drivers/hwmon/sy7636a-hwmon.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  * Functions to access SY3686A power management chip temperature
0004  *
0005  * Copyright (C) 2021 reMarkable AS - http://www.remarkable.com/
0006  *
0007  * Authors: Lars Ivar Miljeteig <lars.ivar.miljeteig@remarkable.com>
0008  *          Alistair Francis <alistair@alistair23.me>
0009  */
0010
0011 #include <linux/err.h>
0012 #include <linux/hwmon.h>
0013 #include <linux/init.h>
0014 #include <linux/module.h>
0015 #include <linux/platform_device.h>
0016 #include <linux/regmap.h>
0017 #include <linux/regulator/machine.h>
0018
0019 #include <linux/mfd/sy7636a.h>
0020
0021 static int sy7636a_read(struct device *dev, enum hwmon_sensor_types type,
0022             u32 attr, int channel, long *temp)
0023 {
0024     struct regmap *regmap = dev_get_drvdata(dev);
0025     int ret, reg_val;
0026
0027     ret = regmap_read(regmap,
0028               SY7636A_REG_TERMISTOR_READOUT, &reg_val);
0029     if (ret)
0030         return ret;
0031
0032     *temp = reg_val * 1000;
0033
0034     return 0;
0035 }
0036
0037 static umode_t sy7636a_is_visible(const void *data,
0038                   enum hwmon_sensor_types type,
0039                   u32 attr, int channel)
0040 {
0041     if (type != hwmon_temp)
0042         return 0;
0043
0044     if (attr != hwmon_temp_input)
0045         return 0;
0046
0047     return 0444;
0048 }
0049
0050 static const struct hwmon_ops sy7636a_hwmon_ops = {
0051     .is_visible = sy7636a_is_visible,
0052     .read = sy7636a_read,
0053 };
0054
0055 static const struct hwmon_channel_info *sy7636a_info[] = {
0056     HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
0057     HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT),
0058     NULL
0059 };
0060
0061 static const struct hwmon_chip_info sy7636a_chip_info = {
0062     .ops = &sy7636a_hwmon_ops,
0063     .info = sy7636a_info,
0064 };
0065
0066 static int sy7636a_sensor_probe(struct platform_device *pdev)
0067 {
0068     struct regmap *regmap = dev_get_regmap(pdev->dev.parent, NULL);
0069     struct regulator *regulator;
0070     struct device *hwmon_dev;
0071     int err;
0072
0073     if (!regmap)
0074         return -EPROBE_DEFER;
0075
0076     regulator = devm_regulator_get(&pdev->dev, "vcom");
0077     if (IS_ERR(regulator))
0078         return PTR_ERR(regulator);
0079
0080     err = regulator_enable(regulator);
0081     if (err)
0082         return err;
0083
0084     hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
0085                              "sy7636a_temperature", regmap,
0086                              &sy7636a_chip_info, NULL);
0087
0088     if (IS_ERR(hwmon_dev)) {
0089         err = PTR_ERR(hwmon_dev);
0090         dev_err(&pdev->dev, "Unable to register hwmon device, returned %d\n", err);
0091         return err;
0092     }
0093
0094     return 0;
0095 }
0096
0097 static struct platform_driver sy7636a_sensor_driver = {
0098     .probe = sy7636a_sensor_probe,
0099     .driver = {
0100         .name = "sy7636a-temperature",
0101     },
0102 };
0103 module_platform_driver(sy7636a_sensor_driver);
0104
0105 MODULE_DESCRIPTION("SY7636A sensor driver");
0106 MODULE_LICENSE("GPL");