Loading...
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/*
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 int get_ohm_of_thermistor(struct ntc_data *data, unsigned int uV)
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)
148 return INT_MAX;
149 return 0;
150 }
151 if (mV >= pmV)
152 return (pdata->connect == NTC_CONNECTED_POSITIVE) ?
153 0 : INT_MAX;
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
165 if (N > INT_MAX)
166 N = INT_MAX;
167 return N;
168}
169
170static void lookup_comp(struct ntc_data *data, unsigned int ohm,
171 int *i_low, int *i_high)
172{
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 }
192
193 /* Do a binary search on compensation table */
194 start = 0;
195 end = data->n_comp;
196 while (start < end) {
197 mid = start + (end - start) / 2;
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) {
208 end = mid;
209 } else {
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;
219 }
220 /*
221 * start <= end
222 * data->comp[start].ohm >= ohm >= data->comp[end].ohm
223 */
224 }
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;
234}
235
236static int get_temp_mC(struct ntc_data *data, unsigned int ohm)
237{
238 int low, high;
239 int temp;
240
241 lookup_comp(data, ohm, &low, &high);
242 if (low == high) {
243 /* Unable to use linear approximation */
244 temp = data->comp[low].temp_C * 1000;
245 } else {
246 temp = data->comp[low].temp_C * 1000 +
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 }
251 return temp;
252}
253
254static int ntc_thermistor_get_ohm(struct ntc_data *data)
255{
256 int read_uV;
257
258 if (data->pdata->read_ohm)
259 return data->pdata->read_ohm();
260
261 if (data->pdata->read_uV) {
262 read_uV = data->pdata->read_uV();
263 if (read_uV < 0)
264 return read_uV;
265 return get_ohm_of_thermistor(data, read_uV);
266 }
267 return -EINVAL;
268}
269
270static 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
278static ssize_t ntc_show_type(struct device *dev,
279 struct device_attribute *attr, char *buf)
280{
281 return sprintf(buf, "4\n");
282}
283
284static 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);
288 int ohm;
289
290 ohm = ntc_thermistor_get_ohm(data);
291 if (ohm < 0)
292 return ohm;
293
294 return sprintf(buf, "%d\n", get_temp_mC(data, ohm));
295}
296
297static SENSOR_DEVICE_ATTR(temp1_type, S_IRUGO, ntc_show_type, NULL, 0);
298static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ntc_show_temp, NULL, 0);
299static DEVICE_ATTR(name, S_IRUGO, ntc_show_name, NULL);
300
301static 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
308static const struct attribute_group ntc_attr_group = {
309 .attrs = ntc_attributes,
310};
311
312static 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) {
325 dev_err(&pdev->dev,
326 "Both read_uV and read_ohm missing. Need either one of the two.\n");
327 return -EINVAL;
328 }
329
330 if (pdata->read_uV && pdata->read_ohm) {
331 dev_warn(&pdev->dev,
332 "Only one of read_uV and read_ohm is needed; ignoring read_uV.\n");
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))) {
343 dev_err(&pdev->dev,
344 "Required data to use read_uV not supplied.\n");
345 return -EINVAL;
346 }
347
348 data = devm_kzalloc(&pdev->dev, sizeof(struct ntc_data), GFP_KERNEL);
349 if (!data)
350 return -ENOMEM;
351
352 data->dev = &pdev->dev;
353 data->pdata = pdata;
354 strncpy(data->name, pdev->id_entry->name, PLATFORM_NAME_SIZE);
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);
369 return -EINVAL;
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");
377 return ret;
378 }
379
380 data->hwmon_dev = hwmon_device_register(data->dev);
381 if (IS_ERR(data->hwmon_dev)) {
382 dev_err(data->dev, "unable to register as hwmon device.\n");
383 ret = PTR_ERR(data->hwmon_dev);
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;
391err_after_sysfs:
392 sysfs_remove_group(&data->dev->kobj, &ntc_attr_group);
393 return ret;
394}
395
396static 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
404 return 0;
405}
406
407static 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
416static 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
426module_platform_driver(ntc_thermistor_driver);
427
428MODULE_DESCRIPTION("NTC Thermistor Driver");
429MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
430MODULE_LICENSE("GPL");
431MODULE_ALIAS("platform:ntc-thermistor");