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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#define LM70_CHIP_TMP125 5 /* TI TMP125 */
38
39struct lm70 {
40 struct spi_device *spi;
41 struct mutex lock;
42 unsigned int chip;
43};
44
45/* sysfs hook function */
46static ssize_t temp1_input_show(struct device *dev,
47 struct device_attribute *attr, char *buf)
48{
49 struct lm70 *p_lm70 = dev_get_drvdata(dev);
50 struct spi_device *spi = p_lm70->spi;
51 int status, val = 0;
52 u8 rxbuf[2];
53 s16 raw = 0;
54
55 if (mutex_lock_interruptible(&p_lm70->lock))
56 return -ERESTARTSYS;
57
58 /*
59 * spi_read() requires a DMA-safe buffer; so we use
60 * spi_write_then_read(), transmitting 0 bytes.
61 */
62 status = spi_write_then_read(spi, NULL, 0, &rxbuf[0], 2);
63 if (status < 0) {
64 dev_warn(dev, "spi_write_then_read failed with status %d\n",
65 status);
66 goto out;
67 }
68 raw = (rxbuf[0] << 8) + rxbuf[1];
69 dev_dbg(dev, "rxbuf[0] : 0x%02x rxbuf[1] : 0x%02x raw=0x%04x\n",
70 rxbuf[0], rxbuf[1], raw);
71
72 /*
73 * LM70:
74 * The "raw" temperature read into rxbuf[] is a 16-bit signed 2's
75 * complement value. Only the MSB 11 bits (1 sign + 10 temperature
76 * bits) are meaningful; the LSB 5 bits are to be discarded.
77 * See the datasheet.
78 *
79 * Further, each bit represents 0.25 degrees Celsius; so, multiply
80 * by 0.25. Also multiply by 1000 to represent in millidegrees
81 * Celsius.
82 * So it's equivalent to multiplying by 0.25 * 1000 = 250.
83 *
84 * LM74 and TMP121/TMP122/TMP123/TMP124:
85 * 13 bits of 2's complement data, discard LSB 3 bits,
86 * resolution 0.0625 degrees celsius.
87 *
88 * LM71:
89 * 14 bits of 2's complement data, discard LSB 2 bits,
90 * resolution 0.0312 degrees celsius.
91 *
92 * TMP125:
93 * MSB/D15 is a leading zero. D14 is the sign-bit. This is
94 * followed by 9 temperature bits (D13..D5) in 2's complement
95 * data format with a resolution of 0.25 degrees celsius per unit.
96 * LSB 5 bits (D4..D0) share the same value as D5 and get discarded.
97 */
98 switch (p_lm70->chip) {
99 case LM70_CHIP_LM70:
100 val = ((int)raw / 32) * 250;
101 break;
102
103 case LM70_CHIP_TMP121:
104 case LM70_CHIP_TMP122:
105 case LM70_CHIP_LM74:
106 val = ((int)raw / 8) * 625 / 10;
107 break;
108
109 case LM70_CHIP_LM71:
110 val = ((int)raw / 4) * 3125 / 100;
111 break;
112
113 case LM70_CHIP_TMP125:
114 val = (sign_extend32(raw, 14) / 32) * 250;
115 break;
116 }
117
118 status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */
119out:
120 mutex_unlock(&p_lm70->lock);
121 return status;
122}
123
124static DEVICE_ATTR_RO(temp1_input);
125
126static struct attribute *lm70_attrs[] = {
127 &dev_attr_temp1_input.attr,
128 NULL
129};
130
131ATTRIBUTE_GROUPS(lm70);
132
133/*----------------------------------------------------------------------*/
134
135#ifdef CONFIG_OF
136static const struct of_device_id lm70_of_ids[] = {
137 {
138 .compatible = "ti,lm70",
139 .data = (void *) LM70_CHIP_LM70,
140 },
141 {
142 .compatible = "ti,tmp121",
143 .data = (void *) LM70_CHIP_TMP121,
144 },
145 {
146 .compatible = "ti,tmp122",
147 .data = (void *) LM70_CHIP_TMP122,
148 },
149 {
150 .compatible = "ti,tmp125",
151 .data = (void *) LM70_CHIP_TMP125,
152 },
153 {
154 .compatible = "ti,lm71",
155 .data = (void *) LM70_CHIP_LM71,
156 },
157 {
158 .compatible = "ti,lm74",
159 .data = (void *) LM70_CHIP_LM74,
160 },
161 {},
162};
163MODULE_DEVICE_TABLE(of, lm70_of_ids);
164#endif
165
166static int lm70_probe(struct spi_device *spi)
167{
168 struct device *hwmon_dev;
169 struct lm70 *p_lm70;
170 int chip;
171
172 if (dev_fwnode(&spi->dev))
173 chip = (int)(uintptr_t)device_get_match_data(&spi->dev);
174 else
175 chip = spi_get_device_id(spi)->driver_data;
176
177
178 /* signaling is SPI_MODE_0 */
179 if ((spi->mode & SPI_MODE_X_MASK) != SPI_MODE_0)
180 return -EINVAL;
181
182 /* NOTE: we assume 8-bit words, and convert to 16 bits manually */
183
184 p_lm70 = devm_kzalloc(&spi->dev, sizeof(*p_lm70), GFP_KERNEL);
185 if (!p_lm70)
186 return -ENOMEM;
187
188 mutex_init(&p_lm70->lock);
189 p_lm70->chip = chip;
190 p_lm70->spi = spi;
191
192 hwmon_dev = devm_hwmon_device_register_with_groups(&spi->dev,
193 spi->modalias,
194 p_lm70, lm70_groups);
195 return PTR_ERR_OR_ZERO(hwmon_dev);
196}
197
198static const struct spi_device_id lm70_ids[] = {
199 { "lm70", LM70_CHIP_LM70 },
200 { "tmp121", LM70_CHIP_TMP121 },
201 { "tmp122", LM70_CHIP_TMP122 },
202 { "tmp125", LM70_CHIP_TMP125 },
203 { "lm71", LM70_CHIP_LM71 },
204 { "lm74", LM70_CHIP_LM74 },
205 { },
206};
207MODULE_DEVICE_TABLE(spi, lm70_ids);
208
209static struct spi_driver lm70_driver = {
210 .driver = {
211 .name = "lm70",
212 .of_match_table = of_match_ptr(lm70_of_ids),
213 },
214 .id_table = lm70_ids,
215 .probe = lm70_probe,
216};
217
218module_spi_driver(lm70_driver);
219
220MODULE_AUTHOR("Kaiwan N Billimoria");
221MODULE_DESCRIPTION("NS LM70 and compatibles Linux driver");
222MODULE_LICENSE("GPL");