Quelle  rtc-hid-sensor-time.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * HID Sensor Time Driver
 * Copyright (c) 2012, Alexander Holler.
 */
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/hid-sensor-hub.h>
#include <linux/iio/iio.h>
#include <linux/rtc.h>

enum hid_time_channel {
 CHANNEL_SCAN_INDEX_YEAR,
 CHANNEL_SCAN_INDEX_MONTH,
 CHANNEL_SCAN_INDEX_DAY,
 CHANNEL_SCAN_INDEX_HOUR,
 CHANNEL_SCAN_INDEX_MINUTE,
 CHANNEL_SCAN_INDEX_SECOND,
 TIME_RTC_CHANNEL_MAX,
};

struct hid_time_state {
 struct hid_sensor_hub_callbacks callbacks;
 struct hid_sensor_common common_attributes;
 struct hid_sensor_hub_attribute_info info[TIME_RTC_CHANNEL_MAX];
 struct rtc_time last_time;
 spinlock_t lock_last_time;
 struct completion comp_last_time;
 struct rtc_time time_buf;
 struct rtc_device *rtc;
};

static const u32 hid_time_addresses[TIME_RTC_CHANNEL_MAX] = {
 HID_USAGE_SENSOR_TIME_YEAR,
 HID_USAGE_SENSOR_TIME_MONTH,
 HID_USAGE_SENSOR_TIME_DAY,
 HID_USAGE_SENSOR_TIME_HOUR,
 HID_USAGE_SENSOR_TIME_MINUTE,
 HID_USAGE_SENSOR_TIME_SECOND,
};

/* Channel names for verbose error messages */
static const char * const hid_time_channel_names[TIME_RTC_CHANNEL_MAX] = {
 "year", "month", "day", "hour", "minute", "second",
};

/* Callback handler to send event after all samples are received and captured */
static int hid_time_proc_event(struct hid_sensor_hub_device *hsdev,
    unsigned usage_id, void *priv)
{
 unsigned long flags;
 struct hid_time_state *time_state = platform_get_drvdata(priv);

 spin_lock_irqsave(&time_state->lock_last_time, flags);
 time_state->last_time = time_state->time_buf;
 spin_unlock_irqrestore(&time_state->lock_last_time, flags);
 complete(&time_state->comp_last_time);
 return 0;
}

static u32 hid_time_value(size_t raw_len, char *raw_data)
{
 switch (raw_len) {
 case 1:
  return *(u8 *)raw_data;
 case 2:
  return *(u16 *)raw_data;
 case 4:
  return *(u32 *)raw_data;
 default:
  return (u32)(~0U); /* 0xff... or -1 to denote an error */
 }
}

static int hid_time_capture_sample(struct hid_sensor_hub_device *hsdev,
    unsigned usage_id, size_t raw_len,
    char *raw_data, void *priv)
{
 struct hid_time_state *time_state = platform_get_drvdata(priv);
 struct rtc_time *time_buf = &time_state->time_buf;

 switch (usage_id) {
 case HID_USAGE_SENSOR_TIME_YEAR:
  /*
 * The draft for HID-sensors (HUTRR39) currently doesn't define
 * the range for the year attribute. Therefor we support
 * 8 bit (0-99) and 16 or 32 bits (full) as size for the year.
 */
  if (raw_len == 1) {
   time_buf->tm_year = *(u8 *)raw_data;
   if (time_buf->tm_year < 70)
    /* assume we are in 1970...2069 */
    time_buf->tm_year += 100;
  } else
   time_buf->tm_year =
    (int)hid_time_value(raw_len, raw_data)-1900;
  break;
 case HID_USAGE_SENSOR_TIME_MONTH:
  /* sensors are sending the month as 1-12, we need 0-11 */
  time_buf->tm_mon = (int)hid_time_value(raw_len, raw_data)-1;
  break;
 case HID_USAGE_SENSOR_TIME_DAY:
  time_buf->tm_mday = (int)hid_time_value(raw_len, raw_data);
  break;
 case HID_USAGE_SENSOR_TIME_HOUR:
  time_buf->tm_hour = (int)hid_time_value(raw_len, raw_data);
  break;
 case HID_USAGE_SENSOR_TIME_MINUTE:
  time_buf->tm_min = (int)hid_time_value(raw_len, raw_data);
  break;
 case HID_USAGE_SENSOR_TIME_SECOND:
  time_buf->tm_sec = (int)hid_time_value(raw_len, raw_data);
  break;
 default:
  return -EINVAL;
 }
 return 0;
}

/* small helper, haven't found any other way */
static const char *hid_time_attrib_name(u32 attrib_id)
{
 static const char unknown[] = "unknown";
 unsigned i;

 for (i = 0; i < TIME_RTC_CHANNEL_MAX; ++i) {
  if (hid_time_addresses[i] == attrib_id)
   return hid_time_channel_names[i];
 }
 return unknown; /* should never happen */
}

static int hid_time_parse_report(struct platform_device *pdev,
    struct hid_sensor_hub_device *hsdev,
    unsigned usage_id,
    struct hid_time_state *time_state)
{
 int report_id, i;

 for (i = 0; i < TIME_RTC_CHANNEL_MAX; ++i)
  if (sensor_hub_input_get_attribute_info(hsdev,
    HID_INPUT_REPORT, usage_id,
    hid_time_addresses[i],
    &time_state->info[i]) < 0)
   return -EINVAL;
 /* Check the (needed) attributes for sanity */
 report_id = time_state->info[0].report_id;
 if (report_id < 0) {
  dev_err(&pdev->dev, "bad report ID!\n");
  return -EINVAL;
 }
 for (i = 0; i < TIME_RTC_CHANNEL_MAX; ++i) {
  if (time_state->info[i].report_id != report_id) {
   dev_err(&pdev->dev,
    "not all needed attributes inside the same report!\n");
   return -EINVAL;
  }
  if (time_state->info[i].size == 3 ||
    time_state->info[i].size > 4) {
   dev_err(&pdev->dev,
    "attribute '%s' not 8, 16 or 32 bits wide!\n",
    hid_time_attrib_name(
     time_state->info[i].attrib_id));
   return -EINVAL;
  }
  if (time_state->info[i].units !=
    HID_USAGE_SENSOR_UNITS_NOT_SPECIFIED &&
    /* allow attribute seconds with unit seconds */
    !(time_state->info[i].attrib_id ==
    HID_USAGE_SENSOR_TIME_SECOND &&
    time_state->info[i].units ==
    HID_USAGE_SENSOR_UNITS_SECOND)) {
   dev_err(&pdev->dev,
    "attribute '%s' hasn't a unit of type 'none'!\n",
    hid_time_attrib_name(
     time_state->info[i].attrib_id));
   return -EINVAL;
  }
  if (time_state->info[i].unit_expo) {
   dev_err(&pdev->dev,
    "attribute '%s' hasn't a unit exponent of 1!\n",
    hid_time_attrib_name(
     time_state->info[i].attrib_id));
   return -EINVAL;
  }
 }

 return 0;
}

static int hid_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
 unsigned long flags;
 struct hid_time_state *time_state = dev_get_drvdata(dev);
 int ret;

 reinit_completion(&time_state->comp_last_time);
 /* get a report with all values through requesting one value */
 sensor_hub_input_attr_get_raw_value(time_state->common_attributes.hsdev,
   HID_USAGE_SENSOR_TIME, hid_time_addresses[0],
   time_state->info[0].report_id, SENSOR_HUB_SYNC, false);
 /* wait for all values (event) */
 ret = wait_for_completion_killable_timeout(
   &time_state->comp_last_time, HZ*6);
 if (ret > 0) {
  /* no error */
  spin_lock_irqsave(&time_state->lock_last_time, flags);
  *tm = time_state->last_time;
  spin_unlock_irqrestore(&time_state->lock_last_time, flags);
  return 0;
 }
 if (!ret)
  return -EIO; /* timeouted */
 return ret; /* killed (-ERESTARTSYS) */
}

static const struct rtc_class_ops hid_time_rtc_ops = {
 .read_time = hid_rtc_read_time,
};

static int hid_time_probe(struct platform_device *pdev)
{
 int ret = 0;
 struct hid_sensor_hub_device *hsdev = dev_get_platdata(&pdev->dev);
 struct hid_time_state *time_state = devm_kzalloc(&pdev->dev,
  sizeof(struct hid_time_state), GFP_KERNEL);

 if (time_state == NULL)
  return -ENOMEM;

 platform_set_drvdata(pdev, time_state);

 spin_lock_init(&time_state->lock_last_time);
 init_completion(&time_state->comp_last_time);
 time_state->common_attributes.hsdev = hsdev;
 time_state->common_attributes.pdev = pdev;

 ret = hid_sensor_parse_common_attributes(hsdev,
    HID_USAGE_SENSOR_TIME,
    &time_state->common_attributes,
    NULL,
    0);
 if (ret) {
  dev_err(&pdev->dev, "failed to setup common attributes!\n");
  return ret;
 }

 ret = hid_time_parse_report(pdev, hsdev, HID_USAGE_SENSOR_TIME,
     time_state);
 if (ret) {
  dev_err(&pdev->dev, "failed to setup attributes!\n");
  return ret;
 }

 time_state->callbacks.send_event = hid_time_proc_event;
 time_state->callbacks.capture_sample = hid_time_capture_sample;
 time_state->callbacks.pdev = pdev;
 ret = sensor_hub_register_callback(hsdev, HID_USAGE_SENSOR_TIME,
     &time_state->callbacks);
 if (ret < 0) {
  dev_err(&pdev->dev, "register callback failed!\n");
  return ret;
 }

 ret = sensor_hub_device_open(hsdev);
 if (ret) {
  dev_err(&pdev->dev, "failed to open sensor hub device!\n");
  goto err_open;
 }

 /*
 * Enable HID input processing early in order to be able to read the
 * clock already in devm_rtc_device_register().
 */
 hid_device_io_start(hsdev->hdev);

 time_state->rtc = devm_rtc_device_register(&pdev->dev,
     "hid-sensor-time", &hid_time_rtc_ops,
     THIS_MODULE);

 if (IS_ERR(time_state->rtc)) {
  hid_device_io_stop(hsdev->hdev);
  ret = PTR_ERR(time_state->rtc);
  time_state->rtc = NULL;
  dev_err(&pdev->dev, "rtc device register failed!\n");
  goto err_rtc;
 }

 return ret;

err_rtc:
 sensor_hub_device_close(hsdev);
err_open:
 sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_TIME);
 return ret;
}

static void hid_time_remove(struct platform_device *pdev)
{
 struct hid_sensor_hub_device *hsdev = dev_get_platdata(&pdev->dev);

 sensor_hub_device_close(hsdev);
 sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_TIME);
}

static const struct platform_device_id hid_time_ids[] = {
 {
  /* Format: HID-SENSOR-usage_id_in_hex_lowercase */
  .name = "HID-SENSOR-2000a0",
 },
 { /* sentinel */ }
};
MODULE_DEVICE_TABLE(platform, hid_time_ids);

static struct platform_driver hid_time_platform_driver = {
 .id_table = hid_time_ids,
 .driver = {
  .name = KBUILD_MODNAME,
 },
 .probe  = hid_time_probe,
 .remove  = hid_time_remove,
};
module_platform_driver(hid_time_platform_driver);

MODULE_DESCRIPTION("HID Sensor Time");
MODULE_AUTHOR("Alexander Holler ");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("IIO_HID");