555 lines
13 KiB
C
555 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Driver for voltage controller regulators
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*
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* Copyright (C) 2017 Google, Inc.
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*/
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/regulator/coupler.h>
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#include <linux/regulator/driver.h>
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#include <linux/regulator/of_regulator.h>
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#include <linux/sort.h>
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#include "internal.h"
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struct vctrl_voltage_range {
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int min_uV;
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int max_uV;
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};
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struct vctrl_voltage_ranges {
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struct vctrl_voltage_range ctrl;
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struct vctrl_voltage_range out;
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};
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struct vctrl_voltage_table {
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int ctrl;
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int out;
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int ovp_min_sel;
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};
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struct vctrl_data {
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struct regulator_dev *rdev;
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struct regulator_desc desc;
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bool enabled;
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unsigned int min_slew_down_rate;
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unsigned int ovp_threshold;
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struct vctrl_voltage_ranges vrange;
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struct vctrl_voltage_table *vtable;
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unsigned int sel;
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};
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static int vctrl_calc_ctrl_voltage(struct vctrl_data *vctrl, int out_uV)
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{
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struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl;
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struct vctrl_voltage_range *out = &vctrl->vrange.out;
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return ctrl->min_uV +
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DIV_ROUND_CLOSEST_ULL((s64)(out_uV - out->min_uV) *
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(ctrl->max_uV - ctrl->min_uV),
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out->max_uV - out->min_uV);
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}
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static int vctrl_calc_output_voltage(struct vctrl_data *vctrl, int ctrl_uV)
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{
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struct vctrl_voltage_range *ctrl = &vctrl->vrange.ctrl;
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struct vctrl_voltage_range *out = &vctrl->vrange.out;
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if (ctrl_uV < 0) {
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pr_err("vctrl: failed to get control voltage\n");
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return ctrl_uV;
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}
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if (ctrl_uV < ctrl->min_uV)
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return out->min_uV;
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if (ctrl_uV > ctrl->max_uV)
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return out->max_uV;
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return out->min_uV +
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DIV_ROUND_CLOSEST_ULL((s64)(ctrl_uV - ctrl->min_uV) *
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(out->max_uV - out->min_uV),
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ctrl->max_uV - ctrl->min_uV);
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}
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static int vctrl_get_voltage(struct regulator_dev *rdev)
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{
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
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int ctrl_uV;
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if (!rdev->supply)
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return -EPROBE_DEFER;
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ctrl_uV = regulator_get_voltage_rdev(rdev->supply->rdev);
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return vctrl_calc_output_voltage(vctrl, ctrl_uV);
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}
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static int vctrl_set_voltage(struct regulator_dev *rdev,
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int req_min_uV, int req_max_uV,
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unsigned int *selector)
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{
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
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int orig_ctrl_uV;
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int uV;
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int ret;
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if (!rdev->supply)
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return -EPROBE_DEFER;
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orig_ctrl_uV = regulator_get_voltage_rdev(rdev->supply->rdev);
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uV = vctrl_calc_output_voltage(vctrl, orig_ctrl_uV);
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if (req_min_uV >= uV || !vctrl->ovp_threshold)
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/* voltage rising or no OVP */
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return regulator_set_voltage_rdev(rdev->supply->rdev,
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vctrl_calc_ctrl_voltage(vctrl, req_min_uV),
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vctrl_calc_ctrl_voltage(vctrl, req_max_uV),
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PM_SUSPEND_ON);
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while (uV > req_min_uV) {
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int max_drop_uV = (uV * vctrl->ovp_threshold) / 100;
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int next_uV;
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int next_ctrl_uV;
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int delay;
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/* Make sure no infinite loop even in crazy cases */
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if (max_drop_uV == 0)
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max_drop_uV = 1;
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next_uV = max_t(int, req_min_uV, uV - max_drop_uV);
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next_ctrl_uV = vctrl_calc_ctrl_voltage(vctrl, next_uV);
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ret = regulator_set_voltage_rdev(rdev->supply->rdev,
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next_ctrl_uV,
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next_ctrl_uV,
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PM_SUSPEND_ON);
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if (ret)
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goto err;
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delay = DIV_ROUND_UP(uV - next_uV, vctrl->min_slew_down_rate);
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usleep_range(delay, delay + DIV_ROUND_UP(delay, 10));
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uV = next_uV;
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}
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return 0;
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err:
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/* Try to go back to original voltage */
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regulator_set_voltage_rdev(rdev->supply->rdev, orig_ctrl_uV, orig_ctrl_uV,
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PM_SUSPEND_ON);
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return ret;
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}
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static int vctrl_get_voltage_sel(struct regulator_dev *rdev)
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{
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
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return vctrl->sel;
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}
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static int vctrl_set_voltage_sel(struct regulator_dev *rdev,
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unsigned int selector)
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{
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
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unsigned int orig_sel = vctrl->sel;
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int ret;
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if (!rdev->supply)
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return -EPROBE_DEFER;
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if (selector >= rdev->desc->n_voltages)
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return -EINVAL;
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if (selector >= vctrl->sel || !vctrl->ovp_threshold) {
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/* voltage rising or no OVP */
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ret = regulator_set_voltage_rdev(rdev->supply->rdev,
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vctrl->vtable[selector].ctrl,
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vctrl->vtable[selector].ctrl,
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PM_SUSPEND_ON);
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if (!ret)
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vctrl->sel = selector;
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return ret;
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}
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while (vctrl->sel != selector) {
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unsigned int next_sel;
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int delay;
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next_sel = max_t(unsigned int, selector, vctrl->vtable[vctrl->sel].ovp_min_sel);
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ret = regulator_set_voltage_rdev(rdev->supply->rdev,
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vctrl->vtable[next_sel].ctrl,
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vctrl->vtable[next_sel].ctrl,
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PM_SUSPEND_ON);
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if (ret) {
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dev_err(&rdev->dev,
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"failed to set control voltage to %duV\n",
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vctrl->vtable[next_sel].ctrl);
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goto err;
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}
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vctrl->sel = next_sel;
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delay = DIV_ROUND_UP(vctrl->vtable[vctrl->sel].out -
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vctrl->vtable[next_sel].out,
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vctrl->min_slew_down_rate);
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usleep_range(delay, delay + DIV_ROUND_UP(delay, 10));
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}
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return 0;
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err:
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if (vctrl->sel != orig_sel) {
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/* Try to go back to original voltage */
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if (!regulator_set_voltage_rdev(rdev->supply->rdev,
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vctrl->vtable[orig_sel].ctrl,
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vctrl->vtable[orig_sel].ctrl,
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PM_SUSPEND_ON))
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vctrl->sel = orig_sel;
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else
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dev_warn(&rdev->dev,
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"failed to restore original voltage\n");
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}
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return ret;
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}
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static int vctrl_list_voltage(struct regulator_dev *rdev,
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unsigned int selector)
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{
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
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if (selector >= rdev->desc->n_voltages)
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return -EINVAL;
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return vctrl->vtable[selector].out;
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}
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static int vctrl_parse_dt(struct platform_device *pdev,
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struct vctrl_data *vctrl)
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{
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int ret;
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struct device_node *np = pdev->dev.of_node;
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u32 pval;
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u32 vrange_ctrl[2];
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ret = of_property_read_u32(np, "ovp-threshold-percent", &pval);
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if (!ret) {
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vctrl->ovp_threshold = pval;
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if (vctrl->ovp_threshold > 100) {
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dev_err(&pdev->dev,
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"ovp-threshold-percent (%u) > 100\n",
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vctrl->ovp_threshold);
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return -EINVAL;
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}
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}
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ret = of_property_read_u32(np, "min-slew-down-rate", &pval);
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if (!ret) {
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vctrl->min_slew_down_rate = pval;
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/* We use the value as int and as divider; sanity check */
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if (vctrl->min_slew_down_rate == 0) {
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dev_err(&pdev->dev,
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"min-slew-down-rate must not be 0\n");
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return -EINVAL;
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} else if (vctrl->min_slew_down_rate > INT_MAX) {
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dev_err(&pdev->dev, "min-slew-down-rate (%u) too big\n",
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vctrl->min_slew_down_rate);
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return -EINVAL;
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}
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}
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if (vctrl->ovp_threshold && !vctrl->min_slew_down_rate) {
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dev_err(&pdev->dev,
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"ovp-threshold-percent requires min-slew-down-rate\n");
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return -EINVAL;
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}
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ret = of_property_read_u32(np, "regulator-min-microvolt", &pval);
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if (ret) {
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dev_err(&pdev->dev,
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"failed to read regulator-min-microvolt: %d\n", ret);
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return ret;
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}
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vctrl->vrange.out.min_uV = pval;
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ret = of_property_read_u32(np, "regulator-max-microvolt", &pval);
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if (ret) {
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dev_err(&pdev->dev,
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"failed to read regulator-max-microvolt: %d\n", ret);
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return ret;
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}
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vctrl->vrange.out.max_uV = pval;
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ret = of_property_read_u32_array(np, "ctrl-voltage-range", vrange_ctrl,
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2);
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if (ret) {
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dev_err(&pdev->dev, "failed to read ctrl-voltage-range: %d\n",
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ret);
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return ret;
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}
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if (vrange_ctrl[0] >= vrange_ctrl[1]) {
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dev_err(&pdev->dev, "ctrl-voltage-range is invalid: %d-%d\n",
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vrange_ctrl[0], vrange_ctrl[1]);
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return -EINVAL;
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}
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vctrl->vrange.ctrl.min_uV = vrange_ctrl[0];
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vctrl->vrange.ctrl.max_uV = vrange_ctrl[1];
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return 0;
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}
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static int vctrl_cmp_ctrl_uV(const void *a, const void *b)
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{
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const struct vctrl_voltage_table *at = a;
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const struct vctrl_voltage_table *bt = b;
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return at->ctrl - bt->ctrl;
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}
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static int vctrl_init_vtable(struct platform_device *pdev,
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struct regulator *ctrl_reg)
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{
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struct vctrl_data *vctrl = platform_get_drvdata(pdev);
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struct regulator_desc *rdesc = &vctrl->desc;
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struct vctrl_voltage_range *vrange_ctrl = &vctrl->vrange.ctrl;
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int n_voltages;
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int ctrl_uV;
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int i, idx_vt;
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n_voltages = regulator_count_voltages(ctrl_reg);
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rdesc->n_voltages = n_voltages;
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/* determine number of steps within the range of the vctrl regulator */
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for (i = 0; i < n_voltages; i++) {
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ctrl_uV = regulator_list_voltage(ctrl_reg, i);
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if (ctrl_uV < vrange_ctrl->min_uV ||
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ctrl_uV > vrange_ctrl->max_uV)
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rdesc->n_voltages--;
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}
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if (rdesc->n_voltages == 0) {
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dev_err(&pdev->dev, "invalid configuration\n");
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return -EINVAL;
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}
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vctrl->vtable = devm_kcalloc(&pdev->dev, rdesc->n_voltages,
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sizeof(struct vctrl_voltage_table),
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GFP_KERNEL);
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if (!vctrl->vtable)
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return -ENOMEM;
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/* create mapping control <=> output voltage */
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for (i = 0, idx_vt = 0; i < n_voltages; i++) {
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ctrl_uV = regulator_list_voltage(ctrl_reg, i);
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if (ctrl_uV < vrange_ctrl->min_uV ||
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ctrl_uV > vrange_ctrl->max_uV)
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continue;
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vctrl->vtable[idx_vt].ctrl = ctrl_uV;
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vctrl->vtable[idx_vt].out =
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vctrl_calc_output_voltage(vctrl, ctrl_uV);
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idx_vt++;
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}
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/* we rely on the table to be ordered by ascending voltage */
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sort(vctrl->vtable, rdesc->n_voltages,
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sizeof(struct vctrl_voltage_table), vctrl_cmp_ctrl_uV,
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NULL);
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/* pre-calculate OVP-safe downward transitions */
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for (i = rdesc->n_voltages - 1; i > 0; i--) {
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int j;
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int ovp_min_uV = (vctrl->vtable[i].out *
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(100 - vctrl->ovp_threshold)) / 100;
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for (j = 0; j < i; j++) {
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if (vctrl->vtable[j].out >= ovp_min_uV) {
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vctrl->vtable[i].ovp_min_sel = j;
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break;
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}
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}
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if (j == i) {
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dev_warn(&pdev->dev, "switching down from %duV may cause OVP shutdown\n",
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vctrl->vtable[i].out);
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/* use next lowest voltage */
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vctrl->vtable[i].ovp_min_sel = i - 1;
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}
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}
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return 0;
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}
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static int vctrl_enable(struct regulator_dev *rdev)
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{
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
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vctrl->enabled = true;
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return 0;
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}
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static int vctrl_disable(struct regulator_dev *rdev)
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{
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
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vctrl->enabled = false;
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return 0;
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}
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static int vctrl_is_enabled(struct regulator_dev *rdev)
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{
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struct vctrl_data *vctrl = rdev_get_drvdata(rdev);
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return vctrl->enabled;
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}
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static const struct regulator_ops vctrl_ops_cont = {
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.enable = vctrl_enable,
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.disable = vctrl_disable,
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.is_enabled = vctrl_is_enabled,
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.get_voltage = vctrl_get_voltage,
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.set_voltage = vctrl_set_voltage,
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};
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static const struct regulator_ops vctrl_ops_non_cont = {
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.enable = vctrl_enable,
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.disable = vctrl_disable,
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.is_enabled = vctrl_is_enabled,
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.set_voltage_sel = vctrl_set_voltage_sel,
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.get_voltage_sel = vctrl_get_voltage_sel,
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.list_voltage = vctrl_list_voltage,
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.map_voltage = regulator_map_voltage_iterate,
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};
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static int vctrl_probe(struct platform_device *pdev)
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{
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struct device_node *np = pdev->dev.of_node;
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struct vctrl_data *vctrl;
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const struct regulator_init_data *init_data;
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struct regulator_desc *rdesc;
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struct regulator_config cfg = { };
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struct vctrl_voltage_range *vrange_ctrl;
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struct regulator *ctrl_reg;
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int ctrl_uV;
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int ret;
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vctrl = devm_kzalloc(&pdev->dev, sizeof(struct vctrl_data),
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GFP_KERNEL);
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if (!vctrl)
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return -ENOMEM;
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platform_set_drvdata(pdev, vctrl);
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ret = vctrl_parse_dt(pdev, vctrl);
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if (ret)
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return ret;
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ctrl_reg = devm_regulator_get(&pdev->dev, "ctrl");
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if (IS_ERR(ctrl_reg))
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return PTR_ERR(ctrl_reg);
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vrange_ctrl = &vctrl->vrange.ctrl;
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rdesc = &vctrl->desc;
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rdesc->name = "vctrl";
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rdesc->type = REGULATOR_VOLTAGE;
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rdesc->owner = THIS_MODULE;
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rdesc->supply_name = "ctrl";
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if ((regulator_get_linear_step(ctrl_reg) == 1) ||
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(regulator_count_voltages(ctrl_reg) == -EINVAL)) {
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rdesc->continuous_voltage_range = true;
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rdesc->ops = &vctrl_ops_cont;
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} else {
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rdesc->ops = &vctrl_ops_non_cont;
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}
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init_data = of_get_regulator_init_data(&pdev->dev, np, rdesc);
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if (!init_data)
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return -ENOMEM;
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cfg.of_node = np;
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cfg.dev = &pdev->dev;
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cfg.driver_data = vctrl;
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cfg.init_data = init_data;
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if (!rdesc->continuous_voltage_range) {
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ret = vctrl_init_vtable(pdev, ctrl_reg);
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if (ret)
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return ret;
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/* Use locked consumer API when not in regulator framework */
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ctrl_uV = regulator_get_voltage(ctrl_reg);
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if (ctrl_uV < 0) {
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dev_err(&pdev->dev, "failed to get control voltage\n");
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return ctrl_uV;
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}
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/* determine current voltage selector from control voltage */
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if (ctrl_uV < vrange_ctrl->min_uV) {
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vctrl->sel = 0;
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} else if (ctrl_uV > vrange_ctrl->max_uV) {
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vctrl->sel = rdesc->n_voltages - 1;
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} else {
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int i;
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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",
|
|
.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");
|