Patch "regulator: core: Limit propagation of parent voltage count and list" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

regulator: core: Limit propagation of parent voltage count and list

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
regulator-core-limit-propagation-of-parent-voltage-count-and-list.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Matthias Kaehlcke <[email protected]>
Date: Mon, 27 Mar 2017 16:54:12 -0700
Subject: regulator: core: Limit propagation of parent voltage count and list

From: Matthias Kaehlcke <[email protected]>

[ Upstream commit fd086045559d90cd7854818b4c60a7119eda6231 ]

Commit 26988efe11b1 ("regulator: core: Allow to get voltage count and list from parent") introduces the propagation of the parent voltage count and list for regulators that don't provide this information themselves. The goal is to support simple switch regulators, however as a side effect normal continuous regulators can leak details of their supplies and provide consumers with inconsistent information.

Limit the propagation of the voltage count and list to switch regulators.

list from parent")

---
 drivers/regulator/core.c         |    9 +++++++--
 include/linux/regulator/driver.h |    2 ++
 2 files changed, 9 insertions(+), 2 deletions(-)

@@ -2465,7 +2465,7 @@ static int _regulator_list_voltage(struc
 		ret = ops->list_voltage(rdev, selector);
 		if (lock)
 			mutex_unlock(&rdev->mutex);
-	} else if (rdev->supply) {
+	} else if (rdev->is_switch && rdev->supply) {
 		ret = _regulator_list_voltage(rdev->supply, selector, lock);
 	} else {
 		return -EINVAL;

@@ -2523,7 +2523,7 @@ int regulator_count_voltages(struct regu
 	if (rdev->desc->n_voltages)
 		return rdev->desc->n_voltages;
 
-	if (!rdev->supply)
+	if (!rdev->is_switch || !rdev->supply)
 		return -EINVAL;
 
 	return regulator_count_voltages(rdev->supply);

@@ -4049,6 +4049,11 @@ regulator_register(const struct regulato
 		mutex_unlock(&regulator_list_mutex);
 	}
 
+	if (!rdev->desc->ops->get_voltage &&
+	    !rdev->desc->ops->list_voltage &&
+	    !rdev->desc->fixed_uV)
+		rdev->is_switch = true;
+
 	ret = device_register(&rdev->dev);
 	if (ret != 0) {
 		put_device(&rdev->dev);

@@ -425,6 +425,8 @@ struct regulator_dev {
 	struct regulator_enable_gpio *ena_pin;
 	unsigned int ena_gpio_state:1;
 
+	unsigned int is_switch:1;
+
 	/* time when this regulator was disabled last time */
 	unsigned long last_off_jiffy;
 };

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/regulator-core-limit-propagation-of-parent-voltage-count-and-list.patch