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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hmc6352.c (3530B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * hmc6352.c - Honeywell Compass Driver
      4 *
      5 * Copyright (C) 2009 Intel Corp
      6 *
      7 *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      8 *
      9 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     10 */
     11
     12#include <linux/module.h>
     13#include <linux/slab.h>
     14#include <linux/i2c.h>
     15#include <linux/err.h>
     16#include <linux/delay.h>
     17#include <linux/sysfs.h>
     18#include <linux/nospec.h>
     19
     20static DEFINE_MUTEX(compass_mutex);
     21
     22static int compass_command(struct i2c_client *c, u8 cmd)
     23{
     24	int ret = i2c_master_send(c, &cmd, 1);
     25	if (ret < 0)
     26		dev_warn(&c->dev, "command '%c' failed.\n", cmd);
     27	return ret;
     28}
     29
     30static int compass_store(struct device *dev, const char *buf, size_t count,
     31			const char *map)
     32{
     33	struct i2c_client *c = to_i2c_client(dev);
     34	int ret;
     35	unsigned long val;
     36
     37	ret = kstrtoul(buf, 10, &val);
     38	if (ret)
     39		return ret;
     40	if (val >= strlen(map))
     41		return -EINVAL;
     42	val = array_index_nospec(val, strlen(map));
     43	mutex_lock(&compass_mutex);
     44	ret = compass_command(c, map[val]);
     45	mutex_unlock(&compass_mutex);
     46	if (ret < 0)
     47		return ret;
     48	return count;
     49}
     50
     51static ssize_t compass_calibration_store(struct device *dev,
     52		struct device_attribute *attr, const char *buf, size_t count)
     53{
     54	return compass_store(dev, buf, count, "EC");
     55}
     56
     57static ssize_t compass_power_mode_store(struct device *dev,
     58		struct device_attribute *attr, const  char *buf, size_t count)
     59{
     60	return compass_store(dev, buf, count, "SW");
     61}
     62
     63static ssize_t compass_heading_data_show(struct device *dev,
     64			struct device_attribute *attr, char *buf)
     65{
     66	struct i2c_client *client = to_i2c_client(dev);
     67	unsigned char i2c_data[2];
     68	int ret;
     69
     70	mutex_lock(&compass_mutex);
     71	ret = compass_command(client, 'A');
     72	if (ret != 1) {
     73		mutex_unlock(&compass_mutex);
     74		return ret;
     75	}
     76	msleep(10); /* sending 'A' cmd we need to wait for 7-10 millisecs */
     77	ret = i2c_master_recv(client, i2c_data, 2);
     78	mutex_unlock(&compass_mutex);
     79	if (ret < 0) {
     80		dev_warn(dev, "i2c read data cmd failed\n");
     81		return ret;
     82	}
     83	ret = (i2c_data[0] << 8) | i2c_data[1];
     84	return sprintf(buf, "%d.%d\n", ret/10, ret%10);
     85}
     86
     87
     88static DEVICE_ATTR(heading0_input, S_IRUGO, compass_heading_data_show, NULL);
     89static DEVICE_ATTR(calibration, S_IWUSR, NULL, compass_calibration_store);
     90static DEVICE_ATTR(power_state, S_IWUSR, NULL, compass_power_mode_store);
     91
     92static struct attribute *mid_att_compass[] = {
     93	&dev_attr_heading0_input.attr,
     94	&dev_attr_calibration.attr,
     95	&dev_attr_power_state.attr,
     96	NULL
     97};
     98
     99static const struct attribute_group m_compass_gr = {
    100	.name = "hmc6352",
    101	.attrs = mid_att_compass
    102};
    103
    104static int hmc6352_probe(struct i2c_client *client,
    105					const struct i2c_device_id *id)
    106{
    107	int res;
    108
    109	res = sysfs_create_group(&client->dev.kobj, &m_compass_gr);
    110	if (res) {
    111		dev_err(&client->dev, "device_create_file failed\n");
    112		return res;
    113	}
    114	dev_info(&client->dev, "%s HMC6352 compass chip found\n",
    115							client->name);
    116	return 0;
    117}
    118
    119static int hmc6352_remove(struct i2c_client *client)
    120{
    121	sysfs_remove_group(&client->dev.kobj, &m_compass_gr);
    122	return 0;
    123}
    124
    125static const struct i2c_device_id hmc6352_id[] = {
    126	{ "hmc6352", 0 },
    127	{ }
    128};
    129
    130MODULE_DEVICE_TABLE(i2c, hmc6352_id);
    131
    132static struct i2c_driver hmc6352_driver = {
    133	.driver = {
    134		.name = "hmc6352",
    135	},
    136	.probe = hmc6352_probe,
    137	.remove = hmc6352_remove,
    138	.id_table = hmc6352_id,
    139};
    140
    141module_i2c_driver(hmc6352_driver);
    142
    143MODULE_AUTHOR("Kalhan Trisal <kalhan.trisal@intel.com");
    144MODULE_DESCRIPTION("hmc6352 Compass Driver");
    145MODULE_LICENSE("GPL v2");