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f22aaaa7 DK |
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 | ||
35 | struct 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 | */ | |
46 | const 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 | }; | |
82 | const 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 | ||
119 | struct 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 | ||
128 | static 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 | ||
dbe43a62 | 137 | static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uV) |
f22aaaa7 DK |
138 | { |
139 | struct ntc_thermistor_platform_data *pdata = data->pdata; | |
140 | u64 mV = uV / 1000; | |
141 | u64 pmV = pdata->pullup_uV / 1000; | |
142 | u64 N, puO, pdO; | |
143 | puO = pdata->pullup_ohm; | |
144 | pdO = pdata->pulldown_ohm; | |
145 | ||
146 | if (mV == 0) { | |
147 | if (pdata->connect == NTC_CONNECTED_POSITIVE) | |
dbe43a62 | 148 | return INT_MAX; |
f22aaaa7 DK |
149 | return 0; |
150 | } | |
151 | if (mV >= pmV) | |
152 | return (pdata->connect == NTC_CONNECTED_POSITIVE) ? | |
dbe43a62 | 153 | 0 : INT_MAX; |
f22aaaa7 DK |
154 | |
155 | if (pdata->connect == NTC_CONNECTED_POSITIVE && puO == 0) | |
156 | N = div64_u64_safe(pdO * (pmV - mV), mV); | |
157 | else if (pdata->connect == NTC_CONNECTED_GROUND && pdO == 0) | |
158 | N = div64_u64_safe(puO * mV, pmV - mV); | |
159 | else if (pdata->connect == NTC_CONNECTED_POSITIVE) | |
160 | N = div64_u64_safe(pdO * puO * (pmV - mV), | |
161 | puO * mV - pdO * (pmV - mV)); | |
162 | else | |
163 | N = div64_u64_safe(pdO * puO * mV, pdO * (pmV - mV) - puO * mV); | |
164 | ||
dbe43a62 GR |
165 | if (N > INT_MAX) |
166 | N = INT_MAX; | |
167 | return N; | |
f22aaaa7 DK |
168 | } |
169 | ||
dbe43a62 GR |
170 | static void lookup_comp(struct ntc_data *data, unsigned int ohm, |
171 | int *i_low, int *i_high) | |
f22aaaa7 | 172 | { |
dbe43a62 GR |
173 | int start, end, mid; |
174 | ||
175 | /* | |
176 | * Handle special cases: Resistance is higher than or equal to | |
177 | * resistance in first table entry, or resistance is lower or equal | |
178 | * to resistance in last table entry. | |
179 | * In these cases, return i_low == i_high, either pointing to the | |
180 | * beginning or to the end of the table depending on the condition. | |
181 | */ | |
182 | if (ohm >= data->comp[0].ohm) { | |
183 | *i_low = 0; | |
184 | *i_high = 0; | |
185 | return; | |
186 | } | |
187 | if (ohm <= data->comp[data->n_comp - 1].ohm) { | |
188 | *i_low = data->n_comp - 1; | |
189 | *i_high = data->n_comp - 1; | |
190 | return; | |
191 | } | |
f22aaaa7 DK |
192 | |
193 | /* Do a binary search on compensation table */ | |
194 | start = 0; | |
195 | end = data->n_comp; | |
dbe43a62 | 196 | while (start < end) { |
f22aaaa7 | 197 | mid = start + (end - start) / 2; |
dbe43a62 GR |
198 | /* |
199 | * start <= mid < end | |
200 | * data->comp[start].ohm > ohm >= data->comp[end].ohm | |
201 | * | |
202 | * We could check for "ohm == data->comp[mid].ohm" here, but | |
203 | * that is a quite unlikely condition, and we would have to | |
204 | * check again after updating start. Check it at the end instead | |
205 | * for simplicity. | |
206 | */ | |
207 | if (ohm >= data->comp[mid].ohm) { | |
f22aaaa7 | 208 | end = mid; |
f22aaaa7 | 209 | } else { |
dbe43a62 GR |
210 | start = mid + 1; |
211 | /* | |
212 | * ohm >= data->comp[start].ohm might be true here, | |
213 | * since we set start to mid + 1. In that case, we are | |
214 | * done. We could keep going, but the condition is quite | |
215 | * likely to occur, so it is worth checking for it. | |
216 | */ | |
217 | if (ohm >= data->comp[start].ohm) | |
218 | end = start; | |
f22aaaa7 | 219 | } |
dbe43a62 GR |
220 | /* |
221 | * start <= end | |
222 | * data->comp[start].ohm >= ohm >= data->comp[end].ohm | |
223 | */ | |
f22aaaa7 | 224 | } |
dbe43a62 GR |
225 | /* |
226 | * start == end | |
227 | * ohm >= data->comp[end].ohm | |
228 | */ | |
229 | *i_low = end; | |
230 | if (ohm == data->comp[end].ohm) | |
231 | *i_high = end; | |
232 | else | |
233 | *i_high = end - 1; | |
f22aaaa7 DK |
234 | } |
235 | ||
dbe43a62 | 236 | static int get_temp_mC(struct ntc_data *data, unsigned int ohm) |
f22aaaa7 DK |
237 | { |
238 | int low, high; | |
dbe43a62 | 239 | int temp; |
f22aaaa7 | 240 | |
dbe43a62 GR |
241 | lookup_comp(data, ohm, &low, &high); |
242 | if (low == high) { | |
f22aaaa7 | 243 | /* Unable to use linear approximation */ |
dbe43a62 | 244 | temp = data->comp[low].temp_C * 1000; |
f22aaaa7 | 245 | } else { |
dbe43a62 | 246 | temp = data->comp[low].temp_C * 1000 + |
f22aaaa7 DK |
247 | ((data->comp[high].temp_C - data->comp[low].temp_C) * |
248 | 1000 * ((int)ohm - (int)data->comp[low].ohm)) / | |
249 | ((int)data->comp[high].ohm - (int)data->comp[low].ohm); | |
250 | } | |
dbe43a62 | 251 | return temp; |
f22aaaa7 DK |
252 | } |
253 | ||
dbe43a62 | 254 | static int ntc_thermistor_get_ohm(struct ntc_data *data) |
f22aaaa7 | 255 | { |
dbe43a62 | 256 | int read_uV; |
f22aaaa7 | 257 | |
dbe43a62 GR |
258 | if (data->pdata->read_ohm) |
259 | return data->pdata->read_ohm(); | |
f22aaaa7 DK |
260 | |
261 | if (data->pdata->read_uV) { | |
262 | read_uV = data->pdata->read_uV(); | |
263 | if (read_uV < 0) | |
264 | return read_uV; | |
dbe43a62 | 265 | return get_ohm_of_thermistor(data, read_uV); |
f22aaaa7 | 266 | } |
dbe43a62 | 267 | return -EINVAL; |
f22aaaa7 DK |
268 | } |
269 | ||
270 | static ssize_t ntc_show_name(struct device *dev, | |
271 | struct device_attribute *attr, char *buf) | |
272 | { | |
273 | struct ntc_data *data = dev_get_drvdata(dev); | |
274 | ||
275 | return sprintf(buf, "%s\n", data->name); | |
276 | } | |
277 | ||
278 | static ssize_t ntc_show_type(struct device *dev, | |
279 | struct device_attribute *attr, char *buf) | |
280 | { | |
281 | return sprintf(buf, "4\n"); | |
282 | } | |
283 | ||
284 | static ssize_t ntc_show_temp(struct device *dev, | |
285 | struct device_attribute *attr, char *buf) | |
286 | { | |
287 | struct ntc_data *data = dev_get_drvdata(dev); | |
dbe43a62 GR |
288 | int ohm; |
289 | ||
290 | ohm = ntc_thermistor_get_ohm(data); | |
291 | if (ohm < 0) | |
292 | return ohm; | |
f22aaaa7 | 293 | |
dbe43a62 | 294 | return sprintf(buf, "%d\n", get_temp_mC(data, ohm)); |
f22aaaa7 DK |
295 | } |
296 | ||
297 | static SENSOR_DEVICE_ATTR(temp1_type, S_IRUGO, ntc_show_type, NULL, 0); | |
298 | static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ntc_show_temp, NULL, 0); | |
299 | static DEVICE_ATTR(name, S_IRUGO, ntc_show_name, NULL); | |
300 | ||
301 | static struct attribute *ntc_attributes[] = { | |
302 | &dev_attr_name.attr, | |
303 | &sensor_dev_attr_temp1_type.dev_attr.attr, | |
304 | &sensor_dev_attr_temp1_input.dev_attr.attr, | |
305 | NULL, | |
306 | }; | |
307 | ||
308 | static const struct attribute_group ntc_attr_group = { | |
309 | .attrs = ntc_attributes, | |
310 | }; | |
311 | ||
312 | static int __devinit ntc_thermistor_probe(struct platform_device *pdev) | |
313 | { | |
314 | struct ntc_data *data; | |
315 | struct ntc_thermistor_platform_data *pdata = pdev->dev.platform_data; | |
316 | int ret = 0; | |
317 | ||
318 | if (!pdata) { | |
319 | dev_err(&pdev->dev, "No platform init data supplied.\n"); | |
320 | return -ENODEV; | |
321 | } | |
322 | ||
323 | /* Either one of the two is required. */ | |
324 | if (!pdata->read_uV && !pdata->read_ohm) { | |
a7871def GR |
325 | dev_err(&pdev->dev, |
326 | "Both read_uV and read_ohm missing. Need either one of the two.\n"); | |
f22aaaa7 DK |
327 | return -EINVAL; |
328 | } | |
329 | ||
330 | if (pdata->read_uV && pdata->read_ohm) { | |
a7871def GR |
331 | dev_warn(&pdev->dev, |
332 | "Only one of read_uV and read_ohm is needed; ignoring read_uV.\n"); | |
f22aaaa7 DK |
333 | pdata->read_uV = NULL; |
334 | } | |
335 | ||
336 | if (pdata->read_uV && (pdata->pullup_uV == 0 || | |
337 | (pdata->pullup_ohm == 0 && pdata->connect == | |
338 | NTC_CONNECTED_GROUND) || | |
339 | (pdata->pulldown_ohm == 0 && pdata->connect == | |
340 | NTC_CONNECTED_POSITIVE) || | |
341 | (pdata->connect != NTC_CONNECTED_POSITIVE && | |
342 | pdata->connect != NTC_CONNECTED_GROUND))) { | |
a7871def GR |
343 | dev_err(&pdev->dev, |
344 | "Required data to use read_uV not supplied.\n"); | |
f22aaaa7 DK |
345 | return -EINVAL; |
346 | } | |
347 | ||
41141e64 | 348 | data = devm_kzalloc(&pdev->dev, sizeof(struct ntc_data), GFP_KERNEL); |
f22aaaa7 DK |
349 | if (!data) |
350 | return -ENOMEM; | |
351 | ||
352 | data->dev = &pdev->dev; | |
353 | data->pdata = pdata; | |
0ef63e48 | 354 | strlcpy(data->name, pdev->id_entry->name, sizeof(data->name)); |
f22aaaa7 DK |
355 | |
356 | switch (pdev->id_entry->driver_data) { | |
357 | case TYPE_NCPXXWB473: | |
358 | data->comp = ncpXXwb473; | |
359 | data->n_comp = ARRAY_SIZE(ncpXXwb473); | |
360 | break; | |
361 | case TYPE_NCPXXWL333: | |
362 | data->comp = ncpXXwl333; | |
363 | data->n_comp = ARRAY_SIZE(ncpXXwl333); | |
364 | break; | |
365 | default: | |
366 | dev_err(&pdev->dev, "Unknown device type: %lu(%s)\n", | |
367 | pdev->id_entry->driver_data, | |
368 | pdev->id_entry->name); | |
41141e64 | 369 | return -EINVAL; |
f22aaaa7 DK |
370 | } |
371 | ||
372 | platform_set_drvdata(pdev, data); | |
373 | ||
374 | ret = sysfs_create_group(&data->dev->kobj, &ntc_attr_group); | |
375 | if (ret) { | |
376 | dev_err(data->dev, "unable to create sysfs files\n"); | |
41141e64 | 377 | return ret; |
f22aaaa7 DK |
378 | } |
379 | ||
380 | data->hwmon_dev = hwmon_device_register(data->dev); | |
425d2476 | 381 | if (IS_ERR(data->hwmon_dev)) { |
f22aaaa7 | 382 | dev_err(data->dev, "unable to register as hwmon device.\n"); |
425d2476 | 383 | ret = PTR_ERR(data->hwmon_dev); |
f22aaaa7 DK |
384 | goto err_after_sysfs; |
385 | } | |
386 | ||
387 | dev_info(&pdev->dev, "Thermistor %s:%d (type: %s/%lu) successfully probed.\n", | |
388 | pdev->name, pdev->id, pdev->id_entry->name, | |
389 | pdev->id_entry->driver_data); | |
390 | return 0; | |
391 | err_after_sysfs: | |
392 | sysfs_remove_group(&data->dev->kobj, &ntc_attr_group); | |
f22aaaa7 DK |
393 | return ret; |
394 | } | |
395 | ||
396 | static int __devexit ntc_thermistor_remove(struct platform_device *pdev) | |
397 | { | |
398 | struct ntc_data *data = platform_get_drvdata(pdev); | |
399 | ||
400 | hwmon_device_unregister(data->hwmon_dev); | |
401 | sysfs_remove_group(&data->dev->kobj, &ntc_attr_group); | |
402 | platform_set_drvdata(pdev, NULL); | |
403 | ||
f22aaaa7 DK |
404 | return 0; |
405 | } | |
406 | ||
407 | static const struct platform_device_id ntc_thermistor_id[] = { | |
408 | { "ncp15wb473", TYPE_NCPXXWB473 }, | |
409 | { "ncp18wb473", TYPE_NCPXXWB473 }, | |
410 | { "ncp21wb473", TYPE_NCPXXWB473 }, | |
411 | { "ncp03wb473", TYPE_NCPXXWB473 }, | |
412 | { "ncp15wl333", TYPE_NCPXXWL333 }, | |
413 | { }, | |
414 | }; | |
415 | ||
416 | static struct platform_driver ntc_thermistor_driver = { | |
417 | .driver = { | |
418 | .name = "ntc-thermistor", | |
419 | .owner = THIS_MODULE, | |
420 | }, | |
421 | .probe = ntc_thermistor_probe, | |
422 | .remove = __devexit_p(ntc_thermistor_remove), | |
423 | .id_table = ntc_thermistor_id, | |
424 | }; | |
425 | ||
25a236a5 | 426 | module_platform_driver(ntc_thermistor_driver); |
f22aaaa7 DK |
427 | |
428 | MODULE_DESCRIPTION("NTC Thermistor Driver"); | |
429 | MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); | |
430 | MODULE_LICENSE("GPL"); | |
431 | MODULE_ALIAS("platform:ntc-thermistor"); |