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/mod_devicetable.h> |
13 | #include <linux/platform_device.h> |
14 | #include <linux/property.h> |
15 | #include <linux/err.h> |
16 | #include <linux/fixp-arith.h> |
17 | #include <linux/iio/consumer.h> |
18 | #include <linux/hwmon.h> |
19 | |
20 | enum ntc_thermistor_type { |
21 | TYPE_B57330V2103, |
22 | TYPE_B57891S0103, |
23 | TYPE_NCPXXWB473, |
24 | TYPE_NCPXXWF104, |
25 | TYPE_NCPXXWL333, |
26 | TYPE_NCPXXXH103, |
27 | }; |
28 | |
29 | struct ntc_compensation { |
30 | int temp_c; |
31 | unsigned int ohm; |
32 | }; |
33 | |
34 | /* |
35 | * Used as index in a zero-terminated array, holes not allowed so |
36 | * that NTC_LAST is the first empty array entry. |
37 | */ |
38 | enum { |
39 | NTC_B57330V2103, |
40 | NTC_B57891S0103, |
41 | NTC_NCP03WB473, |
42 | NTC_NCP03WF104, |
43 | NTC_NCP15WB473, |
44 | NTC_NCP15WL333, |
45 | NTC_NCP15XH103, |
46 | NTC_NCP18WB473, |
47 | NTC_NCP21WB473, |
48 | NTC_SSG1404001221, |
49 | NTC_LAST, |
50 | }; |
51 | |
52 | static const struct platform_device_id ntc_thermistor_id[] = { |
53 | [NTC_B57330V2103] = { "b57330v2103" , TYPE_B57330V2103 }, |
54 | [NTC_B57891S0103] = { .name: "b57891s0103" , .driver_data: TYPE_B57891S0103 }, |
55 | [NTC_NCP03WB473] = { .name: "ncp03wb473" , .driver_data: TYPE_NCPXXWB473 }, |
56 | [NTC_NCP03WF104] = { .name: "ncp03wf104" , .driver_data: TYPE_NCPXXWF104 }, |
57 | [NTC_NCP15WB473] = { .name: "ncp15wb473" , .driver_data: TYPE_NCPXXWB473 }, |
58 | [NTC_NCP15WL333] = { .name: "ncp15wl333" , .driver_data: TYPE_NCPXXWL333 }, |
59 | [NTC_NCP15XH103] = { .name: "ncp15xh103" , .driver_data: TYPE_NCPXXXH103 }, |
60 | [NTC_NCP18WB473] = { .name: "ncp18wb473" , .driver_data: TYPE_NCPXXWB473 }, |
61 | [NTC_NCP21WB473] = { .name: "ncp21wb473" , .driver_data: TYPE_NCPXXWB473 }, |
62 | [NTC_SSG1404001221] = { .name: "ssg1404_001221" , .driver_data: TYPE_NCPXXWB473 }, |
63 | [NTC_LAST] = { }, |
64 | }; |
65 | |
66 | /* |
67 | * A compensation table should be sorted by the values of .ohm |
68 | * in descending order. |
69 | * The following compensation tables are from the specification of Murata NTC |
70 | * Thermistors Datasheet |
71 | */ |
72 | static const struct ntc_compensation ncpXXwb473[] = { |
73 | { .temp_c = -40, .ohm = 1747920 }, |
74 | { .temp_c = -35, .ohm = 1245428 }, |
75 | { .temp_c = -30, .ohm = 898485 }, |
76 | { .temp_c = -25, .ohm = 655802 }, |
77 | { .temp_c = -20, .ohm = 483954 }, |
78 | { .temp_c = -15, .ohm = 360850 }, |
79 | { .temp_c = -10, .ohm = 271697 }, |
80 | { .temp_c = -5, .ohm = 206463 }, |
81 | { .temp_c = 0, .ohm = 158214 }, |
82 | { .temp_c = 5, .ohm = 122259 }, |
83 | { .temp_c = 10, .ohm = 95227 }, |
84 | { .temp_c = 15, .ohm = 74730 }, |
85 | { .temp_c = 20, .ohm = 59065 }, |
86 | { .temp_c = 25, .ohm = 47000 }, |
87 | { .temp_c = 30, .ohm = 37643 }, |
88 | { .temp_c = 35, .ohm = 30334 }, |
89 | { .temp_c = 40, .ohm = 24591 }, |
90 | { .temp_c = 45, .ohm = 20048 }, |
91 | { .temp_c = 50, .ohm = 16433 }, |
92 | { .temp_c = 55, .ohm = 13539 }, |
93 | { .temp_c = 60, .ohm = 11209 }, |
94 | { .temp_c = 65, .ohm = 9328 }, |
95 | { .temp_c = 70, .ohm = 7798 }, |
96 | { .temp_c = 75, .ohm = 6544 }, |
97 | { .temp_c = 80, .ohm = 5518 }, |
98 | { .temp_c = 85, .ohm = 4674 }, |
99 | { .temp_c = 90, .ohm = 3972 }, |
100 | { .temp_c = 95, .ohm = 3388 }, |
101 | { .temp_c = 100, .ohm = 2902 }, |
102 | { .temp_c = 105, .ohm = 2494 }, |
103 | { .temp_c = 110, .ohm = 2150 }, |
104 | { .temp_c = 115, .ohm = 1860 }, |
105 | { .temp_c = 120, .ohm = 1615 }, |
106 | { .temp_c = 125, .ohm = 1406 }, |
107 | }; |
108 | static const struct ntc_compensation ncpXXwl333[] = { |
109 | { .temp_c = -40, .ohm = 1610154 }, |
110 | { .temp_c = -35, .ohm = 1130850 }, |
111 | { .temp_c = -30, .ohm = 802609 }, |
112 | { .temp_c = -25, .ohm = 575385 }, |
113 | { .temp_c = -20, .ohm = 416464 }, |
114 | { .temp_c = -15, .ohm = 304219 }, |
115 | { .temp_c = -10, .ohm = 224193 }, |
116 | { .temp_c = -5, .ohm = 166623 }, |
117 | { .temp_c = 0, .ohm = 124850 }, |
118 | { .temp_c = 5, .ohm = 94287 }, |
119 | { .temp_c = 10, .ohm = 71747 }, |
120 | { .temp_c = 15, .ohm = 54996 }, |
121 | { .temp_c = 20, .ohm = 42455 }, |
122 | { .temp_c = 25, .ohm = 33000 }, |
123 | { .temp_c = 30, .ohm = 25822 }, |
124 | { .temp_c = 35, .ohm = 20335 }, |
125 | { .temp_c = 40, .ohm = 16115 }, |
126 | { .temp_c = 45, .ohm = 12849 }, |
127 | { .temp_c = 50, .ohm = 10306 }, |
128 | { .temp_c = 55, .ohm = 8314 }, |
129 | { .temp_c = 60, .ohm = 6746 }, |
130 | { .temp_c = 65, .ohm = 5503 }, |
131 | { .temp_c = 70, .ohm = 4513 }, |
132 | { .temp_c = 75, .ohm = 3721 }, |
133 | { .temp_c = 80, .ohm = 3084 }, |
134 | { .temp_c = 85, .ohm = 2569 }, |
135 | { .temp_c = 90, .ohm = 2151 }, |
136 | { .temp_c = 95, .ohm = 1809 }, |
137 | { .temp_c = 100, .ohm = 1529 }, |
138 | { .temp_c = 105, .ohm = 1299 }, |
139 | { .temp_c = 110, .ohm = 1108 }, |
140 | { .temp_c = 115, .ohm = 949 }, |
141 | { .temp_c = 120, .ohm = 817 }, |
142 | { .temp_c = 125, .ohm = 707 }, |
143 | }; |
144 | |
145 | static const struct ntc_compensation ncpXXwf104[] = { |
146 | { .temp_c = -40, .ohm = 4397119 }, |
147 | { .temp_c = -35, .ohm = 3088599 }, |
148 | { .temp_c = -30, .ohm = 2197225 }, |
149 | { .temp_c = -25, .ohm = 1581881 }, |
150 | { .temp_c = -20, .ohm = 1151037 }, |
151 | { .temp_c = -15, .ohm = 846579 }, |
152 | { .temp_c = -10, .ohm = 628988 }, |
153 | { .temp_c = -5, .ohm = 471632 }, |
154 | { .temp_c = 0, .ohm = 357012 }, |
155 | { .temp_c = 5, .ohm = 272500 }, |
156 | { .temp_c = 10, .ohm = 209710 }, |
157 | { .temp_c = 15, .ohm = 162651 }, |
158 | { .temp_c = 20, .ohm = 127080 }, |
159 | { .temp_c = 25, .ohm = 100000 }, |
160 | { .temp_c = 30, .ohm = 79222 }, |
161 | { .temp_c = 35, .ohm = 63167 }, |
162 | { .temp_c = 40, .ohm = 50677 }, |
163 | { .temp_c = 45, .ohm = 40904 }, |
164 | { .temp_c = 50, .ohm = 33195 }, |
165 | { .temp_c = 55, .ohm = 27091 }, |
166 | { .temp_c = 60, .ohm = 22224 }, |
167 | { .temp_c = 65, .ohm = 18323 }, |
168 | { .temp_c = 70, .ohm = 15184 }, |
169 | { .temp_c = 75, .ohm = 12635 }, |
170 | { .temp_c = 80, .ohm = 10566 }, |
171 | { .temp_c = 85, .ohm = 8873 }, |
172 | { .temp_c = 90, .ohm = 7481 }, |
173 | { .temp_c = 95, .ohm = 6337 }, |
174 | { .temp_c = 100, .ohm = 5384 }, |
175 | { .temp_c = 105, .ohm = 4594 }, |
176 | { .temp_c = 110, .ohm = 3934 }, |
177 | { .temp_c = 115, .ohm = 3380 }, |
178 | { .temp_c = 120, .ohm = 2916 }, |
179 | { .temp_c = 125, .ohm = 2522 }, |
180 | }; |
181 | |
182 | static const struct ntc_compensation ncpXXxh103[] = { |
183 | { .temp_c = -40, .ohm = 247565 }, |
184 | { .temp_c = -35, .ohm = 181742 }, |
185 | { .temp_c = -30, .ohm = 135128 }, |
186 | { .temp_c = -25, .ohm = 101678 }, |
187 | { .temp_c = -20, .ohm = 77373 }, |
188 | { .temp_c = -15, .ohm = 59504 }, |
189 | { .temp_c = -10, .ohm = 46222 }, |
190 | { .temp_c = -5, .ohm = 36244 }, |
191 | { .temp_c = 0, .ohm = 28674 }, |
192 | { .temp_c = 5, .ohm = 22878 }, |
193 | { .temp_c = 10, .ohm = 18399 }, |
194 | { .temp_c = 15, .ohm = 14910 }, |
195 | { .temp_c = 20, .ohm = 12169 }, |
196 | { .temp_c = 25, .ohm = 10000 }, |
197 | { .temp_c = 30, .ohm = 8271 }, |
198 | { .temp_c = 35, .ohm = 6883 }, |
199 | { .temp_c = 40, .ohm = 5762 }, |
200 | { .temp_c = 45, .ohm = 4851 }, |
201 | { .temp_c = 50, .ohm = 4105 }, |
202 | { .temp_c = 55, .ohm = 3492 }, |
203 | { .temp_c = 60, .ohm = 2985 }, |
204 | { .temp_c = 65, .ohm = 2563 }, |
205 | { .temp_c = 70, .ohm = 2211 }, |
206 | { .temp_c = 75, .ohm = 1915 }, |
207 | { .temp_c = 80, .ohm = 1666 }, |
208 | { .temp_c = 85, .ohm = 1454 }, |
209 | { .temp_c = 90, .ohm = 1275 }, |
210 | { .temp_c = 95, .ohm = 1121 }, |
211 | { .temp_c = 100, .ohm = 990 }, |
212 | { .temp_c = 105, .ohm = 876 }, |
213 | { .temp_c = 110, .ohm = 779 }, |
214 | { .temp_c = 115, .ohm = 694 }, |
215 | { .temp_c = 120, .ohm = 620 }, |
216 | { .temp_c = 125, .ohm = 556 }, |
217 | }; |
218 | |
219 | /* |
220 | * The following compensation tables are from the specifications in EPCOS NTC |
221 | * Thermistors Datasheets |
222 | */ |
223 | static const struct ntc_compensation b57330v2103[] = { |
224 | { .temp_c = -40, .ohm = 190030 }, |
225 | { .temp_c = -35, .ohm = 145360 }, |
226 | { .temp_c = -30, .ohm = 112060 }, |
227 | { .temp_c = -25, .ohm = 87041 }, |
228 | { .temp_c = -20, .ohm = 68104 }, |
229 | { .temp_c = -15, .ohm = 53665 }, |
230 | { .temp_c = -10, .ohm = 42576 }, |
231 | { .temp_c = -5, .ohm = 34001 }, |
232 | { .temp_c = 0, .ohm = 27326 }, |
233 | { .temp_c = 5, .ohm = 22096 }, |
234 | { .temp_c = 10, .ohm = 17973 }, |
235 | { .temp_c = 15, .ohm = 14703 }, |
236 | { .temp_c = 20, .ohm = 12090 }, |
237 | { .temp_c = 25, .ohm = 10000 }, |
238 | { .temp_c = 30, .ohm = 8311 }, |
239 | { .temp_c = 35, .ohm = 6941 }, |
240 | { .temp_c = 40, .ohm = 5825 }, |
241 | { .temp_c = 45, .ohm = 4911 }, |
242 | { .temp_c = 50, .ohm = 4158 }, |
243 | { .temp_c = 55, .ohm = 3536 }, |
244 | { .temp_c = 60, .ohm = 3019 }, |
245 | { .temp_c = 65, .ohm = 2588 }, |
246 | { .temp_c = 70, .ohm = 2227 }, |
247 | { .temp_c = 75, .ohm = 1924 }, |
248 | { .temp_c = 80, .ohm = 1668 }, |
249 | { .temp_c = 85, .ohm = 1451 }, |
250 | { .temp_c = 90, .ohm = 1266 }, |
251 | { .temp_c = 95, .ohm = 1108 }, |
252 | { .temp_c = 100, .ohm = 973 }, |
253 | { .temp_c = 105, .ohm = 857 }, |
254 | { .temp_c = 110, .ohm = 757 }, |
255 | { .temp_c = 115, .ohm = 671 }, |
256 | { .temp_c = 120, .ohm = 596 }, |
257 | { .temp_c = 125, .ohm = 531 }, |
258 | }; |
259 | |
260 | static const struct ntc_compensation b57891s0103[] = { |
261 | { .temp_c = -55.0, .ohm = 878900 }, |
262 | { .temp_c = -50.0, .ohm = 617590 }, |
263 | { .temp_c = -45.0, .ohm = 439340 }, |
264 | { .temp_c = -40.0, .ohm = 316180 }, |
265 | { .temp_c = -35.0, .ohm = 230060 }, |
266 | { .temp_c = -30.0, .ohm = 169150 }, |
267 | { .temp_c = -25.0, .ohm = 125550 }, |
268 | { .temp_c = -20.0, .ohm = 94143 }, |
269 | { .temp_c = -15.0, .ohm = 71172 }, |
270 | { .temp_c = -10.0, .ohm = 54308 }, |
271 | { .temp_c = -5.0, .ohm = 41505 }, |
272 | { .temp_c = 0.0, .ohm = 32014 }, |
273 | { .temp_c = 5.0, .ohm = 25011 }, |
274 | { .temp_c = 10.0, .ohm = 19691 }, |
275 | { .temp_c = 15.0, .ohm = 15618 }, |
276 | { .temp_c = 20.0, .ohm = 12474 }, |
277 | { .temp_c = 25.0, .ohm = 10000 }, |
278 | { .temp_c = 30.0, .ohm = 8080 }, |
279 | { .temp_c = 35.0, .ohm = 6569 }, |
280 | { .temp_c = 40.0, .ohm = 5372 }, |
281 | { .temp_c = 45.0, .ohm = 4424 }, |
282 | { .temp_c = 50.0, .ohm = 3661 }, |
283 | { .temp_c = 55.0, .ohm = 3039 }, |
284 | { .temp_c = 60.0, .ohm = 2536 }, |
285 | { .temp_c = 65.0, .ohm = 2128 }, |
286 | { .temp_c = 70.0, .ohm = 1794 }, |
287 | { .temp_c = 75.0, .ohm = 1518 }, |
288 | { .temp_c = 80.0, .ohm = 1290 }, |
289 | { .temp_c = 85.0, .ohm = 1100 }, |
290 | { .temp_c = 90.0, .ohm = 942 }, |
291 | { .temp_c = 95.0, .ohm = 809 }, |
292 | { .temp_c = 100.0, .ohm = 697 }, |
293 | { .temp_c = 105.0, .ohm = 604 }, |
294 | { .temp_c = 110.0, .ohm = 525 }, |
295 | { .temp_c = 115.0, .ohm = 457 }, |
296 | { .temp_c = 120.0, .ohm = 400 }, |
297 | { .temp_c = 125.0, .ohm = 351 }, |
298 | { .temp_c = 130.0, .ohm = 308 }, |
299 | { .temp_c = 135.0, .ohm = 272 }, |
300 | { .temp_c = 140.0, .ohm = 240 }, |
301 | { .temp_c = 145.0, .ohm = 213 }, |
302 | { .temp_c = 150.0, .ohm = 189 }, |
303 | { .temp_c = 155.0, .ohm = 168 }, |
304 | }; |
305 | |
306 | struct ntc_type { |
307 | const struct ntc_compensation *comp; |
308 | int n_comp; |
309 | }; |
310 | |
311 | #define NTC_TYPE(ntc, compensation) \ |
312 | [(ntc)] = { .comp = (compensation), .n_comp = ARRAY_SIZE(compensation) } |
313 | |
314 | static const struct ntc_type ntc_type[] = { |
315 | NTC_TYPE(TYPE_B57330V2103, b57330v2103), |
316 | NTC_TYPE(TYPE_B57891S0103, b57891s0103), |
317 | NTC_TYPE(TYPE_NCPXXWB473, ncpXXwb473), |
318 | NTC_TYPE(TYPE_NCPXXWF104, ncpXXwf104), |
319 | NTC_TYPE(TYPE_NCPXXWL333, ncpXXwl333), |
320 | NTC_TYPE(TYPE_NCPXXXH103, ncpXXxh103), |
321 | }; |
322 | |
323 | /* |
324 | * pullup_uV, pullup_ohm, pulldown_ohm, and connect are required. |
325 | * |
326 | * How to setup pullup_ohm, pulldown_ohm, and connect is |
327 | * described at Documentation/hwmon/ntc_thermistor.rst |
328 | * |
329 | * pullup/down_ohm: 0 for infinite / not-connected |
330 | * |
331 | * chan: iio_channel pointer to communicate with the ADC which the |
332 | * thermistor is using for conversion of the analog values. |
333 | */ |
334 | struct ntc_data { |
335 | const struct ntc_compensation *comp; |
336 | int n_comp; |
337 | unsigned int pullup_uv; |
338 | unsigned int pullup_ohm; |
339 | unsigned int pulldown_ohm; |
340 | enum { NTC_CONNECTED_POSITIVE, NTC_CONNECTED_GROUND } connect; |
341 | struct iio_channel *chan; |
342 | }; |
343 | |
344 | static int ntc_adc_iio_read(struct ntc_data *data) |
345 | { |
346 | struct iio_channel *channel = data->chan; |
347 | int uv, ret; |
348 | |
349 | ret = iio_read_channel_processed_scale(chan: channel, val: &uv, scale: 1000); |
350 | if (ret < 0) { |
351 | int raw; |
352 | |
353 | /* |
354 | * This fallback uses a raw read and then |
355 | * assumes the ADC is 12 bits, scaling with |
356 | * a factor 1000 to get to microvolts. |
357 | */ |
358 | ret = iio_read_channel_raw(chan: channel, val: &raw); |
359 | if (ret < 0) { |
360 | pr_err("read channel() error: %d\n" , ret); |
361 | return ret; |
362 | } |
363 | ret = iio_convert_raw_to_processed(chan: channel, raw, processed: &uv, scale: 1000); |
364 | if (ret < 0) { |
365 | /* Assume 12 bit ADC with vref at pullup_uv */ |
366 | uv = (data->pullup_uv * (s64)raw) >> 12; |
367 | } |
368 | } |
369 | |
370 | return uv; |
371 | } |
372 | |
373 | static inline u64 div64_u64_safe(u64 dividend, u64 divisor) |
374 | { |
375 | if (divisor == 0 && dividend == 0) |
376 | return 0; |
377 | if (divisor == 0) |
378 | return UINT_MAX; |
379 | return div64_u64(dividend, divisor); |
380 | } |
381 | |
382 | static int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uv) |
383 | { |
384 | u32 puv = data->pullup_uv; |
385 | u64 n, puo, pdo; |
386 | puo = data->pullup_ohm; |
387 | pdo = data->pulldown_ohm; |
388 | |
389 | if (uv == 0) |
390 | return (data->connect == NTC_CONNECTED_POSITIVE) ? |
391 | INT_MAX : 0; |
392 | if (uv >= puv) |
393 | return (data->connect == NTC_CONNECTED_POSITIVE) ? |
394 | 0 : INT_MAX; |
395 | |
396 | if (data->connect == NTC_CONNECTED_POSITIVE && puo == 0) |
397 | n = div_u64(dividend: pdo * (puv - uv), divisor: uv); |
398 | else if (data->connect == NTC_CONNECTED_GROUND && pdo == 0) |
399 | n = div_u64(dividend: puo * uv, divisor: puv - uv); |
400 | else if (data->connect == NTC_CONNECTED_POSITIVE) |
401 | n = div64_u64_safe(dividend: pdo * puo * (puv - uv), |
402 | divisor: puo * uv - pdo * (puv - uv)); |
403 | else |
404 | n = div64_u64_safe(dividend: pdo * puo * uv, divisor: pdo * (puv - uv) - puo * uv); |
405 | |
406 | if (n > INT_MAX) |
407 | n = INT_MAX; |
408 | return n; |
409 | } |
410 | |
411 | static void lookup_comp(struct ntc_data *data, unsigned int ohm, |
412 | int *i_low, int *i_high) |
413 | { |
414 | int start, end, mid; |
415 | |
416 | /* |
417 | * Handle special cases: Resistance is higher than or equal to |
418 | * resistance in first table entry, or resistance is lower or equal |
419 | * to resistance in last table entry. |
420 | * In these cases, return i_low == i_high, either pointing to the |
421 | * beginning or to the end of the table depending on the condition. |
422 | */ |
423 | if (ohm >= data->comp[0].ohm) { |
424 | *i_low = 0; |
425 | *i_high = 0; |
426 | return; |
427 | } |
428 | if (ohm <= data->comp[data->n_comp - 1].ohm) { |
429 | *i_low = data->n_comp - 1; |
430 | *i_high = data->n_comp - 1; |
431 | return; |
432 | } |
433 | |
434 | /* Do a binary search on compensation table */ |
435 | start = 0; |
436 | end = data->n_comp; |
437 | while (start < end) { |
438 | mid = start + (end - start) / 2; |
439 | /* |
440 | * start <= mid < end |
441 | * data->comp[start].ohm > ohm >= data->comp[end].ohm |
442 | * |
443 | * We could check for "ohm == data->comp[mid].ohm" here, but |
444 | * that is a quite unlikely condition, and we would have to |
445 | * check again after updating start. Check it at the end instead |
446 | * for simplicity. |
447 | */ |
448 | if (ohm >= data->comp[mid].ohm) { |
449 | end = mid; |
450 | } else { |
451 | start = mid + 1; |
452 | /* |
453 | * ohm >= data->comp[start].ohm might be true here, |
454 | * since we set start to mid + 1. In that case, we are |
455 | * done. We could keep going, but the condition is quite |
456 | * likely to occur, so it is worth checking for it. |
457 | */ |
458 | if (ohm >= data->comp[start].ohm) |
459 | end = start; |
460 | } |
461 | /* |
462 | * start <= end |
463 | * data->comp[start].ohm >= ohm >= data->comp[end].ohm |
464 | */ |
465 | } |
466 | /* |
467 | * start == end |
468 | * ohm >= data->comp[end].ohm |
469 | */ |
470 | *i_low = end; |
471 | if (ohm == data->comp[end].ohm) |
472 | *i_high = end; |
473 | else |
474 | *i_high = end - 1; |
475 | } |
476 | |
477 | static int get_temp_mc(struct ntc_data *data, unsigned int ohm) |
478 | { |
479 | int low, high; |
480 | int temp; |
481 | |
482 | lookup_comp(data, ohm, i_low: &low, i_high: &high); |
483 | /* |
484 | * First multiplying the table temperatures with 1000 to get to |
485 | * millicentigrades (which is what we want) and then interpolating |
486 | * will give the best precision. |
487 | */ |
488 | temp = fixp_linear_interpolate(x0: data->comp[low].ohm, |
489 | y0: data->comp[low].temp_c * 1000, |
490 | x1: data->comp[high].ohm, |
491 | y1: data->comp[high].temp_c * 1000, |
492 | x: ohm); |
493 | return temp; |
494 | } |
495 | |
496 | static int ntc_thermistor_get_ohm(struct ntc_data *data) |
497 | { |
498 | int read_uv; |
499 | |
500 | read_uv = ntc_adc_iio_read(data); |
501 | if (read_uv < 0) |
502 | return read_uv; |
503 | return get_ohm_of_thermistor(data, uv: read_uv); |
504 | } |
505 | |
506 | static int ntc_read(struct device *dev, enum hwmon_sensor_types type, |
507 | u32 attr, int channel, long *val) |
508 | { |
509 | struct ntc_data *data = dev_get_drvdata(dev); |
510 | int ohm; |
511 | |
512 | switch (type) { |
513 | case hwmon_temp: |
514 | switch (attr) { |
515 | case hwmon_temp_input: |
516 | ohm = ntc_thermistor_get_ohm(data); |
517 | if (ohm < 0) |
518 | return ohm; |
519 | *val = get_temp_mc(data, ohm); |
520 | return 0; |
521 | case hwmon_temp_type: |
522 | *val = 4; |
523 | return 0; |
524 | default: |
525 | break; |
526 | } |
527 | break; |
528 | default: |
529 | break; |
530 | } |
531 | return -EINVAL; |
532 | } |
533 | |
534 | static umode_t ntc_is_visible(const void *data, enum hwmon_sensor_types type, |
535 | u32 attr, int channel) |
536 | { |
537 | if (type == hwmon_temp) { |
538 | switch (attr) { |
539 | case hwmon_temp_input: |
540 | case hwmon_temp_type: |
541 | return 0444; |
542 | default: |
543 | break; |
544 | } |
545 | } |
546 | return 0; |
547 | } |
548 | |
549 | static const struct hwmon_channel_info * const ntc_info[] = { |
550 | HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ), |
551 | HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_TYPE), |
552 | NULL |
553 | }; |
554 | |
555 | static const struct hwmon_ops ntc_hwmon_ops = { |
556 | .is_visible = ntc_is_visible, |
557 | .read = ntc_read, |
558 | }; |
559 | |
560 | static const struct hwmon_chip_info ntc_chip_info = { |
561 | .ops = &ntc_hwmon_ops, |
562 | .info = ntc_info, |
563 | }; |
564 | |
565 | static int ntc_thermistor_parse_props(struct device *dev, |
566 | struct ntc_data *data) |
567 | { |
568 | struct iio_channel *chan; |
569 | enum iio_chan_type type; |
570 | int ret; |
571 | |
572 | chan = devm_iio_channel_get(dev, NULL); |
573 | if (IS_ERR(ptr: chan)) |
574 | return PTR_ERR(ptr: chan); |
575 | |
576 | ret = iio_get_channel_type(channel: chan, type: &type); |
577 | if (ret < 0) |
578 | return ret; |
579 | |
580 | if (type != IIO_VOLTAGE) |
581 | return -EINVAL; |
582 | |
583 | ret = device_property_read_u32(dev, propname: "pullup-uv" , val: &data->pullup_uv); |
584 | if (ret) |
585 | return dev_err_probe(dev, err: ret, fmt: "pullup-uv not specified\n" ); |
586 | |
587 | ret = device_property_read_u32(dev, propname: "pullup-ohm" , val: &data->pullup_ohm); |
588 | if (ret) |
589 | return dev_err_probe(dev, err: ret, fmt: "pullup-ohm not specified\n" ); |
590 | |
591 | ret = device_property_read_u32(dev, propname: "pulldown-ohm" , val: &data->pulldown_ohm); |
592 | if (ret) |
593 | return dev_err_probe(dev, err: ret, fmt: "pulldown-ohm not specified\n" ); |
594 | |
595 | if (device_property_read_bool(dev, propname: "connected-positive" )) |
596 | data->connect = NTC_CONNECTED_POSITIVE; |
597 | else /* status change should be possible if not always on. */ |
598 | data->connect = NTC_CONNECTED_GROUND; |
599 | |
600 | data->chan = chan; |
601 | |
602 | return 0; |
603 | } |
604 | |
605 | static int ntc_thermistor_probe(struct platform_device *pdev) |
606 | { |
607 | struct device *dev = &pdev->dev; |
608 | const struct platform_device_id *pdev_id; |
609 | struct device *hwmon_dev; |
610 | struct ntc_data *data; |
611 | int ret; |
612 | |
613 | data = devm_kzalloc(dev, size: sizeof(*data), GFP_KERNEL); |
614 | if (!data) |
615 | return -ENOMEM; |
616 | |
617 | ret = ntc_thermistor_parse_props(dev, data); |
618 | if (ret) |
619 | return ret; |
620 | |
621 | if (data->pullup_uv == 0 || |
622 | (data->pullup_ohm == 0 && data->connect == |
623 | NTC_CONNECTED_GROUND) || |
624 | (data->pulldown_ohm == 0 && data->connect == |
625 | NTC_CONNECTED_POSITIVE) || |
626 | (data->connect != NTC_CONNECTED_POSITIVE && |
627 | data->connect != NTC_CONNECTED_GROUND)) { |
628 | dev_err(dev, "Required data to use NTC driver not supplied.\n" ); |
629 | return -EINVAL; |
630 | } |
631 | |
632 | pdev_id = device_get_match_data(dev); |
633 | |
634 | if (pdev_id->driver_data >= ARRAY_SIZE(ntc_type)) { |
635 | dev_err(dev, "Unknown device type: %lu(%s)\n" , |
636 | pdev_id->driver_data, pdev_id->name); |
637 | return -EINVAL; |
638 | } |
639 | |
640 | data->comp = ntc_type[pdev_id->driver_data].comp; |
641 | data->n_comp = ntc_type[pdev_id->driver_data].n_comp; |
642 | |
643 | hwmon_dev = devm_hwmon_device_register_with_info(dev, name: pdev_id->name, |
644 | drvdata: data, info: &ntc_chip_info, |
645 | NULL); |
646 | if (IS_ERR(ptr: hwmon_dev)) { |
647 | dev_err(dev, "unable to register as hwmon device.\n" ); |
648 | return PTR_ERR(ptr: hwmon_dev); |
649 | } |
650 | |
651 | dev_info(dev, "Thermistor type: %s successfully probed.\n" , |
652 | pdev_id->name); |
653 | |
654 | return 0; |
655 | } |
656 | |
657 | static const struct of_device_id ntc_match[] = { |
658 | { .compatible = "epcos,b57330v2103" , |
659 | .data = &ntc_thermistor_id[NTC_B57330V2103]}, |
660 | { .compatible = "epcos,b57891s0103" , |
661 | .data = &ntc_thermistor_id[NTC_B57891S0103] }, |
662 | { .compatible = "murata,ncp03wb473" , |
663 | .data = &ntc_thermistor_id[NTC_NCP03WB473] }, |
664 | { .compatible = "murata,ncp03wf104" , |
665 | .data = &ntc_thermistor_id[NTC_NCP03WF104] }, |
666 | { .compatible = "murata,ncp15wb473" , |
667 | .data = &ntc_thermistor_id[NTC_NCP15WB473] }, |
668 | { .compatible = "murata,ncp15wl333" , |
669 | .data = &ntc_thermistor_id[NTC_NCP15WL333] }, |
670 | { .compatible = "murata,ncp15xh103" , |
671 | .data = &ntc_thermistor_id[NTC_NCP15XH103] }, |
672 | { .compatible = "murata,ncp18wb473" , |
673 | .data = &ntc_thermistor_id[NTC_NCP18WB473] }, |
674 | { .compatible = "murata,ncp21wb473" , |
675 | .data = &ntc_thermistor_id[NTC_NCP21WB473] }, |
676 | { .compatible = "samsung,1404-001221" , |
677 | .data = &ntc_thermistor_id[NTC_SSG1404001221] }, |
678 | |
679 | /* Usage of vendor name "ntc" is deprecated */ |
680 | { .compatible = "ntc,ncp03wb473" , |
681 | .data = &ntc_thermistor_id[NTC_NCP03WB473] }, |
682 | { .compatible = "ntc,ncp15wb473" , |
683 | .data = &ntc_thermistor_id[NTC_NCP15WB473] }, |
684 | { .compatible = "ntc,ncp15wl333" , |
685 | .data = &ntc_thermistor_id[NTC_NCP15WL333] }, |
686 | { .compatible = "ntc,ncp18wb473" , |
687 | .data = &ntc_thermistor_id[NTC_NCP18WB473] }, |
688 | { .compatible = "ntc,ncp21wb473" , |
689 | .data = &ntc_thermistor_id[NTC_NCP21WB473] }, |
690 | { }, |
691 | }; |
692 | MODULE_DEVICE_TABLE(of, ntc_match); |
693 | |
694 | static struct platform_driver ntc_thermistor_driver = { |
695 | .driver = { |
696 | .name = "ntc-thermistor" , |
697 | .of_match_table = ntc_match, |
698 | }, |
699 | .probe = ntc_thermistor_probe, |
700 | .id_table = ntc_thermistor_id, |
701 | }; |
702 | |
703 | module_platform_driver(ntc_thermistor_driver); |
704 | |
705 | MODULE_DESCRIPTION("NTC Thermistor Driver" ); |
706 | MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>" ); |
707 | MODULE_LICENSE("GPL" ); |
708 | MODULE_ALIAS("platform:ntc-thermistor" ); |
709 | |