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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
28
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>
36#include <linux/mutex.h>
37#include <linux/mod_devicetable.h>
38#include <linux/spi/spi.h>
39#include <linux/slab.h>
40#include <linux/of_device.h>
41
42
43#define DRVNAME "lm70"
44
45#define LM70_CHIP_LM70 0 /* original NS LM70 */
46#define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */
47#define LM70_CHIP_LM71 2 /* NS LM71 */
48#define LM70_CHIP_LM74 3 /* NS LM74 */
49
50struct lm70 {
51 struct spi_device *spi;
52 struct mutex lock;
53 unsigned int chip;
54};
55
56/* sysfs hook function */
57static ssize_t lm70_sense_temp(struct device *dev,
58 struct device_attribute *attr, char *buf)
59{
60 struct lm70 *p_lm70 = dev_get_drvdata(dev);
61 struct spi_device *spi = p_lm70->spi;
62 int status, val = 0;
63 u8 rxbuf[2];
64 s16 raw = 0;
65
66 if (mutex_lock_interruptible(&p_lm70->lock))
67 return -ERESTARTSYS;
68
69 /*
70 * spi_read() requires a DMA-safe buffer; so we use
71 * spi_write_then_read(), transmitting 0 bytes.
72 */
73 status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2);
74 if (status < 0) {
75 pr_warn("spi_write_then_read failed with status %d\n", status);
76 goto out;
77 }
78 raw = (rxbuf[0] << 8) + rxbuf[1];
79 dev_dbg(dev, "rxbuf[0] : 0x%02x rxbuf[1] : 0x%02x raw=0x%04x\n",
80 rxbuf[0], rxbuf[1], raw);
81
82 /*
83 * LM70:
84 * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's
85 * complement value. Only the MSB 11 bits (1 sign + 10 temperature
86 * bits) are meaningful; the LSB 5 bits are to be discarded.
87 * See the datasheet.
88 *
89 * Further, each bit represents 0.25 degrees Celsius; so, multiply
90 * by 0.25. Also multiply by 1000 to represent in millidegrees
91 * Celsius.
92 * So it's equivalent to multiplying by 0.25 * 1000 = 250.
93 *
94 * LM74 and TMP121/TMP123:
95 * 13 bits of 2's complement data, discard LSB 3 bits,
96 * resolution 0.0625 degrees celsius.
97 *
98 * LM71:
99 * 14 bits of 2's complement data, discard LSB 2 bits,
100 * resolution 0.0312 degrees celsius.
101 */
102 switch (p_lm70->chip) {
103 case LM70_CHIP_LM70:
104 val = ((int)raw / 32) * 250;
105 break;
106
107 case LM70_CHIP_TMP121:
108 case LM70_CHIP_LM74:
109 val = ((int)raw / 8) * 625 / 10;
110 break;
111
112 case LM70_CHIP_LM71:
113 val = ((int)raw / 4) * 3125 / 100;
114 break;
115 }
116
117 status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
118out:
119 mutex_unlock(&p_lm70->lock);
120 return status;
121}
122
123static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL);
124
125static struct attribute *lm70_attrs[] = {
126 &dev_attr_temp1_input.attr,
127 NULL
128};
129
130ATTRIBUTE_GROUPS(lm70);
131
132/*----------------------------------------------------------------------*/
133
134#ifdef CONFIG_OF
135static const struct of_device_id lm70_of_ids[] = {
136 {
137 .compatible = "ti,lm70",
138 .data = (void *) LM70_CHIP_LM70,
139 },
140 {
141 .compatible = "ti,tmp121",
142 .data = (void *) LM70_CHIP_TMP121,
143 },
144 {
145 .compatible = "ti,lm71",
146 .data = (void *) LM70_CHIP_LM71,
147 },
148 {
149 .compatible = "ti,lm74",
150 .data = (void *) LM70_CHIP_LM74,
151 },
152 {},
153};
154MODULE_DEVICE_TABLE(of, lm70_of_ids);
155#endif
156
157static int lm70_probe(struct spi_device *spi)
158{
159 const struct of_device_id *match;
160 struct device *hwmon_dev;
161 struct lm70 *p_lm70;
162 int chip;
163
164 match = of_match_device(lm70_of_ids, &spi->dev);
165 if (match)
166 chip = (int)(uintptr_t)match->data;
167 else
168 chip = spi_get_device_id(spi)->driver_data;
169
170 /* signaling is SPI_MODE_0 */
171 if (spi->mode & (SPI_CPOL | SPI_CPHA))
172 return -EINVAL;
173
174 /* NOTE: we assume 8-bit words, and convert to 16 bits manually */
175
176 p_lm70 = devm_kzalloc(&spi->dev, sizeof(*p_lm70), GFP_KERNEL);
177 if (!p_lm70)
178 return -ENOMEM;
179
180 mutex_init(&p_lm70->lock);
181 p_lm70->chip = chip;
182 p_lm70->spi = spi;
183
184 hwmon_dev = devm_hwmon_device_register_with_groups(&spi->dev,
185 spi->modalias,
186 p_lm70, lm70_groups);
187 return PTR_ERR_OR_ZERO(hwmon_dev);
188}
189
190static const struct spi_device_id lm70_ids[] = {
191 { "lm70", LM70_CHIP_LM70 },
192 { "tmp121", LM70_CHIP_TMP121 },
193 { "lm71", LM70_CHIP_LM71 },
194 { "lm74", LM70_CHIP_LM74 },
195 { },
196};
197MODULE_DEVICE_TABLE(spi, lm70_ids);
198
199static struct spi_driver lm70_driver = {
200 .driver = {
201 .name = "lm70",
202 .of_match_table = of_match_ptr(lm70_of_ids),
203 },
204 .id_table = lm70_ids,
205 .probe = lm70_probe,
206};
207
208module_spi_driver(lm70_driver);
209
210MODULE_AUTHOR("Kaiwan N Billimoria");
211MODULE_DESCRIPTION("NS LM70 and compatibles Linux driver");
212MODULE_LICENSE("GPL");
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
28
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>
36#include <linux/mutex.h>
37#include <linux/mod_devicetable.h>
38#include <linux/spi/spi.h>
39#include <linux/slab.h>
40
41
42#define DRVNAME "lm70"
43
44#define LM70_CHIP_LM70 0 /* original NS LM70 */
45#define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */
46
47struct lm70 {
48 struct device *hwmon_dev;
49 struct mutex lock;
50 unsigned int chip;
51};
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);
58 int status, val = 0;
59 u8 rxbuf[2];
60 s16 raw = 0;
61 struct lm70 *p_lm70 = spi_get_drvdata(spi);
62
63 if (mutex_lock_interruptible(&p_lm70->lock))
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) {
72 pr_warn("spi_write_then_read failed with status %d\n", status);
73 goto out;
74 }
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);
78
79 /*
80 * LM70:
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.
90 *
91 * TMP121/TMP123:
92 * 13 bits of 2's complement data, discard LSB 3 bits,
93 * resolution 0.0625 degrees celsius.
94 */
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
105 status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
106out:
107 mutex_unlock(&p_lm70->lock);
108 return status;
109}
110
111static DEVICE_ATTR(temp1_input, S_IRUGO, lm70_sense_temp, NULL);
112
113static ssize_t lm70_show_name(struct device *dev, struct device_attribute
114 *devattr, char *buf)
115{
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;
130}
131
132static DEVICE_ATTR(name, S_IRUGO, lm70_show_name, NULL);
133
134/*----------------------------------------------------------------------*/
135
136static int __devinit lm70_probe(struct spi_device *spi)
137{
138 int chip = spi_get_device_id(spi)->driver_data;
139 struct lm70 *p_lm70;
140 int status;
141
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
150 /* NOTE: we assume 8-bit words, and convert to 16 bits manually */
151
152 p_lm70 = kzalloc(sizeof *p_lm70, GFP_KERNEL);
153 if (!p_lm70)
154 return -ENOMEM;
155
156 mutex_init(&p_lm70->lock);
157 p_lm70->chip = chip;
158
159 spi_set_drvdata(spi, p_lm70);
160
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)
166 goto out_dev_create_file_failed;
167
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
176 return 0;
177
178out_dev_reg_failed:
179 device_remove_file(&spi->dev, &dev_attr_name);
180out_dev_create_file_failed:
181 device_remove_file(&spi->dev, &dev_attr_temp1_input);
182out_dev_create_temp_file_failed:
183 spi_set_drvdata(spi, NULL);
184 kfree(p_lm70);
185 return status;
186}
187
188static int __devexit lm70_remove(struct spi_device *spi)
189{
190 struct lm70 *p_lm70 = spi_get_drvdata(spi);
191
192 hwmon_device_unregister(p_lm70->hwmon_dev);
193 device_remove_file(&spi->dev, &dev_attr_temp1_input);
194 device_remove_file(&spi->dev, &dev_attr_name);
195 spi_set_drvdata(spi, NULL);
196 kfree(p_lm70);
197
198 return 0;
199}
200
201
202static const struct spi_device_id lm70_ids[] = {
203 { "lm70", LM70_CHIP_LM70 },
204 { "tmp121", LM70_CHIP_TMP121 },
205 { },
206};
207MODULE_DEVICE_TABLE(spi, lm70_ids);
208
209static struct spi_driver lm70_driver = {
210 .driver = {
211 .name = "lm70",
212 .owner = THIS_MODULE,
213 },
214 .id_table = lm70_ids,
215 .probe = lm70_probe,
216 .remove = __devexit_p(lm70_remove),
217};
218
219module_spi_driver(lm70_driver);
220
221MODULE_AUTHOR("Kaiwan N Billimoria");
222MODULE_DESCRIPTION("NS LM70 / TI TMP121/TMP123 Linux driver");
223MODULE_LICENSE("GPL");