tmp421.c 8.5 KB
Newer Older
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
/* tmp421.c
 *
 * Copyright (C) 2009 Andre Prendel <andre.prendel@gmx.de>
 * Preliminary support by:
 * Melvin Rook, Raymond Ng
 *
 * 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.
 */

/*
 * Driver for the Texas Instruments TMP421 SMBus temperature sensor IC.
 * Supported models: TMP421, TMP422, TMP423
 */

#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>

/* Addresses to scan */
static unsigned short normal_i2c[] = { 0x2a, 0x4c, 0x4d, 0x4e, 0x4f,
				       I2C_CLIENT_END };

42
enum chips { tmp421, tmp422, tmp423 };
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224

/* The TMP421 registers */
#define TMP421_CONFIG_REG_1			0x09
#define TMP421_CONVERSION_RATE_REG		0x0B
#define TMP421_MANUFACTURER_ID_REG		0xFE
#define TMP421_DEVICE_ID_REG			0xFF

static const u8 TMP421_TEMP_MSB[4]		= { 0x00, 0x01, 0x02, 0x03 };
static const u8 TMP421_TEMP_LSB[4]		= { 0x10, 0x11, 0x12, 0x13 };

/* Flags */
#define TMP421_CONFIG_SHUTDOWN			0x40
#define TMP421_CONFIG_RANGE			0x04

/* Manufacturer / Device ID's */
#define TMP421_MANUFACTURER_ID			0x55
#define TMP421_DEVICE_ID			0x21
#define TMP422_DEVICE_ID			0x22
#define TMP423_DEVICE_ID			0x23

static const struct i2c_device_id tmp421_id[] = {
	{ "tmp421", tmp421 },
	{ "tmp422", tmp422 },
	{ "tmp423", tmp423 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, tmp421_id);

struct tmp421_data {
	struct device *hwmon_dev;
	struct mutex update_lock;
	char valid;
	unsigned long last_updated;
	int kind;
	u8 config;
	s16 temp[4];
};

static int temp_from_s16(s16 reg)
{
	int temp = reg;

	return (temp * 1000 + 128) / 256;
}

static int temp_from_u16(u16 reg)
{
	int temp = reg;

	/* Add offset for extended temperature range. */
	temp -= 64 * 256;

	return (temp * 1000 + 128) / 256;
}

static struct tmp421_data *tmp421_update_device(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct tmp421_data *data = i2c_get_clientdata(client);
	int i;

	mutex_lock(&data->update_lock);

	if (time_after(jiffies, data->last_updated + 2 * HZ) || !data->valid) {
		data->config = i2c_smbus_read_byte_data(client,
			TMP421_CONFIG_REG_1);

		for (i = 0; i <= data->kind; i++) {
			data->temp[i] = i2c_smbus_read_byte_data(client,
				TMP421_TEMP_MSB[i]) << 8;
			data->temp[i] |= i2c_smbus_read_byte_data(client,
				TMP421_TEMP_LSB[i]);
		}
		data->last_updated = jiffies;
		data->valid = 1;
	}

	mutex_unlock(&data->update_lock);

	return data;
}

static ssize_t show_temp_value(struct device *dev,
			       struct device_attribute *devattr, char *buf)
{
	int index = to_sensor_dev_attr(devattr)->index;
	struct tmp421_data *data = tmp421_update_device(dev);
	int temp;

	mutex_lock(&data->update_lock);
	if (data->config & TMP421_CONFIG_RANGE)
		temp = temp_from_u16(data->temp[index]);
	else
		temp = temp_from_s16(data->temp[index]);
	mutex_unlock(&data->update_lock);

	return sprintf(buf, "%d\n", temp);
}

static ssize_t show_fault(struct device *dev,
			  struct device_attribute *devattr, char *buf)
{
	int index = to_sensor_dev_attr(devattr)->index;
	struct tmp421_data *data = tmp421_update_device(dev);

	/*
	 * The OPEN bit signals a fault. This is bit 0 of the temperature
	 * register (low byte).
	 */
	if (data->temp[index] & 0x01)
		return sprintf(buf, "1\n");
	else
		return sprintf(buf, "0\n");
}

static mode_t tmp421_is_visible(struct kobject *kobj, struct attribute *a,
				int n)
{
	struct device *dev = container_of(kobj, struct device, kobj);
	struct tmp421_data *data = dev_get_drvdata(dev);
	struct device_attribute *devattr;
	unsigned int index;

	devattr = container_of(a, struct device_attribute, attr);
	index = to_sensor_dev_attr(devattr)->index;

	if (data->kind > index)
		return a->mode;

	return 0;
}

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp_value, NULL, 0);
static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp_value, NULL, 1);
static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_fault, NULL, 1);
static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp_value, NULL, 2);
static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_fault, NULL, 2);
static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp_value, NULL, 3);
static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_fault, NULL, 3);

static struct attribute *tmp421_attr[] = {
	&sensor_dev_attr_temp1_input.dev_attr.attr,
	&sensor_dev_attr_temp2_input.dev_attr.attr,
	&sensor_dev_attr_temp2_fault.dev_attr.attr,
	&sensor_dev_attr_temp3_input.dev_attr.attr,
	&sensor_dev_attr_temp3_fault.dev_attr.attr,
	&sensor_dev_attr_temp4_input.dev_attr.attr,
	&sensor_dev_attr_temp4_fault.dev_attr.attr,
	NULL
};

static const struct attribute_group tmp421_group = {
	.attrs = tmp421_attr,
	.is_visible = tmp421_is_visible,
};

static int tmp421_init_client(struct i2c_client *client)
{
	int config, config_orig;

	/* Set the conversion rate to 2 Hz */
	i2c_smbus_write_byte_data(client, TMP421_CONVERSION_RATE_REG, 0x05);

	/* Start conversions (disable shutdown if necessary) */
	config = i2c_smbus_read_byte_data(client, TMP421_CONFIG_REG_1);
	if (config < 0) {
		dev_err(&client->dev, "Could not read configuration"
			 " register (%d)\n", config);
		return -ENODEV;
	}

	config_orig = config;
	config &= ~TMP421_CONFIG_SHUTDOWN;

	if (config != config_orig) {
		dev_info(&client->dev, "Enable monitoring chip\n");
		i2c_smbus_write_byte_data(client, TMP421_CONFIG_REG_1, config);
	}

	return 0;
}

225
static int tmp421_detect(struct i2c_client *client,
226 227
			 struct i2c_board_info *info)
{
228
	enum chips kind;
229 230
	struct i2c_adapter *adapter = client->adapter;
	const char *names[] = { "TMP421", "TMP422", "TMP423" };
231
	u8 reg;
232 233 234 235

	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
		return -ENODEV;

236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252
	reg = i2c_smbus_read_byte_data(client, TMP421_MANUFACTURER_ID_REG);
	if (reg != TMP421_MANUFACTURER_ID)
		return -ENODEV;

	reg = i2c_smbus_read_byte_data(client, TMP421_DEVICE_ID_REG);
	switch (reg) {
	case TMP421_DEVICE_ID:
		kind = tmp421;
		break;
	case TMP422_DEVICE_ID:
		kind = tmp422;
		break;
	case TMP423_DEVICE_ID:
		kind = tmp423;
		break;
	default:
		return -ENODEV;
253
	}
254

255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323
	strlcpy(info->type, tmp421_id[kind - 1].name, I2C_NAME_SIZE);
	dev_info(&adapter->dev, "Detected TI %s chip at 0x%02x\n",
		 names[kind - 1], client->addr);

	return 0;
}

static int tmp421_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct tmp421_data *data;
	int err;

	data = kzalloc(sizeof(struct tmp421_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	i2c_set_clientdata(client, data);
	mutex_init(&data->update_lock);
	data->kind = id->driver_data;

	err = tmp421_init_client(client);
	if (err)
		goto exit_free;

	err = sysfs_create_group(&client->dev.kobj, &tmp421_group);
	if (err)
		goto exit_free;

	data->hwmon_dev = hwmon_device_register(&client->dev);
	if (IS_ERR(data->hwmon_dev)) {
		err = PTR_ERR(data->hwmon_dev);
		data->hwmon_dev = NULL;
		goto exit_remove;
	}
	return 0;

exit_remove:
	sysfs_remove_group(&client->dev.kobj, &tmp421_group);

exit_free:
	i2c_set_clientdata(client, NULL);
	kfree(data);

	return err;
}

static int tmp421_remove(struct i2c_client *client)
{
	struct tmp421_data *data = i2c_get_clientdata(client);

	hwmon_device_unregister(data->hwmon_dev);
	sysfs_remove_group(&client->dev.kobj, &tmp421_group);

	i2c_set_clientdata(client, NULL);
	kfree(data);

	return 0;
}

static struct i2c_driver tmp421_driver = {
	.class = I2C_CLASS_HWMON,
	.driver = {
		.name	= "tmp421",
	},
	.probe = tmp421_probe,
	.remove = tmp421_remove,
	.id_table = tmp421_id,
	.detect = tmp421_detect,
324
	.address_list = normal_i2c,
325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343
};

static int __init tmp421_init(void)
{
	return i2c_add_driver(&tmp421_driver);
}

static void __exit tmp421_exit(void)
{
	i2c_del_driver(&tmp421_driver);
}

MODULE_AUTHOR("Andre Prendel <andre.prendel@gmx.de>");
MODULE_DESCRIPTION("Texas Instruments TMP421/422/423 temperature sensor"
		   " driver");
MODULE_LICENSE("GPL");

module_init(tmp421_init);
module_exit(tmp421_exit);