Quelle  userspace-consumer.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * userspace-consumer.c
 *
 * Copyright 2009 CompuLab, Ltd.
 *
 * Author: Mike Rapoport <mike@compulab.co.il>
 *
 * Based of virtual consumer driver:
 *   Copyright 2008 Wolfson Microelectronics PLC.
 *   Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
 */

#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/regulator/userspace-consumer.h>
#include <linux/slab.h>

struct userspace_consumer_data {
 const char *name;

 struct mutex lock;
 bool enabled;
 bool no_autoswitch;

 int num_supplies;
 struct regulator_bulk_data *supplies;
};

static ssize_t name_show(struct device *dev,
    struct device_attribute *attr, char *buf)
{
 struct userspace_consumer_data *data = dev_get_drvdata(dev);

 return sprintf(buf, "%s\n", data->name);
}

static ssize_t state_show(struct device *dev,
     struct device_attribute *attr, char *buf)
{
 struct userspace_consumer_data *data = dev_get_drvdata(dev);

 if (data->enabled)
  return sprintf(buf, "enabled\n");

 return sprintf(buf, "disabled\n");
}

static ssize_t state_store(struct device *dev, struct device_attribute *attr,
      const char *buf, size_t count)
{
 struct userspace_consumer_data *data = dev_get_drvdata(dev);
 bool enabled;
 int ret;

 /*
 * sysfs_streq() doesn't need the \n's, but we add them so the strings
 * will be shared with show_state(), above.
 */
 if (sysfs_streq(buf, "enabled\n") || sysfs_streq(buf, "1"))
  enabled = true;
 else if (sysfs_streq(buf, "disabled\n") || sysfs_streq(buf, "0"))
  enabled = false;
 else {
  dev_err(dev, "Configuring invalid mode\n");
  return count;
 }

 mutex_lock(&data->lock);
 if (enabled != data->enabled) {
  if (enabled)
   ret = regulator_bulk_enable(data->num_supplies,
          data->supplies);
  else
   ret = regulator_bulk_disable(data->num_supplies,
           data->supplies);

  if (ret == 0)
   data->enabled = enabled;
  else
   dev_err(dev, "Failed to configure state: %d\n", ret);
 }
 mutex_unlock(&data->lock);

 return count;
}

static DEVICE_ATTR_RO(name);
static DEVICE_ATTR_RW(state);

static struct attribute *attributes[] = {
 &dev_attr_name.attr,
 &dev_attr_state.attr,
 NULL,
};

static umode_t attr_visible(struct kobject *kobj, struct attribute *attr, int idx)
{
 struct device *dev = kobj_to_dev(kobj);
 struct userspace_consumer_data *data = dev_get_drvdata(dev);

 /* If a name hasn't been set, don't bother with the attribute */
 if (attr == &dev_attr_name.attr && !data->name)
  return 0;

 return attr->mode;
}

static const struct attribute_group attr_group = {
 .attrs = attributes,
 .is_visible =  attr_visible,
};

static int regulator_userspace_consumer_probe(struct platform_device *pdev)
{
 struct regulator_userspace_consumer_data tmpdata;
 struct regulator_userspace_consumer_data *pdata;
 struct userspace_consumer_data *drvdata;
 int ret;

 pdata = dev_get_platdata(&pdev->dev);
 if (!pdata) {
  if (!pdev->dev.of_node)
   return -EINVAL;

  pdata = &tmpdata;
  memset(pdata, 0, sizeof(*pdata));

  pdata->no_autoswitch = true;
  pdata->num_supplies = 1;
  pdata->supplies = devm_kzalloc(&pdev->dev, sizeof(*pdata->supplies), GFP_KERNEL);
  if (!pdata->supplies)
   return -ENOMEM;
  pdata->supplies[0].supply = "vout";
 }

 if (pdata->num_supplies < 1) {
  dev_err(&pdev->dev, "At least one supply required\n");
  return -EINVAL;
 }

 drvdata = devm_kzalloc(&pdev->dev,
          sizeof(struct userspace_consumer_data),
          GFP_KERNEL);
 if (drvdata == NULL)
  return -ENOMEM;

 drvdata->name = pdata->name;
 drvdata->num_supplies = pdata->num_supplies;
 drvdata->supplies = pdata->supplies;
 drvdata->no_autoswitch = pdata->no_autoswitch;

 mutex_init(&drvdata->lock);

 ret = devm_regulator_bulk_get_exclusive(&pdev->dev, drvdata->num_supplies,
      drvdata->supplies);
 if (ret)
  return dev_err_probe(&pdev->dev, ret, "Failed to get supplies\n");

 platform_set_drvdata(pdev, drvdata);

 ret = sysfs_create_group(&pdev->dev.kobj, &attr_group);
 if (ret != 0)
  return ret;

 if (pdata->init_on && !pdata->no_autoswitch) {
  ret = regulator_bulk_enable(drvdata->num_supplies,
         drvdata->supplies);
  if (ret) {
   dev_err(&pdev->dev,
    "Failed to set initial state: %d\n", ret);
   goto err_enable;
  }
 }

 ret = regulator_is_enabled(pdata->supplies[0].consumer);
 if (ret < 0) {
  dev_err(&pdev->dev, "Failed to get regulator status\n");
  goto err_enable;
 }
 drvdata->enabled = !!ret;

 return 0;

err_enable:
 sysfs_remove_group(&pdev->dev.kobj, &attr_group);

 return ret;
}

static void regulator_userspace_consumer_remove(struct platform_device *pdev)
{
 struct userspace_consumer_data *data = platform_get_drvdata(pdev);

 sysfs_remove_group(&pdev->dev.kobj, &attr_group);

 if (data->enabled && !data->no_autoswitch)
  regulator_bulk_disable(data->num_supplies, data->supplies);
}

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

static struct platform_driver regulator_userspace_consumer_driver = {
 .probe  = regulator_userspace_consumer_probe,
 .remove  = regulator_userspace_consumer_remove,
 .driver  = {
  .name  = "reg-userspace-consumer",
  .probe_type = PROBE_PREFER_ASYNCHRONOUS,
  .of_match_table = regulator_userspace_consumer_of_match,
 },
};

module_platform_driver(regulator_userspace_consumer_driver);

MODULE_AUTHOR("Mike Rapoport ");
MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
MODULE_LICENSE("GPL");