cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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sy7636a-hwmon.c (2419B)

      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 *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");