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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 TI's website
10 * here:
11 * https://www.ti.com/product/LM70
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 chip = (kernel_ulong_t)spi_get_device_match_data(spi);
173
174 /* signaling is SPI_MODE_0 */
175 if ((spi->mode & SPI_MODE_X_MASK) != SPI_MODE_0)
176 return -EINVAL;
177
178 /* NOTE: we assume 8-bit words, and convert to 16 bits manually */
179
180 p_lm70 = devm_kzalloc(&spi->dev, sizeof(*p_lm70), GFP_KERNEL);
181 if (!p_lm70)
182 return -ENOMEM;
183
184 mutex_init(&p_lm70->lock);
185 p_lm70->chip = chip;
186 p_lm70->spi = spi;
187
188 hwmon_dev = devm_hwmon_device_register_with_groups(&spi->dev,
189 spi->modalias,
190 p_lm70, lm70_groups);
191 return PTR_ERR_OR_ZERO(hwmon_dev);
192}
193
194static const struct spi_device_id lm70_ids[] = {
195 { "lm70", LM70_CHIP_LM70 },
196 { "tmp121", LM70_CHIP_TMP121 },
197 { "tmp122", LM70_CHIP_TMP122 },
198 { "tmp125", LM70_CHIP_TMP125 },
199 { "lm71", LM70_CHIP_LM71 },
200 { "lm74", LM70_CHIP_LM74 },
201 { },
202};
203MODULE_DEVICE_TABLE(spi, lm70_ids);
204
205static struct spi_driver lm70_driver = {
206 .driver = {
207 .name = "lm70",
208 .of_match_table = of_match_ptr(lm70_of_ids),
209 },
210 .id_table = lm70_ids,
211 .probe = lm70_probe,
212};
213
214module_spi_driver(lm70_driver);
215
216MODULE_AUTHOR("Kaiwan N Billimoria");
217MODULE_DESCRIPTION("NS LM70 and compatibles Linux driver");
218MODULE_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");