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1 | /* |
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> | |
4bfe6604 | 34 | #include <linux/mutex.h> |
e1a8e913 | 35 | #include <linux/spi/spi.h> |
4bfe6604 | 36 | |
e1a8e913 KB |
37 | |
38 | #define DRVNAME "lm70" | |
39 | ||
c8ac32e4 ML |
40 | #define LM70_CHIP_LM70 0 /* original NS LM70 */ |
41 | #define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */ | |
42 | ||
e1a8e913 | 43 | struct lm70 { |
1beeffe4 | 44 | struct device *hwmon_dev; |
4bfe6604 | 45 | struct mutex lock; |
c8ac32e4 | 46 | unsigned int chip; |
e1a8e913 KB |
47 | }; |
48 | ||
49 | /* sysfs hook function */ | |
50 | static 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); | |
c8ac32e4 | 54 | int status, val = 0; |
e1a8e913 KB |
55 | u8 rxbuf[2]; |
56 | s16 raw=0; | |
57 | struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev); | |
58 | ||
4bfe6604 | 59 | if (mutex_lock_interruptible(&p_lm70->lock)) |
e1a8e913 KB |
60 | 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 | } | |
2b730051 KB |
72 | 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); | |
e1a8e913 KB |
75 | |
76 | /* | |
c8ac32e4 | 77 | * LM70: |
e1a8e913 KB |
78 | * 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. | |
c8ac32e4 ML |
87 | * |
88 | * TMP121/TMP123: | |
89 | * 13 bits of 2's complement data, discard LSB 3 bits, | |
90 | * resolution 0.0625 degrees celsius. | |
e1a8e913 | 91 | */ |
c8ac32e4 ML |
92 | 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 | ||
67f921d1 | 102 | status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */ |
e1a8e913 | 103 | out: |
4bfe6604 | 104 | mutex_unlock(&p_lm70->lock); |
e1a8e913 KB |
105 | return status; |
106 | } | |
107 | ||
108 | static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL); | |
109 | ||
67f921d1 JD |
110 | static ssize_t lm70_show_name(struct device *dev, struct device_attribute |
111 | *devattr, char *buf) | |
112 | { | |
c8ac32e4 ML |
113 | 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; | |
67f921d1 JD |
127 | } |
128 | ||
129 | static DEVICE_ATTR(name, S_IRUGO, lm70_show_name, NULL); | |
130 | ||
e1a8e913 KB |
131 | /*----------------------------------------------------------------------*/ |
132 | ||
c8ac32e4 | 133 | static int __devinit common_probe(struct spi_device *spi, int chip) |
e1a8e913 KB |
134 | { |
135 | struct lm70 *p_lm70; | |
136 | int status; | |
137 | ||
2b730051 KB |
138 | /* NOTE: we assume 8-bit words, and convert to 16 bits manually */ |
139 | ||
e1a8e913 KB |
140 | p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL); |
141 | if (!p_lm70) | |
142 | return -ENOMEM; | |
143 | ||
4bfe6604 | 144 | mutex_init(&p_lm70->lock); |
c8ac32e4 | 145 | p_lm70->chip = chip; |
e1a8e913 KB |
146 | |
147 | /* sysfs hook */ | |
1beeffe4 TJ |
148 | p_lm70->hwmon_dev = hwmon_device_register(&spi->dev); |
149 | if (IS_ERR(p_lm70->hwmon_dev)) { | |
e1a8e913 | 150 | dev_dbg(&spi->dev, "hwmon_device_register failed.\n"); |
1beeffe4 | 151 | status = PTR_ERR(p_lm70->hwmon_dev); |
e1a8e913 KB |
152 | goto out_dev_reg_failed; |
153 | } | |
154 | dev_set_drvdata(&spi->dev, p_lm70); | |
155 | ||
67f921d1 JD |
156 | if ((status = device_create_file(&spi->dev, &dev_attr_temp1_input)) |
157 | || (status = device_create_file(&spi->dev, &dev_attr_name))) { | |
e1a8e913 KB |
158 | dev_dbg(&spi->dev, "device_create_file failure.\n"); |
159 | goto out_dev_create_file_failed; | |
160 | } | |
161 | ||
162 | return 0; | |
163 | ||
164 | out_dev_create_file_failed: | |
67f921d1 | 165 | device_remove_file(&spi->dev, &dev_attr_temp1_input); |
1beeffe4 | 166 | hwmon_device_unregister(p_lm70->hwmon_dev); |
e1a8e913 KB |
167 | out_dev_reg_failed: |
168 | dev_set_drvdata(&spi->dev, NULL); | |
169 | kfree(p_lm70); | |
170 | return status; | |
171 | } | |
172 | ||
c8ac32e4 ML |
173 | static 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 | ||
182 | static 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 | ||
41be722b | 191 | static int __devexit lm70_remove(struct spi_device *spi) |
e1a8e913 KB |
192 | { |
193 | struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev); | |
194 | ||
195 | device_remove_file(&spi->dev, &dev_attr_temp1_input); | |
67f921d1 | 196 | device_remove_file(&spi->dev, &dev_attr_name); |
1beeffe4 | 197 | hwmon_device_unregister(p_lm70->hwmon_dev); |
e1a8e913 KB |
198 | dev_set_drvdata(&spi->dev, NULL); |
199 | kfree(p_lm70); | |
200 | ||
201 | return 0; | |
202 | } | |
203 | ||
c8ac32e4 ML |
204 | static 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 | ||
e1a8e913 KB |
213 | static 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 | ||
222 | static int __init init_lm70(void) | |
223 | { | |
c8ac32e4 ML |
224 | 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; | |
e1a8e913 KB |
233 | } |
234 | ||
235 | static void __exit cleanup_lm70(void) | |
236 | { | |
237 | spi_unregister_driver(&lm70_driver); | |
c8ac32e4 | 238 | spi_unregister_driver(&tmp121_driver); |
e1a8e913 KB |
239 | } |
240 | ||
241 | module_init(init_lm70); | |
242 | module_exit(cleanup_lm70); | |
243 | ||
244 | MODULE_AUTHOR("Kaiwan N Billimoria"); | |
c8ac32e4 | 245 | MODULE_DESCRIPTION("NS LM70 / TI TMP121/TMP123 Linux driver"); |
e1a8e913 | 246 | MODULE_LICENSE("GPL"); |