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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
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 /* sysfs hook */
160 p_lm70->hwmon_dev = hwmon_device_register(&spi->dev);
161 if (IS_ERR(p_lm70->hwmon_dev)) {
162 dev_dbg(&spi->dev, "hwmon_device_register failed.\n");
163 status = PTR_ERR(p_lm70->hwmon_dev);
164 goto out_dev_reg_failed;
165 }
166 spi_set_drvdata(spi, p_lm70);
167
168 if ((status = device_create_file(&spi->dev, &dev_attr_temp1_input))
169 || (status = device_create_file(&spi->dev, &dev_attr_name))) {
170 dev_dbg(&spi->dev, "device_create_file failure.\n");
171 goto out_dev_create_file_failed;
172 }
173
174 return 0;
175
176out_dev_create_file_failed:
177 device_remove_file(&spi->dev, &dev_attr_temp1_input);
178 hwmon_device_unregister(p_lm70->hwmon_dev);
179out_dev_reg_failed:
180 spi_set_drvdata(spi, NULL);
181 kfree(p_lm70);
182 return status;
183}
184
185static int __devexit lm70_remove(struct spi_device *spi)
186{
187 struct lm70 *p_lm70 = spi_get_drvdata(spi);
188
189 device_remove_file(&spi->dev, &dev_attr_temp1_input);
190 device_remove_file(&spi->dev, &dev_attr_name);
191 hwmon_device_unregister(p_lm70->hwmon_dev);
192 spi_set_drvdata(spi, NULL);
193 kfree(p_lm70);
194
195 return 0;
196}
197
198
199static const struct spi_device_id lm70_ids[] = {
200 { "lm70", LM70_CHIP_LM70 },
201 { "tmp121", LM70_CHIP_TMP121 },
202 { },
203};
204MODULE_DEVICE_TABLE(spi, lm70_ids);
205
206static struct spi_driver lm70_driver = {
207 .driver = {
208 .name = "lm70",
209 .owner = THIS_MODULE,
210 },
211 .id_table = lm70_ids,
212 .probe = lm70_probe,
213 .remove = __devexit_p(lm70_remove),
214};
215
216static int __init init_lm70(void)
217{
218 return spi_register_driver(&lm70_driver);
219}
220
221static void __exit cleanup_lm70(void)
222{
223 spi_unregister_driver(&lm70_driver);
224}
225
226module_init(init_lm70);
227module_exit(cleanup_lm70);
228
229MODULE_AUTHOR("Kaiwan N Billimoria");
230MODULE_DESCRIPTION("NS LM70 / TI TMP121/TMP123 Linux driver");
231MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * lm70.c
4 *
5 * The LM70 is a temperature sensor chip from National Semiconductor (NS).
6 * Copyright (C) 2006 Kaiwan N Billimoria <kaiwan@designergraphix.com>
7 *
8 * The LM70 communicates with a host processor via an SPI/Microwire Bus
9 * interface. The complete datasheet is available at National's website
10 * here:
11 * http://www.national.com/pf/LM/LM70.html
12 */
13
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/init.h>
17#include <linux/module.h>
18#include <linux/kernel.h>
19#include <linux/device.h>
20#include <linux/err.h>
21#include <linux/sysfs.h>
22#include <linux/hwmon.h>
23#include <linux/mutex.h>
24#include <linux/mod_devicetable.h>
25#include <linux/of.h>
26#include <linux/property.h>
27#include <linux/spi/spi.h>
28#include <linux/slab.h>
29
30#define DRVNAME "lm70"
31
32#define LM70_CHIP_LM70 0 /* original NS LM70 */
33#define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */
34#define LM70_CHIP_LM71 2 /* NS LM71 */
35#define LM70_CHIP_LM74 3 /* NS LM74 */
36#define LM70_CHIP_TMP122 4 /* TI TMP122/TMP124 */
37
38struct lm70 {
39 struct spi_device *spi;
40 struct mutex lock;
41 unsigned int chip;
42};
43
44/* sysfs hook function */
45static ssize_t temp1_input_show(struct device *dev,
46 struct device_attribute *attr, char *buf)
47{
48 struct lm70 *p_lm70 = dev_get_drvdata(dev);
49 struct spi_device *spi = p_lm70->spi;
50 int status, val = 0;
51 u8 rxbuf[2];
52 s16 raw = 0;
53
54 if (mutex_lock_interruptible(&p_lm70->lock))
55 return -ERESTARTSYS;
56
57 /*
58 * spi_read() requires a DMA-safe buffer; so we use
59 * spi_write_then_read(), transmitting 0 bytes.
60 */
61 status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2);
62 if (status < 0) {
63 dev_warn(dev, "spi_write_then_read failed with status %d\n",
64 status);
65 goto out;
66 }
67 raw = (rxbuf[0] << 8) + rxbuf[1];
68 dev_dbg(dev, "rxbuf[0] : 0x%02x rxbuf[1] : 0x%02x raw=0x%04x\n",
69 rxbuf[0], rxbuf[1], raw);
70
71 /*
72 * LM70:
73 * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's
74 * complement value. Only the MSB 11 bits (1 sign + 10 temperature
75 * bits) are meaningful; the LSB 5 bits are to be discarded.
76 * See the datasheet.
77 *
78 * Further, each bit represents 0.25 degrees Celsius; so, multiply
79 * by 0.25. Also multiply by 1000 to represent in millidegrees
80 * Celsius.
81 * So it's equivalent to multiplying by 0.25 * 1000 = 250.
82 *
83 * LM74 and TMP121/TMP122/TMP123/TMP124:
84 * 13 bits of 2's complement data, discard LSB 3 bits,
85 * resolution 0.0625 degrees celsius.
86 *
87 * LM71:
88 * 14 bits of 2's complement data, discard LSB 2 bits,
89 * resolution 0.0312 degrees celsius.
90 */
91 switch (p_lm70->chip) {
92 case LM70_CHIP_LM70:
93 val = ((int)raw / 32) * 250;
94 break;
95
96 case LM70_CHIP_TMP121:
97 case LM70_CHIP_TMP122:
98 case LM70_CHIP_LM74:
99 val = ((int)raw / 8) * 625 / 10;
100 break;
101
102 case LM70_CHIP_LM71:
103 val = ((int)raw / 4) * 3125 / 100;
104 break;
105 }
106
107 status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
108out:
109 mutex_unlock(&p_lm70->lock);
110 return status;
111}
112
113static DEVICE_ATTR_RO(temp1_input);
114
115static struct attribute *lm70_attrs[] = {
116 &dev_attr_temp1_input.attr,
117 NULL
118};
119
120ATTRIBUTE_GROUPS(lm70);
121
122/*----------------------------------------------------------------------*/
123
124#ifdef CONFIG_OF
125static const struct of_device_id lm70_of_ids[] = {
126 {
127 .compatible = "ti,lm70",
128 .data = (void *) LM70_CHIP_LM70,
129 },
130 {
131 .compatible = "ti,tmp121",
132 .data = (void *) LM70_CHIP_TMP121,
133 },
134 {
135 .compatible = "ti,tmp122",
136 .data = (void *) LM70_CHIP_TMP122,
137 },
138 {
139 .compatible = "ti,lm71",
140 .data = (void *) LM70_CHIP_LM71,
141 },
142 {
143 .compatible = "ti,lm74",
144 .data = (void *) LM70_CHIP_LM74,
145 },
146 {},
147};
148MODULE_DEVICE_TABLE(of, lm70_of_ids);
149#endif
150
151static int lm70_probe(struct spi_device *spi)
152{
153 struct device *hwmon_dev;
154 struct lm70 *p_lm70;
155 int chip;
156
157 if (dev_fwnode(&spi->dev))
158 chip = (int)(uintptr_t)device_get_match_data(&spi->dev);
159 else
160 chip = spi_get_device_id(spi)->driver_data;
161
162
163 /* signaling is SPI_MODE_0 */
164 if ((spi->mode & SPI_MODE_X_MASK) != SPI_MODE_0)
165 return -EINVAL;
166
167 /* NOTE: we assume 8-bit words, and convert to 16 bits manually */
168
169 p_lm70 = devm_kzalloc(&spi->dev, sizeof(*p_lm70), GFP_KERNEL);
170 if (!p_lm70)
171 return -ENOMEM;
172
173 mutex_init(&p_lm70->lock);
174 p_lm70->chip = chip;
175 p_lm70->spi = spi;
176
177 hwmon_dev = devm_hwmon_device_register_with_groups(&spi->dev,
178 spi->modalias,
179 p_lm70, lm70_groups);
180 return PTR_ERR_OR_ZERO(hwmon_dev);
181}
182
183static const struct spi_device_id lm70_ids[] = {
184 { "lm70", LM70_CHIP_LM70 },
185 { "tmp121", LM70_CHIP_TMP121 },
186 { "tmp122", LM70_CHIP_TMP122 },
187 { "lm71", LM70_CHIP_LM71 },
188 { "lm74", LM70_CHIP_LM74 },
189 { },
190};
191MODULE_DEVICE_TABLE(spi, lm70_ids);
192
193static struct spi_driver lm70_driver = {
194 .driver = {
195 .name = "lm70",
196 .of_match_table = of_match_ptr(lm70_of_ids),
197 },
198 .id_table = lm70_ids,
199 .probe = lm70_probe,
200};
201
202module_spi_driver(lm70_driver);
203
204MODULE_AUTHOR("Kaiwan N Billimoria");
205MODULE_DESCRIPTION("NS LM70 and compatibles Linux driver");
206MODULE_LICENSE("GPL");