Quelle  pwm-regulator.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Regulator driver for PWM Regulators
 *
 * Copyright (C) 2014 - STMicroelectronics Inc.
 *
 * Author: Lee Jones <lee.jones@linaro.org>
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/of_regulator.h>
#include <linux/of.h>
#include <linux/pwm.h>
#include <linux/gpio/consumer.h>

struct pwm_continuous_reg_data {
 unsigned int min_uV_dutycycle;
 unsigned int max_uV_dutycycle;
 unsigned int dutycycle_unit;
};

struct pwm_regulator_data {
 /*  Shared */
 struct pwm_device *pwm;

 /* Voltage table */
 struct pwm_voltages *duty_cycle_table;

 /* Continuous mode info */
 struct pwm_continuous_reg_data continuous;

 /* regulator descriptor */
 struct regulator_desc desc;

 int state;

 /* Enable GPIO */
 struct gpio_desc *enb_gpio;
};

struct pwm_voltages {
 unsigned int uV;
 unsigned int dutycycle;
};

/*
 * Voltage table call-backs
 */
static void pwm_regulator_init_state(struct regulator_dev *rdev)
{
 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 struct pwm_state pwm_state;
 unsigned int dutycycle;
 int i;

 pwm_get_state(drvdata->pwm, &pwm_state);
 dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);

 for (i = 0; i < rdev->desc->n_voltages; i++) {
  if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
   drvdata->state = i;
   return;
  }
 }
}

static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
{
 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);

 if (drvdata->state < 0)
  pwm_regulator_init_state(rdev);

 return drvdata->state;
}

static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
      unsigned selector)
{
 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 struct pwm_state pstate;
 int ret;

 pwm_init_state(drvdata->pwm, &pstate);
 pwm_set_relative_duty_cycle(&pstate,
   drvdata->duty_cycle_table[selector].dutycycle, 100);

 ret = pwm_apply_might_sleep(drvdata->pwm, &pstate);
 if (ret) {
  dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
  return ret;
 }

 drvdata->state = selector;

 return 0;
}

static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
          unsigned selector)
{
 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);

 if (selector >= rdev->desc->n_voltages)
  return -EINVAL;

 return drvdata->duty_cycle_table[selector].uV;
}

static int pwm_regulator_enable(struct regulator_dev *dev)
{
 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);

 gpiod_set_value_cansleep(drvdata->enb_gpio, 1);

 return pwm_enable(drvdata->pwm);
}

static int pwm_regulator_disable(struct regulator_dev *dev)
{
 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);

 pwm_disable(drvdata->pwm);

 gpiod_set_value_cansleep(drvdata->enb_gpio, 0);

 return 0;
}

static int pwm_regulator_is_enabled(struct regulator_dev *dev)
{
 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);

 if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
  return false;

 return pwm_is_enabled(drvdata->pwm);
}

static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
{
 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 int min_uV = rdev->constraints->min_uV;
 int max_uV = rdev->constraints->max_uV;
 int diff_uV = max_uV - min_uV;
 struct pwm_state pstate;
 unsigned int diff_duty;
 unsigned int voltage;

 pwm_get_state(drvdata->pwm, &pstate);

 if (!pstate.enabled) {
  if (pstate.polarity == PWM_POLARITY_INVERSED)
   pstate.duty_cycle = pstate.period;
  else
   pstate.duty_cycle = 0;
 }

 voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
 if (voltage < min(max_uV_duty, min_uV_duty) ||
     voltage > max(max_uV_duty, min_uV_duty))
  return -ENOTRECOVERABLE;

 /*
 * The dutycycle for min_uV might be greater than the one for max_uV.
 * This is happening when the user needs an inversed polarity, but the
 * PWM device does not support inversing it in hardware.
 */
 if (max_uV_duty < min_uV_duty) {
  voltage = min_uV_duty - voltage;
  diff_duty = min_uV_duty - max_uV_duty;
 } else {
  voltage = voltage - min_uV_duty;
  diff_duty = max_uV_duty - min_uV_duty;
 }

 voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);

 return voltage + min_uV;
}

static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
         int req_min_uV, int req_max_uV,
         unsigned int *selector)
{
 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 int min_uV = rdev->constraints->min_uV;
 int max_uV = rdev->constraints->max_uV;
 int diff_uV = max_uV - min_uV;
 struct pwm_state pstate;
 unsigned int diff_duty;
 unsigned int dutycycle;
 int ret;

 pwm_init_state(drvdata->pwm, &pstate);

 /*
 * The dutycycle for min_uV might be greater than the one for max_uV.
 * This is happening when the user needs an inversed polarity, but the
 * PWM device does not support inversing it in hardware.
 */
 if (max_uV_duty < min_uV_duty)
  diff_duty = min_uV_duty - max_uV_duty;
 else
  diff_duty = max_uV_duty - min_uV_duty;

 dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
       diff_duty,
       diff_uV);

 if (max_uV_duty < min_uV_duty)
  dutycycle = min_uV_duty - dutycycle;
 else
  dutycycle = min_uV_duty + dutycycle;

 pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);

 ret = pwm_apply_might_sleep(drvdata->pwm, &pstate);
 if (ret) {
  dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
  return ret;
 }

 return 0;
}

static const struct regulator_ops pwm_regulator_voltage_table_ops = {
 .set_voltage_sel = pwm_regulator_set_voltage_sel,
 .get_voltage_sel = pwm_regulator_get_voltage_sel,
 .list_voltage    = pwm_regulator_list_voltage,
 .map_voltage     = regulator_map_voltage_iterate,
 .enable          = pwm_regulator_enable,
 .disable         = pwm_regulator_disable,
 .is_enabled      = pwm_regulator_is_enabled,
};

static const struct regulator_ops pwm_regulator_voltage_continuous_ops = {
 .get_voltage = pwm_regulator_get_voltage,
 .set_voltage = pwm_regulator_set_voltage,
 .enable          = pwm_regulator_enable,
 .disable         = pwm_regulator_disable,
 .is_enabled      = pwm_regulator_is_enabled,
};

static const struct regulator_desc pwm_regulator_desc = {
 .name  = "pwm-regulator",
 .type  = REGULATOR_VOLTAGE,
 .owner  = THIS_MODULE,
 .supply_name    = "pwm",
};

static int pwm_regulator_init_table(struct platform_device *pdev,
        struct pwm_regulator_data *drvdata)
{
 struct device_node *np = pdev->dev.of_node;
 struct pwm_voltages *duty_cycle_table;
 unsigned int length = 0;
 int ret;

 of_find_property(np, "voltage-table", &length);

 if ((length < sizeof(*duty_cycle_table)) ||
     (length % sizeof(*duty_cycle_table)))
  return dev_err_probe(&pdev->dev, -EINVAL,
         "voltage-table length(%d) is invalid\n",
         length);

 duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
 if (!duty_cycle_table)
  return -ENOMEM;

 ret = of_property_read_u32_array(np, "voltage-table",
      (u32 *)duty_cycle_table,
      length / sizeof(u32));
 if (ret)
  return dev_err_probe(&pdev->dev, ret,
         "Failed to read voltage-table\n");

 drvdata->state   = -ENOTRECOVERABLE;
 drvdata->duty_cycle_table = duty_cycle_table;
 drvdata->desc.ops = &pwm_regulator_voltage_table_ops;
 drvdata->desc.n_voltages = length / sizeof(*duty_cycle_table);

 return 0;
}

static int pwm_regulator_init_continuous(struct platform_device *pdev,
      struct pwm_regulator_data *drvdata)
{
 u32 dutycycle_range[2] = { 0, 100 };
 u32 dutycycle_unit = 100;

 drvdata->desc.ops = &pwm_regulator_voltage_continuous_ops;
 drvdata->desc.continuous_voltage_range = true;

 of_property_read_u32_array(pdev->dev.of_node,
       "pwm-dutycycle-range",
       dutycycle_range, 2);
 of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
        &dutycycle_unit);

 if (dutycycle_range[0] > dutycycle_unit ||
     dutycycle_range[1] > dutycycle_unit)
  return -EINVAL;

 drvdata->continuous.dutycycle_unit = dutycycle_unit;
 drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
 drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];

 return 0;
}

static int pwm_regulator_init_boot_on(struct platform_device *pdev,
          struct pwm_regulator_data *drvdata,
          const struct regulator_init_data *init_data)
{
 struct pwm_state pstate;

 if (!init_data->constraints.boot_on || drvdata->enb_gpio)
  return 0;

 pwm_get_state(drvdata->pwm, &pstate);
 if (pstate.enabled)
  return 0;

 /*
 * Update the duty cycle so the output does not change
 * when the regulator core enables the regulator (and
 * thus the PWM channel).
 */
 if (pstate.polarity == PWM_POLARITY_INVERSED)
  pstate.duty_cycle = pstate.period;
 else
  pstate.duty_cycle = 0;

 return pwm_apply_might_sleep(drvdata->pwm, &pstate);
}

static int pwm_regulator_probe(struct platform_device *pdev)
{
 const struct regulator_init_data *init_data;
 struct pwm_regulator_data *drvdata;
 struct regulator_dev *regulator;
 struct regulator_config config = { };
 struct device_node *np = pdev->dev.of_node;
 enum gpiod_flags gpio_flags;
 int ret;

 if (!np)
  return dev_err_probe(&pdev->dev, -EINVAL,
         "Device Tree node missing\n");

 drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
 if (!drvdata)
  return -ENOMEM;

 memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));

 if (of_property_present(np, "voltage-table"))
  ret = pwm_regulator_init_table(pdev, drvdata);
 else
  ret = pwm_regulator_init_continuous(pdev, drvdata);
 if (ret)
  return ret;

 init_data = of_get_regulator_init_data(&pdev->dev, np,
            &drvdata->desc);
 if (!init_data)
  return -ENOMEM;

 config.of_node = np;
 config.dev = &pdev->dev;
 config.driver_data = drvdata;
 config.init_data = init_data;

 drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
 if (IS_ERR(drvdata->pwm))
  return dev_err_probe(&pdev->dev, PTR_ERR(drvdata->pwm),
         "Failed to get PWM\n");

 if (init_data->constraints.boot_on || init_data->constraints.always_on)
  gpio_flags = GPIOD_OUT_HIGH;
 else
  gpio_flags = GPIOD_OUT_LOW;
 drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
          gpio_flags);
 if (IS_ERR(drvdata->enb_gpio)) {
  ret = PTR_ERR(drvdata->enb_gpio);
  return dev_err_probe(&pdev->dev, ret, "Failed to get enable GPIO\n");
 }

 ret = pwm_adjust_config(drvdata->pwm);
 if (ret)
  return ret;

 ret = pwm_regulator_init_boot_on(pdev, drvdata, init_data);
 if (ret)
  return dev_err_probe(&pdev->dev, ret,
         "Failed to apply boot_on settings\n");

 regulator = devm_regulator_register(&pdev->dev,
         &drvdata->desc, &config);
 if (IS_ERR(regulator)) {
  ret = PTR_ERR(regulator);
  return dev_err_probe(&pdev->dev, ret,
         "Failed to register regulator %s\n",
         drvdata->desc.name);
 }

 return 0;
}

static const struct of_device_id __maybe_unused pwm_of_match[] = {
 { .compatible = "pwm-regulator" },
 { },
};
MODULE_DEVICE_TABLE(of, pwm_of_match);

static struct platform_driver pwm_regulator_driver = {
 .driver = {
  .name  = "pwm-regulator",
  .probe_type = PROBE_PREFER_ASYNCHRONOUS,
  .of_match_table = of_match_ptr(pwm_of_match),
 },
 .probe = pwm_regulator_probe,
};

module_platform_driver(pwm_regulator_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Lee Jones ");
MODULE_DESCRIPTION("PWM Regulator Driver");
MODULE_ALIAS("platform:pwm-regulator");