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1/*
2 * ntc_thermistor.c - NTC Thermistors
3 *
4 * Copyright (C) 2010 Samsung Electronics
5 * MyungJoo Ham <myungjoo.ham@samsung.com>
6 *
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.
11 *
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.
16 *
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
20 *
21 */
22
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>
29
30#include <linux/platform_data/ntc_thermistor.h>
31
32#include <linux/hwmon.h>
33#include <linux/hwmon-sysfs.h>
34
35struct ntc_compensation {
36 int temp_C;
37 unsigned int ohm;
38};
39
40/*
41 * A compensation table should be sorted by the values of .ohm
42 * in descending order.
43 * The following compensation tables are from the specification of Murata NTC
44 * Thermistors Datasheet
45 */
46const struct ntc_compensation ncpXXwb473[] = {
47 { .temp_C = -40, .ohm = 1747920 },
48 { .temp_C = -35, .ohm = 1245428 },
49 { .temp_C = -30, .ohm = 898485 },
50 { .temp_C = -25, .ohm = 655802 },
51 { .temp_C = -20, .ohm = 483954 },
52 { .temp_C = -15, .ohm = 360850 },
53 { .temp_C = -10, .ohm = 271697 },
54 { .temp_C = -5, .ohm = 206463 },
55 { .temp_C = 0, .ohm = 158214 },
56 { .temp_C = 5, .ohm = 122259 },
57 { .temp_C = 10, .ohm = 95227 },
58 { .temp_C = 15, .ohm = 74730 },
59 { .temp_C = 20, .ohm = 59065 },
60 { .temp_C = 25, .ohm = 47000 },
61 { .temp_C = 30, .ohm = 37643 },
62 { .temp_C = 35, .ohm = 30334 },
63 { .temp_C = 40, .ohm = 24591 },
64 { .temp_C = 45, .ohm = 20048 },
65 { .temp_C = 50, .ohm = 16433 },
66 { .temp_C = 55, .ohm = 13539 },
67 { .temp_C = 60, .ohm = 11209 },
68 { .temp_C = 65, .ohm = 9328 },
69 { .temp_C = 70, .ohm = 7798 },
70 { .temp_C = 75, .ohm = 6544 },
71 { .temp_C = 80, .ohm = 5518 },
72 { .temp_C = 85, .ohm = 4674 },
73 { .temp_C = 90, .ohm = 3972 },
74 { .temp_C = 95, .ohm = 3388 },
75 { .temp_C = 100, .ohm = 2902 },
76 { .temp_C = 105, .ohm = 2494 },
77 { .temp_C = 110, .ohm = 2150 },
78 { .temp_C = 115, .ohm = 1860 },
79 { .temp_C = 120, .ohm = 1615 },
80 { .temp_C = 125, .ohm = 1406 },
81};
82const struct ntc_compensation ncpXXwl333[] = {
83 { .temp_C = -40, .ohm = 1610154 },
84 { .temp_C = -35, .ohm = 1130850 },
85 { .temp_C = -30, .ohm = 802609 },
86 { .temp_C = -25, .ohm = 575385 },
87 { .temp_C = -20, .ohm = 416464 },
88 { .temp_C = -15, .ohm = 304219 },
89 { .temp_C = -10, .ohm = 224193 },
90 { .temp_C = -5, .ohm = 166623 },
91 { .temp_C = 0, .ohm = 124850 },
92 { .temp_C = 5, .ohm = 94287 },
93 { .temp_C = 10, .ohm = 71747 },
94 { .temp_C = 15, .ohm = 54996 },
95 { .temp_C = 20, .ohm = 42455 },
96 { .temp_C = 25, .ohm = 33000 },
97 { .temp_C = 30, .ohm = 25822 },
98 { .temp_C = 35, .ohm = 20335 },
99 { .temp_C = 40, .ohm = 16115 },
100 { .temp_C = 45, .ohm = 12849 },
101 { .temp_C = 50, .ohm = 10306 },
102 { .temp_C = 55, .ohm = 8314 },
103 { .temp_C = 60, .ohm = 6746 },
104 { .temp_C = 65, .ohm = 5503 },
105 { .temp_C = 70, .ohm = 4513 },
106 { .temp_C = 75, .ohm = 3721 },
107 { .temp_C = 80, .ohm = 3084 },
108 { .temp_C = 85, .ohm = 2569 },
109 { .temp_C = 90, .ohm = 2151 },
110 { .temp_C = 95, .ohm = 1809 },
111 { .temp_C = 100, .ohm = 1529 },
112 { .temp_C = 105, .ohm = 1299 },
113 { .temp_C = 110, .ohm = 1108 },
114 { .temp_C = 115, .ohm = 949 },
115 { .temp_C = 120, .ohm = 817 },
116 { .temp_C = 125, .ohm = 707 },
117};
118
119struct ntc_data {
120 struct device *hwmon_dev;
121 struct ntc_thermistor_platform_data *pdata;
122 const struct ntc_compensation *comp;
123 struct device *dev;
124 int n_comp;
125 char name[PLATFORM_NAME_SIZE];
126};
127
128static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
129{
130 if (divisor == 0 && dividend == 0)
131 return 0;
132 if (divisor == 0)
133 return UINT_MAX;
134 return div64_u64(dividend, divisor);
135}
136
137static unsigned int get_ohm_of_thermistor(struct ntc_data *data,
138 unsigned int uV)
139{
140 struct ntc_thermistor_platform_data *pdata = data->pdata;
141 u64 mV = uV / 1000;
142 u64 pmV = pdata->pullup_uV / 1000;
143 u64 N, puO, pdO;
144 puO = pdata->pullup_ohm;
145 pdO = pdata->pulldown_ohm;
146
147 if (mV == 0) {
148 if (pdata->connect == NTC_CONNECTED_POSITIVE)
149 return UINT_MAX;
150 return 0;
151 }
152 if (mV >= pmV)
153 return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
154 0 : UINT_MAX;
155
156 if (pdata->connect == NTC_CONNECTED_POSITIVE && puO == 0)
157 N = div64_u64_safe(pdO * (pmV - mV), mV);
158 else if (pdata->connect == NTC_CONNECTED_GROUND && pdO == 0)
159 N = div64_u64_safe(puO * mV, pmV - mV);
160 else if (pdata->connect == NTC_CONNECTED_POSITIVE)
161 N = div64_u64_safe(pdO * puO * (pmV - mV),
162 puO * mV - pdO * (pmV - mV));
163 else
164 N = div64_u64_safe(pdO * puO * mV, pdO * (pmV - mV) - puO * mV);
165
166 return (unsigned int) N;
167}
168
169static int lookup_comp(struct ntc_data *data,
170 unsigned int ohm, int *i_low, int *i_high)
171{
172 int start, end, mid = -1;
173
174 /* Do a binary search on compensation table */
175 start = 0;
176 end = data->n_comp;
177
178 while (end > start) {
179 mid = start + (end - start) / 2;
180 if (data->comp[mid].ohm < ohm)
181 end = mid;
182 else if (data->comp[mid].ohm > ohm)
183 start = mid + 1;
184 else
185 break;
186 }
187
188 if (mid == 0) {
189 if (data->comp[mid].ohm > ohm) {
190 *i_high = mid;
191 *i_low = mid + 1;
192 return 0;
193 } else {
194 *i_low = mid;
195 *i_high = -1;
196 return -EINVAL;
197 }
198 }
199 if (mid == (data->n_comp - 1)) {
200 if (data->comp[mid].ohm <= ohm) {
201 *i_low = mid;
202 *i_high = mid - 1;
203 return 0;
204 } else {
205 *i_low = -1;
206 *i_high = mid;
207 return -EINVAL;
208 }
209 }
210
211 if (data->comp[mid].ohm <= ohm) {
212 *i_low = mid;
213 *i_high = mid - 1;
214 } else {
215 *i_low = mid + 1;
216 *i_high = mid;
217 }
218
219 return 0;
220}
221
222static int get_temp_mC(struct ntc_data *data, unsigned int ohm, int *temp)
223{
224 int low, high;
225 int ret;
226
227 ret = lookup_comp(data, ohm, &low, &high);
228 if (ret) {
229 /* Unable to use linear approximation */
230 if (low != -1)
231 *temp = data->comp[low].temp_C * 1000;
232 else if (high != -1)
233 *temp = data->comp[high].temp_C * 1000;
234 else
235 return ret;
236 } else {
237 *temp = data->comp[low].temp_C * 1000 +
238 ((data->comp[high].temp_C - data->comp[low].temp_C) *
239 1000 * ((int)ohm - (int)data->comp[low].ohm)) /
240 ((int)data->comp[high].ohm - (int)data->comp[low].ohm);
241 }
242
243 return 0;
244}
245
246static int ntc_thermistor_read(struct ntc_data *data, int *temp)
247{
248 int ret;
249 int read_ohm, read_uV;
250 unsigned int ohm = 0;
251
252 if (data->pdata->read_ohm) {
253 read_ohm = data->pdata->read_ohm();
254 if (read_ohm < 0)
255 return read_ohm;
256 ohm = (unsigned int)read_ohm;
257 }
258
259 if (data->pdata->read_uV) {
260 read_uV = data->pdata->read_uV();
261 if (read_uV < 0)
262 return read_uV;
263 ohm = get_ohm_of_thermistor(data, (unsigned int)read_uV);
264 }
265
266 ret = get_temp_mC(data, ohm, temp);
267 if (ret) {
268 dev_dbg(data->dev, "Sensor reading function not available.\n");
269 return ret;
270 }
271
272 return 0;
273}
274
275static ssize_t ntc_show_name(struct device *dev,
276 struct device_attribute *attr, char *buf)
277{
278 struct ntc_data *data = dev_get_drvdata(dev);
279
280 return sprintf(buf, "%s\n", data->name);
281}
282
283static ssize_t ntc_show_type(struct device *dev,
284 struct device_attribute *attr, char *buf)
285{
286 return sprintf(buf, "4\n");
287}
288
289static ssize_t ntc_show_temp(struct device *dev,
290 struct device_attribute *attr, char *buf)
291{
292 struct ntc_data *data = dev_get_drvdata(dev);
293 int temp, ret;
294
295 ret = ntc_thermistor_read(data, &temp);
296 if (ret)
297 return ret;
298 return sprintf(buf, "%d\n", temp);
299}
300
301static SENSOR_DEVICE_ATTR(temp1_type, S_IRUGO, ntc_show_type, NULL, 0);
302static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ntc_show_temp, NULL, 0);
303static DEVICE_ATTR(name, S_IRUGO, ntc_show_name, NULL);
304
305static struct attribute *ntc_attributes[] = {
306 &dev_attr_name.attr,
307 &sensor_dev_attr_temp1_type.dev_attr.attr,
308 &sensor_dev_attr_temp1_input.dev_attr.attr,
309 NULL,
310};
311
312static const struct attribute_group ntc_attr_group = {
313 .attrs = ntc_attributes,
314};
315
316static int __devinit ntc_thermistor_probe(struct platform_device *pdev)
317{
318 struct ntc_data *data;
319 struct ntc_thermistor_platform_data *pdata = pdev->dev.platform_data;
320 int ret = 0;
321
322 if (!pdata) {
323 dev_err(&pdev->dev, "No platform init data supplied.\n");
324 return -ENODEV;
325 }
326
327 /* Either one of the two is required. */
328 if (!pdata->read_uV && !pdata->read_ohm) {
329 dev_err(&pdev->dev, "Both read_uV and read_ohm missing."
330 "Need either one of the two.\n");
331 return -EINVAL;
332 }
333
334 if (pdata->read_uV && pdata->read_ohm) {
335 dev_warn(&pdev->dev, "Only one of read_uV and read_ohm "
336 "is needed; ignoring read_uV.\n");
337 pdata->read_uV = NULL;
338 }
339
340 if (pdata->read_uV && (pdata->pullup_uV == 0 ||
341 (pdata->pullup_ohm == 0 && pdata->connect ==
342 NTC_CONNECTED_GROUND) ||
343 (pdata->pulldown_ohm == 0 && pdata->connect ==
344 NTC_CONNECTED_POSITIVE) ||
345 (pdata->connect != NTC_CONNECTED_POSITIVE &&
346 pdata->connect != NTC_CONNECTED_GROUND))) {
347 dev_err(&pdev->dev, "Required data to use read_uV not "
348 "supplied.\n");
349 return -EINVAL;
350 }
351
352 data = kzalloc(sizeof(struct ntc_data), GFP_KERNEL);
353 if (!data)
354 return -ENOMEM;
355
356 data->dev = &pdev->dev;
357 data->pdata = pdata;
358 strncpy(data->name, pdev->id_entry->name, PLATFORM_NAME_SIZE);
359
360 switch (pdev->id_entry->driver_data) {
361 case TYPE_NCPXXWB473:
362 data->comp = ncpXXwb473;
363 data->n_comp = ARRAY_SIZE(ncpXXwb473);
364 break;
365 case TYPE_NCPXXWL333:
366 data->comp = ncpXXwl333;
367 data->n_comp = ARRAY_SIZE(ncpXXwl333);
368 break;
369 default:
370 dev_err(&pdev->dev, "Unknown device type: %lu(%s)\n",
371 pdev->id_entry->driver_data,
372 pdev->id_entry->name);
373 ret = -EINVAL;
374 goto err;
375 }
376
377 platform_set_drvdata(pdev, data);
378
379 ret = sysfs_create_group(&data->dev->kobj, &ntc_attr_group);
380 if (ret) {
381 dev_err(data->dev, "unable to create sysfs files\n");
382 goto err;
383 }
384
385 data->hwmon_dev = hwmon_device_register(data->dev);
386 if (IS_ERR_OR_NULL(data->hwmon_dev)) {
387 dev_err(data->dev, "unable to register as hwmon device.\n");
388 ret = -EINVAL;
389 goto err_after_sysfs;
390 }
391
392 dev_info(&pdev->dev, "Thermistor %s:%d (type: %s/%lu) successfully probed.\n",
393 pdev->name, pdev->id, pdev->id_entry->name,
394 pdev->id_entry->driver_data);
395 return 0;
396err_after_sysfs:
397 sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
398err:
399 kfree(data);
400 return ret;
401}
402
403static int __devexit ntc_thermistor_remove(struct platform_device *pdev)
404{
405 struct ntc_data *data = platform_get_drvdata(pdev);
406
407 hwmon_device_unregister(data->hwmon_dev);
408 sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
409 platform_set_drvdata(pdev, NULL);
410
411 kfree(data);
412
413 return 0;
414}
415
416static const struct platform_device_id ntc_thermistor_id[] = {
417 { "ncp15wb473", TYPE_NCPXXWB473 },
418 { "ncp18wb473", TYPE_NCPXXWB473 },
419 { "ncp21wb473", TYPE_NCPXXWB473 },
420 { "ncp03wb473", TYPE_NCPXXWB473 },
421 { "ncp15wl333", TYPE_NCPXXWL333 },
422 { },
423};
424
425static struct platform_driver ntc_thermistor_driver = {
426 .driver = {
427 .name = "ntc-thermistor",
428 .owner = THIS_MODULE,
429 },
430 .probe = ntc_thermistor_probe,
431 .remove = __devexit_p(ntc_thermistor_remove),
432 .id_table = ntc_thermistor_id,
433};
434
435static int __init ntc_thermistor_init(void)
436{
437 return platform_driver_register(&ntc_thermistor_driver);
438}
439
440module_init(ntc_thermistor_init);
441
442static void __exit ntc_thermistor_cleanup(void)
443{
444 platform_driver_unregister(&ntc_thermistor_driver);
445}
446
447module_exit(ntc_thermistor_cleanup);
448
449MODULE_DESCRIPTION("NTC Thermistor Driver");
450MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
451MODULE_LICENSE("GPL");
452MODULE_ALIAS("platform:ntc-thermistor");
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * ntc_thermistor.c - NTC Thermistors
4 *
5 * Copyright (C) 2010 Samsung Electronics
6 * MyungJoo Ham <myungjoo.ham@samsung.com>
7 */
8
9#include <linux/slab.h>
10#include <linux/module.h>
11#include <linux/math64.h>
12#include <linux/platform_device.h>
13#include <linux/err.h>
14#include <linux/of.h>
15#include <linux/of_device.h>
16
17#include <linux/platform_data/ntc_thermistor.h>
18
19#include <linux/iio/consumer.h>
20
21#include <linux/hwmon.h>
22
23struct ntc_compensation {
24 int temp_c;
25 unsigned int ohm;
26};
27
28/*
29 * Used as index in a zero-terminated array, holes not allowed so
30 * that NTC_LAST is the first empty array entry.
31 */
32enum {
33 NTC_B57330V2103,
34 NTC_B57891S0103,
35 NTC_NCP03WB473,
36 NTC_NCP03WF104,
37 NTC_NCP15WB473,
38 NTC_NCP15WL333,
39 NTC_NCP15XH103,
40 NTC_NCP18WB473,
41 NTC_NCP21WB473,
42 NTC_LAST,
43};
44
45static const struct platform_device_id ntc_thermistor_id[] = {
46 [NTC_B57330V2103] = { "b57330v2103", TYPE_B57330V2103 },
47 [NTC_B57891S0103] = { "b57891s0103", TYPE_B57891S0103 },
48 [NTC_NCP03WB473] = { "ncp03wb473", TYPE_NCPXXWB473 },
49 [NTC_NCP03WF104] = { "ncp03wf104", TYPE_NCPXXWF104 },
50 [NTC_NCP15WB473] = { "ncp15wb473", TYPE_NCPXXWB473 },
51 [NTC_NCP15WL333] = { "ncp15wl333", TYPE_NCPXXWL333 },
52 [NTC_NCP15XH103] = { "ncp15xh103", TYPE_NCPXXXH103 },
53 [NTC_NCP18WB473] = { "ncp18wb473", TYPE_NCPXXWB473 },
54 [NTC_NCP21WB473] = { "ncp21wb473", TYPE_NCPXXWB473 },
55 [NTC_LAST] = { },
56};
57
58/*
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
63 */
64static 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 },
99};
100static 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 },
135};
136
137static const struct ntc_compensation ncpXXwf104[] = {
138 { .temp_c = -40, .ohm = 4397119 },
139 { .temp_c = -35, .ohm = 3088599 },
140 { .temp_c = -30, .ohm = 2197225 },
141 { .temp_c = -25, .ohm = 1581881 },
142 { .temp_c = -20, .ohm = 1151037 },
143 { .temp_c = -15, .ohm = 846579 },
144 { .temp_c = -10, .ohm = 628988 },
145 { .temp_c = -5, .ohm = 471632 },
146 { .temp_c = 0, .ohm = 357012 },
147 { .temp_c = 5, .ohm = 272500 },
148 { .temp_c = 10, .ohm = 209710 },
149 { .temp_c = 15, .ohm = 162651 },
150 { .temp_c = 20, .ohm = 127080 },
151 { .temp_c = 25, .ohm = 100000 },
152 { .temp_c = 30, .ohm = 79222 },
153 { .temp_c = 35, .ohm = 63167 },
154 { .temp_c = 40, .ohm = 50677 },
155 { .temp_c = 45, .ohm = 40904 },
156 { .temp_c = 50, .ohm = 33195 },
157 { .temp_c = 55, .ohm = 27091 },
158 { .temp_c = 60, .ohm = 22224 },
159 { .temp_c = 65, .ohm = 18323 },
160 { .temp_c = 70, .ohm = 15184 },
161 { .temp_c = 75, .ohm = 12635 },
162 { .temp_c = 80, .ohm = 10566 },
163 { .temp_c = 85, .ohm = 8873 },
164 { .temp_c = 90, .ohm = 7481 },
165 { .temp_c = 95, .ohm = 6337 },
166 { .temp_c = 100, .ohm = 5384 },
167 { .temp_c = 105, .ohm = 4594 },
168 { .temp_c = 110, .ohm = 3934 },
169 { .temp_c = 115, .ohm = 3380 },
170 { .temp_c = 120, .ohm = 2916 },
171 { .temp_c = 125, .ohm = 2522 },
172};
173
174static const struct ntc_compensation ncpXXxh103[] = {
175 { .temp_c = -40, .ohm = 247565 },
176 { .temp_c = -35, .ohm = 181742 },
177 { .temp_c = -30, .ohm = 135128 },
178 { .temp_c = -25, .ohm = 101678 },
179 { .temp_c = -20, .ohm = 77373 },
180 { .temp_c = -15, .ohm = 59504 },
181 { .temp_c = -10, .ohm = 46222 },
182 { .temp_c = -5, .ohm = 36244 },
183 { .temp_c = 0, .ohm = 28674 },
184 { .temp_c = 5, .ohm = 22878 },
185 { .temp_c = 10, .ohm = 18399 },
186 { .temp_c = 15, .ohm = 14910 },
187 { .temp_c = 20, .ohm = 12169 },
188 { .temp_c = 25, .ohm = 10000 },
189 { .temp_c = 30, .ohm = 8271 },
190 { .temp_c = 35, .ohm = 6883 },
191 { .temp_c = 40, .ohm = 5762 },
192 { .temp_c = 45, .ohm = 4851 },
193 { .temp_c = 50, .ohm = 4105 },
194 { .temp_c = 55, .ohm = 3492 },
195 { .temp_c = 60, .ohm = 2985 },
196 { .temp_c = 65, .ohm = 2563 },
197 { .temp_c = 70, .ohm = 2211 },
198 { .temp_c = 75, .ohm = 1915 },
199 { .temp_c = 80, .ohm = 1666 },
200 { .temp_c = 85, .ohm = 1454 },
201 { .temp_c = 90, .ohm = 1275 },
202 { .temp_c = 95, .ohm = 1121 },
203 { .temp_c = 100, .ohm = 990 },
204 { .temp_c = 105, .ohm = 876 },
205 { .temp_c = 110, .ohm = 779 },
206 { .temp_c = 115, .ohm = 694 },
207 { .temp_c = 120, .ohm = 620 },
208 { .temp_c = 125, .ohm = 556 },
209};
210
211/*
212 * The following compensation tables are from the specifications in EPCOS NTC
213 * Thermistors Datasheets
214 */
215static const struct ntc_compensation b57330v2103[] = {
216 { .temp_c = -40, .ohm = 190030 },
217 { .temp_c = -35, .ohm = 145360 },
218 { .temp_c = -30, .ohm = 112060 },
219 { .temp_c = -25, .ohm = 87041 },
220 { .temp_c = -20, .ohm = 68104 },
221 { .temp_c = -15, .ohm = 53665 },
222 { .temp_c = -10, .ohm = 42576 },
223 { .temp_c = -5, .ohm = 34001 },
224 { .temp_c = 0, .ohm = 27326 },
225 { .temp_c = 5, .ohm = 22096 },
226 { .temp_c = 10, .ohm = 17973 },
227 { .temp_c = 15, .ohm = 14703 },
228 { .temp_c = 20, .ohm = 12090 },
229 { .temp_c = 25, .ohm = 10000 },
230 { .temp_c = 30, .ohm = 8311 },
231 { .temp_c = 35, .ohm = 6941 },
232 { .temp_c = 40, .ohm = 5825 },
233 { .temp_c = 45, .ohm = 4911 },
234 { .temp_c = 50, .ohm = 4158 },
235 { .temp_c = 55, .ohm = 3536 },
236 { .temp_c = 60, .ohm = 3019 },
237 { .temp_c = 65, .ohm = 2588 },
238 { .temp_c = 70, .ohm = 2227 },
239 { .temp_c = 75, .ohm = 1924 },
240 { .temp_c = 80, .ohm = 1668 },
241 { .temp_c = 85, .ohm = 1451 },
242 { .temp_c = 90, .ohm = 1266 },
243 { .temp_c = 95, .ohm = 1108 },
244 { .temp_c = 100, .ohm = 973 },
245 { .temp_c = 105, .ohm = 857 },
246 { .temp_c = 110, .ohm = 757 },
247 { .temp_c = 115, .ohm = 671 },
248 { .temp_c = 120, .ohm = 596 },
249 { .temp_c = 125, .ohm = 531 },
250};
251
252static const struct ntc_compensation b57891s0103[] = {
253 { .temp_c = -55.0, .ohm = 878900 },
254 { .temp_c = -50.0, .ohm = 617590 },
255 { .temp_c = -45.0, .ohm = 439340 },
256 { .temp_c = -40.0, .ohm = 316180 },
257 { .temp_c = -35.0, .ohm = 230060 },
258 { .temp_c = -30.0, .ohm = 169150 },
259 { .temp_c = -25.0, .ohm = 125550 },
260 { .temp_c = -20.0, .ohm = 94143 },
261 { .temp_c = -15.0, .ohm = 71172 },
262 { .temp_c = -10.0, .ohm = 54308 },
263 { .temp_c = -5.0, .ohm = 41505 },
264 { .temp_c = 0.0, .ohm = 32014 },
265 { .temp_c = 5.0, .ohm = 25011 },
266 { .temp_c = 10.0, .ohm = 19691 },
267 { .temp_c = 15.0, .ohm = 15618 },
268 { .temp_c = 20.0, .ohm = 12474 },
269 { .temp_c = 25.0, .ohm = 10000 },
270 { .temp_c = 30.0, .ohm = 8080 },
271 { .temp_c = 35.0, .ohm = 6569 },
272 { .temp_c = 40.0, .ohm = 5372 },
273 { .temp_c = 45.0, .ohm = 4424 },
274 { .temp_c = 50.0, .ohm = 3661 },
275 { .temp_c = 55.0, .ohm = 3039 },
276 { .temp_c = 60.0, .ohm = 2536 },
277 { .temp_c = 65.0, .ohm = 2128 },
278 { .temp_c = 70.0, .ohm = 1794 },
279 { .temp_c = 75.0, .ohm = 1518 },
280 { .temp_c = 80.0, .ohm = 1290 },
281 { .temp_c = 85.0, .ohm = 1100 },
282 { .temp_c = 90.0, .ohm = 942 },
283 { .temp_c = 95.0, .ohm = 809 },
284 { .temp_c = 100.0, .ohm = 697 },
285 { .temp_c = 105.0, .ohm = 604 },
286 { .temp_c = 110.0, .ohm = 525 },
287 { .temp_c = 115.0, .ohm = 457 },
288 { .temp_c = 120.0, .ohm = 400 },
289 { .temp_c = 125.0, .ohm = 351 },
290 { .temp_c = 130.0, .ohm = 308 },
291 { .temp_c = 135.0, .ohm = 272 },
292 { .temp_c = 140.0, .ohm = 240 },
293 { .temp_c = 145.0, .ohm = 213 },
294 { .temp_c = 150.0, .ohm = 189 },
295 { .temp_c = 155.0, .ohm = 168 },
296};
297
298struct ntc_type {
299 const struct ntc_compensation *comp;
300 int n_comp;
301};
302
303#define NTC_TYPE(ntc, compensation) \
304[(ntc)] = { .comp = (compensation), .n_comp = ARRAY_SIZE(compensation) }
305
306static const struct ntc_type ntc_type[] = {
307 NTC_TYPE(TYPE_B57330V2103, b57330v2103),
308 NTC_TYPE(TYPE_B57891S0103, b57891s0103),
309 NTC_TYPE(TYPE_NCPXXWB473, ncpXXwb473),
310 NTC_TYPE(TYPE_NCPXXWF104, ncpXXwf104),
311 NTC_TYPE(TYPE_NCPXXWL333, ncpXXwl333),
312 NTC_TYPE(TYPE_NCPXXXH103, ncpXXxh103),
313};
314
315struct ntc_data {
316 struct ntc_thermistor_platform_data *pdata;
317 const struct ntc_compensation *comp;
318 int n_comp;
319};
320
321#if defined(CONFIG_OF) && IS_ENABLED(CONFIG_IIO)
322static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
323{
324 struct iio_channel *channel = pdata->chan;
325 int uv, ret;
326
327 ret = iio_read_channel_processed_scale(channel, &uv, 1000);
328 if (ret < 0) {
329 int raw;
330
331 /*
332 * This fallback uses a raw read and then
333 * assumes the ADC is 12 bits, scaling with
334 * a factor 1000 to get to microvolts.
335 */
336 ret = iio_read_channel_raw(channel, &raw);
337 if (ret < 0) {
338 pr_err("read channel() error: %d\n", ret);
339 return ret;
340 }
341 ret = iio_convert_raw_to_processed(channel, raw, &uv, 1000);
342 if (ret < 0) {
343 /* Assume 12 bit ADC with vref at pullup_uv */
344 uv = (pdata->pullup_uv * (s64)raw) >> 12;
345 }
346 }
347
348 return uv;
349}
350
351static const struct of_device_id ntc_match[] = {
352 { .compatible = "epcos,b57330v2103",
353 .data = &ntc_thermistor_id[NTC_B57330V2103]},
354 { .compatible = "epcos,b57891s0103",
355 .data = &ntc_thermistor_id[NTC_B57891S0103] },
356 { .compatible = "murata,ncp03wb473",
357 .data = &ntc_thermistor_id[NTC_NCP03WB473] },
358 { .compatible = "murata,ncp03wf104",
359 .data = &ntc_thermistor_id[NTC_NCP03WF104] },
360 { .compatible = "murata,ncp15wb473",
361 .data = &ntc_thermistor_id[NTC_NCP15WB473] },
362 { .compatible = "murata,ncp15wl333",
363 .data = &ntc_thermistor_id[NTC_NCP15WL333] },
364 { .compatible = "murata,ncp15xh103",
365 .data = &ntc_thermistor_id[NTC_NCP15XH103] },
366 { .compatible = "murata,ncp18wb473",
367 .data = &ntc_thermistor_id[NTC_NCP18WB473] },
368 { .compatible = "murata,ncp21wb473",
369 .data = &ntc_thermistor_id[NTC_NCP21WB473] },
370
371 /* Usage of vendor name "ntc" is deprecated */
372 { .compatible = "ntc,ncp03wb473",
373 .data = &ntc_thermistor_id[NTC_NCP03WB473] },
374 { .compatible = "ntc,ncp15wb473",
375 .data = &ntc_thermistor_id[NTC_NCP15WB473] },
376 { .compatible = "ntc,ncp15wl333",
377 .data = &ntc_thermistor_id[NTC_NCP15WL333] },
378 { .compatible = "ntc,ncp18wb473",
379 .data = &ntc_thermistor_id[NTC_NCP18WB473] },
380 { .compatible = "ntc,ncp21wb473",
381 .data = &ntc_thermistor_id[NTC_NCP21WB473] },
382 { },
383};
384MODULE_DEVICE_TABLE(of, ntc_match);
385
386static struct ntc_thermistor_platform_data *
387ntc_thermistor_parse_dt(struct device *dev)
388{
389 struct iio_channel *chan;
390 enum iio_chan_type type;
391 struct device_node *np = dev->of_node;
392 struct ntc_thermistor_platform_data *pdata;
393 int ret;
394
395 if (!np)
396 return NULL;
397
398 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
399 if (!pdata)
400 return ERR_PTR(-ENOMEM);
401
402 chan = devm_iio_channel_get(dev, NULL);
403 if (IS_ERR(chan))
404 return ERR_CAST(chan);
405
406 ret = iio_get_channel_type(chan, &type);
407 if (ret < 0)
408 return ERR_PTR(ret);
409
410 if (type != IIO_VOLTAGE)
411 return ERR_PTR(-EINVAL);
412
413 if (of_property_read_u32(np, "pullup-uv", &pdata->pullup_uv))
414 return ERR_PTR(-ENODEV);
415 if (of_property_read_u32(np, "pullup-ohm", &pdata->pullup_ohm))
416 return ERR_PTR(-ENODEV);
417 if (of_property_read_u32(np, "pulldown-ohm", &pdata->pulldown_ohm))
418 return ERR_PTR(-ENODEV);
419
420 if (of_find_property(np, "connected-positive", NULL))
421 pdata->connect = NTC_CONNECTED_POSITIVE;
422 else /* status change should be possible if not always on. */
423 pdata->connect = NTC_CONNECTED_GROUND;
424
425 pdata->chan = chan;
426 pdata->read_uv = ntc_adc_iio_read;
427
428 return pdata;
429}
430#else
431static struct ntc_thermistor_platform_data *
432ntc_thermistor_parse_dt(struct device *dev)
433{
434 return NULL;
435}
436
437#define ntc_match NULL
438
439#endif
440
441static inline u64 div64_u64_safe(u64 dividend, u64 divisor)
442{
443 if (divisor == 0 && dividend == 0)
444 return 0;
445 if (divisor == 0)
446 return UINT_MAX;
447 return div64_u64(dividend, divisor);
448}
449
450static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv)
451{
452 struct ntc_thermistor_platform_data *pdata = data->pdata;
453 u32 puv = pdata->pullup_uv;
454 u64 n, puo, pdo;
455 puo = pdata->pullup_ohm;
456 pdo = pdata->pulldown_ohm;
457
458 if (uv == 0)
459 return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
460 INT_MAX : 0;
461 if (uv >= puv)
462 return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
463 0 : INT_MAX;
464
465 if (pdata->connect == NTC_CONNECTED_POSITIVE && puo == 0)
466 n = div_u64(pdo * (puv - uv), uv);
467 else if (pdata->connect == NTC_CONNECTED_GROUND && pdo == 0)
468 n = div_u64(puo * uv, puv - uv);
469 else if (pdata->connect == NTC_CONNECTED_POSITIVE)
470 n = div64_u64_safe(pdo * puo * (puv - uv),
471 puo * uv - pdo * (puv - uv));
472 else
473 n = div64_u64_safe(pdo * puo * uv, pdo * (puv - uv) - puo * uv);
474
475 if (n > INT_MAX)
476 n = INT_MAX;
477 return n;
478}
479
480static void lookup_comp(struct ntc_data *data, unsigned int ohm,
481 int *i_low, int *i_high)
482{
483 int start, end, mid;
484
485 /*
486 * Handle special cases: Resistance is higher than or equal to
487 * resistance in first table entry, or resistance is lower or equal
488 * to resistance in last table entry.
489 * In these cases, return i_low == i_high, either pointing to the
490 * beginning or to the end of the table depending on the condition.
491 */
492 if (ohm >= data->comp[0].ohm) {
493 *i_low = 0;
494 *i_high = 0;
495 return;
496 }
497 if (ohm <= data->comp[data->n_comp - 1].ohm) {
498 *i_low = data->n_comp - 1;
499 *i_high = data->n_comp - 1;
500 return;
501 }
502
503 /* Do a binary search on compensation table */
504 start = 0;
505 end = data->n_comp;
506 while (start < end) {
507 mid = start + (end - start) / 2;
508 /*
509 * start <= mid < end
510 * data->comp[start].ohm > ohm >= data->comp[end].ohm
511 *
512 * We could check for "ohm == data->comp[mid].ohm" here, but
513 * that is a quite unlikely condition, and we would have to
514 * check again after updating start. Check it at the end instead
515 * for simplicity.
516 */
517 if (ohm >= data->comp[mid].ohm) {
518 end = mid;
519 } else {
520 start = mid + 1;
521 /*
522 * ohm >= data->comp[start].ohm might be true here,
523 * since we set start to mid + 1. In that case, we are
524 * done. We could keep going, but the condition is quite
525 * likely to occur, so it is worth checking for it.
526 */
527 if (ohm >= data->comp[start].ohm)
528 end = start;
529 }
530 /*
531 * start <= end
532 * data->comp[start].ohm >= ohm >= data->comp[end].ohm
533 */
534 }
535 /*
536 * start == end
537 * ohm >= data->comp[end].ohm
538 */
539 *i_low = end;
540 if (ohm == data->comp[end].ohm)
541 *i_high = end;
542 else
543 *i_high = end - 1;
544}
545
546static int get_temp_mc(struct ntc_data *data, unsigned int ohm)
547{
548 int low, high;
549 int temp;
550
551 lookup_comp(data, ohm, &low, &high);
552 if (low == high) {
553 /* Unable to use linear approximation */
554 temp = data->comp[low].temp_c * 1000;
555 } else {
556 temp = data->comp[low].temp_c * 1000 +
557 ((data->comp[high].temp_c - data->comp[low].temp_c) *
558 1000 * ((int)ohm - (int)data->comp[low].ohm)) /
559 ((int)data->comp[high].ohm - (int)data->comp[low].ohm);
560 }
561 return temp;
562}
563
564static int ntc_thermistor_get_ohm(struct ntc_data *data)
565{
566 int read_uv;
567
568 if (data->pdata->read_ohm)
569 return data->pdata->read_ohm();
570
571 if (data->pdata->read_uv) {
572 read_uv = data->pdata->read_uv(data->pdata);
573 if (read_uv < 0)
574 return read_uv;
575 return get_ohm_of_thermistor(data, read_uv);
576 }
577 return -EINVAL;
578}
579
580static int ntc_read(struct device *dev, enum hwmon_sensor_types type,
581 u32 attr, int channel, long *val)
582{
583 struct ntc_data *data = dev_get_drvdata(dev);
584 int ohm;
585
586 switch (type) {
587 case hwmon_temp:
588 switch (attr) {
589 case hwmon_temp_input:
590 ohm = ntc_thermistor_get_ohm(data);
591 if (ohm < 0)
592 return ohm;
593 *val = get_temp_mc(data, ohm);
594 return 0;
595 case hwmon_temp_type:
596 *val = 4;
597 return 0;
598 default:
599 break;
600 }
601 break;
602 default:
603 break;
604 }
605 return -EINVAL;
606}
607
608static umode_t ntc_is_visible(const void *data, enum hwmon_sensor_types type,
609 u32 attr, int channel)
610{
611 if (type == hwmon_temp) {
612 switch (attr) {
613 case hwmon_temp_input:
614 case hwmon_temp_type:
615 return 0444;
616 default:
617 break;
618 }
619 }
620 return 0;
621}
622
623static const struct hwmon_channel_info *ntc_info[] = {
624 HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
625 HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_TYPE),
626 NULL
627};
628
629static const struct hwmon_ops ntc_hwmon_ops = {
630 .is_visible = ntc_is_visible,
631 .read = ntc_read,
632};
633
634static const struct hwmon_chip_info ntc_chip_info = {
635 .ops = &ntc_hwmon_ops,
636 .info = ntc_info,
637};
638
639static int ntc_thermistor_probe(struct platform_device *pdev)
640{
641 struct device *dev = &pdev->dev;
642 const struct of_device_id *of_id =
643 of_match_device(of_match_ptr(ntc_match), dev);
644 const struct platform_device_id *pdev_id;
645 struct ntc_thermistor_platform_data *pdata;
646 struct device *hwmon_dev;
647 struct ntc_data *data;
648
649 pdata = ntc_thermistor_parse_dt(dev);
650 if (IS_ERR(pdata))
651 return PTR_ERR(pdata);
652 else if (pdata == NULL)
653 pdata = dev_get_platdata(dev);
654
655 if (!pdata) {
656 dev_err(dev, "No platform init data supplied.\n");
657 return -ENODEV;
658 }
659
660 /* Either one of the two is required. */
661 if (!pdata->read_uv && !pdata->read_ohm) {
662 dev_err(dev,
663 "Both read_uv and read_ohm missing. Need either one of the two.\n");
664 return -EINVAL;
665 }
666
667 if (pdata->read_uv && pdata->read_ohm) {
668 dev_warn(dev,
669 "Only one of read_uv and read_ohm is needed; ignoring read_uv.\n");
670 pdata->read_uv = NULL;
671 }
672
673 if (pdata->read_uv && (pdata->pullup_uv == 0 ||
674 (pdata->pullup_ohm == 0 && pdata->connect ==
675 NTC_CONNECTED_GROUND) ||
676 (pdata->pulldown_ohm == 0 && pdata->connect ==
677 NTC_CONNECTED_POSITIVE) ||
678 (pdata->connect != NTC_CONNECTED_POSITIVE &&
679 pdata->connect != NTC_CONNECTED_GROUND))) {
680 dev_err(dev, "Required data to use read_uv not supplied.\n");
681 return -EINVAL;
682 }
683
684 data = devm_kzalloc(dev, sizeof(struct ntc_data), GFP_KERNEL);
685 if (!data)
686 return -ENOMEM;
687
688 pdev_id = of_id ? of_id->data : platform_get_device_id(pdev);
689
690 data->pdata = pdata;
691
692 if (pdev_id->driver_data >= ARRAY_SIZE(ntc_type)) {
693 dev_err(dev, "Unknown device type: %lu(%s)\n",
694 pdev_id->driver_data, pdev_id->name);
695 return -EINVAL;
696 }
697
698 data->comp = ntc_type[pdev_id->driver_data].comp;
699 data->n_comp = ntc_type[pdev_id->driver_data].n_comp;
700
701 hwmon_dev = devm_hwmon_device_register_with_info(dev, pdev_id->name,
702 data, &ntc_chip_info,
703 NULL);
704 if (IS_ERR(hwmon_dev)) {
705 dev_err(dev, "unable to register as hwmon device.\n");
706 return PTR_ERR(hwmon_dev);
707 }
708
709 dev_info(dev, "Thermistor type: %s successfully probed.\n",
710 pdev_id->name);
711
712 return 0;
713}
714
715static struct platform_driver ntc_thermistor_driver = {
716 .driver = {
717 .name = "ntc-thermistor",
718 .of_match_table = of_match_ptr(ntc_match),
719 },
720 .probe = ntc_thermistor_probe,
721 .id_table = ntc_thermistor_id,
722};
723
724module_platform_driver(ntc_thermistor_driver);
725
726MODULE_DESCRIPTION("NTC Thermistor Driver");
727MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
728MODULE_LICENSE("GPL");
729MODULE_ALIAS("platform:ntc-thermistor");