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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 | ||
5713017e JP |
27 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
28 | ||
e1a8e913 KB |
29 | #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> | |
4bfe6604 | 36 | #include <linux/mutex.h> |
8cec03ee | 37 | #include <linux/mod_devicetable.h> |
e1a8e913 | 38 | #include <linux/spi/spi.h> |
5a0e3ad6 | 39 | #include <linux/slab.h> |
4bfe6604 | 40 | |
e1a8e913 KB |
41 | |
42 | #define DRVNAME "lm70" | |
43 | ||
c8ac32e4 ML |
44 | #define LM70_CHIP_LM70 0 /* original NS LM70 */ |
45 | #define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */ | |
46 | ||
e1a8e913 | 47 | struct lm70 { |
1beeffe4 | 48 | struct device *hwmon_dev; |
4bfe6604 | 49 | struct mutex lock; |
c8ac32e4 | 50 | unsigned int chip; |
e1a8e913 KB |
51 | }; |
52 | ||
53 | /* sysfs hook function */ | |
54 | static 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); | |
c8ac32e4 | 58 | int status, val = 0; |
e1a8e913 | 59 | u8 rxbuf[2]; |
56c24af8 | 60 | s16 raw = 0; |
95de3b25 | 61 | struct lm70 *p_lm70 = spi_get_drvdata(spi); |
e1a8e913 | 62 | |
4bfe6604 | 63 | if (mutex_lock_interruptible(&p_lm70->lock)) |
e1a8e913 KB |
64 | 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) { | |
5713017e | 72 | pr_warn("spi_write_then_read failed with status %d\n", status); |
e1a8e913 KB |
73 | goto out; |
74 | } | |
2b730051 KB |
75 | 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); | |
e1a8e913 KB |
78 | |
79 | /* | |
c8ac32e4 | 80 | * LM70: |
e1a8e913 KB |
81 | * 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. | |
c8ac32e4 ML |
90 | * |
91 | * TMP121/TMP123: | |
92 | * 13 bits of 2's complement data, discard LSB 3 bits, | |
93 | * resolution 0.0625 degrees celsius. | |
e1a8e913 | 94 | */ |
c8ac32e4 ML |
95 | 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 | ||
67f921d1 | 105 | status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */ |
e1a8e913 | 106 | out: |
4bfe6604 | 107 | mutex_unlock(&p_lm70->lock); |
e1a8e913 KB |
108 | return status; |
109 | } | |
110 | ||
111 | static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL); | |
112 | ||
67f921d1 JD |
113 | static ssize_t lm70_show_name(struct device *dev, struct device_attribute |
114 | *devattr, char *buf) | |
115 | { | |
c8ac32e4 ML |
116 | 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; | |
67f921d1 JD |
130 | } |
131 | ||
132 | static DEVICE_ATTR(name, S_IRUGO, lm70_show_name, NULL); | |
133 | ||
e1a8e913 KB |
134 | /*----------------------------------------------------------------------*/ |
135 | ||
8cec03ee | 136 | static int __devinit lm70_probe(struct spi_device *spi) |
e1a8e913 | 137 | { |
8cec03ee | 138 | int chip = spi_get_device_id(spi)->driver_data; |
e1a8e913 KB |
139 | struct lm70 *p_lm70; |
140 | int status; | |
141 | ||
8cec03ee AV |
142 | /* 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 | ||
2b730051 KB |
150 | /* NOTE: we assume 8-bit words, and convert to 16 bits manually */ |
151 | ||
e1a8e913 KB |
152 | p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL); |
153 | if (!p_lm70) | |
154 | return -ENOMEM; | |
155 | ||
4bfe6604 | 156 | mutex_init(&p_lm70->lock); |
c8ac32e4 | 157 | p_lm70->chip = chip; |
e1a8e913 | 158 | |
95de3b25 | 159 | spi_set_drvdata(spi, p_lm70); |
e1a8e913 | 160 | |
7599d32b GR |
161 | status = device_create_file(&spi->dev, &dev_attr_temp1_input); |
162 | if (status) | |
163 | goto out_dev_create_temp_file_failed; | |
164 | status = device_create_file(&spi->dev, &dev_attr_name); | |
165 | if (status) | |
e1a8e913 | 166 | goto out_dev_create_file_failed; |
e1a8e913 | 167 | |
e200c14f GR |
168 | /* sysfs hook */ |
169 | p_lm70->hwmon_dev = hwmon_device_register(&spi->dev); | |
170 | if (IS_ERR(p_lm70->hwmon_dev)) { | |
171 | dev_dbg(&spi->dev, "hwmon_device_register failed.\n"); | |
172 | status = PTR_ERR(p_lm70->hwmon_dev); | |
173 | goto out_dev_reg_failed; | |
174 | } | |
175 | ||
e1a8e913 KB |
176 | return 0; |
177 | ||
e200c14f GR |
178 | out_dev_reg_failed: |
179 | device_remove_file(&spi->dev, &dev_attr_name); | |
e1a8e913 | 180 | out_dev_create_file_failed: |
67f921d1 | 181 | device_remove_file(&spi->dev, &dev_attr_temp1_input); |
7599d32b | 182 | out_dev_create_temp_file_failed: |
95de3b25 | 183 | spi_set_drvdata(spi, NULL); |
e1a8e913 KB |
184 | kfree(p_lm70); |
185 | return status; | |
186 | } | |
187 | ||
41be722b | 188 | static int __devexit lm70_remove(struct spi_device *spi) |
e1a8e913 | 189 | { |
95de3b25 | 190 | struct lm70 *p_lm70 = spi_get_drvdata(spi); |
e1a8e913 | 191 | |
e200c14f | 192 | hwmon_device_unregister(p_lm70->hwmon_dev); |
e1a8e913 | 193 | device_remove_file(&spi->dev, &dev_attr_temp1_input); |
67f921d1 | 194 | device_remove_file(&spi->dev, &dev_attr_name); |
95de3b25 | 195 | spi_set_drvdata(spi, NULL); |
e1a8e913 KB |
196 | kfree(p_lm70); |
197 | ||
198 | return 0; | |
199 | } | |
200 | ||
8cec03ee AV |
201 | |
202 | static const struct spi_device_id lm70_ids[] = { | |
203 | { "lm70", LM70_CHIP_LM70 }, | |
204 | { "tmp121", LM70_CHIP_TMP121 }, | |
205 | { }, | |
c8ac32e4 | 206 | }; |
8cec03ee | 207 | MODULE_DEVICE_TABLE(spi, lm70_ids); |
c8ac32e4 | 208 | |
e1a8e913 KB |
209 | static struct spi_driver lm70_driver = { |
210 | .driver = { | |
211 | .name = "lm70", | |
212 | .owner = THIS_MODULE, | |
213 | }, | |
8cec03ee | 214 | .id_table = lm70_ids, |
e1a8e913 KB |
215 | .probe = lm70_probe, |
216 | .remove = __devexit_p(lm70_remove), | |
217 | }; | |
218 | ||
91efffe2 | 219 | module_spi_driver(lm70_driver); |
e1a8e913 KB |
220 | |
221 | MODULE_AUTHOR("Kaiwan N Billimoria"); | |
c8ac32e4 | 222 | MODULE_DESCRIPTION("NS LM70 / TI TMP121/TMP123 Linux driver"); |
e1a8e913 | 223 | MODULE_LICENSE("GPL"); |