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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * hmc6352.c - Honeywell Compass Driver4 *5 * Copyright (C) 2009 Intel Corp6 *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 NULL97};98 99static const struct attribute_group m_compass_gr = {100 .name = "hmc6352",101 .attrs = mid_att_compass102};103 104static int hmc6352_probe(struct i2c_client *client)105{106 int res;107 108 res = sysfs_create_group(&client->dev.kobj, &m_compass_gr);109 if (res) {110 dev_err(&client->dev, "device_create_file failed\n");111 return res;112 }113 dev_info(&client->dev, "%s HMC6352 compass chip found\n",114 client->name);115 return 0;116}117 118static void hmc6352_remove(struct i2c_client *client)119{120 sysfs_remove_group(&client->dev.kobj, &m_compass_gr);121}122 123static const struct i2c_device_id hmc6352_id[] = {124 { "hmc6352" },125 { }126};127 128MODULE_DEVICE_TABLE(i2c, hmc6352_id);129 130static struct i2c_driver hmc6352_driver = {131 .driver = {132 .name = "hmc6352",133 },134 .probe = hmc6352_probe,135 .remove = hmc6352_remove,136 .id_table = hmc6352_id,137};138 139module_i2c_driver(hmc6352_driver);140 141MODULE_AUTHOR("Kalhan Trisal <kalhan.trisal@intel.com");142MODULE_DESCRIPTION("hmc6352 Compass Driver");143MODULE_LICENSE("GPL v2");144