a small cleanup.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Anton Vorontsov <anton@enomsg.org>

drivers/power/generic-adc-battery.c

@@ -263,9 +263,6 @@ static int gab_probe(struct platform_device *pdev)
 	psy->external_power_changed = gab_ext_power_changed;
 	adc_bat->pdata = pdata;
 
-	/* calculate the total number of channels */
-	chan = ARRAY_SIZE(gab_chan_name);
-
 	/*
 	 * copying the static properties and allocating extra memory for holding
 	 * the extra configurable properties received from platform data.
@@ -291,6 +288,7 @@ static int gab_probe(struct platform_device *pdev)
 						gab_chan_name[chan]);
 		if (IS_ERR(adc_bat->channel[chan])) {
 			ret = PTR_ERR(adc_bat->channel[chan]);
+			adc_bat->channel[chan] = NULL;
 		} else {
 			/* copying properties for supported channels only */
 			memcpy(properties + sizeof(*(psy->properties)) * index,
@@ -344,8 +342,10 @@ err_gpio:
 gpio_req_fail:
 	power_supply_unregister(psy);
 err_reg_fail:
-	for (chan = 0; ARRAY_SIZE(gab_chan_name); chan++)
-		iio_channel_release(adc_bat->channel[chan]);
+	for (chan = 0; chan < ARRAY_SIZE(gab_chan_name); chan++) {
+		if (adc_bat->channel[chan])
+			iio_channel_release(adc_bat->channel[chan]);
+	}
 second_mem_fail:
 	kfree(psy->properties);
 first_mem_fail:
@@ -365,8 +365,10 @@ static int gab_remove(struct platform_device *pdev)
 		gpio_free(pdata->gpio_charge_finished);
 	}
 
-	for (chan = 0; ARRAY_SIZE(gab_chan_name); chan++)
-		iio_channel_release(adc_bat->channel[chan]);
+	for (chan = 0; chan < ARRAY_SIZE(gab_chan_name); chan++) {
+		if (adc_bat->channel[chan])
+			iio_channel_release(adc_bat->channel[chan]);
+	}
 
 	kfree(adc_bat->psy.properties);
 	cancel_delayed_work(&adc_bat->bat_work);