regulator: IRQ based event/error notification helpers

Provide helper function for IC's implementing regulator notifications
when an IRQ fires. The helper also works for IRQs which can not be acked.
Helper can be set to disable the IRQ at handler and then re-enabling it
on delayed work later. The helper also adds regulator_get_error_flags()
errors in cache for the duration of IRQ disabling.

Signed-off-by: Matti Vaittinen <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Link: https://lore.kernel.org/r/ebdf86d8c22b924667ec2385330e30fcbfac0119.1622628334.git.matti.vaittinen@fi.rohmeurope.com
Signed-off-by: Mark Brown <[email protected]>

Author: M-Vaittinen

drivers/regulator/Makefile

@@ -4,7 +4,7 @@
 #
 
 
-obj-$(CONFIG_REGULATOR) += core.o dummy.o fixed-helper.o helpers.o devres.o
+obj-$(CONFIG_REGULATOR) += core.o dummy.o fixed-helper.o helpers.o devres.o irq_helpers.o
 obj-$(CONFIG_OF) += of_regulator.o
 obj-$(CONFIG_REGULATOR_FIXED_VOLTAGE) += fixed.o
 obj-$(CONFIG_REGULATOR_VIRTUAL_CONSUMER) += virtual.o

drivers/regulator/core.c

@@ -4370,22 +4370,36 @@ unsigned int regulator_get_mode(struct regulator *regulator)
 }
 EXPORT_SYMBOL_GPL(regulator_get_mode);
 
+static int rdev_get_cached_err_flags(struct regulator_dev *rdev)
+{
+	int ret = 0;
+
+	if (rdev->use_cached_err) {
+		spin_lock(&rdev->err_lock);
+		ret = rdev->cached_err;
+		spin_unlock(&rdev->err_lock);
+	}
+	return ret;
+}
+
 static int _regulator_get_error_flags(struct regulator_dev *rdev,
 					unsigned int *flags)
 {
-	int ret;
+	int cached_flags, ret = 0;
 
 	regulator_lock(rdev);
 
-	/* sanity check */
-	if (!rdev->desc->ops->get_error_flags) {
+	cached_flags = rdev_get_cached_err_flags(rdev);
+
+	if (rdev->desc->ops->get_error_flags)
+		ret = rdev->desc->ops->get_error_flags(rdev, flags);
+	else if (!rdev->use_cached_err)
 		ret = -EINVAL;
-		goto out;
-	}
 
-	ret = rdev->desc->ops->get_error_flags(rdev, flags);
-out:
+	*flags |= cached_flags;
+
 	regulator_unlock(rdev);
+
 	return ret;
 }
 
@@ -5218,6 +5232,7 @@ regulator_register(const struct regulator_desc *regulator_desc,
 		goto rinse;
 	}
 	device_initialize(&rdev->dev);
+	spin_lock_init(&rdev->err_lock);
 
 	/*
 	 * Duplicate the config so the driver could override it after

drivers/regulator/devres.c

@@ -481,3 +481,55 @@ void devm_regulator_unregister_notifier(struct regulator *regulator,
 		WARN_ON(rc);
 }
 EXPORT_SYMBOL_GPL(devm_regulator_unregister_notifier);
+
+static void regulator_irq_helper_drop(void *res)
+{
+	regulator_irq_helper_cancel(&res);
+}
+
+/**
+ * devm_regulator_irq_helper - resource managed registration of IRQ based
+ * regulator event/error notifier
+ *
+ * @dev:		device to which lifetime the helper's lifetime is
+ *			bound.
+ * @d:			IRQ helper descriptor.
+ * @irq:		IRQ used to inform events/errors to be notified.
+ * @irq_flags:		Extra IRQ flags to be OR'ed with the default
+ *			IRQF_ONESHOT when requesting the (threaded) irq.
+ * @common_errs:	Errors which can be flagged by this IRQ for all rdevs.
+ *			When IRQ is re-enabled these errors will be cleared
+ *			from all associated regulators
+ * @per_rdev_errs:	Optional error flag array describing errors specific
+ *			for only some of the regulators. These errors will be
+ *			or'ed with common errors. If this is given the array
+ *			should contain rdev_amount flags. Can be set to NULL
+ *			if there is no regulator specific error flags for this
+ *			IRQ.
+ * @rdev:		Array of pointers to regulators associated with this
+ *			IRQ.
+ * @rdev_amount:	Amount of regulators associated with this IRQ.
+ *
+ * Return: handle to irq_helper or an ERR_PTR() encoded error code.
+ */
+void *devm_regulator_irq_helper(struct device *dev,
+				const struct regulator_irq_desc *d, int irq,
+				int irq_flags, int common_errs,
+				int *per_rdev_errs,
+				struct regulator_dev **rdev, int rdev_amount)
+{
+	void *ptr;
+	int ret;
+
+	ptr = regulator_irq_helper(dev, d, irq, irq_flags, common_errs,
+				    per_rdev_errs, rdev, rdev_amount);
+	if (IS_ERR(ptr))
+		return ptr;
+
+	ret = devm_add_action_or_reset(dev, regulator_irq_helper_drop, ptr);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return ptr;
+}
+EXPORT_SYMBOL_GPL(devm_regulator_irq_helper);