--- /dev/null
+// 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);
projects / platform / kernel / linux-rpi.git / commitdiff