2 * ntc_thermistor.c - NTC Thermistors
4 * Copyright (C) 2010 Samsung Electronics
5 * MyungJoo Ham <myungjoo.ham@samsung.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 #include <linux/slab.h>
24 #include <linux/module.h>
25 #include <linux/pm_runtime.h>
26 #include <linux/math64.h>
27 #include <linux/platform_device.h>
28 #include <linux/err.h>
30 #include <linux/of_device.h>
32 #include <linux/platform_data/ntc_thermistor.h>
34 #include <linux/iio/iio.h>
35 #include <linux/iio/machine.h>
36 #include <linux/iio/driver.h>
37 #include <linux/iio/consumer.h>
39 #include <linux/hwmon.h>
40 #include <linux/hwmon-sysfs.h>
42 struct ntc_compensation
{
47 /* Order matters, ntc_match references the entries by index */
48 static const struct platform_device_id ntc_thermistor_id
[] = {
49 { "ncp15wb473", TYPE_NCPXXWB473
},
50 { "ncp18wb473", TYPE_NCPXXWB473
},
51 { "ncp21wb473", TYPE_NCPXXWB473
},
52 { "ncp03wb473", TYPE_NCPXXWB473
},
53 { "ncp15wl333", TYPE_NCPXXWL333
},
54 { "b57330v2103", TYPE_B57330V2103
},
59 * A compensation table should be sorted by the values of .ohm
60 * in descending order.
61 * The following compensation tables are from the specification of Murata NTC
62 * Thermistors Datasheet
64 static const struct ntc_compensation ncpXXwb473
[] = {
65 { .temp_c
= -40, .ohm
= 1747920 },
66 { .temp_c
= -35, .ohm
= 1245428 },
67 { .temp_c
= -30, .ohm
= 898485 },
68 { .temp_c
= -25, .ohm
= 655802 },
69 { .temp_c
= -20, .ohm
= 483954 },
70 { .temp_c
= -15, .ohm
= 360850 },
71 { .temp_c
= -10, .ohm
= 271697 },
72 { .temp_c
= -5, .ohm
= 206463 },
73 { .temp_c
= 0, .ohm
= 158214 },
74 { .temp_c
= 5, .ohm
= 122259 },
75 { .temp_c
= 10, .ohm
= 95227 },
76 { .temp_c
= 15, .ohm
= 74730 },
77 { .temp_c
= 20, .ohm
= 59065 },
78 { .temp_c
= 25, .ohm
= 47000 },
79 { .temp_c
= 30, .ohm
= 37643 },
80 { .temp_c
= 35, .ohm
= 30334 },
81 { .temp_c
= 40, .ohm
= 24591 },
82 { .temp_c
= 45, .ohm
= 20048 },
83 { .temp_c
= 50, .ohm
= 16433 },
84 { .temp_c
= 55, .ohm
= 13539 },
85 { .temp_c
= 60, .ohm
= 11209 },
86 { .temp_c
= 65, .ohm
= 9328 },
87 { .temp_c
= 70, .ohm
= 7798 },
88 { .temp_c
= 75, .ohm
= 6544 },
89 { .temp_c
= 80, .ohm
= 5518 },
90 { .temp_c
= 85, .ohm
= 4674 },
91 { .temp_c
= 90, .ohm
= 3972 },
92 { .temp_c
= 95, .ohm
= 3388 },
93 { .temp_c
= 100, .ohm
= 2902 },
94 { .temp_c
= 105, .ohm
= 2494 },
95 { .temp_c
= 110, .ohm
= 2150 },
96 { .temp_c
= 115, .ohm
= 1860 },
97 { .temp_c
= 120, .ohm
= 1615 },
98 { .temp_c
= 125, .ohm
= 1406 },
100 static const struct ntc_compensation ncpXXwl333
[] = {
101 { .temp_c
= -40, .ohm
= 1610154 },
102 { .temp_c
= -35, .ohm
= 1130850 },
103 { .temp_c
= -30, .ohm
= 802609 },
104 { .temp_c
= -25, .ohm
= 575385 },
105 { .temp_c
= -20, .ohm
= 416464 },
106 { .temp_c
= -15, .ohm
= 304219 },
107 { .temp_c
= -10, .ohm
= 224193 },
108 { .temp_c
= -5, .ohm
= 166623 },
109 { .temp_c
= 0, .ohm
= 124850 },
110 { .temp_c
= 5, .ohm
= 94287 },
111 { .temp_c
= 10, .ohm
= 71747 },
112 { .temp_c
= 15, .ohm
= 54996 },
113 { .temp_c
= 20, .ohm
= 42455 },
114 { .temp_c
= 25, .ohm
= 33000 },
115 { .temp_c
= 30, .ohm
= 25822 },
116 { .temp_c
= 35, .ohm
= 20335 },
117 { .temp_c
= 40, .ohm
= 16115 },
118 { .temp_c
= 45, .ohm
= 12849 },
119 { .temp_c
= 50, .ohm
= 10306 },
120 { .temp_c
= 55, .ohm
= 8314 },
121 { .temp_c
= 60, .ohm
= 6746 },
122 { .temp_c
= 65, .ohm
= 5503 },
123 { .temp_c
= 70, .ohm
= 4513 },
124 { .temp_c
= 75, .ohm
= 3721 },
125 { .temp_c
= 80, .ohm
= 3084 },
126 { .temp_c
= 85, .ohm
= 2569 },
127 { .temp_c
= 90, .ohm
= 2151 },
128 { .temp_c
= 95, .ohm
= 1809 },
129 { .temp_c
= 100, .ohm
= 1529 },
130 { .temp_c
= 105, .ohm
= 1299 },
131 { .temp_c
= 110, .ohm
= 1108 },
132 { .temp_c
= 115, .ohm
= 949 },
133 { .temp_c
= 120, .ohm
= 817 },
134 { .temp_c
= 125, .ohm
= 707 },
138 * The following compensation table is from the specification of EPCOS NTC
139 * Thermistors Datasheet
141 static const struct ntc_compensation b57330v2103
[] = {
142 { .temp_c
= -40, .ohm
= 190030 },
143 { .temp_c
= -35, .ohm
= 145360 },
144 { .temp_c
= -30, .ohm
= 112060 },
145 { .temp_c
= -25, .ohm
= 87041 },
146 { .temp_c
= -20, .ohm
= 68104 },
147 { .temp_c
= -15, .ohm
= 53665 },
148 { .temp_c
= -10, .ohm
= 42576 },
149 { .temp_c
= -5, .ohm
= 34001 },
150 { .temp_c
= 0, .ohm
= 27326 },
151 { .temp_c
= 5, .ohm
= 22096 },
152 { .temp_c
= 10, .ohm
= 17973 },
153 { .temp_c
= 15, .ohm
= 14703 },
154 { .temp_c
= 20, .ohm
= 12090 },
155 { .temp_c
= 25, .ohm
= 10000 },
156 { .temp_c
= 30, .ohm
= 8311 },
157 { .temp_c
= 35, .ohm
= 6941 },
158 { .temp_c
= 40, .ohm
= 5825 },
159 { .temp_c
= 45, .ohm
= 4911 },
160 { .temp_c
= 50, .ohm
= 4158 },
161 { .temp_c
= 55, .ohm
= 3536 },
162 { .temp_c
= 60, .ohm
= 3019 },
163 { .temp_c
= 65, .ohm
= 2588 },
164 { .temp_c
= 70, .ohm
= 2227 },
165 { .temp_c
= 75, .ohm
= 1924 },
166 { .temp_c
= 80, .ohm
= 1668 },
167 { .temp_c
= 85, .ohm
= 1451 },
168 { .temp_c
= 90, .ohm
= 1266 },
169 { .temp_c
= 95, .ohm
= 1108 },
170 { .temp_c
= 100, .ohm
= 973 },
171 { .temp_c
= 105, .ohm
= 857 },
172 { .temp_c
= 110, .ohm
= 757 },
173 { .temp_c
= 115, .ohm
= 671 },
174 { .temp_c
= 120, .ohm
= 596 },
175 { .temp_c
= 125, .ohm
= 531 },
179 struct device
*hwmon_dev
;
180 struct ntc_thermistor_platform_data
*pdata
;
181 const struct ntc_compensation
*comp
;
184 char name
[PLATFORM_NAME_SIZE
];
187 #if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO)
188 static int ntc_adc_iio_read(struct ntc_thermistor_platform_data
*pdata
)
190 struct iio_channel
*channel
= pdata
->chan
;
194 ret
= iio_read_channel_raw(channel
, &val
);
196 pr_err("read channel() error: %d\n", ret
);
201 result
= pdata
->pullup_uv
* (s64
) val
;
207 static const struct of_device_id ntc_match
[] = {
208 { .compatible
= "murata,ncp15wb473",
209 .data
= &ntc_thermistor_id
[0] },
210 { .compatible
= "murata,ncp18wb473",
211 .data
= &ntc_thermistor_id
[1] },
212 { .compatible
= "murata,ncp21wb473",
213 .data
= &ntc_thermistor_id
[2] },
214 { .compatible
= "murata,ncp03wb473",
215 .data
= &ntc_thermistor_id
[3] },
216 { .compatible
= "murata,ncp15wl333",
217 .data
= &ntc_thermistor_id
[4] },
218 { .compatible
= "epcos,b57330v2103",
219 .data
= &ntc_thermistor_id
[5]},
221 /* Usage of vendor name "ntc" is deprecated */
222 { .compatible
= "ntc,ncp15wb473",
223 .data
= &ntc_thermistor_id
[0] },
224 { .compatible
= "ntc,ncp18wb473",
225 .data
= &ntc_thermistor_id
[1] },
226 { .compatible
= "ntc,ncp21wb473",
227 .data
= &ntc_thermistor_id
[2] },
228 { .compatible
= "ntc,ncp03wb473",
229 .data
= &ntc_thermistor_id
[3] },
230 { .compatible
= "ntc,ncp15wl333",
231 .data
= &ntc_thermistor_id
[4] },
234 MODULE_DEVICE_TABLE(of
, ntc_match
);
236 static struct ntc_thermistor_platform_data
*
237 ntc_thermistor_parse_dt(struct platform_device
*pdev
)
239 struct iio_channel
*chan
;
240 struct device_node
*np
= pdev
->dev
.of_node
;
241 struct ntc_thermistor_platform_data
*pdata
;
246 pdata
= devm_kzalloc(&pdev
->dev
, sizeof(*pdata
), GFP_KERNEL
);
248 return ERR_PTR(-ENOMEM
);
250 chan
= iio_channel_get(&pdev
->dev
, NULL
);
252 return ERR_CAST(chan
);
254 if (of_property_read_u32(np
, "pullup-uv", &pdata
->pullup_uv
))
255 return ERR_PTR(-ENODEV
);
256 if (of_property_read_u32(np
, "pullup-ohm", &pdata
->pullup_ohm
))
257 return ERR_PTR(-ENODEV
);
258 if (of_property_read_u32(np
, "pulldown-ohm", &pdata
->pulldown_ohm
))
259 return ERR_PTR(-ENODEV
);
261 if (of_find_property(np
, "connected-positive", NULL
))
262 pdata
->connect
= NTC_CONNECTED_POSITIVE
;
263 else /* status change should be possible if not always on. */
264 pdata
->connect
= NTC_CONNECTED_GROUND
;
267 pdata
->read_uv
= ntc_adc_iio_read
;
271 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data
*pdata
)
274 iio_channel_release(pdata
->chan
);
277 static struct ntc_thermistor_platform_data
*
278 ntc_thermistor_parse_dt(struct platform_device
*pdev
)
283 #define ntc_match NULL
285 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data
*pdata
)
289 static inline u64
div64_u64_safe(u64 dividend
, u64 divisor
)
291 if (divisor
== 0 && dividend
== 0)
295 return div64_u64(dividend
, divisor
);
298 static int get_ohm_of_thermistor(struct ntc_data
*data
, unsigned int uv
)
300 struct ntc_thermistor_platform_data
*pdata
= data
->pdata
;
302 u64 pmv
= pdata
->pullup_uv
/ 1000;
304 puo
= pdata
->pullup_ohm
;
305 pdo
= pdata
->pulldown_ohm
;
308 if (pdata
->connect
== NTC_CONNECTED_POSITIVE
)
313 return (pdata
->connect
== NTC_CONNECTED_POSITIVE
) ?
316 if (pdata
->connect
== NTC_CONNECTED_POSITIVE
&& puo
== 0)
317 n
= div64_u64_safe(pdo
* (pmv
- mv
), mv
);
318 else if (pdata
->connect
== NTC_CONNECTED_GROUND
&& pdo
== 0)
319 n
= div64_u64_safe(puo
* mv
, pmv
- mv
);
320 else if (pdata
->connect
== NTC_CONNECTED_POSITIVE
)
321 n
= div64_u64_safe(pdo
* puo
* (pmv
- mv
),
322 puo
* mv
- pdo
* (pmv
- mv
));
324 n
= div64_u64_safe(pdo
* puo
* mv
, pdo
* (pmv
- mv
) - puo
* mv
);
331 static void lookup_comp(struct ntc_data
*data
, unsigned int ohm
,
332 int *i_low
, int *i_high
)
337 * Handle special cases: Resistance is higher than or equal to
338 * resistance in first table entry, or resistance is lower or equal
339 * to resistance in last table entry.
340 * In these cases, return i_low == i_high, either pointing to the
341 * beginning or to the end of the table depending on the condition.
343 if (ohm
>= data
->comp
[0].ohm
) {
348 if (ohm
<= data
->comp
[data
->n_comp
- 1].ohm
) {
349 *i_low
= data
->n_comp
- 1;
350 *i_high
= data
->n_comp
- 1;
354 /* Do a binary search on compensation table */
357 while (start
< end
) {
358 mid
= start
+ (end
- start
) / 2;
361 * data->comp[start].ohm > ohm >= data->comp[end].ohm
363 * We could check for "ohm == data->comp[mid].ohm" here, but
364 * that is a quite unlikely condition, and we would have to
365 * check again after updating start. Check it at the end instead
368 if (ohm
>= data
->comp
[mid
].ohm
) {
373 * ohm >= data->comp[start].ohm might be true here,
374 * since we set start to mid + 1. In that case, we are
375 * done. We could keep going, but the condition is quite
376 * likely to occur, so it is worth checking for it.
378 if (ohm
>= data
->comp
[start
].ohm
)
383 * data->comp[start].ohm >= ohm >= data->comp[end].ohm
388 * ohm >= data->comp[end].ohm
391 if (ohm
== data
->comp
[end
].ohm
)
397 static int get_temp_mc(struct ntc_data
*data
, unsigned int ohm
)
402 lookup_comp(data
, ohm
, &low
, &high
);
404 /* Unable to use linear approximation */
405 temp
= data
->comp
[low
].temp_c
* 1000;
407 temp
= data
->comp
[low
].temp_c
* 1000 +
408 ((data
->comp
[high
].temp_c
- data
->comp
[low
].temp_c
) *
409 1000 * ((int)ohm
- (int)data
->comp
[low
].ohm
)) /
410 ((int)data
->comp
[high
].ohm
- (int)data
->comp
[low
].ohm
);
415 static int ntc_thermistor_get_ohm(struct ntc_data
*data
)
419 if (data
->pdata
->read_ohm
)
420 return data
->pdata
->read_ohm();
422 if (data
->pdata
->read_uv
) {
423 read_uv
= data
->pdata
->read_uv(data
->pdata
);
426 return get_ohm_of_thermistor(data
, read_uv
);
431 static ssize_t
ntc_show_name(struct device
*dev
,
432 struct device_attribute
*attr
, char *buf
)
434 struct ntc_data
*data
= dev_get_drvdata(dev
);
436 return sprintf(buf
, "%s\n", data
->name
);
439 static ssize_t
ntc_show_type(struct device
*dev
,
440 struct device_attribute
*attr
, char *buf
)
442 return sprintf(buf
, "4\n");
445 static ssize_t
ntc_show_temp(struct device
*dev
,
446 struct device_attribute
*attr
, char *buf
)
448 struct ntc_data
*data
= dev_get_drvdata(dev
);
451 ohm
= ntc_thermistor_get_ohm(data
);
455 return sprintf(buf
, "%d\n", get_temp_mc(data
, ohm
));
458 static SENSOR_DEVICE_ATTR(temp1_type
, S_IRUGO
, ntc_show_type
, NULL
, 0);
459 static SENSOR_DEVICE_ATTR(temp1_input
, S_IRUGO
, ntc_show_temp
, NULL
, 0);
460 static DEVICE_ATTR(name
, S_IRUGO
, ntc_show_name
, NULL
);
462 static struct attribute
*ntc_attributes
[] = {
464 &sensor_dev_attr_temp1_type
.dev_attr
.attr
,
465 &sensor_dev_attr_temp1_input
.dev_attr
.attr
,
469 static const struct attribute_group ntc_attr_group
= {
470 .attrs
= ntc_attributes
,
473 static int ntc_thermistor_probe(struct platform_device
*pdev
)
475 const struct of_device_id
*of_id
=
476 of_match_device(of_match_ptr(ntc_match
), &pdev
->dev
);
477 const struct platform_device_id
*pdev_id
;
478 struct ntc_thermistor_platform_data
*pdata
;
479 struct ntc_data
*data
;
482 pdata
= ntc_thermistor_parse_dt(pdev
);
484 return PTR_ERR(pdata
);
485 else if (pdata
== NULL
)
486 pdata
= dev_get_platdata(&pdev
->dev
);
489 dev_err(&pdev
->dev
, "No platform init data supplied.\n");
493 /* Either one of the two is required. */
494 if (!pdata
->read_uv
&& !pdata
->read_ohm
) {
496 "Both read_uv and read_ohm missing. Need either one of the two.\n");
500 if (pdata
->read_uv
&& pdata
->read_ohm
) {
502 "Only one of read_uv and read_ohm is needed; ignoring read_uv.\n");
503 pdata
->read_uv
= NULL
;
506 if (pdata
->read_uv
&& (pdata
->pullup_uv
== 0 ||
507 (pdata
->pullup_ohm
== 0 && pdata
->connect
==
508 NTC_CONNECTED_GROUND
) ||
509 (pdata
->pulldown_ohm
== 0 && pdata
->connect
==
510 NTC_CONNECTED_POSITIVE
) ||
511 (pdata
->connect
!= NTC_CONNECTED_POSITIVE
&&
512 pdata
->connect
!= NTC_CONNECTED_GROUND
))) {
514 "Required data to use read_uv not supplied.\n");
518 data
= devm_kzalloc(&pdev
->dev
, sizeof(struct ntc_data
), GFP_KERNEL
);
522 pdev_id
= of_id
? of_id
->data
: platform_get_device_id(pdev
);
524 data
->dev
= &pdev
->dev
;
526 strlcpy(data
->name
, pdev_id
->name
, sizeof(data
->name
));
528 switch (pdev_id
->driver_data
) {
529 case TYPE_NCPXXWB473
:
530 data
->comp
= ncpXXwb473
;
531 data
->n_comp
= ARRAY_SIZE(ncpXXwb473
);
533 case TYPE_NCPXXWL333
:
534 data
->comp
= ncpXXwl333
;
535 data
->n_comp
= ARRAY_SIZE(ncpXXwl333
);
537 case TYPE_B57330V2103
:
538 data
->comp
= b57330v2103
;
539 data
->n_comp
= ARRAY_SIZE(b57330v2103
);
542 dev_err(&pdev
->dev
, "Unknown device type: %lu(%s)\n",
543 pdev_id
->driver_data
, pdev_id
->name
);
547 platform_set_drvdata(pdev
, data
);
549 ret
= sysfs_create_group(&data
->dev
->kobj
, &ntc_attr_group
);
551 dev_err(data
->dev
, "unable to create sysfs files\n");
555 data
->hwmon_dev
= hwmon_device_register(data
->dev
);
556 if (IS_ERR(data
->hwmon_dev
)) {
557 dev_err(data
->dev
, "unable to register as hwmon device.\n");
558 ret
= PTR_ERR(data
->hwmon_dev
);
559 goto err_after_sysfs
;
562 dev_info(&pdev
->dev
, "Thermistor type: %s successfully probed.\n",
567 sysfs_remove_group(&data
->dev
->kobj
, &ntc_attr_group
);
568 ntc_iio_channel_release(pdata
);
572 static int ntc_thermistor_remove(struct platform_device
*pdev
)
574 struct ntc_data
*data
= platform_get_drvdata(pdev
);
575 struct ntc_thermistor_platform_data
*pdata
= data
->pdata
;
577 hwmon_device_unregister(data
->hwmon_dev
);
578 sysfs_remove_group(&data
->dev
->kobj
, &ntc_attr_group
);
579 ntc_iio_channel_release(pdata
);
584 static struct platform_driver ntc_thermistor_driver
= {
586 .name
= "ntc-thermistor",
587 .owner
= THIS_MODULE
,
588 .of_match_table
= of_match_ptr(ntc_match
),
590 .probe
= ntc_thermistor_probe
,
591 .remove
= ntc_thermistor_remove
,
592 .id_table
= ntc_thermistor_id
,
595 module_platform_driver(ntc_thermistor_driver
);
597 MODULE_DESCRIPTION("NTC Thermistor Driver");
598 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
599 MODULE_LICENSE("GPL");
600 MODULE_ALIAS("platform:ntc-thermistor");