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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>
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020035#include <linux/spi/spi.h>
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020036
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020037
38#define DRVNAME "lm70"
39
Manuel Laussc8ac32e2009-01-07 16:37:34 +010040#define LM70_CHIP_LM70 0 /* original NS LM70 */
41#define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */
42
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020043struct lm70 {
Tony Jones1beeffe2007-08-20 13:46:20 -070044 struct device *hwmon_dev;
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020045 struct mutex lock;
Manuel Laussc8ac32e2009-01-07 16:37:34 +010046 unsigned int chip;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020047};
48
49/* sysfs hook function */
50static ssize_t lm70_sense_temp(struct device *dev,
51 struct device_attribute *attr, char *buf)
52{
53 struct spi_device *spi = to_spi_device(dev);
Manuel Laussc8ac32e2009-01-07 16:37:34 +010054 int status, val = 0;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020055 u8 rxbuf[2];
56 s16 raw=0;
57 struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
58
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020059 if (mutex_lock_interruptible(&p_lm70->lock))
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020060 return -ERESTARTSYS;
61
62 /*
63 * spi_read() requires a DMA-safe buffer; so we use
64 * spi_write_then_read(), transmitting 0 bytes.
65 */
66 status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2);
67 if (status < 0) {
68 printk(KERN_WARNING
69 "spi_write_then_read failed with status %d\n", status);
70 goto out;
71 }
Kaiwan N Billimoria2b730052009-01-07 16:37:34 +010072 raw = (rxbuf[0] << 8) + rxbuf[1];
73 dev_dbg(dev, "rxbuf[0] : 0x%02x rxbuf[1] : 0x%02x raw=0x%04x\n",
74 rxbuf[0], rxbuf[1], raw);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020075
76 /*
Manuel Laussc8ac32e2009-01-07 16:37:34 +010077 * LM70:
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020078 * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's
79 * complement value. Only the MSB 11 bits (1 sign + 10 temperature
80 * bits) are meaningful; the LSB 5 bits are to be discarded.
81 * See the datasheet.
82 *
83 * Further, each bit represents 0.25 degrees Celsius; so, multiply
84 * by 0.25. Also multiply by 1000 to represent in millidegrees
85 * Celsius.
86 * So it's equivalent to multiplying by 0.25 * 1000 = 250.
Manuel Laussc8ac32e2009-01-07 16:37:34 +010087 *
88 * TMP121/TMP123:
89 * 13 bits of 2's complement data, discard LSB 3 bits,
90 * resolution 0.0625 degrees celsius.
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020091 */
Manuel Laussc8ac32e2009-01-07 16:37:34 +010092 switch (p_lm70->chip) {
93 case LM70_CHIP_LM70:
94 val = ((int)raw / 32) * 250;
95 break;
96
97 case LM70_CHIP_TMP121:
98 val = ((int)raw / 8) * 625 / 10;
99 break;
100 }
101
Jean Delvare67f921d2007-08-17 17:31:35 +0200102 status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200103out:
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +0200104 mutex_unlock(&p_lm70->lock);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200105 return status;
106}
107
108static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL);
109
Jean Delvare67f921d2007-08-17 17:31:35 +0200110static ssize_t lm70_show_name(struct device *dev, struct device_attribute
111 *devattr, char *buf)
112{
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100113 struct lm70 *p_lm70 = dev_get_drvdata(dev);
114 int ret;
115
116 switch (p_lm70->chip) {
117 case LM70_CHIP_LM70:
118 ret = sprintf(buf, "lm70\n");
119 break;
120 case LM70_CHIP_TMP121:
121 ret = sprintf(buf, "tmp121\n");
122 break;
123 default:
124 ret = -EINVAL;
125 }
126 return ret;
Jean Delvare67f921d2007-08-17 17:31:35 +0200127}
128
129static DEVICE_ATTR(name, S_IRUGO, lm70_show_name, NULL);
130
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200131/*----------------------------------------------------------------------*/
132
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100133static int __devinit common_probe(struct spi_device *spi, int chip)
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200134{
135 struct lm70 *p_lm70;
136 int status;
137
Kaiwan N Billimoria2b730052009-01-07 16:37:34 +0100138 /* NOTE: we assume 8-bit words, and convert to 16 bits manually */
139
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200140 p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL);
141 if (!p_lm70)
142 return -ENOMEM;
143
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +0200144 mutex_init(&p_lm70->lock);
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100145 p_lm70->chip = chip;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200146
147 /* sysfs hook */
Tony Jones1beeffe2007-08-20 13:46:20 -0700148 p_lm70->hwmon_dev = hwmon_device_register(&spi->dev);
149 if (IS_ERR(p_lm70->hwmon_dev)) {
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200150 dev_dbg(&spi->dev, "hwmon_device_register failed.\n");
Tony Jones1beeffe2007-08-20 13:46:20 -0700151 status = PTR_ERR(p_lm70->hwmon_dev);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200152 goto out_dev_reg_failed;
153 }
154 dev_set_drvdata(&spi->dev, p_lm70);
155
Jean Delvare67f921d2007-08-17 17:31:35 +0200156 if ((status = device_create_file(&spi->dev, &dev_attr_temp1_input))
157 || (status = device_create_file(&spi->dev, &dev_attr_name))) {
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200158 dev_dbg(&spi->dev, "device_create_file failure.\n");
159 goto out_dev_create_file_failed;
160 }
161
162 return 0;
163
164out_dev_create_file_failed:
Jean Delvare67f921d2007-08-17 17:31:35 +0200165 device_remove_file(&spi->dev, &dev_attr_temp1_input);
Tony Jones1beeffe2007-08-20 13:46:20 -0700166 hwmon_device_unregister(p_lm70->hwmon_dev);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200167out_dev_reg_failed:
168 dev_set_drvdata(&spi->dev, NULL);
169 kfree(p_lm70);
170 return status;
171}
172
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100173static int __devinit lm70_probe(struct spi_device *spi)
174{
175 /* signaling is SPI_MODE_0 on a 3-wire link (shared SI/SO) */
176 if ((spi->mode & (SPI_CPOL | SPI_CPHA)) || !(spi->mode & SPI_3WIRE))
177 return -EINVAL;
178
179 return common_probe(spi, LM70_CHIP_LM70);
180}
181
182static int __devinit tmp121_probe(struct spi_device *spi)
183{
184 /* signaling is SPI_MODE_0 with only MISO connected */
185 if (spi->mode & (SPI_CPOL | SPI_CPHA))
186 return -EINVAL;
187
188 return common_probe(spi, LM70_CHIP_TMP121);
189}
190
Ralf Baechle41be7222007-02-14 21:15:04 +0100191static int __devexit lm70_remove(struct spi_device *spi)
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200192{
193 struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
194
195 device_remove_file(&spi->dev, &dev_attr_temp1_input);
Jean Delvare67f921d2007-08-17 17:31:35 +0200196 device_remove_file(&spi->dev, &dev_attr_name);
Tony Jones1beeffe2007-08-20 13:46:20 -0700197 hwmon_device_unregister(p_lm70->hwmon_dev);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200198 dev_set_drvdata(&spi->dev, NULL);
199 kfree(p_lm70);
200
201 return 0;
202}
203
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100204static struct spi_driver tmp121_driver = {
205 .driver = {
206 .name = "tmp121",
207 .owner = THIS_MODULE,
208 },
209 .probe = tmp121_probe,
210 .remove = __devexit_p(lm70_remove),
211};
212
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200213static struct spi_driver lm70_driver = {
214 .driver = {
215 .name = "lm70",
216 .owner = THIS_MODULE,
217 },
218 .probe = lm70_probe,
219 .remove = __devexit_p(lm70_remove),
220};
221
222static int __init init_lm70(void)
223{
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100224 int ret = spi_register_driver(&lm70_driver);
225 if (ret)
226 return ret;
227
228 ret = spi_register_driver(&tmp121_driver);
229 if (ret)
230 spi_unregister_driver(&lm70_driver);
231
232 return ret;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200233}
234
235static void __exit cleanup_lm70(void)
236{
237 spi_unregister_driver(&lm70_driver);
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100238 spi_unregister_driver(&tmp121_driver);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200239}
240
241module_init(init_lm70);
242module_exit(cleanup_lm70);
243
244MODULE_AUTHOR("Kaiwan N Billimoria");
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100245MODULE_DESCRIPTION("NS LM70 / TI TMP121/TMP123 Linux driver");
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200246MODULE_LICENSE("GPL");