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From:   Maciej Purski <m.purski@samsung.com>
To:     Mark Brown <broonie@kernel.org>, Tony Lindgren <tony@atomide.com>
Cc:     linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-omap@vger.kernel.org, Carlos Hernandez <ceh@ti.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Maciej Purski <m.purski@samsung.com>
Subject: [PATCH 5/7] regulator: core: Lock dependent regulators
Date:   Mon, 04 Jun 2018 15:59:22 +0200
Message-id: <1528120764-14316-6-git-send-email-m.purski@samsung.com>
In-reply-to: <1528120764-14316-1-git-send-email-m.purski@samsung.com>
CMS-TYPE: 201P
References: <20180530144505.GB5705@atomide.com>
        <1528120764-14316-1-git-send-email-m.purski@samsung.com>
        <CGME20180604135954eucas1p2156fed3300b5514a4efa2baf9e7b9bc5@eucas1p2.samsung.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Implementing coupled regulators adds a new dependency between
regulators. Therefore, the current locking model should be changed.
Coupled regulators should be locked with regulator's supplies at the
same time.

Add new function regulator_lock_dependent(), which locks all regulators
related with the one, that is being changed.

Signed-off-by: Maciej Purski <m.purski@samsung.com>
---
 drivers/regulator/core.c | 75 +++++++++++++++++++++++++++++++++---------------
 1 file changed, 52 insertions(+), 23 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 0b366c5..7c57268 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -201,38 +201,67 @@ static void regulator_unlock(struct regulator_dev *rdev)
 	}
 }
 
-/**
- * regulator_lock_supply - lock a regulator and its supplies
- * @rdev:         regulator source
- */
-static void regulator_lock_supply(struct regulator_dev *rdev)
+static int regulator_lock_recursive(struct regulator_dev *rdev,
+				    unsigned int subclass)
 {
+	struct regulator_dev *c_rdev;
 	int i;
 
-	for (i = 0; rdev; rdev = rdev_get_supply(rdev), i++)
-		regulator_lock_nested(rdev, i);
+	for (i = 0; i < rdev->coupling_desc.n_coupled; i++) {
+		c_rdev = rdev->coupling_desc.coupled_rdevs[i];
+
+		if (!c_rdev)
+			continue;
+
+		regulator_lock_nested(c_rdev, subclass++);
+
+		if (c_rdev->supply)
+			subclass =
+				regulator_lock_recursive(c_rdev->supply->rdev,
+							 subclass);
+	}
+
+	return subclass;
 }
 
 /**
- * regulator_unlock_supply - unlock a regulator and its supplies
- * @rdev:         regulator source
+ * regulator_unlock_dependent - unlock regulator's suppliers and coupled
+ *				regulators
+ * @rdev:			regulator source
+ *
+ * Unlock all regulators related with rdev by coupling or suppling.
  */
-static void regulator_unlock_supply(struct regulator_dev *rdev)
+static void regulator_unlock_dependent(struct regulator_dev *rdev)
 {
-	struct regulator *supply;
+	struct regulator_dev *c_rdev;
+	int i;
 
-	while (1) {
-		regulator_unlock(rdev);
-		supply = rdev->supply;
+	for (i = 0; i < rdev->coupling_desc.n_coupled; i++) {
+		c_rdev = rdev->coupling_desc.coupled_rdevs[i];
 
-		if (!rdev->supply)
-			return;
+		if (!c_rdev)
+			continue;
+
+		regulator_unlock(c_rdev);
 
-		rdev = supply->rdev;
+		if (c_rdev->supply)
+			regulator_unlock_dependent(c_rdev->supply->rdev);
 	}
 }
 
 /**
+ * regulator_lock_dependent - lock regulator's suppliers and coupled regulators
+ * @rdev:			regulator source
+ *
+ * This function as a wrapper on regulator_lock_recursive(), which locks
+ * all regulators related with rdev by coupling or suppling.
+ */
+static inline void regulator_lock_dependent(struct regulator_dev *rdev)
+{
+	regulator_lock_recursive(rdev, 0);
+}
+
+/**
  * of_get_regulator - get a regulator device node based on supply name
  * @dev: Device pointer for the consumer (of regulator) device
  * @supply: regulator supply name
@@ -3332,12 +3361,12 @@ int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV)
 	int ret = 0;
 
 	pr_err("%s: %d\n", __func__, __LINE__);
-	regulator_lock_supply(regulator->rdev);
+	regulator_lock_dependent(regulator->rdev);
 
 	ret = regulator_set_voltage_unlocked(regulator, min_uV, max_uV,
 					     PM_SUSPEND_ON);
 
-	regulator_unlock_supply(regulator->rdev);
+	regulator_unlock_dependent(regulator->rdev);
 
 	return ret;
 }
@@ -3415,12 +3444,12 @@ int regulator_set_suspend_voltage(struct regulator *regulator, int min_uV,
 	if (regulator_check_states(state) || state == PM_SUSPEND_ON)
 		return -EINVAL;
 
-	regulator_lock_supply(regulator->rdev);
+	regulator_lock_dependent(regulator->rdev);
 
 	ret = _regulator_set_suspend_voltage(regulator, min_uV,
 					     max_uV, state);
 
-	regulator_unlock_supply(regulator->rdev);
+	regulator_unlock_dependent(regulator->rdev);
 
 	return ret;
 }
@@ -3612,11 +3641,11 @@ int regulator_get_voltage(struct regulator *regulator)
 {
 	int ret;
 
-	regulator_lock_supply(regulator->rdev);
+	regulator_lock_dependent(regulator->rdev);
 
 	ret = _regulator_get_voltage(regulator->rdev);
 
-	regulator_unlock_supply(regulator->rdev);
+	regulator_unlock_dependent(regulator->rdev);
 
 	return ret;
 }
-- 
2.7.4