regulator: core: Change voltage setting path

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 and supplies. 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@samsung.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index a2a513780fd7f788dc22f19ebeb0a073a067f048..5105eaaf3cefdacf9ca2a3e248a2f921f403bba7 100644 (file)
--- 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);
@@ -198,37 +201,66 @@ 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;
 
-               rdev = supply->rdev;
+               regulator_unlock(c_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
@@ -2289,9 +2321,16 @@ int regulator_enable(struct regulator *regulator)
                        return ret;
        }
 
-       mutex_lock(&rdev->mutex);
+       regulator_lock_dependent(rdev);
+       /* balance only if there are regulators coupled */
+       if (rdev->coupling_desc.n_coupled > 1) {
+               ret = regulator_balance_voltage(rdev, PM_SUSPEND_ON);
+               if (ret != 0)
+                       goto unlock;
+       }
        ret = _regulator_enable(rdev);
-       mutex_unlock(&rdev->mutex);
+unlock:
+       regulator_unlock_dependent(rdev);
 
        if (ret != 0 && rdev->supply)
                regulator_disable(rdev->supply);
@@ -2397,9 +2436,11 @@ int regulator_disable(struct regulator *regulator)
        if (regulator->always_on)
                return 0;
 
-       mutex_lock(&rdev->mutex);
+       regulator_lock_dependent(rdev);
        ret = _regulator_disable(rdev);
-       mutex_unlock(&rdev->mutex);
+       if (rdev->coupling_desc.n_coupled > 1)
+               regulator_balance_voltage(rdev, PM_SUSPEND_ON);
+       regulator_unlock_dependent(rdev);
 
        if (ret == 0 && rdev->supply)
                regulator_disable(rdev->supply);
@@ -2448,10 +2489,12 @@ int regulator_force_disable(struct regulator *regulator)
        struct regulator_dev *rdev = regulator->rdev;
        int ret;
 
-       mutex_lock(&rdev->mutex);
+       regulator_lock_dependent(rdev);
        regulator->uA_load = 0;
        ret = _regulator_force_disable(regulator->rdev);
-       mutex_unlock(&rdev->mutex);
+       if (rdev->coupling_desc.n_coupled > 1)
+               regulator_balance_voltage(rdev, PM_SUSPEND_ON);
+       regulator_unlock_dependent(rdev);
 
        if (rdev->supply)
                while (rdev->open_count--)
@@ -2599,9 +2642,9 @@ int regulator_is_enabled(struct regulator *regulator)
        if (regulator->always_on)
                return 1;
 
-       mutex_lock(&regulator->rdev->mutex);
+       regulator_lock_dependent(regulator->rdev);
        ret = _regulator_is_enabled(regulator->rdev);
-       mutex_unlock(&regulator->rdev->mutex);
+       regulator_unlock_dependent(regulator->rdev);
 
        return ret;
 }
@@ -3015,8 +3058,6 @@ 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 we're setting the same range as last time the change
         * should be a noop (some cpufreq implementations use the same
@@ -3056,10 +3097,27 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
        voltage->min_uV = min_uV;
        voltage->max_uV = max_uV;
 
-       ret = regulator_check_consumers(rdev, &min_uV, &max_uV, state);
+       /* 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) &&
@@ -3071,13 +3129,13 @@ 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(rdev, selector, 0);
                if (best_supply_uV < 0) {
                        ret = best_supply_uV;
-                       goto out2;
+                       goto out;
                }
 
                best_supply_uV += rdev->desc->min_dropout_uV;
@@ -3085,7 +3143,7 @@ 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;
@@ -3097,7 +3155,7 @@ 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;
                }
        }
 
@@ -3107,7 +3165,7 @@ static int regulator_set_voltage_unlocked(struct regulator *regulator,
                ret = _regulator_do_set_suspend_voltage(rdev, min_uV,
                                                        max_uV, state);
        if (ret < 0)
-               goto out2;
+               goto out;
 
        if (supply_change_uV < 0) {
                ret = regulator_set_voltage_unlocked(rdev->supply,
@@ -3120,11 +3178,6 @@ 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;
 }
 
@@ -3340,10 +3393,10 @@ static int regulator_balance_voltage(struct regulator_dev *rdev,
                        ret = 0;
                        goto out;
                }
-#if 0
+
                ret = regulator_set_voltage_rdev(best_rdev, best_min_uV,
                                                 best_max_uV, state);
-#endif
+
                if (ret < 0)
                        goto out;
 
@@ -3377,12 +3430,12 @@ int regulator_set_voltage(struct regulator *regulator, int min_uV, int max_uV)
 {
        int ret = 0;
 
-       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;
 }
@@ -3460,12 +3513,12 @@ 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;
 }
@@ -3657,11 +3710,11 @@ 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;
 }