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linux/drivers/hwmon/ds620.c
Guenter Roeck e36ce99ee0 hwmon: (ds620) Fix overflows seen when writing temperature limits 
Module test reports:

temp1_max: Suspected overflow: [160000 vs. 0]
temp1_min: Suspected overflow: [160000 vs. 0]

This is seen because the values passed when writing temperature limits
are unbound.

Reviewed-by: Jean Delvare <jdelvare@suse.de>
Fixes: 6099469805 ("hwmon: Support for Dallas Semiconductor DS620")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2016-12-09 06:09:34 -08:00

273 lines
7.4 KiB
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/*
* ds620.c - Support for temperature sensor and thermostat DS620
*
* Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
*
* based on ds1621.c by Christian W. Zuckschwerdt <zany@triq.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>
#include <linux/i2c/ds620.h>
/*
* Many DS620 constants specified below
* 15 14 13 12 11 10 09 08
* |Done|NVB |THF |TLF |R1 |R0 |AUTOC|1SHOT|
*
* 07 06 05 04 03 02 01 00
* |PO2 |PO1 |A2 |A1 |A0 | | | |
*/
#define DS620_REG_CONFIG_DONE 0x8000
#define DS620_REG_CONFIG_NVB 0x4000
#define DS620_REG_CONFIG_THF 0x2000
#define DS620_REG_CONFIG_TLF 0x1000
#define DS620_REG_CONFIG_R1 0x0800
#define DS620_REG_CONFIG_R0 0x0400
#define DS620_REG_CONFIG_AUTOC 0x0200
#define DS620_REG_CONFIG_1SHOT 0x0100
#define DS620_REG_CONFIG_PO2 0x0080
#define DS620_REG_CONFIG_PO1 0x0040
#define DS620_REG_CONFIG_A2 0x0020
#define DS620_REG_CONFIG_A1 0x0010
#define DS620_REG_CONFIG_A0 0x0008
/* The DS620 registers */
static const u8 DS620_REG_TEMP[3] = {
0xAA, /* input, word, RO */
0xA2, /* min, word, RW */
0xA0, /* max, word, RW */
};
#define DS620_REG_CONF 0xAC /* word, RW */
#define DS620_COM_START 0x51 /* no data */
#define DS620_COM_STOP 0x22 /* no data */
/* Each client has this additional data */
struct ds620_data {
struct i2c_client *client;
struct mutex update_lock;
char valid; /* !=0 if following fields are valid */
unsigned long last_updated; /* In jiffies */
s16 temp[3]; /* Register values, word */
};
static void ds620_init_client(struct i2c_client *client)
{
struct ds620_platform_data *ds620_info = dev_get_platdata(&client->dev);
u16 conf, new_conf;
new_conf = conf =
i2c_smbus_read_word_swapped(client, DS620_REG_CONF);
/* switch to continuous conversion mode */
new_conf &= ~DS620_REG_CONFIG_1SHOT;
/* already high at power-on, but don't trust the BIOS! */
new_conf |= DS620_REG_CONFIG_PO2;
/* thermostat mode according to platform data */
if (ds620_info && ds620_info->pomode == 1)
new_conf &= ~DS620_REG_CONFIG_PO1; /* PO_LOW */
else if (ds620_info && ds620_info->pomode == 2)
new_conf |= DS620_REG_CONFIG_PO1; /* PO_HIGH */
else
new_conf &= ~DS620_REG_CONFIG_PO2; /* always low */
/* with highest precision */
new_conf |= DS620_REG_CONFIG_R1 | DS620_REG_CONFIG_R0;
if (conf != new_conf)
i2c_smbus_write_word_swapped(client, DS620_REG_CONF, new_conf);
/* start conversion */
i2c_smbus_write_byte(client, DS620_COM_START);
}
static struct ds620_data *ds620_update_client(struct device *dev)
{
struct ds620_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
struct ds620_data *ret = data;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
|| !data->valid) {
int i;
int res;
dev_dbg(&client->dev, "Starting ds620 update\n");
for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
res = i2c_smbus_read_word_swapped(client,
DS620_REG_TEMP[i]);
if (res < 0) {
ret = ERR_PTR(res);
goto abort;
}
data->temp[i] = res;
}
data->last_updated = jiffies;
data->valid = 1;
}
abort:
mutex_unlock(&data->update_lock);
return ret;
}
static ssize_t show_temp(struct device *dev, struct device_attribute *da,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ds620_data *data = ds620_update_client(dev);
if (IS_ERR(data))
return PTR_ERR(data);
return sprintf(buf, "%d\n", ((data->temp[attr->index] / 8) * 625) / 10);
}
static ssize_t set_temp(struct device *dev, struct device_attribute *da,
const char *buf, size_t count)
{
int res;
long val;
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ds620_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
res = kstrtol(buf, 10, &val);
if (res)
return res;
val = (clamp_val(val, -128000, 128000) * 10 / 625) * 8;
mutex_lock(&data->update_lock);
data->temp[attr->index] = val;
i2c_smbus_write_word_swapped(client, DS620_REG_TEMP[attr->index],
data->temp[attr->index]);
mutex_unlock(&data->update_lock);
return count;
}
static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ds620_data *data = ds620_update_client(dev);
struct i2c_client *client;
u16 conf, new_conf;
int res;
if (IS_ERR(data))
return PTR_ERR(data);
client = data->client;
/* reset alarms if necessary */
res = i2c_smbus_read_word_swapped(client, DS620_REG_CONF);
if (res < 0)
return res;
new_conf = conf = res;
new_conf &= ~attr->index;
if (conf != new_conf) {
res = i2c_smbus_write_word_swapped(client, DS620_REG_CONF,
new_conf);
if (res < 0)
return res;
}
return sprintf(buf, "%d\n", !!(conf & attr->index));
}
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
DS620_REG_CONFIG_TLF);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
DS620_REG_CONFIG_THF);
static struct attribute *ds620_attrs[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_temp1_min.dev_attr.attr,
&sensor_dev_attr_temp1_max.dev_attr.attr,
&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
NULL
};
ATTRIBUTE_GROUPS(ds620);
static int ds620_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct device *hwmon_dev;
struct ds620_data *data;
data = devm_kzalloc(dev, sizeof(struct ds620_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->client = client;
mutex_init(&data->update_lock);
/* Initialize the DS620 chip */
ds620_init_client(client);
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
data, ds620_groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id ds620_id[] = {
{"ds620", 0},
{}
};
MODULE_DEVICE_TABLE(i2c, ds620_id);
/* This is the driver that will be inserted */
static struct i2c_driver ds620_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "ds620",
},
.probe = ds620_probe,
.id_table = ds620_id,
};
module_i2c_driver(ds620_driver);
MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
MODULE_DESCRIPTION("DS620 driver");
MODULE_LICENSE("GPL");
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