Quelle  vctrl-regulator.c   Sprache: C

// 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 ");
MODULE_LICENSE("GPL v2");