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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 */
Christophe Leroya86e94d2012-09-05 11:49:14 +020046#define LM70_CHIP_LM71 2 /* NS LM71 */
47#define LM70_CHIP_LM74 3 /* NS LM74 */
Manuel Laussc8ac32e2009-01-07 16:37:34 +010048
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020049struct lm70 {
Tony Jones1beeffe2007-08-20 13:46:20 -070050 struct device *hwmon_dev;
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020051 struct mutex lock;
Manuel Laussc8ac32e2009-01-07 16:37:34 +010052 unsigned int chip;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020053};
54
55/* sysfs hook function */
56static ssize_t lm70_sense_temp(struct device *dev,
57 struct device_attribute *attr, char *buf)
58{
59 struct spi_device *spi = to_spi_device(dev);
Manuel Laussc8ac32e2009-01-07 16:37:34 +010060 int status, val = 0;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020061 u8 rxbuf[2];
Frans Meulenbroeks56c24af2012-01-08 19:34:11 +010062 s16 raw = 0;
Jean Delvare95de3b22011-05-25 20:43:31 +020063 struct lm70 *p_lm70 = spi_get_drvdata(spi);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020064
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +020065 if (mutex_lock_interruptible(&p_lm70->lock))
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020066 return -ERESTARTSYS;
67
68 /*
69 * spi_read() requires a DMA-safe buffer; so we use
70 * spi_write_then_read(), transmitting 0 bytes.
71 */
72 status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2);
73 if (status < 0) {
Joe Perches57130172010-10-20 06:51:41 +000074 pr_warn("spi_write_then_read failed with status %d\n", status);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020075 goto out;
76 }
Kaiwan N Billimoria2b730052009-01-07 16:37:34 +010077 raw = (rxbuf[0] << 8) + rxbuf[1];
78 dev_dbg(dev, "rxbuf[0] : 0x%02x rxbuf[1] : 0x%02x raw=0x%04x\n",
79 rxbuf[0], rxbuf[1], raw);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020080
81 /*
Manuel Laussc8ac32e2009-01-07 16:37:34 +010082 * LM70:
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +020083 * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's
84 * complement value. Only the MSB 11 bits (1 sign + 10 temperature
85 * bits) are meaningful; the LSB 5 bits are to be discarded.
86 * See the datasheet.
87 *
88 * Further, each bit represents 0.25 degrees Celsius; so, multiply
89 * by 0.25. Also multiply by 1000 to represent in millidegrees
90 * Celsius.
91 * So it's equivalent to multiplying by 0.25 * 1000 = 250.
Manuel Laussc8ac32e2009-01-07 16:37:34 +010092 *
Christophe Leroya86e94d2012-09-05 11:49:14 +020093 * LM74 and TMP121/TMP123:
Manuel Laussc8ac32e2009-01-07 16:37:34 +010094 * 13 bits of 2's complement data, discard LSB 3 bits,
95 * resolution 0.0625 degrees celsius.
Christophe Leroya86e94d2012-09-05 11:49:14 +020096 *
97 * LM71:
98 * 14 bits of 2's complement data, discard LSB 2 bits,
99 * resolution 0.0312 degrees celsius.
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200100 */
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100101 switch (p_lm70->chip) {
102 case LM70_CHIP_LM70:
103 val = ((int)raw / 32) * 250;
104 break;
105
106 case LM70_CHIP_TMP121:
Christophe Leroya86e94d2012-09-05 11:49:14 +0200107 case LM70_CHIP_LM74:
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100108 val = ((int)raw / 8) * 625 / 10;
109 break;
Christophe Leroya86e94d2012-09-05 11:49:14 +0200110
111 case LM70_CHIP_LM71:
112 val = ((int)raw / 4) * 3125 / 100;
113 break;
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100114 }
115
Jean Delvare67f921d2007-08-17 17:31:35 +0200116 status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200117out:
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +0200118 mutex_unlock(&p_lm70->lock);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200119 return status;
120}
121
122static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL);
123
Jean Delvare67f921d2007-08-17 17:31:35 +0200124static ssize_t lm70_show_name(struct device *dev, struct device_attribute
125 *devattr, char *buf)
126{
Guenter Roeck860f3732012-09-11 13:34:29 -0700127 return sprintf(buf, "%s\n", to_spi_device(dev)->modalias);
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
Bill Pemberton6c931ae2012-11-19 13:22:35 -0500134static int 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
Christophe Leroya86e94d2012-09-05 11:49:14 +0200140 /* signaling is SPI_MODE_0 */
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700141 if (spi->mode & (SPI_CPOL | SPI_CPHA))
142 return -EINVAL;
143
Kaiwan N Billimoria2b730052009-01-07 16:37:34 +0100144 /* NOTE: we assume 8-bit words, and convert to 16 bits manually */
145
Guenter Roeck33ed6d42012-06-02 09:58:08 -0700146 p_lm70 = devm_kzalloc(&spi->dev, sizeof(*p_lm70), GFP_KERNEL);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200147 if (!p_lm70)
148 return -ENOMEM;
149
Matthias Kaehlcke4bfe6602007-10-24 14:59:09 +0200150 mutex_init(&p_lm70->lock);
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100151 p_lm70->chip = chip;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200152
Jean Delvare95de3b22011-05-25 20:43:31 +0200153 spi_set_drvdata(spi, p_lm70);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200154
Guenter Roeck7599d322012-01-19 21:05:07 -0800155 status = device_create_file(&spi->dev, &dev_attr_temp1_input);
156 if (status)
157 goto out_dev_create_temp_file_failed;
158 status = device_create_file(&spi->dev, &dev_attr_name);
159 if (status)
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200160 goto out_dev_create_file_failed;
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200161
Guenter Roecke200c142012-01-19 20:58:13 -0800162 /* sysfs hook */
163 p_lm70->hwmon_dev = hwmon_device_register(&spi->dev);
164 if (IS_ERR(p_lm70->hwmon_dev)) {
165 dev_dbg(&spi->dev, "hwmon_device_register failed.\n");
166 status = PTR_ERR(p_lm70->hwmon_dev);
167 goto out_dev_reg_failed;
168 }
169
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200170 return 0;
171
Guenter Roecke200c142012-01-19 20:58:13 -0800172out_dev_reg_failed:
173 device_remove_file(&spi->dev, &dev_attr_name);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200174out_dev_create_file_failed:
Jean Delvare67f921d2007-08-17 17:31:35 +0200175 device_remove_file(&spi->dev, &dev_attr_temp1_input);
Guenter Roeck7599d322012-01-19 21:05:07 -0800176out_dev_create_temp_file_failed:
Jean Delvare95de3b22011-05-25 20:43:31 +0200177 spi_set_drvdata(spi, NULL);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200178 return status;
179}
180
Bill Pemberton281dfd02012-11-19 13:25:51 -0500181static int lm70_remove(struct spi_device *spi)
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200182{
Jean Delvare95de3b22011-05-25 20:43:31 +0200183 struct lm70 *p_lm70 = spi_get_drvdata(spi);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200184
Guenter Roecke200c142012-01-19 20:58:13 -0800185 hwmon_device_unregister(p_lm70->hwmon_dev);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200186 device_remove_file(&spi->dev, &dev_attr_temp1_input);
Jean Delvare67f921d2007-08-17 17:31:35 +0200187 device_remove_file(&spi->dev, &dev_attr_name);
Jean Delvare95de3b22011-05-25 20:43:31 +0200188 spi_set_drvdata(spi, NULL);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200189
190 return 0;
191}
192
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700193
194static const struct spi_device_id lm70_ids[] = {
195 { "lm70", LM70_CHIP_LM70 },
196 { "tmp121", LM70_CHIP_TMP121 },
Christophe Leroya86e94d2012-09-05 11:49:14 +0200197 { "lm71", LM70_CHIP_LM71 },
198 { "lm74", LM70_CHIP_LM74 },
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700199 { },
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100200};
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700201MODULE_DEVICE_TABLE(spi, lm70_ids);
Manuel Laussc8ac32e2009-01-07 16:37:34 +0100202
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200203static struct spi_driver lm70_driver = {
204 .driver = {
205 .name = "lm70",
206 .owner = THIS_MODULE,
207 },
Anton Vorontsov8cec03e2009-09-22 16:46:07 -0700208 .id_table = lm70_ids,
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200209 .probe = lm70_probe,
Bill Pemberton9e5e9b72012-11-19 13:21:20 -0500210 .remove = lm70_remove,
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200211};
212
Axel Lin91efffe2012-01-20 15:53:47 +0800213module_spi_driver(lm70_driver);
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200214
215MODULE_AUTHOR("Kaiwan N Billimoria");
Christophe Leroya86e94d2012-09-05 11:49:14 +0200216MODULE_DESCRIPTION("NS LM70 and compatibles Linux driver");
Kaiwan N Billimoriae1a8e912006-06-12 22:00:05 +0200217MODULE_LICENSE("GPL");