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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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090037#include <linux/slab.h>
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020038
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020039
40#define DRVNAME "lm70"
41
Manuel Laussc8ac32e2009-01-07 16:37:34 +010042#define LM70_CHIP_LM70 0 /* original NS LM70 */
43#define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */
44
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020045struct lm70 {
Tony Jones1beeffe2007-08-20 13:46:20 -070046 struct device *hwmon_dev;
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020047 struct mutex lock;
Manuel Laussc8ac32e2009-01-07 16:37:34 +010048 unsigned int chip;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020049};
50
51/* sysfs hook function */
52static ssize_t lm70_sense_temp(struct device *dev,
53 struct device_attribute *attr, char *buf)
54{
55 struct spi_device *spi = to_spi_device(dev);
Manuel Laussc8ac32e2009-01-07 16:37:34 +010056 int status, val = 0;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020057 u8 rxbuf[2];
58 s16 raw=0;
59 struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
60
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020061 if (mutex_lock_interruptible(&p_lm70->lock))
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020062 return -ERESTARTSYS;
63
64 /*
65 * spi_read() requires a DMA-safe buffer; so we use
66 * spi_write_then_read(), transmitting 0 bytes.
67 */
68 status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2);
69 if (status < 0) {
70 printk(KERN_WARNING
71 "spi_write_then_read failed with status %d\n", status);
72 goto out;
73 }
Kaiwan N Billimoria2b730052009-01-07 16:37:34 +010074 raw = (rxbuf[0] << 8) + rxbuf[1];
75 dev_dbg(dev, "rxbuf[0] : 0x%02x rxbuf[1] : 0x%02x raw=0x%04x\n",
76 rxbuf[0], rxbuf[1], raw);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020077
78 /*
Manuel Laussc8ac32e2009-01-07 16:37:34 +010079 * LM70:
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020080 * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's
81 * complement value. Only the MSB 11 bits (1 sign + 10 temperature
82 * bits) are meaningful; the LSB 5 bits are to be discarded.
83 * See the datasheet.
84 *
85 * Further, each bit represents 0.25 degrees Celsius; so, multiply
86 * by 0.25. Also multiply by 1000 to represent in millidegrees
87 * Celsius.
88 * So it's equivalent to multiplying by 0.25 * 1000 = 250.
Manuel Laussc8ac32e2009-01-07 16:37:34 +010089 *
90 * TMP121/TMP123:
91 * 13 bits of 2's complement data, discard LSB 3 bits,
92 * resolution 0.0625 degrees celsius.
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020093 */
Manuel Laussc8ac32e2009-01-07 16:37:34 +010094 switch (p_lm70->chip) {
95 case LM70_CHIP_LM70:
96 val = ((int)raw / 32) * 250;
97 break;
98
99 case LM70_CHIP_TMP121:
100 val = ((int)raw / 8) * 625 / 10;
101 break;
102 }
103
Jean Delvare67f921d2007-08-17 17:31:35 +0200104 status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200105out:
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +0200106 mutex_unlock(&p_lm70->lock);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200107 return status;
108}
109
110static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL);
111
Jean Delvare67f921d2007-08-17 17:31:35 +0200112static ssize_t lm70_show_name(struct device *dev, struct device_attribute
113 *devattr, char *buf)
114{
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100115 struct lm70 *p_lm70 = dev_get_drvdata(dev);
116 int ret;
117
118 switch (p_lm70->chip) {
119 case LM70_CHIP_LM70:
120 ret = sprintf(buf, "lm70\n");
121 break;
122 case LM70_CHIP_TMP121:
123 ret = sprintf(buf, "tmp121\n");
124 break;
125 default:
126 ret = -EINVAL;
127 }
128 return ret;
Jean Delvare67f921d2007-08-17 17:31:35 +0200129}
130
131static DEVICE_ATTR(name, S_IRUGO, lm70_show_name, NULL);
132
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200133/*----------------------------------------------------------------------*/
134
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700135static int __devinit lm70_probe(struct spi_device *spi)
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200136{
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700137 int chip = spi_get_device_id(spi)->driver_data;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200138 struct lm70 *p_lm70;
139 int status;
140
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700141 /* signaling is SPI_MODE_0 for both LM70 and TMP121 */
142 if (spi->mode & (SPI_CPOL | SPI_CPHA))
143 return -EINVAL;
144
145 /* 3-wire link (shared SI/SO) for LM70 */
146 if (chip == LM70_CHIP_LM70 && !(spi->mode & SPI_3WIRE))
147 return -EINVAL;
148
Kaiwan N Billimoria2b730052009-01-07 16:37:34 +0100149 /* NOTE: we assume 8-bit words, and convert to 16 bits manually */
150
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200151 p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL);
152 if (!p_lm70)
153 return -ENOMEM;
154
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +0200155 mutex_init(&p_lm70->lock);
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100156 p_lm70->chip = chip;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200157
158 /* sysfs hook */
Tony Jones1beeffe2007-08-20 13:46:20 -0700159 p_lm70->hwmon_dev = hwmon_device_register(&spi->dev);
160 if (IS_ERR(p_lm70->hwmon_dev)) {
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200161 dev_dbg(&spi->dev, "hwmon_device_register failed.\n");
Tony Jones1beeffe2007-08-20 13:46:20 -0700162 status = PTR_ERR(p_lm70->hwmon_dev);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200163 goto out_dev_reg_failed;
164 }
165 dev_set_drvdata(&spi->dev, p_lm70);
166
Jean Delvare67f921d2007-08-17 17:31:35 +0200167 if ((status = device_create_file(&spi->dev, &dev_attr_temp1_input))
168 || (status = device_create_file(&spi->dev, &dev_attr_name))) {
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200169 dev_dbg(&spi->dev, "device_create_file failure.\n");
170 goto out_dev_create_file_failed;
171 }
172
173 return 0;
174
175out_dev_create_file_failed:
Jean Delvare67f921d2007-08-17 17:31:35 +0200176 device_remove_file(&spi->dev, &dev_attr_temp1_input);
Tony Jones1beeffe2007-08-20 13:46:20 -0700177 hwmon_device_unregister(p_lm70->hwmon_dev);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200178out_dev_reg_failed:
179 dev_set_drvdata(&spi->dev, NULL);
180 kfree(p_lm70);
181 return status;
182}
183
Ralf Baechle41be7222007-02-14 21:15:04 +0100184static int __devexit lm70_remove(struct spi_device *spi)
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200185{
186 struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
187
188 device_remove_file(&spi->dev, &dev_attr_temp1_input);
Jean Delvare67f921d2007-08-17 17:31:35 +0200189 device_remove_file(&spi->dev, &dev_attr_name);
Tony Jones1beeffe2007-08-20 13:46:20 -0700190 hwmon_device_unregister(p_lm70->hwmon_dev);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200191 dev_set_drvdata(&spi->dev, NULL);
192 kfree(p_lm70);
193
194 return 0;
195}
196
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700197
198static const struct spi_device_id lm70_ids[] = {
199 { "lm70", LM70_CHIP_LM70 },
200 { "tmp121", LM70_CHIP_TMP121 },
201 { },
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100202};
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700203MODULE_DEVICE_TABLE(spi, lm70_ids);
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100204
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200205static struct spi_driver lm70_driver = {
206 .driver = {
207 .name = "lm70",
208 .owner = THIS_MODULE,
209 },
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700210 .id_table = lm70_ids,
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200211 .probe = lm70_probe,
212 .remove = __devexit_p(lm70_remove),
213};
214
215static int __init init_lm70(void)
216{
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700217 return spi_register_driver(&lm70_driver);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200218}
219
220static void __exit cleanup_lm70(void)
221{
222 spi_unregister_driver(&lm70_driver);
223}
224
225module_init(init_lm70);
226module_exit(cleanup_lm70);
227
228MODULE_AUTHOR("Kaiwan N Billimoria");
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100229MODULE_DESCRIPTION("NS LM70 / TI TMP121/TMP123 Linux driver");
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200230MODULE_LICENSE("GPL");