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Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +02001/*
2 * lm70.c
3 *
4 * The LM70 is a temperature sensor chip from National Semiconductor (NS).
5 * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com>
6 *
7 * The LM70 communicates with a host processor via an SPI/Microwire Bus
8 * interface. The complete datasheet is available at National's website
9 * here:
10 * http://www.national.com/pf/LM/LM70.html
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 */
26
27#include <linux/init.h>
28#include <linux/module.h>
29#include <linux/kernel.h>
30#include <linux/device.h>
31#include <linux/err.h>
32#include <linux/sysfs.h>
33#include <linux/hwmon.h>
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020034#include <linux/mutex.h>
Anton Vorontsov8cec03e2009-09-22 16:46:07 -070035#include <linux/mod_devicetable.h>
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020036#include <linux/spi/spi.h>
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020037
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020038
39#define DRVNAME "lm70"
40
Manuel Laussc8ac32e2009-01-07 16:37:34 +010041#define LM70_CHIP_LM70 0 /* original NS LM70 */
42#define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */
43
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020044struct lm70 {
Tony Jones1beeffe2007-08-20 13:46:20 -070045 struct device *hwmon_dev;
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020046 struct mutex lock;
Manuel Laussc8ac32e2009-01-07 16:37:34 +010047 unsigned int chip;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020048};
49
50/* sysfs hook function */
51static ssize_t lm70_sense_temp(struct device *dev,
52 struct device_attribute *attr, char *buf)
53{
54 struct spi_device *spi = to_spi_device(dev);
Manuel Laussc8ac32e2009-01-07 16:37:34 +010055 int status, val = 0;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020056 u8 rxbuf[2];
57 s16 raw=0;
58 struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
59
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020060 if (mutex_lock_interruptible(&p_lm70->lock))
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020061 return -ERESTARTSYS;
62
63 /*
64 * spi_read() requires a DMA-safe buffer; so we use
65 * spi_write_then_read(), transmitting 0 bytes.
66 */
67 status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2);
68 if (status < 0) {
69 printk(KERN_WARNING
70 "spi_write_then_read failed with status %d\n", status);
71 goto out;
72 }
Kaiwan N Billimoria2b730052009-01-07 16:37:34 +010073 raw = (rxbuf[0] << 8) + rxbuf[1];
74 dev_dbg(dev, "rxbuf[0] : 0x%02x rxbuf[1] : 0x%02x raw=0x%04x\n",
75 rxbuf[0], rxbuf[1], raw);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020076
77 /*
Manuel Laussc8ac32e2009-01-07 16:37:34 +010078 * LM70:
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020079 * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's
80 * complement value. Only the MSB 11 bits (1 sign + 10 temperature
81 * bits) are meaningful; the LSB 5 bits are to be discarded.
82 * See the datasheet.
83 *
84 * Further, each bit represents 0.25 degrees Celsius; so, multiply
85 * by 0.25. Also multiply by 1000 to represent in millidegrees
86 * Celsius.
87 * So it's equivalent to multiplying by 0.25 * 1000 = 250.
Manuel Laussc8ac32e2009-01-07 16:37:34 +010088 *
89 * TMP121/TMP123:
90 * 13 bits of 2's complement data, discard LSB 3 bits,
91 * resolution 0.0625 degrees celsius.
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020092 */
Manuel Laussc8ac32e2009-01-07 16:37:34 +010093 switch (p_lm70->chip) {
94 case LM70_CHIP_LM70:
95 val = ((int)raw / 32) * 250;
96 break;
97
98 case LM70_CHIP_TMP121:
99 val = ((int)raw / 8) * 625 / 10;
100 break;
101 }
102
Jean Delvare67f921d2007-08-17 17:31:35 +0200103 status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200104out:
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +0200105 mutex_unlock(&p_lm70->lock);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200106 return status;
107}
108
109static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL);
110
Jean Delvare67f921d2007-08-17 17:31:35 +0200111static ssize_t lm70_show_name(struct device *dev, struct device_attribute
112 *devattr, char *buf)
113{
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100114 struct lm70 *p_lm70 = dev_get_drvdata(dev);
115 int ret;
116
117 switch (p_lm70->chip) {
118 case LM70_CHIP_LM70:
119 ret = sprintf(buf, "lm70\n");
120 break;
121 case LM70_CHIP_TMP121:
122 ret = sprintf(buf, "tmp121\n");
123 break;
124 default:
125 ret = -EINVAL;
126 }
127 return ret;
Jean Delvare67f921d2007-08-17 17:31:35 +0200128}
129
130static DEVICE_ATTR(name, S_IRUGO, lm70_show_name, NULL);
131
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200132/*----------------------------------------------------------------------*/
133
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700134static int __devinit lm70_probe(struct spi_device *spi)
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200135{
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700136 int chip = spi_get_device_id(spi)->driver_data;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200137 struct lm70 *p_lm70;
138 int status;
139
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700140 /* signaling is SPI_MODE_0 for both LM70 and TMP121 */
141 if (spi->mode & (SPI_CPOL | SPI_CPHA))
142 return -EINVAL;
143
144 /* 3-wire link (shared SI/SO) for LM70 */
145 if (chip == LM70_CHIP_LM70 && !(spi->mode & SPI_3WIRE))
146 return -EINVAL;
147
Kaiwan N Billimoria2b730052009-01-07 16:37:34 +0100148 /* NOTE: we assume 8-bit words, and convert to 16 bits manually */
149
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200150 p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL);
151 if (!p_lm70)
152 return -ENOMEM;
153
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +0200154 mutex_init(&p_lm70->lock);
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100155 p_lm70->chip = chip;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200156
157 /* sysfs hook */
Tony Jones1beeffe2007-08-20 13:46:20 -0700158 p_lm70->hwmon_dev = hwmon_device_register(&spi->dev);
159 if (IS_ERR(p_lm70->hwmon_dev)) {
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200160 dev_dbg(&spi->dev, "hwmon_device_register failed.\n");
Tony Jones1beeffe2007-08-20 13:46:20 -0700161 status = PTR_ERR(p_lm70->hwmon_dev);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200162 goto out_dev_reg_failed;
163 }
164 dev_set_drvdata(&spi->dev, p_lm70);
165
Jean Delvare67f921d2007-08-17 17:31:35 +0200166 if ((status = device_create_file(&spi->dev, &dev_attr_temp1_input))
167 || (status = device_create_file(&spi->dev, &dev_attr_name))) {
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200168 dev_dbg(&spi->dev, "device_create_file failure.\n");
169 goto out_dev_create_file_failed;
170 }
171
172 return 0;
173
174out_dev_create_file_failed:
Jean Delvare67f921d2007-08-17 17:31:35 +0200175 device_remove_file(&spi->dev, &dev_attr_temp1_input);
Tony Jones1beeffe2007-08-20 13:46:20 -0700176 hwmon_device_unregister(p_lm70->hwmon_dev);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200177out_dev_reg_failed:
178 dev_set_drvdata(&spi->dev, NULL);
179 kfree(p_lm70);
180 return status;
181}
182
Ralf Baechle41be7222007-02-14 21:15:04 +0100183static int __devexit lm70_remove(struct spi_device *spi)
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200184{
185 struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
186
187 device_remove_file(&spi->dev, &dev_attr_temp1_input);
Jean Delvare67f921d2007-08-17 17:31:35 +0200188 device_remove_file(&spi->dev, &dev_attr_name);
Tony Jones1beeffe2007-08-20 13:46:20 -0700189 hwmon_device_unregister(p_lm70->hwmon_dev);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200190 dev_set_drvdata(&spi->dev, NULL);
191 kfree(p_lm70);
192
193 return 0;
194}
195
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700196
197static const struct spi_device_id lm70_ids[] = {
198 { "lm70", LM70_CHIP_LM70 },
199 { "tmp121", LM70_CHIP_TMP121 },
200 { },
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100201};
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700202MODULE_DEVICE_TABLE(spi, lm70_ids);
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100203
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200204static struct spi_driver lm70_driver = {
205 .driver = {
206 .name = "lm70",
207 .owner = THIS_MODULE,
208 },
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700209 .id_table = lm70_ids,
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200210 .probe = lm70_probe,
211 .remove = __devexit_p(lm70_remove),
212};
213
214static int __init init_lm70(void)
215{
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700216 return spi_register_driver(&lm70_driver);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200217}
218
219static void __exit cleanup_lm70(void)
220{
221 spi_unregister_driver(&lm70_driver);
222}
223
224module_init(init_lm70);
225module_exit(cleanup_lm70);
226
227MODULE_AUTHOR("Kaiwan N Billimoria");
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100228MODULE_DESCRIPTION("NS LM70 / TI TMP121/TMP123 Linux driver");
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200229MODULE_LICENSE("GPL");