diff options
Diffstat (limited to 'drivers/regulator')
| -rw-r--r-- | drivers/regulator/core.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 6ed568b96c0e..225eaca24921 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -105,6 +105,8 @@ static int _notifier_call_chain(struct regulator_dev *rdev, unsigned long event, void *data); 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 struct regulator *create_regulator(struct regulator_dev *rdev, struct device *dev, const char *supply_name); @@ -3102,6 +3104,196 @@ out2: return ret; } +static int regulator_get_optimal_voltage(struct regulator_dev *rdev) +{ + struct coupling_desc *c_desc = &rdev->coupling_desc; + struct regulator_dev **c_rdevs = c_desc->coupled_rdevs; + int max_spread = rdev->constraints->max_spread; + int n_coupled = c_desc->n_coupled; + int desired_min_uV, desired_max_uV, min_current_uV = INT_MAX; + int max_current_uV = 0, highest_min_uV = 0, target_uV, possible_uV; + int i, ret; + + /* If consumers don't provide any demands, set voltage to min_uV */ + desired_min_uV = rdev->constraints->min_uV; + desired_max_uV = rdev->constraints->max_uV; + ret = regulator_check_consumers(rdev, + &desired_min_uV, + &desired_max_uV, PM_SUSPEND_ON); + if (ret < 0) + goto out; + + /* + * If there are no coupled regulators, simply set the voltage demanded + * by consumers. + */ + if (n_coupled == 1) { + ret = desired_min_uV; + goto out; + } + + /* Find highest min desired voltage */ + for (i = 0; i < n_coupled; i++) { + int tmp_min = 0; + int tmp_max = INT_MAX; + + if (!_regulator_is_enabled(c_rdevs[i])) + continue; + + ret = regulator_check_consumers(c_rdevs[i], + &tmp_min, + &tmp_max, PM_SUSPEND_ON); + if (ret < 0) + goto out; + + if (tmp_min > highest_min_uV) + highest_min_uV = tmp_min; + } + + /* + * Let target_uV be equal to the desired one if possible. + * If not, set it to minimum voltage, allowed by other coupled + * regulators. + */ + target_uV = max(desired_min_uV, highest_min_uV - max_spread); + + /* + * Find min and max voltages, which currently aren't + * violating max_spread + */ + for (i = 0; i < n_coupled; i++) { + int tmp_act; + + /* + * Don't check the regulator, which is about + * to change voltage + */ + if (c_rdevs[i] == rdev) + continue; + if (!_regulator_is_enabled(c_rdevs[i])) + continue; + + tmp_act = _regulator_get_voltage(c_rdevs[i]); + if (tmp_act < 0) { + ret = tmp_act; + goto out; + } + + if (tmp_act < min_current_uV) + min_current_uV = tmp_act; + + if (tmp_act > max_current_uV) + max_current_uV = tmp_act; + } + + /* There aren't any other regulators enabled */ + if (max_current_uV == 0) { + possible_uV = target_uV; + } else { + /* + * Correct target voltage, so as it currently isn't + * violating max_spread + */ + possible_uV = max(target_uV, max_current_uV - max_spread); + possible_uV = min(possible_uV, min_current_uV + max_spread); + } + + if (possible_uV > desired_max_uV) { + ret = -EINVAL; + goto out; + } + ret = possible_uV; + +out: + return ret; +} + +static int regulator_balance_voltage(struct regulator_dev *rdev, + suspend_state_t state) +{ + struct regulator_dev **c_rdevs; + struct regulator_dev *best_rdev; + struct coupling_desc *c_desc = &rdev->coupling_desc; + int n_coupled; + int i, best_delta, best_uV, ret = 1; + + c_rdevs = c_desc->coupled_rdevs; + n_coupled = c_desc->n_coupled; + + /* + * if system is in a state other than PM_SUSPEND_ON, don't check + * other coupled regulators + */ + if (state != PM_SUSPEND_ON) + n_coupled = 1; + + /* + * Find the best possible voltage change on each loop. Leave the loop + * if there isn't any possible change. + */ + while (1) { + best_delta = 0; + best_uV = 0; + best_rdev = NULL; + + /* + * Find highest difference between optimal voltage + * and current voltage. + */ + for (i = 0; i < n_coupled; i++) { + /* + * optimal_uV is the best voltage that can be set for + * i-th regulator at the moment without violating + * max_spread constraint in order to balance + * the coupled voltages. + */ + int optimal_uV, current_uV; + + optimal_uV = regulator_get_optimal_voltage(c_rdevs[i]); + if (optimal_uV < 0) { + ret = optimal_uV; + goto out; + } + + current_uV = _regulator_get_voltage(c_rdevs[i]); + if (current_uV < 0) { + ret = optimal_uV; + goto out; + } + + if (abs(best_delta) < abs(optimal_uV - current_uV)) { + best_delta = optimal_uV - current_uV; + best_rdev = c_rdevs[i]; + best_uV = optimal_uV; + } + } + + /* Nothing to change, return successfully */ + if (!best_rdev) { + ret = 0; + goto out; + } + + /* + * Lock just the supply regulators, as the regulator itself + * is already locked by regulator_lock_coupled(). + */ + if (best_rdev->supply) + regulator_lock_supply(best_rdev->supply->rdev); + + ret = regulator_set_voltage_rdev(best_rdev, best_uV, + best_uV, state); + if (best_rdev->supply) + regulator_unlock_supply(best_rdev->supply->rdev); + + if (ret < 0) + goto out; + } + +out: + return ret; +} + /** * regulator_set_voltage - set regulator output voltage * @regulator: regulator source |
