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74ba9207 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
e1a8e913 KB |
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 | |
e1a8e913 KB |
12 | */ |
13 | ||
5713017e JP |
14 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
15 | ||
e1a8e913 KB |
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> | |
4bfe6604 | 23 | #include <linux/mutex.h> |
8cec03ee | 24 | #include <linux/mod_devicetable.h> |
e1a8e913 | 25 | #include <linux/spi/spi.h> |
5a0e3ad6 | 26 | #include <linux/slab.h> |
a1dc86eb | 27 | #include <linux/of_device.h> |
4bfe6604 | 28 | |
e1a8e913 KB |
29 | |
30 | #define DRVNAME "lm70" | |
31 | ||
c8ac32e4 ML |
32 | #define LM70_CHIP_LM70 0 /* original NS LM70 */ |
33 | #define LM70_CHIP_TMP121 1 /* TI TMP121/TMP123 */ | |
a86e94dc CL |
34 | #define LM70_CHIP_LM71 2 /* NS LM71 */ |
35 | #define LM70_CHIP_LM74 3 /* NS LM74 */ | |
68f0c8c9 | 36 | #define LM70_CHIP_TMP122 4 /* TI TMP122/TMP124 */ |
c8ac32e4 | 37 | |
e1a8e913 | 38 | struct lm70 { |
aa9bcdda | 39 | struct spi_device *spi; |
4bfe6604 | 40 | struct mutex lock; |
c8ac32e4 | 41 | unsigned int chip; |
e1a8e913 KB |
42 | }; |
43 | ||
44 | /* sysfs hook function */ | |
89cb4af8 JL |
45 | static ssize_t temp1_input_show(struct device *dev, |
46 | struct device_attribute *attr, char *buf) | |
e1a8e913 | 47 | { |
aa9bcdda GR |
48 | struct lm70 *p_lm70 = dev_get_drvdata(dev); |
49 | struct spi_device *spi = p_lm70->spi; | |
c8ac32e4 | 50 | int status, val = 0; |
e1a8e913 | 51 | u8 rxbuf[2]; |
56c24af8 | 52 | s16 raw = 0; |
e1a8e913 | 53 | |
4bfe6604 | 54 | if (mutex_lock_interruptible(&p_lm70->lock)) |
e1a8e913 KB |
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) { | |
e8295146 FF |
63 | dev_warn(dev, "spi_write_then_read failed with status %d\n", |
64 | status); | |
e1a8e913 KB |
65 | goto out; |
66 | } | |
2b730051 KB |
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); | |
e1a8e913 KB |
70 | |
71 | /* | |
c8ac32e4 | 72 | * LM70: |
e1a8e913 KB |
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. | |
c8ac32e4 | 82 | * |
68f0c8c9 | 83 | * LM74 and TMP121/TMP122/TMP123/TMP124: |
c8ac32e4 ML |
84 | * 13 bits of 2's complement data, discard LSB 3 bits, |
85 | * resolution 0.0625 degrees celsius. | |
a86e94dc CL |
86 | * |
87 | * LM71: | |
88 | * 14 bits of 2's complement data, discard LSB 2 bits, | |
89 | * resolution 0.0312 degrees celsius. | |
e1a8e913 | 90 | */ |
c8ac32e4 ML |
91 | switch (p_lm70->chip) { |
92 | case LM70_CHIP_LM70: | |
93 | val = ((int)raw / 32) * 250; | |
94 | break; | |
95 | ||
96 | case LM70_CHIP_TMP121: | |
68f0c8c9 | 97 | case LM70_CHIP_TMP122: |
a86e94dc | 98 | case LM70_CHIP_LM74: |
c8ac32e4 ML |
99 | val = ((int)raw / 8) * 625 / 10; |
100 | break; | |
a86e94dc CL |
101 | |
102 | case LM70_CHIP_LM71: | |
103 | val = ((int)raw / 4) * 3125 / 100; | |
104 | break; | |
c8ac32e4 ML |
105 | } |
106 | ||
67f921d1 | 107 | status = sprintf(buf, "%d\n", val); /* millidegrees Celsius */ |
e1a8e913 | 108 | out: |
4bfe6604 | 109 | mutex_unlock(&p_lm70->lock); |
e1a8e913 KB |
110 | return status; |
111 | } | |
112 | ||
89cb4af8 | 113 | static DEVICE_ATTR_RO(temp1_input); |
e1a8e913 | 114 | |
aa9bcdda GR |
115 | static struct attribute *lm70_attrs[] = { |
116 | &dev_attr_temp1_input.attr, | |
117 | NULL | |
118 | }; | |
67f921d1 | 119 | |
aa9bcdda | 120 | ATTRIBUTE_GROUPS(lm70); |
67f921d1 | 121 | |
e1a8e913 KB |
122 | /*----------------------------------------------------------------------*/ |
123 | ||
a1dc86eb RV |
124 | #ifdef CONFIG_OF |
125 | static 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 | }, | |
68f0c8c9 FF |
134 | { |
135 | .compatible = "ti,tmp122", | |
136 | .data = (void *) LM70_CHIP_TMP122, | |
137 | }, | |
a1dc86eb RV |
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 | }; | |
148 | MODULE_DEVICE_TABLE(of, lm70_of_ids); | |
149 | #endif | |
150 | ||
6c931ae1 | 151 | static int lm70_probe(struct spi_device *spi) |
e1a8e913 | 152 | { |
a1dc86eb | 153 | const struct of_device_id *match; |
aa9bcdda | 154 | struct device *hwmon_dev; |
e1a8e913 | 155 | struct lm70 *p_lm70; |
a1dc86eb RV |
156 | int chip; |
157 | ||
158 | match = of_match_device(lm70_of_ids, &spi->dev); | |
159 | if (match) | |
160 | chip = (int)(uintptr_t)match->data; | |
161 | else | |
162 | chip = spi_get_device_id(spi)->driver_data; | |
e1a8e913 | 163 | |
a86e94dc | 164 | /* signaling is SPI_MODE_0 */ |
8cec03ee AV |
165 | if (spi->mode & (SPI_CPOL | SPI_CPHA)) |
166 | return -EINVAL; | |
167 | ||
2b730051 KB |
168 | /* NOTE: we assume 8-bit words, and convert to 16 bits manually */ |
169 | ||
33ed6d4a | 170 | p_lm70 = devm_kzalloc(&spi->dev, sizeof(*p_lm70), GFP_KERNEL); |
e1a8e913 KB |
171 | if (!p_lm70) |
172 | return -ENOMEM; | |
173 | ||
4bfe6604 | 174 | mutex_init(&p_lm70->lock); |
c8ac32e4 | 175 | p_lm70->chip = chip; |
aa9bcdda | 176 | p_lm70->spi = spi; |
e1a8e913 | 177 | |
aa9bcdda GR |
178 | hwmon_dev = devm_hwmon_device_register_with_groups(&spi->dev, |
179 | spi->modalias, | |
180 | p_lm70, lm70_groups); | |
181 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
e1a8e913 KB |
182 | } |
183 | ||
8cec03ee AV |
184 | static const struct spi_device_id lm70_ids[] = { |
185 | { "lm70", LM70_CHIP_LM70 }, | |
186 | { "tmp121", LM70_CHIP_TMP121 }, | |
68f0c8c9 | 187 | { "tmp122", LM70_CHIP_TMP122 }, |
a86e94dc CL |
188 | { "lm71", LM70_CHIP_LM71 }, |
189 | { "lm74", LM70_CHIP_LM74 }, | |
8cec03ee | 190 | { }, |
c8ac32e4 | 191 | }; |
8cec03ee | 192 | MODULE_DEVICE_TABLE(spi, lm70_ids); |
c8ac32e4 | 193 | |
e1a8e913 KB |
194 | static struct spi_driver lm70_driver = { |
195 | .driver = { | |
196 | .name = "lm70", | |
a1dc86eb | 197 | .of_match_table = of_match_ptr(lm70_of_ids), |
e1a8e913 | 198 | }, |
8cec03ee | 199 | .id_table = lm70_ids, |
e1a8e913 | 200 | .probe = lm70_probe, |
e1a8e913 KB |
201 | }; |
202 | ||
91efffe2 | 203 | module_spi_driver(lm70_driver); |
e1a8e913 KB |
204 | |
205 | MODULE_AUTHOR("Kaiwan N Billimoria"); | |
a86e94dc | 206 | MODULE_DESCRIPTION("NS LM70 and compatibles Linux driver"); |
e1a8e913 | 207 | MODULE_LICENSE("GPL"); |