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