drivers/hwmon/sy7636a-hwmon.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Functions to access SY3686A power management chip temperature
   4  *
   5  * Copyright (C) 2021 reMarkable AS - http://www.remarkable.com/
   6  *
   7  * Authors: Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>
   8  *          Alistair Francis <alistair@alistair23.me>
   9  */
  10
  11 #include <linux/err.h>
  12 #include <linux/hwmon.h>
  13 #include <linux/init.h>
  14 #include <linux/module.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/regmap.h>
  17 #include <linux/regulator/machine.h>
  18
  19 #include <linux/mfd/sy7636a.h>
  20
  21 static int sy7636a_read(struct device *dev, enum hwmon_sensor_types type,
  22                         u32 attr, int channel, long *temp)
  23 {
  24         struct regmap *regmap = dev_get_drvdata(dev);
  25         int ret, reg_val;
  26
  27         ret = regmap_read(regmap,
  28                           SY7636A_REG_TERMISTOR_READOUT, &reg_val);
  29         if (ret)
  30                 return ret;
  31
  32         *temp = reg_val * 1000;
  33
  34         return 0;
  35 }
  36
  37 static umode_t sy7636a_is_visible(const void *data,
  38                                   enum hwmon_sensor_types type,
  39                                   u32 attr, int channel)
  40 {
  41         if (type != hwmon_temp)
  42                 return 0;
  43
  44         if (attr != hwmon_temp_input)
  45                 return 0;
  46
  47         return 0444;
  48 }
  49
  50 static const struct hwmon_ops sy7636a_hwmon_ops = {
  51         .is_visible = sy7636a_is_visible,
  52         .read = sy7636a_read,
  53 };
  54
  55 static const struct hwmon_channel_info * const sy7636a_info[] = {
  56         HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
  57         HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
  58         NULL
  59 };
  60
  61 static const struct hwmon_chip_info sy7636a_chip_info = {
  62         .ops = &sy7636a_hwmon_ops,
  63         .info = sy7636a_info,
  64 };
  65
  66 static int sy7636a_sensor_probe(struct platform_device *pdev)
  67 {
  68         struct regmap *regmap = dev_get_regmap(pdev->dev.parent, NULL);
  69         struct regulator *regulator;
  70         struct device *hwmon_dev;
  71         int err;
  72
  73         if (!regmap)
  74                 return -EPROBE_DEFER;
  75
  76         regulator = devm_regulator_get(&pdev->dev, "vcom");
  77         if (IS_ERR(regulator))
  78                 return PTR_ERR(regulator);
  79
  80         err = regulator_enable(regulator);
  81         if (err)
  82                 return err;
  83
  84         hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
  85                                                          "sy7636a_temperature", regmap,
  86                                                          &sy7636a_chip_info, NULL);
  87
  88         if (IS_ERR(hwmon_dev)) {
  89                 err = PTR_ERR(hwmon_dev);
  90                 dev_err(&pdev->dev, "Unable to register hwmon device, returned %d\n", err);
  91                 return err;
  92         }
  93
  94         return 0;
  95 }
  96
  97 static struct platform_driver sy7636a_sensor_driver = {
  98         .probe = sy7636a_sensor_probe,
  99         .driver = {
 100                 .name = "sy7636a-temperature",
 101         },
 102 };
 103 module_platform_driver(sy7636a_sensor_driver);
 104
 105 MODULE_DESCRIPTION("SY7636A sensor driver");
 106 MODULE_LICENSE("GPL");