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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max31722.c (3942B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * max31722 - hwmon driver for Maxim Integrated MAX31722/MAX31723 SPI
      4 * digital thermometer and thermostats.
      5 *
      6 * Copyright (c) 2016, Intel Corporation.
      7 */
      8
      9#include <linux/hwmon.h>
     10#include <linux/hwmon-sysfs.h>
     11#include <linux/kernel.h>
     12#include <linux/module.h>
     13#include <linux/spi/spi.h>
     14
     15#define MAX31722_REG_CFG				0x00
     16#define MAX31722_REG_TEMP_LSB				0x01
     17
     18#define MAX31722_MODE_CONTINUOUS			0x00
     19#define MAX31722_MODE_STANDBY				0x01
     20#define MAX31722_MODE_MASK				0xFE
     21#define MAX31722_RESOLUTION_12BIT			0x06
     22#define MAX31722_WRITE_MASK				0x80
     23
     24struct max31722_data {
     25	struct device *hwmon_dev;
     26	struct spi_device *spi_device;
     27	u8 mode;
     28};
     29
     30static int max31722_set_mode(struct max31722_data *data, u8 mode)
     31{
     32	int ret;
     33	struct spi_device *spi = data->spi_device;
     34	u8 buf[2] = {
     35		MAX31722_REG_CFG | MAX31722_WRITE_MASK,
     36		(data->mode & MAX31722_MODE_MASK) | mode
     37	};
     38
     39	ret = spi_write(spi, &buf, sizeof(buf));
     40	if (ret < 0) {
     41		dev_err(&spi->dev, "failed to set sensor mode.\n");
     42		return ret;
     43	}
     44	data->mode = (data->mode & MAX31722_MODE_MASK) | mode;
     45
     46	return 0;
     47}
     48
     49static ssize_t max31722_temp_show(struct device *dev,
     50				  struct device_attribute *attr, char *buf)
     51{
     52	ssize_t ret;
     53	struct max31722_data *data = dev_get_drvdata(dev);
     54
     55	ret = spi_w8r16(data->spi_device, MAX31722_REG_TEMP_LSB);
     56	if (ret < 0)
     57		return ret;
     58	/* Keep 12 bits and multiply by the scale of 62.5 millidegrees/bit. */
     59	return sprintf(buf, "%d\n", (s16)le16_to_cpu(ret) * 125 / 32);
     60}
     61
     62static SENSOR_DEVICE_ATTR_RO(temp1_input, max31722_temp, 0);
     63
     64static struct attribute *max31722_attrs[] = {
     65	&sensor_dev_attr_temp1_input.dev_attr.attr,
     66	NULL,
     67};
     68
     69ATTRIBUTE_GROUPS(max31722);
     70
     71static int max31722_probe(struct spi_device *spi)
     72{
     73	int ret;
     74	struct max31722_data *data;
     75
     76	data = devm_kzalloc(&spi->dev, sizeof(*data), GFP_KERNEL);
     77	if (!data)
     78		return -ENOMEM;
     79
     80	spi_set_drvdata(spi, data);
     81	data->spi_device = spi;
     82	/*
     83	 * Set SD bit to 0 so we can have continuous measurements.
     84	 * Set resolution to 12 bits for maximum precision.
     85	 */
     86	data->mode = MAX31722_MODE_CONTINUOUS | MAX31722_RESOLUTION_12BIT;
     87	ret = max31722_set_mode(data, MAX31722_MODE_CONTINUOUS);
     88	if (ret < 0)
     89		return ret;
     90
     91	data->hwmon_dev = hwmon_device_register_with_groups(&spi->dev,
     92							    spi->modalias,
     93							    data,
     94							    max31722_groups);
     95	if (IS_ERR(data->hwmon_dev)) {
     96		max31722_set_mode(data, MAX31722_MODE_STANDBY);
     97		return PTR_ERR(data->hwmon_dev);
     98	}
     99
    100	return 0;
    101}
    102
    103static void max31722_remove(struct spi_device *spi)
    104{
    105	struct max31722_data *data = spi_get_drvdata(spi);
    106	int ret;
    107
    108	hwmon_device_unregister(data->hwmon_dev);
    109
    110	ret = max31722_set_mode(data, MAX31722_MODE_STANDBY);
    111	if (ret)
    112		/* There is nothing we can do about this ... */
    113		dev_warn(&spi->dev, "Failed to put device in stand-by mode\n");
    114}
    115
    116static int __maybe_unused max31722_suspend(struct device *dev)
    117{
    118	struct spi_device *spi_device = to_spi_device(dev);
    119	struct max31722_data *data = spi_get_drvdata(spi_device);
    120
    121	return max31722_set_mode(data, MAX31722_MODE_STANDBY);
    122}
    123
    124static int __maybe_unused max31722_resume(struct device *dev)
    125{
    126	struct spi_device *spi_device = to_spi_device(dev);
    127	struct max31722_data *data = spi_get_drvdata(spi_device);
    128
    129	return max31722_set_mode(data, MAX31722_MODE_CONTINUOUS);
    130}
    131
    132static SIMPLE_DEV_PM_OPS(max31722_pm_ops, max31722_suspend, max31722_resume);
    133
    134static const struct spi_device_id max31722_spi_id[] = {
    135	{"max31722", 0},
    136	{"max31723", 0},
    137	{}
    138};
    139MODULE_DEVICE_TABLE(spi, max31722_spi_id);
    140
    141static struct spi_driver max31722_driver = {
    142	.driver = {
    143		.name = "max31722",
    144		.pm = &max31722_pm_ops,
    145	},
    146	.probe =            max31722_probe,
    147	.remove =           max31722_remove,
    148	.id_table =         max31722_spi_id,
    149};
    150
    151module_spi_driver(max31722_driver);
    152
    153MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
    154MODULE_DESCRIPTION("max31722 sensor driver");
    155MODULE_LICENSE("GPL v2");