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/drivers/hwmon/w83l785ts.c

https://bitbucket.org/ndreys/linux-sunxi
C | 320 lines | 191 code | 54 blank | 75 comment | 17 complexity | 84093cda5ce2ec78c4905c4608821cc1 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  1/*
  2 * w83l785ts.c - Part of lm_sensors, Linux kernel modules for hardware
  3 *               monitoring
  4 * Copyright (C) 2003-2009  Jean Delvare <khali@linux-fr.org>
  5 *
  6 * Inspired from the lm83 driver. The W83L785TS-S is a sensor chip made
  7 * by Winbond. It reports a single external temperature with a 1 deg
  8 * resolution and a 3 deg accuracy. Datasheet can be obtained from
  9 * Winbond's website at:
 10 *   http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83L785TS-S.pdf
 11 *
 12 * Ported to Linux 2.6 by Wolfgang Ziegler <nuppla@gmx.at> and Jean Delvare
 13 * <khali@linux-fr.org>.
 14 *
 15 * Thanks to James Bolt <james@evilpenguin.com> for benchmarking the read
 16 * error handling mechanism.
 17 *
 18 * This program is free software; you can redistribute it and/or modify
 19 * it under the terms of the GNU General Public License as published by
 20 * the Free Software Foundation; either version 2 of the License, or
 21 * (at your option) any later version.
 22 *
 23 * This program is distributed in the hope that it will be useful,
 24 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 25 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 26 * GNU General Public License for more details.
 27 *
 28 * You should have received a copy of the GNU General Public License
 29 * along with this program; if not, write to the Free Software
 30 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 31 */
 32
 33#include <linux/module.h>
 34#include <linux/delay.h>
 35#include <linux/init.h>
 36#include <linux/slab.h>
 37#include <linux/jiffies.h>
 38#include <linux/i2c.h>
 39#include <linux/hwmon.h>
 40#include <linux/hwmon-sysfs.h>
 41#include <linux/err.h>
 42#include <linux/mutex.h>
 43
 44/* How many retries on register read error */
 45#define MAX_RETRIES	5
 46
 47/*
 48 * Address to scan
 49 * Address is fully defined internally and cannot be changed.
 50 */
 51
 52static const unsigned short normal_i2c[] = { 0x2e, I2C_CLIENT_END };
 53
 54/*
 55 * The W83L785TS-S registers
 56 * Manufacturer ID is 0x5CA3 for Winbond.
 57 */
 58
 59#define W83L785TS_REG_MAN_ID1		0x4D
 60#define W83L785TS_REG_MAN_ID2		0x4C
 61#define W83L785TS_REG_CHIP_ID		0x4E
 62#define W83L785TS_REG_CONFIG		0x40
 63#define W83L785TS_REG_TYPE		0x52
 64#define W83L785TS_REG_TEMP		0x27
 65#define W83L785TS_REG_TEMP_OVER		0x53 /* not sure about this one */
 66
 67/*
 68 * Conversions
 69 * The W83L785TS-S uses signed 8-bit values.
 70 */
 71
 72#define TEMP_FROM_REG(val)	((val) * 1000)
 73
 74/*
 75 * Functions declaration
 76 */
 77
 78static int w83l785ts_probe(struct i2c_client *client,
 79			   const struct i2c_device_id *id);
 80static int w83l785ts_detect(struct i2c_client *client,
 81			    struct i2c_board_info *info);
 82static int w83l785ts_remove(struct i2c_client *client);
 83static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval);
 84static struct w83l785ts_data *w83l785ts_update_device(struct device *dev);
 85
 86/*
 87 * Driver data (common to all clients)
 88 */
 89 
 90static const struct i2c_device_id w83l785ts_id[] = {
 91	{ "w83l785ts", 0 },
 92	{ }
 93};
 94MODULE_DEVICE_TABLE(i2c, w83l785ts_id);
 95
 96static struct i2c_driver w83l785ts_driver = {
 97	.class		= I2C_CLASS_HWMON,
 98	.driver = {
 99		.name	= "w83l785ts",
100	},
101	.probe		= w83l785ts_probe,
102	.remove		= w83l785ts_remove,
103	.id_table	= w83l785ts_id,
104	.detect		= w83l785ts_detect,
105	.address_list	= normal_i2c,
106};
107
108/*
109 * Client data (each client gets its own)
110 */
111
112struct w83l785ts_data {
113	struct device *hwmon_dev;
114	struct mutex update_lock;
115	char valid; /* zero until following fields are valid */
116	unsigned long last_updated; /* in jiffies */
117
118	/* registers values */
119	s8 temp[2]; /* 0: input
120		       1: critical limit */
121};
122
123/*
124 * Sysfs stuff
125 */
126
127static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
128	char *buf)
129{
130	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
131	struct w83l785ts_data *data = w83l785ts_update_device(dev);
132	return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
133}
134
135static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
136static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp, NULL, 1);
137
138/*
139 * Real code
140 */
141
142/* Return 0 if detection is successful, -ENODEV otherwise */
143static int w83l785ts_detect(struct i2c_client *client,
144			    struct i2c_board_info *info)
145{
146	struct i2c_adapter *adapter = client->adapter;
147	u16 man_id;
148	u8 chip_id;
149
150	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
151		return -ENODEV;
152
153	/* detection */
154	if ((w83l785ts_read_value(client, W83L785TS_REG_CONFIG, 0) & 0x80)
155	 || (w83l785ts_read_value(client, W83L785TS_REG_TYPE, 0) & 0xFC)) {
156		dev_dbg(&adapter->dev,
157			"W83L785TS-S detection failed at 0x%02x\n",
158			client->addr);
159		return -ENODEV;
160	}
161
162	/* Identification */
163	man_id = (w83l785ts_read_value(client, W83L785TS_REG_MAN_ID1, 0) << 8)
164	       + w83l785ts_read_value(client, W83L785TS_REG_MAN_ID2, 0);
165	chip_id = w83l785ts_read_value(client, W83L785TS_REG_CHIP_ID, 0);
166
167	if (man_id != 0x5CA3		/* Winbond */
168	 || chip_id != 0x70) {		/* W83L785TS-S */
169		dev_dbg(&adapter->dev,
170			"Unsupported chip (man_id=0x%04X, chip_id=0x%02X)\n",
171			man_id, chip_id);
172		return -ENODEV;
173	}
174
175	strlcpy(info->type, "w83l785ts", I2C_NAME_SIZE);
176
177	return 0;
178}
179
180static int w83l785ts_probe(struct i2c_client *new_client,
181			   const struct i2c_device_id *id)
182{
183	struct w83l785ts_data *data;
184	int err = 0;
185
186	data = kzalloc(sizeof(struct w83l785ts_data), GFP_KERNEL);
187	if (!data) {
188		err = -ENOMEM;
189		goto exit;
190	}
191
192	i2c_set_clientdata(new_client, data);
193	data->valid = 0;
194	mutex_init(&data->update_lock);
195
196	/* Default values in case the first read fails (unlikely). */
197	data->temp[1] = data->temp[0] = 0;
198
199	/*
200	 * Initialize the W83L785TS chip
201	 * Nothing yet, assume it is already started.
202	 */
203
204	err = device_create_file(&new_client->dev,
205				 &sensor_dev_attr_temp1_input.dev_attr);
206	if (err)
207		goto exit_remove;
208
209	err = device_create_file(&new_client->dev,
210				 &sensor_dev_attr_temp1_max.dev_attr);
211	if (err)
212		goto exit_remove;
213
214	/* Register sysfs hooks */
215	data->hwmon_dev = hwmon_device_register(&new_client->dev);
216	if (IS_ERR(data->hwmon_dev)) {
217		err = PTR_ERR(data->hwmon_dev);
218		goto exit_remove;
219	}
220
221	return 0;
222
223exit_remove:
224	device_remove_file(&new_client->dev,
225			   &sensor_dev_attr_temp1_input.dev_attr);
226	device_remove_file(&new_client->dev,
227			   &sensor_dev_attr_temp1_max.dev_attr);
228	kfree(data);
229exit:
230	return err;
231}
232
233static int w83l785ts_remove(struct i2c_client *client)
234{
235	struct w83l785ts_data *data = i2c_get_clientdata(client);
236
237	hwmon_device_unregister(data->hwmon_dev);
238	device_remove_file(&client->dev,
239			   &sensor_dev_attr_temp1_input.dev_attr);
240	device_remove_file(&client->dev,
241			   &sensor_dev_attr_temp1_max.dev_attr);
242
243	kfree(data);
244	return 0;
245}
246
247static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval)
248{
249	int value, i;
250	struct device *dev;
251	const char *prefix;
252
253	/* We might be called during detection, at which point the client
254	   isn't yet fully initialized, so we can't use dev_dbg on it */
255	if (i2c_get_clientdata(client)) {
256		dev = &client->dev;
257		prefix = "";
258	} else {
259		dev = &client->adapter->dev;
260		prefix = "w83l785ts: ";
261	}
262
263	/* Frequent read errors have been reported on Asus boards, so we
264	 * retry on read errors. If it still fails (unlikely), return the
265	 * default value requested by the caller. */
266	for (i = 1; i <= MAX_RETRIES; i++) {
267		value = i2c_smbus_read_byte_data(client, reg);
268		if (value >= 0) {
269			dev_dbg(dev, "%sRead 0x%02x from register 0x%02x.\n",
270				prefix, value, reg);
271			return value;
272		}
273		dev_dbg(dev, "%sRead failed, will retry in %d.\n", prefix, i);
274		msleep(i);
275	}
276
277	dev_err(dev, "%sCouldn't read value from register 0x%02x.\n", prefix,
278		reg);
279	return defval;
280}
281
282static struct w83l785ts_data *w83l785ts_update_device(struct device *dev)
283{
284	struct i2c_client *client = to_i2c_client(dev);
285	struct w83l785ts_data *data = i2c_get_clientdata(client);
286
287	mutex_lock(&data->update_lock);
288
289	if (!data->valid || time_after(jiffies, data->last_updated + HZ * 2)) {
290		dev_dbg(&client->dev, "Updating w83l785ts data.\n");
291		data->temp[0] = w83l785ts_read_value(client,
292				W83L785TS_REG_TEMP, data->temp[0]);
293		data->temp[1] = w83l785ts_read_value(client,
294				W83L785TS_REG_TEMP_OVER, data->temp[1]);
295
296		data->last_updated = jiffies;
297		data->valid = 1;
298	}
299
300	mutex_unlock(&data->update_lock);
301
302	return data;
303}
304
305static int __init sensors_w83l785ts_init(void)
306{
307	return i2c_add_driver(&w83l785ts_driver);
308}
309
310static void __exit sensors_w83l785ts_exit(void)
311{
312	i2c_del_driver(&w83l785ts_driver);
313}
314
315MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
316MODULE_DESCRIPTION("W83L785TS-S driver");
317MODULE_LICENSE("GPL");
318
319module_init(sensors_w83l785ts_init);
320module_exit(sensors_w83l785ts_exit);