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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> |
8cec03ee | 35 | #include <linux/mod_devicetable.h> |
e1a8e913 | 36 | #include <linux/spi/spi.h> |
5a0e3ad6 | 37 | #include <linux/slab.h> |
4bfe6604 | 38 | |
e1a8e913 KB |
39 | |
40 | #define DRVNAME "lm70" | |
41 | ||
c8ac32e4 ML |
42 | #define LM70_CHIP_LM70 0 /* original NS LM70 */ |
43 | #define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */ | |
44 | ||
e1a8e913 | 45 | struct lm70 { |
1beeffe4 | 46 | struct device *hwmon_dev; |
4bfe6604 | 47 | struct mutex lock; |
c8ac32e4 | 48 | unsigned int chip; |
e1a8e913 KB |
49 | }; |
50 | ||
51 | /* sysfs hook function */ | |
52 | static 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); | |
c8ac32e4 | 56 | int status, val = 0; |
e1a8e913 KB |
57 | u8 rxbuf[2]; |
58 | s16 raw=0; | |
59 | struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev); | |
60 | ||
4bfe6604 | 61 | if (mutex_lock_interruptible(&p_lm70->lock)) |
e1a8e913 KB |
62 | 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 | } | |
2b730051 KB |
74 | 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); | |
e1a8e913 KB |
77 | |
78 | /* | |
c8ac32e4 | 79 | * LM70: |
e1a8e913 KB |
80 | * 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. | |
c8ac32e4 ML |
89 | * |
90 | * TMP121/TMP123: | |
91 | * 13 bits of 2's complement data, discard LSB 3 bits, | |
92 | * resolution 0.0625 degrees celsius. | |
e1a8e913 | 93 | */ |
c8ac32e4 ML |
94 | 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 | ||
67f921d1 | 104 | status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */ |
e1a8e913 | 105 | out: |
4bfe6604 | 106 | mutex_unlock(&p_lm70->lock); |
e1a8e913 KB |
107 | return status; |
108 | } | |
109 | ||
110 | static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL); | |
111 | ||
67f921d1 JD |
112 | static ssize_t lm70_show_name(struct device *dev, struct device_attribute |
113 | *devattr, char *buf) | |
114 | { | |
c8ac32e4 ML |
115 | 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; | |
67f921d1 JD |
129 | } |
130 | ||
131 | static DEVICE_ATTR(name, S_IRUGO, lm70_show_name, NULL); | |
132 | ||
e1a8e913 KB |
133 | /*----------------------------------------------------------------------*/ |
134 | ||
8cec03ee | 135 | static int __devinit lm70_probe(struct spi_device *spi) |
e1a8e913 | 136 | { |
8cec03ee | 137 | int chip = spi_get_device_id(spi)->driver_data; |
e1a8e913 KB |
138 | struct lm70 *p_lm70; |
139 | int status; | |
140 | ||
8cec03ee AV |
141 | /* 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 | ||
2b730051 KB |
149 | /* NOTE: we assume 8-bit words, and convert to 16 bits manually */ |
150 | ||
e1a8e913 KB |
151 | p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL); |
152 | if (!p_lm70) | |
153 | return -ENOMEM; | |
154 | ||
4bfe6604 | 155 | mutex_init(&p_lm70->lock); |
c8ac32e4 | 156 | p_lm70->chip = chip; |
e1a8e913 KB |
157 | |
158 | /* sysfs hook */ | |
1beeffe4 TJ |
159 | p_lm70->hwmon_dev = hwmon_device_register(&spi->dev); |
160 | if (IS_ERR(p_lm70->hwmon_dev)) { | |
e1a8e913 | 161 | dev_dbg(&spi->dev, "hwmon_device_register failed.\n"); |
1beeffe4 | 162 | status = PTR_ERR(p_lm70->hwmon_dev); |
e1a8e913 KB |
163 | goto out_dev_reg_failed; |
164 | } | |
165 | dev_set_drvdata(&spi->dev, p_lm70); | |
166 | ||
67f921d1 JD |
167 | if ((status = device_create_file(&spi->dev, &dev_attr_temp1_input)) |
168 | || (status = device_create_file(&spi->dev, &dev_attr_name))) { | |
e1a8e913 KB |
169 | dev_dbg(&spi->dev, "device_create_file failure.\n"); |
170 | goto out_dev_create_file_failed; | |
171 | } | |
172 | ||
173 | return 0; | |
174 | ||
175 | out_dev_create_file_failed: | |
67f921d1 | 176 | device_remove_file(&spi->dev, &dev_attr_temp1_input); |
1beeffe4 | 177 | hwmon_device_unregister(p_lm70->hwmon_dev); |
e1a8e913 KB |
178 | out_dev_reg_failed: |
179 | dev_set_drvdata(&spi->dev, NULL); | |
180 | kfree(p_lm70); | |
181 | return status; | |
182 | } | |
183 | ||
41be722b | 184 | static int __devexit lm70_remove(struct spi_device *spi) |
e1a8e913 KB |
185 | { |
186 | struct lm70 *p_lm70 = dev_get_drvdata(&spi->dev); | |
187 | ||
188 | device_remove_file(&spi->dev, &dev_attr_temp1_input); | |
67f921d1 | 189 | device_remove_file(&spi->dev, &dev_attr_name); |
1beeffe4 | 190 | hwmon_device_unregister(p_lm70->hwmon_dev); |
e1a8e913 KB |
191 | dev_set_drvdata(&spi->dev, NULL); |
192 | kfree(p_lm70); | |
193 | ||
194 | return 0; | |
195 | } | |
196 | ||
8cec03ee AV |
197 | |
198 | static const struct spi_device_id lm70_ids[] = { | |
199 | { "lm70", LM70_CHIP_LM70 }, | |
200 | { "tmp121", LM70_CHIP_TMP121 }, | |
201 | { }, | |
c8ac32e4 | 202 | }; |
8cec03ee | 203 | MODULE_DEVICE_TABLE(spi, lm70_ids); |
c8ac32e4 | 204 | |
e1a8e913 KB |
205 | static struct spi_driver lm70_driver = { |
206 | .driver = { | |
207 | .name = "lm70", | |
208 | .owner = THIS_MODULE, | |
209 | }, | |
8cec03ee | 210 | .id_table = lm70_ids, |
e1a8e913 KB |
211 | .probe = lm70_probe, |
212 | .remove = __devexit_p(lm70_remove), | |
213 | }; | |
214 | ||
215 | static int __init init_lm70(void) | |
216 | { | |
8cec03ee | 217 | return spi_register_driver(&lm70_driver); |
e1a8e913 KB |
218 | } |
219 | ||
220 | static void __exit cleanup_lm70(void) | |
221 | { | |
222 | spi_unregister_driver(&lm70_driver); | |
223 | } | |
224 | ||
225 | module_init(init_lm70); | |
226 | module_exit(cleanup_lm70); | |
227 | ||
228 | MODULE_AUTHOR("Kaiwan N Billimoria"); | |
c8ac32e4 | 229 | MODULE_DESCRIPTION("NS LM70 / TI TMP121/TMP123 Linux driver"); |
e1a8e913 | 230 | MODULE_LICENSE("GPL"); |