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Release 4.14 drivers/regulator/vctrl-regulator.c

/*
 * 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); }

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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); }

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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); }

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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; }

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static int vctrl_get_voltage_sel(struct regulator_dev *rdev) { struct vctrl_data *vctrl = rdev_get_drvdata(rdev); return vctrl->sel; }

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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; }

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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; }

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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; }

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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; }

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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_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; }

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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; }

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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; }

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static int vctrl_is_enabled(struct regulator_dev *rdev) { struct vctrl_data *vctrl = rdev_get_drvdata(rdev); return vctrl->enabled; }

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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; }

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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");

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