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
},
58 * A compensation table should be sorted by the values of .ohm
59 * in descending order.
60 * The following compensation tables are from the specification of Murata NTC
61 * Thermistors Datasheet
63 static const struct ntc_compensation ncpXXwb473
[] = {
64 { .temp_c
= -40, .ohm
= 1747920 },
65 { .temp_c
= -35, .ohm
= 1245428 },
66 { .temp_c
= -30, .ohm
= 898485 },
67 { .temp_c
= -25, .ohm
= 655802 },
68 { .temp_c
= -20, .ohm
= 483954 },
69 { .temp_c
= -15, .ohm
= 360850 },
70 { .temp_c
= -10, .ohm
= 271697 },
71 { .temp_c
= -5, .ohm
= 206463 },
72 { .temp_c
= 0, .ohm
= 158214 },
73 { .temp_c
= 5, .ohm
= 122259 },
74 { .temp_c
= 10, .ohm
= 95227 },
75 { .temp_c
= 15, .ohm
= 74730 },
76 { .temp_c
= 20, .ohm
= 59065 },
77 { .temp_c
= 25, .ohm
= 47000 },
78 { .temp_c
= 30, .ohm
= 37643 },
79 { .temp_c
= 35, .ohm
= 30334 },
80 { .temp_c
= 40, .ohm
= 24591 },
81 { .temp_c
= 45, .ohm
= 20048 },
82 { .temp_c
= 50, .ohm
= 16433 },
83 { .temp_c
= 55, .ohm
= 13539 },
84 { .temp_c
= 60, .ohm
= 11209 },
85 { .temp_c
= 65, .ohm
= 9328 },
86 { .temp_c
= 70, .ohm
= 7798 },
87 { .temp_c
= 75, .ohm
= 6544 },
88 { .temp_c
= 80, .ohm
= 5518 },
89 { .temp_c
= 85, .ohm
= 4674 },
90 { .temp_c
= 90, .ohm
= 3972 },
91 { .temp_c
= 95, .ohm
= 3388 },
92 { .temp_c
= 100, .ohm
= 2902 },
93 { .temp_c
= 105, .ohm
= 2494 },
94 { .temp_c
= 110, .ohm
= 2150 },
95 { .temp_c
= 115, .ohm
= 1860 },
96 { .temp_c
= 120, .ohm
= 1615 },
97 { .temp_c
= 125, .ohm
= 1406 },
99 static const struct ntc_compensation ncpXXwl333
[] = {
100 { .temp_c
= -40, .ohm
= 1610154 },
101 { .temp_c
= -35, .ohm
= 1130850 },
102 { .temp_c
= -30, .ohm
= 802609 },
103 { .temp_c
= -25, .ohm
= 575385 },
104 { .temp_c
= -20, .ohm
= 416464 },
105 { .temp_c
= -15, .ohm
= 304219 },
106 { .temp_c
= -10, .ohm
= 224193 },
107 { .temp_c
= -5, .ohm
= 166623 },
108 { .temp_c
= 0, .ohm
= 124850 },
109 { .temp_c
= 5, .ohm
= 94287 },
110 { .temp_c
= 10, .ohm
= 71747 },
111 { .temp_c
= 15, .ohm
= 54996 },
112 { .temp_c
= 20, .ohm
= 42455 },
113 { .temp_c
= 25, .ohm
= 33000 },
114 { .temp_c
= 30, .ohm
= 25822 },
115 { .temp_c
= 35, .ohm
= 20335 },
116 { .temp_c
= 40, .ohm
= 16115 },
117 { .temp_c
= 45, .ohm
= 12849 },
118 { .temp_c
= 50, .ohm
= 10306 },
119 { .temp_c
= 55, .ohm
= 8314 },
120 { .temp_c
= 60, .ohm
= 6746 },
121 { .temp_c
= 65, .ohm
= 5503 },
122 { .temp_c
= 70, .ohm
= 4513 },
123 { .temp_c
= 75, .ohm
= 3721 },
124 { .temp_c
= 80, .ohm
= 3084 },
125 { .temp_c
= 85, .ohm
= 2569 },
126 { .temp_c
= 90, .ohm
= 2151 },
127 { .temp_c
= 95, .ohm
= 1809 },
128 { .temp_c
= 100, .ohm
= 1529 },
129 { .temp_c
= 105, .ohm
= 1299 },
130 { .temp_c
= 110, .ohm
= 1108 },
131 { .temp_c
= 115, .ohm
= 949 },
132 { .temp_c
= 120, .ohm
= 817 },
133 { .temp_c
= 125, .ohm
= 707 },
137 struct device
*hwmon_dev
;
138 struct ntc_thermistor_platform_data
*pdata
;
139 const struct ntc_compensation
*comp
;
142 char name
[PLATFORM_NAME_SIZE
];
145 #if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO)
146 static int ntc_adc_iio_read(struct ntc_thermistor_platform_data
*pdata
)
148 struct iio_channel
*channel
= pdata
->chan
;
152 ret
= iio_read_channel_raw(channel
, &val
);
154 pr_err("read channel() error: %d\n", ret
);
159 result
= pdata
->pullup_uv
* (s64
) val
;
165 static const struct of_device_id ntc_match
[] = {
166 { .compatible
= "murata,ncp15wb473",
167 .data
= &ntc_thermistor_id
[0] },
168 { .compatible
= "murata,ncp18wb473",
169 .data
= &ntc_thermistor_id
[1] },
170 { .compatible
= "murata,ncp21wb473",
171 .data
= &ntc_thermistor_id
[2] },
172 { .compatible
= "murata,ncp03wb473",
173 .data
= &ntc_thermistor_id
[3] },
174 { .compatible
= "murata,ncp15wl333",
175 .data
= &ntc_thermistor_id
[4] },
177 /* Usage of vendor name "ntc" is deprecated */
178 { .compatible
= "ntc,ncp15wb473",
179 .data
= &ntc_thermistor_id
[0] },
180 { .compatible
= "ntc,ncp18wb473",
181 .data
= &ntc_thermistor_id
[1] },
182 { .compatible
= "ntc,ncp21wb473",
183 .data
= &ntc_thermistor_id
[2] },
184 { .compatible
= "ntc,ncp03wb473",
185 .data
= &ntc_thermistor_id
[3] },
186 { .compatible
= "ntc,ncp15wl333",
187 .data
= &ntc_thermistor_id
[4] },
190 MODULE_DEVICE_TABLE(of
, ntc_match
);
192 static struct ntc_thermistor_platform_data
*
193 ntc_thermistor_parse_dt(struct platform_device
*pdev
)
195 struct iio_channel
*chan
;
196 enum iio_chan_type type
;
197 struct device_node
*np
= pdev
->dev
.of_node
;
198 struct ntc_thermistor_platform_data
*pdata
;
204 pdata
= devm_kzalloc(&pdev
->dev
, sizeof(*pdata
), GFP_KERNEL
);
206 return ERR_PTR(-ENOMEM
);
208 chan
= iio_channel_get(&pdev
->dev
, NULL
);
210 return ERR_CAST(chan
);
212 ret
= iio_get_channel_type(chan
, &type
);
216 if (type
!= IIO_VOLTAGE
)
217 return ERR_PTR(-EINVAL
);
219 if (of_property_read_u32(np
, "pullup-uv", &pdata
->pullup_uv
))
220 return ERR_PTR(-ENODEV
);
221 if (of_property_read_u32(np
, "pullup-ohm", &pdata
->pullup_ohm
))
222 return ERR_PTR(-ENODEV
);
223 if (of_property_read_u32(np
, "pulldown-ohm", &pdata
->pulldown_ohm
))
224 return ERR_PTR(-ENODEV
);
226 if (of_find_property(np
, "connected-positive", NULL
))
227 pdata
->connect
= NTC_CONNECTED_POSITIVE
;
228 else /* status change should be possible if not always on. */
229 pdata
->connect
= NTC_CONNECTED_GROUND
;
232 pdata
->read_uv
= ntc_adc_iio_read
;
236 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data
*pdata
)
239 iio_channel_release(pdata
->chan
);
242 static struct ntc_thermistor_platform_data
*
243 ntc_thermistor_parse_dt(struct platform_device
*pdev
)
248 #define ntc_match NULL
250 static void ntc_iio_channel_release(struct ntc_thermistor_platform_data
*pdata
)
254 static inline u64
div64_u64_safe(u64 dividend
, u64 divisor
)
256 if (divisor
== 0 && dividend
== 0)
260 return div64_u64(dividend
, divisor
);
263 static int get_ohm_of_thermistor(struct ntc_data
*data
, unsigned int uv
)
265 struct ntc_thermistor_platform_data
*pdata
= data
->pdata
;
267 u64 pmv
= pdata
->pullup_uv
/ 1000;
269 puo
= pdata
->pullup_ohm
;
270 pdo
= pdata
->pulldown_ohm
;
273 if (pdata
->connect
== NTC_CONNECTED_POSITIVE
)
278 return (pdata
->connect
== NTC_CONNECTED_POSITIVE
) ?
281 if (pdata
->connect
== NTC_CONNECTED_POSITIVE
&& puo
== 0)
282 n
= div64_u64_safe(pdo
* (pmv
- mv
), mv
);
283 else if (pdata
->connect
== NTC_CONNECTED_GROUND
&& pdo
== 0)
284 n
= div64_u64_safe(puo
* mv
, pmv
- mv
);
285 else if (pdata
->connect
== NTC_CONNECTED_POSITIVE
)
286 n
= div64_u64_safe(pdo
* puo
* (pmv
- mv
),
287 puo
* mv
- pdo
* (pmv
- mv
));
289 n
= div64_u64_safe(pdo
* puo
* mv
, pdo
* (pmv
- mv
) - puo
* mv
);
296 static void lookup_comp(struct ntc_data
*data
, unsigned int ohm
,
297 int *i_low
, int *i_high
)
302 * Handle special cases: Resistance is higher than or equal to
303 * resistance in first table entry, or resistance is lower or equal
304 * to resistance in last table entry.
305 * In these cases, return i_low == i_high, either pointing to the
306 * beginning or to the end of the table depending on the condition.
308 if (ohm
>= data
->comp
[0].ohm
) {
313 if (ohm
<= data
->comp
[data
->n_comp
- 1].ohm
) {
314 *i_low
= data
->n_comp
- 1;
315 *i_high
= data
->n_comp
- 1;
319 /* Do a binary search on compensation table */
322 while (start
< end
) {
323 mid
= start
+ (end
- start
) / 2;
326 * data->comp[start].ohm > ohm >= data->comp[end].ohm
328 * We could check for "ohm == data->comp[mid].ohm" here, but
329 * that is a quite unlikely condition, and we would have to
330 * check again after updating start. Check it at the end instead
333 if (ohm
>= data
->comp
[mid
].ohm
) {
338 * ohm >= data->comp[start].ohm might be true here,
339 * since we set start to mid + 1. In that case, we are
340 * done. We could keep going, but the condition is quite
341 * likely to occur, so it is worth checking for it.
343 if (ohm
>= data
->comp
[start
].ohm
)
348 * data->comp[start].ohm >= ohm >= data->comp[end].ohm
353 * ohm >= data->comp[end].ohm
356 if (ohm
== data
->comp
[end
].ohm
)
362 static int get_temp_mc(struct ntc_data
*data
, unsigned int ohm
)
367 lookup_comp(data
, ohm
, &low
, &high
);
369 /* Unable to use linear approximation */
370 temp
= data
->comp
[low
].temp_c
* 1000;
372 temp
= data
->comp
[low
].temp_c
* 1000 +
373 ((data
->comp
[high
].temp_c
- data
->comp
[low
].temp_c
) *
374 1000 * ((int)ohm
- (int)data
->comp
[low
].ohm
)) /
375 ((int)data
->comp
[high
].ohm
- (int)data
->comp
[low
].ohm
);
380 static int ntc_thermistor_get_ohm(struct ntc_data
*data
)
384 if (data
->pdata
->read_ohm
)
385 return data
->pdata
->read_ohm();
387 if (data
->pdata
->read_uv
) {
388 read_uv
= data
->pdata
->read_uv(data
->pdata
);
391 return get_ohm_of_thermistor(data
, read_uv
);
396 static ssize_t
ntc_show_name(struct device
*dev
,
397 struct device_attribute
*attr
, char *buf
)
399 struct ntc_data
*data
= dev_get_drvdata(dev
);
401 return sprintf(buf
, "%s\n", data
->name
);
404 static ssize_t
ntc_show_type(struct device
*dev
,
405 struct device_attribute
*attr
, char *buf
)
407 return sprintf(buf
, "4\n");
410 static ssize_t
ntc_show_temp(struct device
*dev
,
411 struct device_attribute
*attr
, char *buf
)
413 struct ntc_data
*data
= dev_get_drvdata(dev
);
416 ohm
= ntc_thermistor_get_ohm(data
);
420 return sprintf(buf
, "%d\n", get_temp_mc(data
, ohm
));
423 static SENSOR_DEVICE_ATTR(temp1_type
, S_IRUGO
, ntc_show_type
, NULL
, 0);
424 static SENSOR_DEVICE_ATTR(temp1_input
, S_IRUGO
, ntc_show_temp
, NULL
, 0);
425 static DEVICE_ATTR(name
, S_IRUGO
, ntc_show_name
, NULL
);
427 static struct attribute
*ntc_attributes
[] = {
429 &sensor_dev_attr_temp1_type
.dev_attr
.attr
,
430 &sensor_dev_attr_temp1_input
.dev_attr
.attr
,
434 static const struct attribute_group ntc_attr_group
= {
435 .attrs
= ntc_attributes
,
438 static int ntc_thermistor_probe(struct platform_device
*pdev
)
440 const struct of_device_id
*of_id
=
441 of_match_device(of_match_ptr(ntc_match
), &pdev
->dev
);
442 const struct platform_device_id
*pdev_id
;
443 struct ntc_thermistor_platform_data
*pdata
;
444 struct ntc_data
*data
;
447 pdata
= ntc_thermistor_parse_dt(pdev
);
449 return PTR_ERR(pdata
);
450 else if (pdata
== NULL
)
451 pdata
= dev_get_platdata(&pdev
->dev
);
454 dev_err(&pdev
->dev
, "No platform init data supplied.\n");
458 /* Either one of the two is required. */
459 if (!pdata
->read_uv
&& !pdata
->read_ohm
) {
461 "Both read_uv and read_ohm missing. Need either one of the two.\n");
465 if (pdata
->read_uv
&& pdata
->read_ohm
) {
467 "Only one of read_uv and read_ohm is needed; ignoring read_uv.\n");
468 pdata
->read_uv
= NULL
;
471 if (pdata
->read_uv
&& (pdata
->pullup_uv
== 0 ||
472 (pdata
->pullup_ohm
== 0 && pdata
->connect
==
473 NTC_CONNECTED_GROUND
) ||
474 (pdata
->pulldown_ohm
== 0 && pdata
->connect
==
475 NTC_CONNECTED_POSITIVE
) ||
476 (pdata
->connect
!= NTC_CONNECTED_POSITIVE
&&
477 pdata
->connect
!= NTC_CONNECTED_GROUND
))) {
479 "Required data to use read_uv not supplied.\n");
483 data
= devm_kzalloc(&pdev
->dev
, sizeof(struct ntc_data
), GFP_KERNEL
);
487 pdev_id
= of_id
? of_id
->data
: platform_get_device_id(pdev
);
489 data
->dev
= &pdev
->dev
;
491 strlcpy(data
->name
, pdev_id
->name
, sizeof(data
->name
));
493 switch (pdev_id
->driver_data
) {
494 case TYPE_NCPXXWB473
:
495 data
->comp
= ncpXXwb473
;
496 data
->n_comp
= ARRAY_SIZE(ncpXXwb473
);
498 case TYPE_NCPXXWL333
:
499 data
->comp
= ncpXXwl333
;
500 data
->n_comp
= ARRAY_SIZE(ncpXXwl333
);
503 dev_err(&pdev
->dev
, "Unknown device type: %lu(%s)\n",
504 pdev_id
->driver_data
, pdev_id
->name
);
508 platform_set_drvdata(pdev
, data
);
510 ret
= sysfs_create_group(&data
->dev
->kobj
, &ntc_attr_group
);
512 dev_err(data
->dev
, "unable to create sysfs files\n");
516 data
->hwmon_dev
= hwmon_device_register(data
->dev
);
517 if (IS_ERR(data
->hwmon_dev
)) {
518 dev_err(data
->dev
, "unable to register as hwmon device.\n");
519 ret
= PTR_ERR(data
->hwmon_dev
);
520 goto err_after_sysfs
;
523 dev_info(&pdev
->dev
, "Thermistor type: %s successfully probed.\n",
528 sysfs_remove_group(&data
->dev
->kobj
, &ntc_attr_group
);
529 ntc_iio_channel_release(pdata
);
533 static int ntc_thermistor_remove(struct platform_device
*pdev
)
535 struct ntc_data
*data
= platform_get_drvdata(pdev
);
536 struct ntc_thermistor_platform_data
*pdata
= data
->pdata
;
538 hwmon_device_unregister(data
->hwmon_dev
);
539 sysfs_remove_group(&data
->dev
->kobj
, &ntc_attr_group
);
540 ntc_iio_channel_release(pdata
);
545 static struct platform_driver ntc_thermistor_driver
= {
547 .name
= "ntc-thermistor",
548 .owner
= THIS_MODULE
,
549 .of_match_table
= of_match_ptr(ntc_match
),
551 .probe
= ntc_thermistor_probe
,
552 .remove
= ntc_thermistor_remove
,
553 .id_table
= ntc_thermistor_id
,
556 module_platform_driver(ntc_thermistor_driver
);
558 MODULE_DESCRIPTION("NTC Thermistor Driver from Murata");
559 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
560 MODULE_LICENSE("GPL");
561 MODULE_ALIAS("platform:ntc-thermistor");