--- /dev/null
+/*
+ * Driver for voltage controller regulators
+ *
+ * Copyright (C) 2017 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/sort.h>
+
+struct vctrl_voltage_range {
+ int min_uV;
+ int max_uV;
+};
+
+struct vctrl_voltage_ranges {
+ struct vctrl_voltage_range ctrl;
+ struct vctrl_voltage_range out;
+};
+
+struct vctrl_voltage_table {
+ int ctrl;
+ int out;
+ int ovp_min_sel;
+};
+
+struct vctrl_data {
+ struct regulator_dev *rdev;
+ struct regulator_desc desc;
+ struct regulator *ctrl_reg;
+ bool enabled;
+ unsigned int min_slew_down_rate;
+ unsigned int ovp_threshold;
+ struct vctrl_voltage_ranges vrange;
+ struct vctrl_voltage_table *vtable;
+ unsigned int sel;
+};
+
+static int vctrl_calc_ctrl_voltage(struct vctrl_data *vctrl, int out_uV)
+{
+ struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl;
+ struct vctrl_voltage_range *out = &vctrl->vrange.out;
+
+ return ctrl->min_uV +
+ DIV_ROUND_CLOSEST_ULL((s64)(out_uV - out->min_uV) *
+ (ctrl->max_uV - ctrl->min_uV),
+ out->max_uV - out->min_uV);
+}
+
+static int vctrl_calc_output_voltage(struct vctrl_data *vctrl, int ctrl_uV)
+{
+ struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl;
+ struct vctrl_voltage_range *out = &vctrl->vrange.out;
+
+ if (ctrl_uV < 0) {
+ pr_err("vctrl: failed to get control voltage\n");
+ return ctrl_uV;
+ }
+
+ if (ctrl_uV < ctrl->min_uV)
+ return out->min_uV;
+
+ if (ctrl_uV > ctrl->max_uV)
+ return out->max_uV;
+
+ return out->min_uV +
+ DIV_ROUND_CLOSEST_ULL((s64)(ctrl_uV - ctrl->min_uV) *
+ (out->max_uV - out->min_uV),
+ ctrl->max_uV - ctrl->min_uV);
+}
+
+static int vctrl_get_voltage(struct regulator_dev *rdev)
+{
+ struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+ int ctrl_uV = regulator_get_voltage(vctrl->ctrl_reg);
+
+ return vctrl_calc_output_voltage(vctrl, ctrl_uV);
+}
+
+static int vctrl_set_voltage(struct regulator_dev *rdev,
+ int req_min_uV, int req_max_uV,
+ unsigned int *selector)
+{
+ struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+ struct regulator *ctrl_reg = vctrl->ctrl_reg;
+ int orig_ctrl_uV = regulator_get_voltage(ctrl_reg);
+ int uV = vctrl_calc_output_voltage(vctrl, orig_ctrl_uV);
+ int ret;
+
+ if (req_min_uV >= uV || !vctrl->ovp_threshold)
+ /* voltage rising or no OVP */
+ return regulator_set_voltage(
+ ctrl_reg,
+ vctrl_calc_ctrl_voltage(vctrl, req_min_uV),
+ vctrl_calc_ctrl_voltage(vctrl, req_max_uV));
+
+ while (uV > req_min_uV) {
+ int max_drop_uV = (uV * vctrl->ovp_threshold) / 100;
+ int next_uV;
+ int next_ctrl_uV;
+ int delay;
+
+ /* Make sure no infinite loop even in crazy cases */
+ if (max_drop_uV == 0)
+ max_drop_uV = 1;
+
+ next_uV = max_t(int, req_min_uV, uV - max_drop_uV);
+ next_ctrl_uV = vctrl_calc_ctrl_voltage(vctrl, next_uV);
+
+ ret = regulator_set_voltage(ctrl_reg,
+ next_ctrl_uV,
+ next_ctrl_uV);
+ if (ret)
+ goto err;
+
+ delay = DIV_ROUND_UP(uV - next_uV, vctrl->min_slew_down_rate);
+ usleep_range(delay, delay + DIV_ROUND_UP(delay, 10));
+
+ uV = next_uV;
+ }
+
+ return 0;
+
+err:
+ /* Try to go back to original voltage */
+ regulator_set_voltage(ctrl_reg, orig_ctrl_uV, orig_ctrl_uV);
+
+ return ret;
+}
+
+static int vctrl_get_voltage_sel(struct regulator_dev *rdev)
+{
+ struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+
+ return vctrl->sel;
+}
+
+static int vctrl_set_voltage_sel(struct regulator_dev *rdev,
+ unsigned int selector)
+{
+ struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+ struct regulator *ctrl_reg = vctrl->ctrl_reg;
+ unsigned int orig_sel = vctrl->sel;
+ int ret;
+
+ if (selector >= rdev->desc->n_voltages)
+ return -EINVAL;
+
+ if (selector >= vctrl->sel || !vctrl->ovp_threshold) {
+ /* voltage rising or no OVP */
+ ret = regulator_set_voltage(ctrl_reg,
+ vctrl->vtable[selector].ctrl,
+ vctrl->vtable[selector].ctrl);
+ if (!ret)
+ vctrl->sel = selector;
+
+ return ret;
+ }
+
+ while (vctrl->sel != selector) {
+ unsigned int next_sel;
+ int delay;
+
+ if (selector >= vctrl->vtable[vctrl->sel].ovp_min_sel)
+ next_sel = selector;
+ else
+ next_sel = vctrl->vtable[vctrl->sel].ovp_min_sel;
+
+ ret = regulator_set_voltage(ctrl_reg,
+ vctrl->vtable[next_sel].ctrl,
+ vctrl->vtable[next_sel].ctrl);
+ if (ret) {
+ dev_err(&rdev->dev,
+ "failed to set control voltage to %duV\n",
+ vctrl->vtable[next_sel].ctrl);
+ goto err;
+ }
+ vctrl->sel = next_sel;
+
+ delay = DIV_ROUND_UP(vctrl->vtable[vctrl->sel].out -
+ vctrl->vtable[next_sel].out,
+ vctrl->min_slew_down_rate);
+ usleep_range(delay, delay + DIV_ROUND_UP(delay, 10));
+ }
+
+ return 0;
+
+err:
+ if (vctrl->sel != orig_sel) {
+ /* Try to go back to original voltage */
+ if (!regulator_set_voltage(ctrl_reg,
+ vctrl->vtable[orig_sel].ctrl,
+ vctrl->vtable[orig_sel].ctrl))
+ vctrl->sel = orig_sel;
+ else
+ dev_warn(&rdev->dev,
+ "failed to restore original voltage\n");
+ }
+
+ return ret;
+}
+
+static int vctrl_list_voltage(struct regulator_dev *rdev,
+ unsigned int selector)
+{
+ struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+
+ if (selector >= rdev->desc->n_voltages)
+ return -EINVAL;
+
+ return vctrl->vtable[selector].out;
+}
+
+static int vctrl_parse_dt(struct platform_device *pdev,
+ struct vctrl_data *vctrl)
+{
+ int ret;
+ struct device_node *np = pdev->dev.of_node;
+ u32 pval;
+ u32 vrange_ctrl[2];
+
+ vctrl->ctrl_reg = devm_regulator_get(&pdev->dev, "ctrl");
+ if (IS_ERR(vctrl->ctrl_reg))
+ return PTR_ERR(vctrl->ctrl_reg);
+
+ ret = of_property_read_u32(np, "ovp-threshold-percent", &pval);
+ if (!ret) {
+ vctrl->ovp_threshold = pval;
+ if (vctrl->ovp_threshold > 100) {
+ dev_err(&pdev->dev,
+ "ovp-threshold-percent (%u) > 100\n",
+ vctrl->ovp_threshold);
+ return -EINVAL;
+ }
+ }
+
+ ret = of_property_read_u32(np, "min-slew-down-rate", &pval);
+ if (!ret) {
+ vctrl->min_slew_down_rate = pval;
+
+ /* We use the value as int and as divider; sanity check */
+ if (vctrl->min_slew_down_rate == 0) {
+ dev_err(&pdev->dev,
+ "min-slew-down-rate must not be 0\n");
+ return -EINVAL;
+ } else if (vctrl->min_slew_down_rate > INT_MAX) {
+ dev_err(&pdev->dev, "min-slew-down-rate (%u) too big\n",
+ vctrl->min_slew_down_rate);
+ return -EINVAL;
+ }
+ }
+
+ if (vctrl->ovp_threshold && !vctrl->min_slew_down_rate) {
+ dev_err(&pdev->dev,
+ "ovp-threshold-percent requires min-slew-down-rate\n");
+ return -EINVAL;
+ }
+
+ ret = of_property_read_u32(np, "regulator-min-microvolt", &pval);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "failed to read regulator-min-microvolt: %d\n", ret);
+ return ret;
+ }
+ vctrl->vrange.out.min_uV = pval;
+
+ ret = of_property_read_u32(np, "regulator-max-microvolt", &pval);
+ if (ret) {
+ dev_err(&pdev->dev,
+ "failed to read regulator-max-microvolt: %d\n", ret);
+ return ret;
+ }
+ vctrl->vrange.out.max_uV = pval;
+
+ ret = of_property_read_u32_array(np, "ctrl-voltage-range", vrange_ctrl,
+ 2);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to read ctrl-voltage-range: %d\n",
+ ret);
+ return ret;
+ }
+
+ if (vrange_ctrl[0] >= vrange_ctrl[1]) {
+ dev_err(&pdev->dev, "ctrl-voltage-range is invalid: %d-%d\n",
+ vrange_ctrl[0], vrange_ctrl[1]);
+ return -EINVAL;
+ }
+
+ vctrl->vrange.ctrl.min_uV = vrange_ctrl[0];
+ vctrl->vrange.ctrl.max_uV = vrange_ctrl[1];
+
+ return 0;
+}
+
+static int vctrl_cmp_ctrl_uV(const void *a, const void *b)
+{
+ const struct vctrl_voltage_table *at = a;
+ const struct vctrl_voltage_table *bt = b;
+
+ return at->ctrl - bt->ctrl;
+}
+
+static int vctrl_init_vtable(struct platform_device *pdev)
+{
+ struct vctrl_data *vctrl = platform_get_drvdata(pdev);
+ struct regulator_desc *rdesc = &vctrl->desc;
+ struct regulator *ctrl_reg = vctrl->ctrl_reg;
+ struct vctrl_voltage_range *vrange_ctrl = &vctrl->vrange.ctrl;
+ int n_voltages;
+ int ctrl_uV;
+ int i, idx_vt;
+
+ n_voltages = regulator_count_voltages(ctrl_reg);
+
+ rdesc->n_voltages = n_voltages;
+
+ /* determine number of steps within the range of the vctrl regulator */
+ for (i = 0; i < n_voltages; i++) {
+ ctrl_uV = regulator_list_voltage(ctrl_reg, i);
+
+ if (ctrl_uV < vrange_ctrl->min_uV ||
+ ctrl_uV > vrange_ctrl->max_uV) {
+ rdesc->n_voltages--;
+ continue;
+ }
+ }
+
+ if (rdesc->n_voltages == 0) {
+ dev_err(&pdev->dev, "invalid configuration\n");
+ return -EINVAL;
+ }
+
+ vctrl->vtable = devm_kmalloc_array(
+ &pdev->dev, sizeof(struct vctrl_voltage_table),
+ rdesc->n_voltages, GFP_KERNEL | __GFP_ZERO);
+ if (!vctrl->vtable)
+ return -ENOMEM;
+
+ /* create mapping control <=> output voltage */
+ for (i = 0, idx_vt = 0; i < n_voltages; i++) {
+ ctrl_uV = regulator_list_voltage(ctrl_reg, i);
+
+ if (ctrl_uV < vrange_ctrl->min_uV ||
+ ctrl_uV > vrange_ctrl->max_uV)
+ continue;
+
+ vctrl->vtable[idx_vt].ctrl = ctrl_uV;
+ vctrl->vtable[idx_vt].out =
+ vctrl_calc_output_voltage(vctrl, ctrl_uV);
+ idx_vt++;
+ }
+
+ /* we rely on the table to be ordered by ascending voltage */
+ sort(vctrl->vtable, rdesc->n_voltages,
+ sizeof(struct vctrl_voltage_table), vctrl_cmp_ctrl_uV,
+ NULL);
+
+ /* pre-calculate OVP-safe downward transitions */
+ for (i = n_voltages - 1; i > 0; i--) {
+ int j;
+ int ovp_min_uV = (vctrl->vtable[i].out *
+ (100 - vctrl->ovp_threshold)) / 100;
+
+ for (j = 0; j < i; j++) {
+ if (vctrl->vtable[j].out >= ovp_min_uV) {
+ vctrl->vtable[i].ovp_min_sel = j;
+ break;
+ }
+ }
+
+ if (j == i) {
+ dev_warn(&pdev->dev, "switching down from %duV may cause OVP shutdown\n",
+ vctrl->vtable[i].out);
+ /* use next lowest voltage */
+ vctrl->vtable[i].ovp_min_sel = i - 1;
+ }
+ }
+
+ return 0;
+}
+
+static int vctrl_enable(struct regulator_dev *rdev)
+{
+ struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+ int ret = regulator_enable(vctrl->ctrl_reg);
+
+ if (!ret)
+ vctrl->enabled = true;
+
+ return ret;
+}
+
+static int vctrl_disable(struct regulator_dev *rdev)
+{
+ struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+ int ret = regulator_disable(vctrl->ctrl_reg);
+
+ if (!ret)
+ vctrl->enabled = false;
+
+ return ret;
+}
+
+static int vctrl_is_enabled(struct regulator_dev *rdev)
+{
+ struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
+
+ return vctrl->enabled;
+}
+
+static const struct regulator_ops vctrl_ops_cont = {
+ .enable = vctrl_enable,
+ .disable = vctrl_disable,
+ .is_enabled = vctrl_is_enabled,
+ .get_voltage = vctrl_get_voltage,
+ .set_voltage = vctrl_set_voltage,
+};
+
+static const struct regulator_ops vctrl_ops_non_cont = {
+ .enable = vctrl_enable,
+ .disable = vctrl_disable,
+ .is_enabled = vctrl_is_enabled,
+ .set_voltage_sel = vctrl_set_voltage_sel,
+ .get_voltage_sel = vctrl_get_voltage_sel,
+ .list_voltage = vctrl_list_voltage,
+ .map_voltage = regulator_map_voltage_iterate,
+};
+
+static int vctrl_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct vctrl_data *vctrl;
+ const struct regulator_init_data *init_data;
+ struct regulator_desc *rdesc;
+ struct regulator_config cfg = { };
+ struct vctrl_voltage_range *vrange_ctrl;
+ int ctrl_uV;
+ int ret;
+
+ vctrl = devm_kzalloc(&pdev->dev, sizeof(struct vctrl_data),
+ GFP_KERNEL);
+ if (!vctrl)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, vctrl);
+
+ ret = vctrl_parse_dt(pdev, vctrl);
+ if (ret)
+ return ret;
+
+ vrange_ctrl = &vctrl->vrange.ctrl;
+
+ rdesc = &vctrl->desc;
+ rdesc->name = "vctrl";
+ rdesc->type = REGULATOR_VOLTAGE;
+ rdesc->owner = THIS_MODULE;
+
+ if ((regulator_get_linear_step(vctrl->ctrl_reg) == 1) ||
+ (regulator_count_voltages(vctrl->ctrl_reg) == -EINVAL)) {
+ rdesc->continuous_voltage_range = true;
+ rdesc->ops = &vctrl_ops_cont;
+ } else {
+ rdesc->ops = &vctrl_ops_non_cont;
+ }
+
+ init_data = of_get_regulator_init_data(&pdev->dev, np, rdesc);
+ if (!init_data)
+ return -ENOMEM;
+
+ cfg.of_node = np;
+ cfg.dev = &pdev->dev;
+ cfg.driver_data = vctrl;
+ cfg.init_data = init_data;
+
+ if (!rdesc->continuous_voltage_range) {
+ ret = vctrl_init_vtable(pdev);
+ if (ret)
+ return ret;
+
+ ctrl_uV = regulator_get_voltage(vctrl->ctrl_reg);
+ if (ctrl_uV < 0) {
+ dev_err(&pdev->dev, "failed to get control voltage\n");
+ return ctrl_uV;
+ }
+
+ /* determine current voltage selector from control voltage */
+ if (ctrl_uV < vrange_ctrl->min_uV) {
+ vctrl->sel = 0;
+ } else if (ctrl_uV > vrange_ctrl->max_uV) {
+ vctrl->sel = rdesc->n_voltages - 1;
+ } else {
+ int i;
+
+ for (i = 0; i < rdesc->n_voltages; i++) {
+ if (ctrl_uV == vctrl->vtable[i].ctrl) {
+ vctrl->sel = i;
+ break;
+ }
+ }
+ }
+ }
+
+ vctrl->rdev = devm_regulator_register(&pdev->dev, rdesc, &cfg);
+ if (IS_ERR(vctrl->rdev)) {
+ ret = PTR_ERR(vctrl->rdev);
+ dev_err(&pdev->dev, "failed to register regulator: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id vctrl_of_match[] = {
+ { .compatible = "vctrl-regulator", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, vctrl_of_match);
+
+static struct platform_driver vctrl_driver = {
+ .probe = vctrl_probe,
+ .driver = {
+ .name = "vctrl-regulator",
+ .of_match_table = of_match_ptr(vctrl_of_match),
+ },
+};
+
+module_platform_driver(vctrl_driver);
+
+MODULE_DESCRIPTION("Voltage Controlled Regulator Driver");
+MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>");
+MODULE_LICENSE("GPL v2");
projects / karo-tx-linux.git / commitdiff