| /* |
| * 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--; |
| } |
| |
| if (rdesc->n_voltages == 0) { |
| dev_err(&pdev->dev, "invalid configuration\n"); |
| return -EINVAL; |
| } |
| |
| vctrl->vtable = devm_kcalloc(&pdev->dev, rdesc->n_voltages, |
| sizeof(struct vctrl_voltage_table), |
| GFP_KERNEL); |
| 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 = rdesc->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"); |