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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// 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");