// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for voltage controller regulators
*
* Copyright (C) 2017 Google, Inc.
*/
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regulator/coupler.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/of_regulator.h>
#include <linux/sort.h>
#include "internal.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;
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;
if (!rdev->supply)
return -EPROBE_DEFER;
ctrl_uV = regulator_get_voltage_rdev(rdev->supply->rdev);
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);
int orig_ctrl_uV;
int uV;
int ret;
if (!rdev->supply)
return -EPROBE_DEFER;
orig_ctrl_uV = regulator_get_voltage_rdev(rdev->supply->rdev);
uV = vctrl_calc_output_voltage(vctrl, orig_ctrl_uV);
if (req_min_uV >= uV || !vctrl->ovp_threshold)
/* voltage rising or no OVP */
return regulator_set_voltage_rdev(rdev->supply->rdev,
vctrl_calc_ctrl_voltage(vctrl, req_min_uV),
vctrl_calc_ctrl_voltage(vctrl, req_max_uV),
PM_SUSPEND_ON);
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_rdev(rdev->supply->rdev,
next_ctrl_uV,
next_ctrl_uV,
PM_SUSPEND_ON);
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_rdev(rdev->supply->rdev, orig_ctrl_uV, orig_ctrl_uV,
PM_SUSPEND_ON);
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);
unsigned int orig_sel = vctrl->sel;
int ret;
if (!rdev->supply)
return -EPROBE_DEFER;
if (selector >= rdev->desc->n_voltages)
return -EINVAL;
if (selector >= vctrl->sel || !vctrl->ovp_threshold) {
/* voltage rising or no OVP */
ret = regulator_set_voltage_rdev(rdev->supply->rdev,
vctrl->vtable[selector].ctrl,
vctrl->vtable[selector].ctrl,
PM_SUSPEND_ON);
if (!ret)
vctrl->sel = selector;
return ret;
}
while (vctrl->sel != selector) {
unsigned int next_sel;
int delay;
next_sel = max_t(unsigned int, selector, vctrl->vtable[vctrl->sel].ovp_min_sel);
ret = regulator_set_voltage_rdev(rdev->supply->rdev,
vctrl->vtable[next_sel].ctrl,
vctrl->vtable[next_sel].ctrl,
PM_SUSPEND_ON);
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_rdev(rdev->supply->rdev,
vctrl->vtable[orig_sel].ctrl,
vctrl->vtable[orig_sel].ctrl,
PM_SUSPEND_ON))
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];
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 regulator *ctrl_reg)
{
struct vctrl_data *vctrl = platform_get_drvdata(pdev);
struct regulator_desc *rdesc = &vctrl->desc;
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);
vctrl->enabled = true;
return 0;
}
static int vctrl_disable(struct regulator_dev *rdev)
{
struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
vctrl->enabled = false;
return 0;
}
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;
struct regulator *ctrl_reg;
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;
ctrl_reg = devm_regulator_get(&pdev->dev, "ctrl");
if (IS_ERR(ctrl_reg))
return PTR_ERR(ctrl_reg);
vrange_ctrl = &vctrl->vrange.ctrl;
rdesc = &vctrl->desc;
rdesc->name = "vctrl";
rdesc->type = REGULATOR_VOLTAGE;
rdesc->owner = THIS_MODULE;
rdesc->supply_name = "ctrl";
if ((regulator_get_linear_step(ctrl_reg) == 1) ||
(regulator_count_voltages(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, ctrl_reg);
if (ret)
return ret;
/* Use locked consumer API when not in regulator framework */
ctrl_uV = regulator_get_voltage(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;
}
}
}
}
/* Drop ctrl-supply here in favor of regulator core managed supply */
devm_regulator_put(ctrl_reg);
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",
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
.of_match_table = of_match_ptr(vctrl_of_match),
},
};
module_platform_driver(vctrl_driver);
MODULE_DESCRIPTION("Voltage Controlled Regulator Driver");
MODULE_AUTHOR("Matthias Kaehlcke <[email protected]>");
MODULE_LICENSE("GPL v2");
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