diff options
Diffstat (limited to 'drivers/regulator/core.c')
| -rw-r--r-- | drivers/regulator/core.c | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 2c66b528aede..a2a513780fd7 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); @@ -3126,6 +3128,233 @@ out2: return ret; } +static int regulator_get_optimal_voltage(struct regulator_dev *rdev, + int *current_uV, + int *min_uV, int *max_uV, + suspend_state_t state, + int n_coupled) +{ + struct coupling_desc *c_desc = &rdev->coupling_desc; + struct regulator_dev **c_rdevs = c_desc->coupled_rdevs; + struct regulation_constraints *constraints = rdev->constraints; + int max_spread = constraints->max_spread; + int desired_min_uV = 0, desired_max_uV = INT_MAX; + int max_current_uV = 0, min_current_uV = INT_MAX; + int highest_min_uV = 0, target_uV, possible_uV; + int i, ret; + bool done; + + *current_uV = -1; + + /* + * If there are no coupled regulators, simply set the voltage + * demanded by consumers. + */ + if (n_coupled == 1) { + /* + * If consumers don't provide any demands, set voltage + * to min_uV + */ + desired_min_uV = constraints->min_uV; + desired_max_uV = constraints->max_uV; + + ret = regulator_check_consumers(rdev, + &desired_min_uV, + &desired_max_uV, state); + if (ret < 0) + return ret; + + possible_uV = desired_min_uV; + done = true; + + goto finish; + } + + /* Find highest min desired voltage */ + for (i = 0; i < n_coupled; i++) { + int tmp_min = 0; + int tmp_max = INT_MAX; + + lockdep_assert_held_once(&c_rdevs[i]->mutex); + + ret = regulator_check_consumers(c_rdevs[i], + &tmp_min, + &tmp_max, state); + if (ret < 0) + return ret; + + ret = regulator_check_voltage(c_rdevs[i], &tmp_min, &tmp_max); + if (ret < 0) + return ret; + + highest_min_uV = max(highest_min_uV, tmp_min); + + if (i == 0) { + desired_min_uV = tmp_min; + desired_max_uV = tmp_max; + } + } + + /* + * 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 = 1; i < n_coupled; i++) { + int tmp_act; + + if (!_regulator_is_enabled(c_rdevs[i])) + continue; + + tmp_act = _regulator_get_voltage(c_rdevs[i]); + if (tmp_act < 0) + return tmp_act; + + min_current_uV = min(tmp_act, min_current_uV); + max_current_uV = max(tmp_act, max_current_uV); + } + + /* 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) + return -EINVAL; + + done = (possible_uV == target_uV); + desired_min_uV = possible_uV; + +finish: + /* Set current_uV if wasn't done earlier in the code and if necessary */ + if (n_coupled > 1 && *current_uV == -1) { + + if (_regulator_is_enabled(rdev)) { + ret = _regulator_get_voltage(rdev); + if (ret < 0) + return ret; + + *current_uV = ret; + } else { + *current_uV = desired_min_uV; + } + } + + *min_uV = desired_min_uV; + *max_uV = desired_max_uV; + + return done; +} + +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 i, ret, n_coupled, best_min_uV, best_max_uV, best_c_rdev; + bool best_c_rdev_done, c_rdev_done[MAX_COUPLED]; + unsigned int delta, best_delta; + + 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; + + if (c_desc->n_resolved < n_coupled) { + rdev_err(rdev, "Not all coupled regulators registered\n"); + return -EPERM; + } + + for (i = 0; i < n_coupled; i++) + c_rdev_done[i] = false; + + /* + * Find the best possible voltage change on each loop. Leave the loop + * if there isn't any possible change. + */ + do { + best_c_rdev_done = false; + best_delta = 0; + best_min_uV = 0; + best_max_uV = 0; + best_c_rdev = 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 = 0, optimal_max_uV = 0, current_uV = 0; + + if (c_rdev_done[i]) + continue; + + ret = regulator_get_optimal_voltage(c_rdevs[i], + ¤t_uV, + &optimal_uV, + &optimal_max_uV, + state, n_coupled); + if (ret < 0) + goto out; + + delta = abs(optimal_uV - current_uV); + + if (delta && best_delta <= delta) { + best_c_rdev_done = ret; + best_delta = delta; + best_rdev = c_rdevs[i]; + best_min_uV = optimal_uV; + best_max_uV = optimal_max_uV; + best_c_rdev = i; + } + } + + /* Nothing to change, return successfully */ + if (!best_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; + + c_rdev_done[best_c_rdev] = best_c_rdev_done; + + } while (n_coupled > 1); + +out: + return ret; +} + /** * regulator_set_voltage - set regulator output voltage * @regulator: regulator source |