// 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" },
        { }
};

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");