regulator: da9211: Use irq handler when ready

If the system does not come from reset (like when it is kexec()), the
regulator might have an IRQ waiting for us.

If we enable the IRQ handler before its structures are ready, we crash.

This patch fixes:

[    1.141839] Unable to handle kernel read from unreadable memory at virtual address 0000000000000078
[    1.316096] Call trace:
[    1.316101]  blocking_notifier_call_chain+0x20/0xa8
[    1.322757] cpu cpu0: dummy supplies not allowed for exclusive requests
[    1.327823]  regulator_notifier_call_chain+0x1c/0x2c
[    1.327825]  da9211_irq_handler+0x68/0xf8
[    1.327829]  irq_thread+0x11c/0x234
[    1.327833]  kthread+0x13c/0x154

Signed-off-by: Ricardo Ribalda <[email protected]>
Reviewed-by: Adam Ward <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>

Author: ribalda

drivers/regulator/da9211-regulator.c

@@ -498,6 +498,12 @@ static int da9211_i2c_probe(struct i2c_client *i2c)
 
 	chip->chip_irq = i2c->irq;
 
+	ret = da9211_regulator_init(chip);
+	if (ret < 0) {
+		dev_err(chip->dev, "Failed to initialize regulator: %d\n", ret);
+		return ret;
+	}
+
 	if (chip->chip_irq != 0) {
 		ret = devm_request_threaded_irq(chip->dev, chip->chip_irq, NULL,
 					da9211_irq_handler,
@@ -512,11 +518,6 @@ static int da9211_i2c_probe(struct i2c_client *i2c)
 		dev_warn(chip->dev, "No IRQ configured\n");
 	}
 
-	ret = da9211_regulator_init(chip);
-
-	if (ret < 0)
-		dev_err(chip->dev, "Failed to initialize regulator: %d\n", ret);
-
 	return ret;
 }