extcon: extcon-max14577: Fix potential work-queue cancellation race

The extcon IRQ schedules a work item. IRQ is requested using devm while
WQ is cancelld at remove(). This mixing of devm and manual unwinding has
potential case where the WQ has been emptied (.remove() was ran) but
devm unwinding of IRQ was not yet done. It is possible the IRQ is triggered
at this point scheduling new work item to the already flushed queue.

Use new devm_work_autocancel() to remove the remove() and to kill the bug.

Signed-off-by: Matti Vaittinen <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: Hans de Goede <[e-mail]>
Acked-by: Chanwoo Choi <[e-mail]>
Link: https://lore.kernel.org/r/ee8545f[e-mail]
Signed-off-by: Hans de Goede <[e-mail]>

drivers/extcon/extcon-max14577.c

···
 // Chanwoo Choi <[e-mail]>
 // Krzysztof Kozlowski <[e-mail]>
 
+#include <linux/devm-helpers.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/i2c.h>
···
 	platform_set_drvdata(pdev, info);
 	mutex_init(&info->mutex);
 
-	INIT_WORK(&info->irq_work, max14577_muic_irq_work);
+	ret = devm_work_autocancel(&pdev->dev, &info->irq_work,
+				   max14577_muic_irq_work);
+	if (ret)
+		return ret;
 
 	switch (max14577->dev_type) {
 	case MAXIM_DEVICE_TYPE_MAX77836:
···
 	return ret;
 }
 
-static int max14577_muic_remove(struct platform_device *pdev)
-{
-	struct max14577_muic_info *info = platform_get_drvdata(pdev);
-
-	cancel_work_sync(&info->irq_work);
-
-	return 0;
-}
-
 static const struct platform_device_id max14577_muic_id[] = {
 	{ "max14577-muic", MAXIM_DEVICE_TYPE_MAX14577, },
 	{ "max77836-muic", MAXIM_DEVICE_TYPE_MAX77836, },
···
 		.of_match_table = of_max14577_muic_dt_match,
 	},
 	.probe		= max14577_muic_probe,
-	.remove		= max14577_muic_remove,
 	.id_table	= max14577_muic_id,
 };