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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
Joe Perches57130172010-10-20 06:51:41 +000027#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
28
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020029#include <linux/init.h>
30#include <linux/module.h>
31#include <linux/kernel.h>
32#include <linux/device.h>
33#include <linux/err.h>
34#include <linux/sysfs.h>
35#include <linux/hwmon.h>
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020036#include <linux/mutex.h>
Anton Vorontsov8cec03e2009-09-22 16:46:07 -070037#include <linux/mod_devicetable.h>
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020038#include <linux/spi/spi.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090039#include <linux/slab.h>
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020040
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020041
42#define DRVNAME "lm70"
43
Manuel Laussc8ac32e2009-01-07 16:37:34 +010044#define LM70_CHIP_LM70 0 /* original NS LM70 */
45#define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */
46
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020047struct lm70 {
Tony Jones1beeffe2007-08-20 13:46:20 -070048 struct device *hwmon_dev;
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020049 struct mutex lock;
Manuel Laussc8ac32e2009-01-07 16:37:34 +010050 unsigned int chip;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020051};
52
53/* sysfs hook function */
54static ssize_t lm70_sense_temp(struct device *dev,
55 struct device_attribute *attr, char *buf)
56{
57 struct spi_device *spi = to_spi_device(dev);
Manuel Laussc8ac32e2009-01-07 16:37:34 +010058 int status, val = 0;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020059 u8 rxbuf[2];
60 s16 raw=0;
61 struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
62
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020063 if (mutex_lock_interruptible(&p_lm70->lock))
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020064 return -ERESTARTSYS;
65
66 /*
67 * spi_read() requires a DMA-safe buffer; so we use
68 * spi_write_then_read(), transmitting 0 bytes.
69 */
70 status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2);
71 if (status < 0) {
Joe Perches57130172010-10-20 06:51:41 +000072 pr_warn("spi_write_then_read failed with status %d\n", status);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020073 goto out;
74 }
Kaiwan N Billimoria2b730052009-01-07 16:37:34 +010075 raw = (rxbuf[0] << 8) + rxbuf[1];
76 dev_dbg(dev, "rxbuf[0] : 0x%02x rxbuf[1] : 0x%02x raw=0x%04x\n",
77 rxbuf[0], rxbuf[1], raw);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020078
79 /*
Manuel Laussc8ac32e2009-01-07 16:37:34 +010080 * LM70:
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020081 * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's
82 * complement value. Only the MSB 11 bits (1 sign + 10 temperature
83 * bits) are meaningful; the LSB 5 bits are to be discarded.
84 * See the datasheet.
85 *
86 * Further, each bit represents 0.25 degrees Celsius; so, multiply
87 * by 0.25. Also multiply by 1000 to represent in millidegrees
88 * Celsius.
89 * So it's equivalent to multiplying by 0.25 * 1000 = 250.
Manuel Laussc8ac32e2009-01-07 16:37:34 +010090 *
91 * TMP121/TMP123:
92 * 13 bits of 2's complement data, discard LSB 3 bits,
93 * resolution 0.0625 degrees celsius.
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020094 */
Manuel Laussc8ac32e2009-01-07 16:37:34 +010095 switch (p_lm70->chip) {
96 case LM70_CHIP_LM70:
97 val = ((int)raw / 32) * 250;
98 break;
99
100 case LM70_CHIP_TMP121:
101 val = ((int)raw / 8) * 625 / 10;
102 break;
103 }
104
Jean Delvare67f921d2007-08-17 17:31:35 +0200105 status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200106out:
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +0200107 mutex_unlock(&p_lm70->lock);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200108 return status;
109}
110
111static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL);
112
Jean Delvare67f921d2007-08-17 17:31:35 +0200113static ssize_t lm70_show_name(struct device *dev, struct device_attribute
114 *devattr, char *buf)
115{
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100116 struct lm70 *p_lm70 = dev_get_drvdata(dev);
117 int ret;
118
119 switch (p_lm70->chip) {
120 case LM70_CHIP_LM70:
121 ret = sprintf(buf, "lm70\n");
122 break;
123 case LM70_CHIP_TMP121:
124 ret = sprintf(buf, "tmp121\n");
125 break;
126 default:
127 ret = -EINVAL;
128 }
129 return ret;
Jean Delvare67f921d2007-08-17 17:31:35 +0200130}
131
132static DEVICE_ATTR(name, S_IRUGO, lm70_show_name, NULL);
133
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200134/*----------------------------------------------------------------------*/
135
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700136static int __devinit lm70_probe(struct spi_device *spi)
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200137{
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700138 int chip = spi_get_device_id(spi)->driver_data;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200139 struct lm70 *p_lm70;
140 int status;
141
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700142 /* signaling is SPI_MODE_0 for both LM70 and TMP121 */
143 if (spi->mode & (SPI_CPOL | SPI_CPHA))
144 return -EINVAL;
145
146 /* 3-wire link (shared SI/SO) for LM70 */
147 if (chip == LM70_CHIP_LM70 && !(spi->mode & SPI_3WIRE))
148 return -EINVAL;
149
Kaiwan N Billimoria2b730052009-01-07 16:37:34 +0100150 /* NOTE: we assume 8-bit words, and convert to 16 bits manually */
151
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200152 p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL);
153 if (!p_lm70)
154 return -ENOMEM;
155
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +0200156 mutex_init(&p_lm70->lock);
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100157 p_lm70->chip = chip;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200158
159 /* sysfs hook */
Tony Jones1beeffe2007-08-20 13:46:20 -0700160 p_lm70->hwmon_dev = hwmon_device_register(&spi->dev);
161 if (IS_ERR(p_lm70->hwmon_dev)) {
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200162 dev_dbg(&spi->dev, "hwmon_device_register failed.\n");
Tony Jones1beeffe2007-08-20 13:46:20 -0700163 status = PTR_ERR(p_lm70->hwmon_dev);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200164 goto out_dev_reg_failed;
165 }
166 dev_set_drvdata(&spi->dev, p_lm70);
167
Jean Delvare67f921d2007-08-17 17:31:35 +0200168 if ((status = device_create_file(&spi->dev, &dev_attr_temp1_input))
169 || (status = device_create_file(&spi->dev, &dev_attr_name))) {
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200170 dev_dbg(&spi->dev, "device_create_file failure.\n");
171 goto out_dev_create_file_failed;
172 }
173
174 return 0;
175
176out_dev_create_file_failed:
Jean Delvare67f921d2007-08-17 17:31:35 +0200177 device_remove_file(&spi->dev, &dev_attr_temp1_input);
Tony Jones1beeffe2007-08-20 13:46:20 -0700178 hwmon_device_unregister(p_lm70->hwmon_dev);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200179out_dev_reg_failed:
180 dev_set_drvdata(&spi->dev, NULL);
181 kfree(p_lm70);
182 return status;
183}
184
Ralf Baechle41be7222007-02-14 21:15:04 +0100185static int __devexit lm70_remove(struct spi_device *spi)
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200186{
187 struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev);
188
189 device_remove_file(&spi->dev, &dev_attr_temp1_input);
Jean Delvare67f921d2007-08-17 17:31:35 +0200190 device_remove_file(&spi->dev, &dev_attr_name);
Tony Jones1beeffe2007-08-20 13:46:20 -0700191 hwmon_device_unregister(p_lm70->hwmon_dev);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200192 dev_set_drvdata(&spi->dev, NULL);
193 kfree(p_lm70);
194
195 return 0;
196}
197
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700198
199static const struct spi_device_id lm70_ids[] = {
200 { "lm70", LM70_CHIP_LM70 },
201 { "tmp121", LM70_CHIP_TMP121 },
202 { },
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100203};
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700204MODULE_DEVICE_TABLE(spi, lm70_ids);
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100205
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200206static struct spi_driver lm70_driver = {
207 .driver = {
208 .name = "lm70",
209 .owner = THIS_MODULE,
210 },
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700211 .id_table = lm70_ids,
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200212 .probe = lm70_probe,
213 .remove = __devexit_p(lm70_remove),
214};
215
216static int __init init_lm70(void)
217{
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700218 return spi_register_driver(&lm70_driver);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200219}
220
221static void __exit cleanup_lm70(void)
222{
223 spi_unregister_driver(&lm70_driver);
224}
225
226module_init(init_lm70);
227module_exit(cleanup_lm70);
228
229MODULE_AUTHOR("Kaiwan N Billimoria");
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100230MODULE_DESCRIPTION("NS LM70 / TI TMP121/TMP123 Linux driver");
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200231MODULE_LICENSE("GPL");