diff options
Diffstat (limited to 'drivers/soc/samsung/exynos-regulator-coupler.c')
| -rw-r--r-- | drivers/soc/samsung/exynos-regulator-coupler.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/drivers/soc/samsung/exynos-regulator-coupler.c b/drivers/soc/samsung/exynos-regulator-coupler.c new file mode 100644 index 000000000000..61a156b44a48 --- /dev/null +++ b/drivers/soc/samsung/exynos-regulator-coupler.c @@ -0,0 +1,221 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2020 Samsung Electronics Co., Ltd. + * http://www.samsung.com/ + * Author: Marek Szyprowski <m.szyprowski@samsung.com> + * + * Simplified generic voltage coupler from regulator core.c + * The main difference is that it keeps current regulator voltage + * if consumers didn't apply their constraints yet. + */ + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/of.h> +#include <linux/regulator/coupler.h> +#include <linux/regulator/driver.h> +#include <linux/regulator/machine.h> + +static int regulator_get_optimal_voltage(struct regulator_dev *rdev, + int *current_uV, + int *min_uV, int *max_uV, + suspend_state_t state) +{ + struct coupling_desc *c_desc = &rdev->coupling_desc; + struct regulator_dev **c_rdevs = c_desc->coupled_rdevs; + struct regulation_constraints *constraints = rdev->constraints; + 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, max_spread, n_coupled = c_desc->n_coupled; + bool done; + + *current_uV = -1; + + /* 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.base); + + ret = regulator_check_consumers(c_rdevs[i], + &tmp_min, + &tmp_max, state); + if (ret < 0) + return ret; + + if (tmp_min == 0) { + ret = regulator_get_voltage_rdev(c_rdevs[i]); + if (ret < 0) + return ret; + tmp_min = ret; + } + + /* apply constraints */ + 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; + } + } + + max_spread = constraints->max_spread[0]; + + /* + * 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; + + tmp_act = regulator_get_voltage_rdev(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); + } + + /* + * 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; + + /* Set current_uV if wasn't done earlier in the code and if necessary */ + if (*current_uV == -1) { + ret = regulator_get_voltage_rdev(rdev); + if (ret < 0) + return ret; + *current_uV = ret; + } + + *min_uV = desired_min_uV; + *max_uV = desired_max_uV; + + return done; +} + +static int exynos_coupler_balance_voltage(struct regulator_coupler *coupler, + 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; + unsigned int delta, best_delta; + unsigned long c_rdev_done = 0; + bool best_c_rdev_done; + + c_rdevs = c_desc->coupled_rdevs; + n_coupled = c_desc->n_coupled; + + /* + * 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 (test_bit(i, &c_rdev_done)) + continue; + + ret = regulator_get_optimal_voltage(c_rdevs[i], + ¤t_uV, + &optimal_uV, + &optimal_max_uV, + state); + 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; + } + + ret = regulator_set_voltage_rdev(best_rdev, best_min_uV, + best_max_uV, state); + + if (ret < 0) + goto out; + + if (best_c_rdev_done) + set_bit(best_c_rdev, &c_rdev_done); + + } while (n_coupled > 1); + +out: + return ret; +} + +static int exynos_coupler_attach(struct regulator_coupler *coupler, + struct regulator_dev *rdev) +{ + return 0; +} + +static struct regulator_coupler exynos_coupler = { + .attach_regulator = exynos_coupler_attach, + .balance_voltage = exynos_coupler_balance_voltage, +}; + +static int __init exynos_coupler_init(void) +{ + if (!of_machine_is_compatible("samsung,exynos5800")) + return 0; + + return regulator_coupler_register(&exynos_coupler); +} +arch_initcall(exynos_coupler_init); |