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
 21static 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
 37static 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
 50static const struct hwmon_ops sy7636a_hwmon_ops = {
 51	.is_visible = sy7636a_is_visible,
 52	.read = sy7636a_read,
 53};
 54
 55static 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
 61static const struct hwmon_chip_info sy7636a_chip_info = {
 62	.ops = &sy7636a_hwmon_ops,
 63	.info = sy7636a_info,
 64};
 65
 66static 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
 97static struct platform_driver sy7636a_sensor_driver = {
 98	.probe = sy7636a_sensor_probe,
 99	.driver = {
100		.name = "sy7636a-temperature",
101	},
102};
103module_platform_driver(sy7636a_sensor_driver);
104
105MODULE_DESCRIPTION("SY7636A sensor driver");
106MODULE_LICENSE("GPL");