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From: Maciej Purski <m.purski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
To: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Liam Girdwood <lgirdwood-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
	Marek Szyprowski
	<m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	Doug Anderson <dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Bartlomiej Zolnierkiewicz
	<b.zolnierkie-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>,
	Maciej Purski <m.purski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
Subject: [PATCH v4 7/7] regulator: core: Change voltage setting path
Date: Mon, 22 Jan 2018 15:30:12 +0100	[thread overview]
Message-ID: <1516631412-17542-8-git-send-email-m.purski@samsung.com> (raw)
In-Reply-To: <1516631412-17542-1-git-send-email-m.purski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>

On Odroid XU3/4 and other Exynos5422 based boards there is a case, that
different devices on the board are supplied by different regulators
with non-fixed voltages. If one of these devices temporarily requires
higher voltage, there might occur a situation that the spread between
two devices' voltages is so high, that there is a risk of changing
'high' and 'low' states on the interconnection between devices powered
by those regulators.

Uncoupled regulators should be a special case of coupled regulators, so
they should share a common voltage setting path. When enabling,
disabling or setting voltage of a coupled regulator, all coupled
regulators should be locked. Regulator's supplies should be locked, when
setting voltage of a single regulator. Enabling a coupled regulator or
setting its voltage should not be possible if some of its coupled
regulators, has not been registered.

Add function for locking coupled regulators. Extract a new function
regulator_set_voltage_rdev() from regulator_set_voltage_unlocked(),
which is called when setting voltage of a single regulator.

Signed-off-by: Maciej Purski <m.purski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
---
 drivers/regulator/core.c | 103 +++++++++++++++++++++++++++++++++++++----------
 1 file changed, 82 insertions(+), 21 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 0492b0e..ce90246 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -107,6 +107,9 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev,
 				     int min_uV, int max_uV);
 static int regulator_balance_voltage(struct regulator_dev *rdev,
 				     suspend_state_t state);
+static int regulator_set_voltage_rdev(struct regulator_dev *rdev,
+				      int min_uV, int max_uV,
+				      suspend_state_t state);
 static struct regulator *create_regulator(struct regulator_dev *rdev,
 					  struct device *dev,
 					  const char *supply_name);
@@ -180,6 +183,36 @@ static void regulator_unlock_supply(struct regulator_dev *rdev)
 }
 
 /**
+ * regulator_lock_coupled - lock a group of coupled regulators
+ * @rdev:      regulator source
+ */
+static void regulator_lock_coupled(struct regulator_dev *rdev)
+{
+	struct coupling_desc *c_desc = &rdev->coupling_desc;
+	int n_coupled = c_desc->n_coupled;
+	int i;
+
+	for (i = 0; i < n_coupled; i++)
+		if (c_desc->coupled_rdevs[i])
+			mutex_lock_nested(&c_desc->coupled_rdevs[i]->mutex, i);
+}
+
+/**
+ * regulator_unlock_coupled - unlock a group of coupled regulators
+ * @rdev:      regulator source
+ */
+static void regulator_unlock_coupled(struct regulator_dev *rdev)
+{
+	struct coupling_desc *c_desc = &rdev->coupling_desc;
+	int n_coupled = c_desc->n_coupled;
+	int i;
+
+	for (i = 0; i < n_coupled; i++)
+		if (c_desc->coupled_rdevs[i])
+			mutex_unlock(&c_desc->coupled_rdevs[i]->mutex);
+}
+
+/**
  * 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
@@ -2184,6 +2217,11 @@ int regulator_enable(struct regulator *regulator)
 	struct regulator_dev *rdev = regulator->rdev;
 	int ret = 0;
 
+	if (rdev->coupling_desc.n_resolved != rdev->coupling_desc.n_coupled) {
+		rdev_err(rdev, "not all coupled regulators registered\n");
+		return -EPERM;
+	}
+
 	if (regulator->always_on)
 		return 0;
 
@@ -2193,9 +2231,10 @@ int regulator_enable(struct regulator *regulator)
 			return ret;
 	}
 
-	mutex_lock(&rdev->mutex);
+	regulator_lock_coupled(rdev);
 	ret = _regulator_enable(rdev);
-	mutex_unlock(&rdev->mutex);
+	regulator_balance_voltage(rdev, PM_SUSPEND_ON);
+	regulator_unlock_coupled(rdev);
 
 	if (ret != 0 && rdev->supply)
 		regulator_disable(rdev->supply);
@@ -2301,9 +2340,10 @@ int regulator_disable(struct regulator *regulator)
 	if (regulator->always_on)
 		return 0;
 
-	mutex_lock(&rdev->mutex);
+	regulator_lock_coupled(rdev);
 	ret = _regulator_disable(rdev);
-	mutex_unlock(&rdev->mutex);
+	regulator_balance_voltage(rdev, PM_SUSPEND_ON);
+	regulator_unlock_coupled(rdev);
 
 	if (ret == 0 && rdev->supply)
 		regulator_disable(rdev->supply);
@@ -2352,10 +2392,11 @@ int regulator_force_disable(struct regulator *regulator)
 	struct regulator_dev *rdev = regulator->rdev;
 	int ret;
 
-	mutex_lock(&rdev->mutex);
+	regulator_lock_coupled(rdev);
 	regulator->uA_load = 0;
 	ret = _regulator_force_disable(regulator->rdev);
-	mutex_unlock(&rdev->mutex);
+	regulator_balance_voltage(rdev, PM_SUSPEND_ON);
+	regulator_unlock_coupled(rdev);
 
 	if (rdev->supply)
 		while (rdev->open_count--)
@@ -2888,8 +2929,12 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
 	int ret = 0;
 	int old_min_uV, old_max_uV;
 	int current_uV;
-	int best_supply_uV = 0;
-	int supply_change_uV = 0;
+
+	if (rdev->coupling_desc.n_resolved != rdev->coupling_desc.n_coupled) {
+		rdev_err(rdev, "not all coupled regulators registered\n");
+		ret = -EPERM;
+		goto out;
+	}
 
 	/* If we're setting the same range as last time the change
 	 * should be a noop (some cpufreq implementations use the same
@@ -2933,6 +2978,27 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
 	if (ret < 0)
 		goto out2;
 
+	/* for not coupled regulators this will just set the voltage */
+	ret = regulator_balance_voltage(rdev, state);
+	if (ret < 0)
+		goto out2;
+
+out:
+	return 0;
+out2:
+	voltage->min_uV = old_min_uV;
+	voltage->max_uV = old_max_uV;
+
+	return ret;
+}
+
+static int regulator_set_voltage_rdev(struct regulator_dev *rdev, int min_uV,
+				      int max_uV, suspend_state_t state)
+{
+	int best_supply_uV = 0;
+	int supply_change_uV = 0;
+	int ret;
+
 	if (rdev->supply &&
 	    regulator_ops_is_valid(rdev->supply->rdev,
 				   REGULATOR_CHANGE_VOLTAGE) &&
@@ -2944,13 +3010,13 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
 		selector = regulator_map_voltage(rdev, min_uV, max_uV);
 		if (selector < 0) {
 			ret = selector;
-			goto out2;
+			goto out;
 		}
 
-		best_supply_uV = _regulator_list_voltage(regulator, selector, 0);
+		best_supply_uV = _regulator_list_voltage(rdev, selector, 0);
 		if (best_supply_uV < 0) {
 			ret = best_supply_uV;
-			goto out2;
+			goto out;
 		}
 
 		best_supply_uV += rdev->desc->min_dropout_uV;
@@ -2958,7 +3024,7 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
 		current_supply_uV = _regulator_get_voltage(rdev->supply->rdev);
 		if (current_supply_uV < 0) {
 			ret = current_supply_uV;
-			goto out2;
+			goto out;
 		}
 
 		supply_change_uV = best_supply_uV - current_supply_uV;
@@ -2970,13 +3036,13 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
 		if (ret) {
 			dev_err(&rdev->dev, "Failed to increase supply voltage: %d\n",
 					ret);
-			goto out2;
+			goto out;
 		}
 	}
 
 	ret = _regulator_do_set_voltage(rdev, min_uV, max_uV);
 	if (ret < 0)
-		goto out2;
+		goto out;
 
 	if (supply_change_uV < 0) {
 		ret = regulator_set_voltage_unlocked(rdev->supply,
@@ -2990,11 +3056,6 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
 
 out:
 	return ret;
-out2:
-	voltage->min_uV = old_min_uV;
-	voltage->max_uV = old_max_uV;
-
-	return ret;
 }
 
 static int regulator_get_optimal_voltage(struct regulator_dev *rdev)
@@ -3209,12 +3270,12 @@ int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV)
 {
 	int ret = 0;
 
-	regulator_lock_supply(regulator->rdev);
+	regulator_lock_coupled(regulator->rdev);
 
 	ret = regulator_set_voltage_unlocked(regulator, min_uV, max_uV,
 					     PM_SUSPEND_ON);
 
-	regulator_unlock_supply(regulator->rdev);
+	regulator_unlock_coupled(regulator->rdev);
 
 	return ret;
 }
-- 
2.7.4

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  parent reply	other threads:[~2018-01-22 14:30 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20180122143019eucas1p213b852c98cde3fb8a77b96ab0d372ee6@eucas1p2.samsung.com>
2018-01-22 14:30 ` [PATCH v4 0/7] Add coupled regulators mechanism Maciej Purski
     [not found]   ` <CGME20180122143029eucas1p284202b6e60a86b428b3aa1e6eef62bda@eucas1p2.samsung.com>
2018-01-22 14:30     ` [PATCH v4 1/7] regulator: core: Move of_find_regulator_by_node() to of_regulator.c Maciej Purski
     [not found]   ` <CGME20180122143030eucas1p2eb1054dd14902eb0be83e5c9efb11d98@eucas1p2.samsung.com>
2018-01-22 14:30     ` [PATCH v4 2/7] regulator: core: Refactor regulator_list_voltage() Maciej Purski
2018-01-26 17:35       ` Applied "regulator: core: Refactor regulator_list_voltage()" to the regulator tree Mark Brown
     [not found]   ` <CGME20180122143031eucas1p205647b3821760ad7e7a3bef5f8873d14@eucas1p2.samsung.com>
     [not found]     ` <1516631412-17542-1-git-send-email-m.purski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2018-01-22 14:30       ` [PATCH v4 3/7] regulator: bindings: Add properties for coupled regulators Maciej Purski
2018-01-22 14:30       ` [PATCH v4 6/7] regulator: core: Add voltage balancing mechanism Maciej Purski
2018-03-02 12:55         ` Applied "regulator: core: Add voltage balancing mechanism" to the regulator tree Mark Brown
2018-05-17 16:41         ` Mark Brown
2018-01-22 14:30       ` Maciej Purski [this message]
     [not found]   ` <CGME20180122143032eucas1p229e2ec741318df3e716e736796bbb9c1@eucas1p2.samsung.com>
2018-01-22 14:30     ` [PATCH v4 4/7] regulator: core: Parse coupled regulators properties Maciej Purski
     [not found]   ` <CGME20180122143033eucas1p2adb3b39af238b2449486389d214a3a68@eucas1p2.samsung.com>
2018-01-22 14:30     ` [PATCH v4 5/7] regulator: core: Resolve coupled regulators Maciej Purski
2018-03-02 12:55       ` Applied "regulator: core: Resolve coupled regulators" to the regulator tree Mark Brown
2018-01-26 17:31   ` [PATCH v4 0/7] Add coupled regulators mechanism Mark Brown
2018-03-01 19:38   ` Mark Brown

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