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a92c344d RG |
1 | /* |
2 | * tsl2550.c - Linux kernel modules for ambient light sensor | |
3 | * | |
4 | * Copyright (C) 2007 Rodolfo Giometti <giometti@linux.it> | |
5 | * Copyright (C) 2007 Eurotech S.p.A. <info@eurotech.it> | |
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., 675 Mass Ave, Cambridge, MA 02139, USA. | |
20 | */ | |
21 | ||
22 | #include <linux/module.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/slab.h> | |
25 | #include <linux/i2c.h> | |
26 | #include <linux/mutex.h> | |
a92c344d RG |
27 | |
28 | #define TSL2550_DRV_NAME "tsl2550" | |
ac780941 | 29 | #define DRIVER_VERSION "1.2" |
a92c344d RG |
30 | |
31 | /* | |
32 | * Defines | |
33 | */ | |
34 | ||
35 | #define TSL2550_POWER_DOWN 0x00 | |
36 | #define TSL2550_POWER_UP 0x03 | |
37 | #define TSL2550_STANDARD_RANGE 0x18 | |
38 | #define TSL2550_EXTENDED_RANGE 0x1d | |
39 | #define TSL2550_READ_ADC0 0x43 | |
40 | #define TSL2550_READ_ADC1 0x83 | |
41 | ||
42 | /* | |
43 | * Structs | |
44 | */ | |
45 | ||
46 | struct tsl2550_data { | |
47 | struct i2c_client *client; | |
48 | struct mutex update_lock; | |
49 | ||
50 | unsigned int power_state : 1; | |
51 | unsigned int operating_mode : 1; | |
52 | }; | |
53 | ||
54 | /* | |
55 | * Global data | |
56 | */ | |
57 | ||
58 | static const u8 TSL2550_MODE_RANGE[2] = { | |
59 | TSL2550_STANDARD_RANGE, TSL2550_EXTENDED_RANGE, | |
60 | }; | |
61 | ||
62 | /* | |
63 | * Management functions | |
64 | */ | |
65 | ||
66 | static int tsl2550_set_operating_mode(struct i2c_client *client, int mode) | |
67 | { | |
68 | struct tsl2550_data *data = i2c_get_clientdata(client); | |
69 | ||
70 | int ret = i2c_smbus_write_byte(client, TSL2550_MODE_RANGE[mode]); | |
71 | ||
72 | data->operating_mode = mode; | |
73 | ||
74 | return ret; | |
75 | } | |
76 | ||
77 | static int tsl2550_set_power_state(struct i2c_client *client, int state) | |
78 | { | |
79 | struct tsl2550_data *data = i2c_get_clientdata(client); | |
80 | int ret; | |
81 | ||
82 | if (state == 0) | |
83 | ret = i2c_smbus_write_byte(client, TSL2550_POWER_DOWN); | |
84 | else { | |
85 | ret = i2c_smbus_write_byte(client, TSL2550_POWER_UP); | |
86 | ||
87 | /* On power up we should reset operating mode also... */ | |
88 | tsl2550_set_operating_mode(client, data->operating_mode); | |
89 | } | |
90 | ||
91 | data->power_state = state; | |
92 | ||
93 | return ret; | |
94 | } | |
95 | ||
96 | static int tsl2550_get_adc_value(struct i2c_client *client, u8 cmd) | |
97 | { | |
ac780941 | 98 | int ret; |
a92c344d | 99 | |
ac780941 JD |
100 | ret = i2c_smbus_read_byte_data(client, cmd); |
101 | if (ret < 0) | |
102 | return ret; | |
a92c344d | 103 | if (!(ret & 0x80)) |
ac780941 | 104 | return -EAGAIN; |
a92c344d RG |
105 | return ret & 0x7f; /* remove the "valid" bit */ |
106 | } | |
107 | ||
108 | /* | |
109 | * LUX calculation | |
110 | */ | |
111 | ||
112 | #define TSL2550_MAX_LUX 1846 | |
113 | ||
114 | static const u8 ratio_lut[] = { | |
115 | 100, 100, 100, 100, 100, 100, 100, 100, | |
116 | 100, 100, 100, 100, 100, 100, 99, 99, | |
117 | 99, 99, 99, 99, 99, 99, 99, 99, | |
118 | 99, 99, 99, 98, 98, 98, 98, 98, | |
119 | 98, 98, 97, 97, 97, 97, 97, 96, | |
120 | 96, 96, 96, 95, 95, 95, 94, 94, | |
121 | 93, 93, 93, 92, 92, 91, 91, 90, | |
122 | 89, 89, 88, 87, 87, 86, 85, 84, | |
123 | 83, 82, 81, 80, 79, 78, 77, 75, | |
124 | 74, 73, 71, 69, 68, 66, 64, 62, | |
125 | 60, 58, 56, 54, 52, 49, 47, 44, | |
126 | 42, 41, 40, 40, 39, 39, 38, 38, | |
127 | 37, 37, 37, 36, 36, 36, 35, 35, | |
128 | 35, 35, 34, 34, 34, 34, 33, 33, | |
129 | 33, 33, 32, 32, 32, 32, 32, 31, | |
130 | 31, 31, 31, 31, 30, 30, 30, 30, | |
131 | 30, | |
132 | }; | |
133 | ||
134 | static const u16 count_lut[] = { | |
135 | 0, 1, 2, 3, 4, 5, 6, 7, | |
136 | 8, 9, 10, 11, 12, 13, 14, 15, | |
137 | 16, 18, 20, 22, 24, 26, 28, 30, | |
138 | 32, 34, 36, 38, 40, 42, 44, 46, | |
139 | 49, 53, 57, 61, 65, 69, 73, 77, | |
140 | 81, 85, 89, 93, 97, 101, 105, 109, | |
141 | 115, 123, 131, 139, 147, 155, 163, 171, | |
142 | 179, 187, 195, 203, 211, 219, 227, 235, | |
143 | 247, 263, 279, 295, 311, 327, 343, 359, | |
144 | 375, 391, 407, 423, 439, 455, 471, 487, | |
145 | 511, 543, 575, 607, 639, 671, 703, 735, | |
146 | 767, 799, 831, 863, 895, 927, 959, 991, | |
147 | 1039, 1103, 1167, 1231, 1295, 1359, 1423, 1487, | |
148 | 1551, 1615, 1679, 1743, 1807, 1871, 1935, 1999, | |
149 | 2095, 2223, 2351, 2479, 2607, 2735, 2863, 2991, | |
150 | 3119, 3247, 3375, 3503, 3631, 3759, 3887, 4015, | |
151 | }; | |
152 | ||
153 | /* | |
154 | * This function is described into Taos TSL2550 Designer's Notebook | |
155 | * pages 2, 3. | |
156 | */ | |
157 | static int tsl2550_calculate_lux(u8 ch0, u8 ch1) | |
158 | { | |
159 | unsigned int lux; | |
160 | ||
161 | /* Look up count from channel values */ | |
162 | u16 c0 = count_lut[ch0]; | |
163 | u16 c1 = count_lut[ch1]; | |
164 | ||
165 | /* | |
166 | * Calculate ratio. | |
167 | * Note: the "128" is a scaling factor | |
168 | */ | |
169 | u8 r = 128; | |
170 | ||
171 | /* Avoid division by 0 and count 1 cannot be greater than count 0 */ | |
96f699ad MJDC |
172 | if (c1 <= c0) |
173 | if (c0) { | |
174 | r = c1 * 128 / c0; | |
175 | ||
176 | /* Calculate LUX */ | |
177 | lux = ((c0 - c1) * ratio_lut[r]) / 256; | |
178 | } else | |
179 | lux = 0; | |
a92c344d | 180 | else |
96f699ad | 181 | return -EAGAIN; |
a92c344d RG |
182 | |
183 | /* LUX range check */ | |
184 | return lux > TSL2550_MAX_LUX ? TSL2550_MAX_LUX : lux; | |
185 | } | |
186 | ||
187 | /* | |
188 | * SysFS support | |
189 | */ | |
190 | ||
191 | static ssize_t tsl2550_show_power_state(struct device *dev, | |
192 | struct device_attribute *attr, char *buf) | |
193 | { | |
194 | struct tsl2550_data *data = i2c_get_clientdata(to_i2c_client(dev)); | |
195 | ||
196 | return sprintf(buf, "%u\n", data->power_state); | |
197 | } | |
198 | ||
199 | static ssize_t tsl2550_store_power_state(struct device *dev, | |
200 | struct device_attribute *attr, const char *buf, size_t count) | |
201 | { | |
202 | struct i2c_client *client = to_i2c_client(dev); | |
203 | struct tsl2550_data *data = i2c_get_clientdata(client); | |
204 | unsigned long val = simple_strtoul(buf, NULL, 10); | |
205 | int ret; | |
206 | ||
207 | if (val < 0 || val > 1) | |
208 | return -EINVAL; | |
209 | ||
210 | mutex_lock(&data->update_lock); | |
211 | ret = tsl2550_set_power_state(client, val); | |
212 | mutex_unlock(&data->update_lock); | |
213 | ||
214 | if (ret < 0) | |
215 | return ret; | |
216 | ||
217 | return count; | |
218 | } | |
219 | ||
220 | static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO, | |
221 | tsl2550_show_power_state, tsl2550_store_power_state); | |
222 | ||
223 | static ssize_t tsl2550_show_operating_mode(struct device *dev, | |
224 | struct device_attribute *attr, char *buf) | |
225 | { | |
226 | struct tsl2550_data *data = i2c_get_clientdata(to_i2c_client(dev)); | |
227 | ||
228 | return sprintf(buf, "%u\n", data->operating_mode); | |
229 | } | |
230 | ||
231 | static ssize_t tsl2550_store_operating_mode(struct device *dev, | |
232 | struct device_attribute *attr, const char *buf, size_t count) | |
233 | { | |
234 | struct i2c_client *client = to_i2c_client(dev); | |
235 | struct tsl2550_data *data = i2c_get_clientdata(client); | |
236 | unsigned long val = simple_strtoul(buf, NULL, 10); | |
237 | int ret; | |
238 | ||
239 | if (val < 0 || val > 1) | |
240 | return -EINVAL; | |
241 | ||
242 | if (data->power_state == 0) | |
243 | return -EBUSY; | |
244 | ||
245 | mutex_lock(&data->update_lock); | |
246 | ret = tsl2550_set_operating_mode(client, val); | |
247 | mutex_unlock(&data->update_lock); | |
248 | ||
249 | if (ret < 0) | |
250 | return ret; | |
251 | ||
252 | return count; | |
253 | } | |
254 | ||
255 | static DEVICE_ATTR(operating_mode, S_IWUSR | S_IRUGO, | |
256 | tsl2550_show_operating_mode, tsl2550_store_operating_mode); | |
257 | ||
258 | static ssize_t __tsl2550_show_lux(struct i2c_client *client, char *buf) | |
259 | { | |
260 | u8 ch0, ch1; | |
261 | int ret; | |
262 | ||
263 | ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC0); | |
264 | if (ret < 0) | |
265 | return ret; | |
266 | ch0 = ret; | |
267 | ||
a92c344d RG |
268 | ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC1); |
269 | if (ret < 0) | |
270 | return ret; | |
271 | ch1 = ret; | |
272 | ||
273 | /* Do the job */ | |
274 | ret = tsl2550_calculate_lux(ch0, ch1); | |
275 | if (ret < 0) | |
276 | return ret; | |
277 | ||
278 | return sprintf(buf, "%d\n", ret); | |
279 | } | |
280 | ||
281 | static ssize_t tsl2550_show_lux1_input(struct device *dev, | |
282 | struct device_attribute *attr, char *buf) | |
283 | { | |
284 | struct i2c_client *client = to_i2c_client(dev); | |
285 | struct tsl2550_data *data = i2c_get_clientdata(client); | |
286 | int ret; | |
287 | ||
288 | /* No LUX data if not operational */ | |
289 | if (!data->power_state) | |
290 | return -EBUSY; | |
291 | ||
292 | mutex_lock(&data->update_lock); | |
293 | ret = __tsl2550_show_lux(client, buf); | |
294 | mutex_unlock(&data->update_lock); | |
295 | ||
296 | return ret; | |
297 | } | |
298 | ||
299 | static DEVICE_ATTR(lux1_input, S_IRUGO, | |
300 | tsl2550_show_lux1_input, NULL); | |
301 | ||
302 | static struct attribute *tsl2550_attributes[] = { | |
303 | &dev_attr_power_state.attr, | |
304 | &dev_attr_operating_mode.attr, | |
305 | &dev_attr_lux1_input.attr, | |
306 | NULL | |
307 | }; | |
308 | ||
309 | static const struct attribute_group tsl2550_attr_group = { | |
310 | .attrs = tsl2550_attributes, | |
311 | }; | |
312 | ||
313 | /* | |
314 | * Initialization function | |
315 | */ | |
316 | ||
e296fb7f | 317 | static int tsl2550_init_client(struct i2c_client *client) |
a92c344d RG |
318 | { |
319 | struct tsl2550_data *data = i2c_get_clientdata(client); | |
e296fb7f | 320 | int err; |
a92c344d | 321 | |
e296fb7f JD |
322 | /* |
323 | * Probe the chip. To do so we try to power up the device and then to | |
324 | * read back the 0x03 code | |
325 | */ | |
ac780941 | 326 | err = i2c_smbus_read_byte_data(client, TSL2550_POWER_UP); |
e296fb7f JD |
327 | if (err < 0) |
328 | return err; | |
ac780941 | 329 | if (err != TSL2550_POWER_UP) |
e296fb7f JD |
330 | return -ENODEV; |
331 | data->power_state = 1; | |
332 | ||
333 | /* Set the default operating mode */ | |
334 | err = i2c_smbus_write_byte(client, | |
335 | TSL2550_MODE_RANGE[data->operating_mode]); | |
336 | if (err < 0) | |
337 | return err; | |
338 | ||
339 | return 0; | |
a92c344d RG |
340 | } |
341 | ||
342 | /* | |
343 | * I2C init/probing/exit functions | |
344 | */ | |
345 | ||
346 | static struct i2c_driver tsl2550_driver; | |
d2653e92 JD |
347 | static int __devinit tsl2550_probe(struct i2c_client *client, |
348 | const struct i2c_device_id *id) | |
a92c344d RG |
349 | { |
350 | struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); | |
351 | struct tsl2550_data *data; | |
352 | int *opmode, err = 0; | |
353 | ||
ac780941 JD |
354 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE |
355 | | I2C_FUNC_SMBUS_READ_BYTE_DATA)) { | |
a92c344d RG |
356 | err = -EIO; |
357 | goto exit; | |
358 | } | |
359 | ||
360 | data = kzalloc(sizeof(struct tsl2550_data), GFP_KERNEL); | |
361 | if (!data) { | |
362 | err = -ENOMEM; | |
363 | goto exit; | |
364 | } | |
365 | data->client = client; | |
366 | i2c_set_clientdata(client, data); | |
367 | ||
368 | /* Check platform data */ | |
369 | opmode = client->dev.platform_data; | |
370 | if (opmode) { | |
371 | if (*opmode < 0 || *opmode > 1) { | |
372 | dev_err(&client->dev, "invalid operating_mode (%d)\n", | |
373 | *opmode); | |
374 | err = -EINVAL; | |
375 | goto exit_kfree; | |
376 | } | |
377 | data->operating_mode = *opmode; | |
378 | } else | |
379 | data->operating_mode = 0; /* default mode is standard */ | |
380 | dev_info(&client->dev, "%s operating mode\n", | |
381 | data->operating_mode ? "extended" : "standard"); | |
382 | ||
a92c344d RG |
383 | mutex_init(&data->update_lock); |
384 | ||
385 | /* Initialize the TSL2550 chip */ | |
e296fb7f JD |
386 | err = tsl2550_init_client(client); |
387 | if (err) | |
388 | goto exit_kfree; | |
a92c344d RG |
389 | |
390 | /* Register sysfs hooks */ | |
391 | err = sysfs_create_group(&client->dev.kobj, &tsl2550_attr_group); | |
392 | if (err) | |
393 | goto exit_kfree; | |
394 | ||
395 | dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION); | |
396 | ||
397 | return 0; | |
398 | ||
399 | exit_kfree: | |
400 | kfree(data); | |
401 | exit: | |
402 | return err; | |
403 | } | |
404 | ||
405 | static int __devexit tsl2550_remove(struct i2c_client *client) | |
406 | { | |
407 | sysfs_remove_group(&client->dev.kobj, &tsl2550_attr_group); | |
408 | ||
409 | /* Power down the device */ | |
410 | tsl2550_set_power_state(client, 0); | |
411 | ||
412 | kfree(i2c_get_clientdata(client)); | |
413 | ||
414 | return 0; | |
415 | } | |
416 | ||
1b3e5baa RG |
417 | #ifdef CONFIG_PM |
418 | ||
419 | static int tsl2550_suspend(struct i2c_client *client, pm_message_t mesg) | |
420 | { | |
421 | return tsl2550_set_power_state(client, 0); | |
422 | } | |
423 | ||
424 | static int tsl2550_resume(struct i2c_client *client) | |
425 | { | |
426 | return tsl2550_set_power_state(client, 1); | |
427 | } | |
428 | ||
429 | #else | |
430 | ||
431 | #define tsl2550_suspend NULL | |
432 | #define tsl2550_resume NULL | |
433 | ||
434 | #endif /* CONFIG_PM */ | |
435 | ||
3760f736 JD |
436 | static const struct i2c_device_id tsl2550_id[] = { |
437 | { "tsl2550", 0 }, | |
438 | { } | |
439 | }; | |
440 | MODULE_DEVICE_TABLE(i2c, tsl2550_id); | |
441 | ||
a92c344d RG |
442 | static struct i2c_driver tsl2550_driver = { |
443 | .driver = { | |
444 | .name = TSL2550_DRV_NAME, | |
445 | .owner = THIS_MODULE, | |
446 | }, | |
1b3e5baa RG |
447 | .suspend = tsl2550_suspend, |
448 | .resume = tsl2550_resume, | |
a92c344d RG |
449 | .probe = tsl2550_probe, |
450 | .remove = __devexit_p(tsl2550_remove), | |
3760f736 | 451 | .id_table = tsl2550_id, |
a92c344d RG |
452 | }; |
453 | ||
454 | static int __init tsl2550_init(void) | |
455 | { | |
456 | return i2c_add_driver(&tsl2550_driver); | |
457 | } | |
458 | ||
459 | static void __exit tsl2550_exit(void) | |
460 | { | |
461 | i2c_del_driver(&tsl2550_driver); | |
462 | } | |
463 | ||
464 | MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>"); | |
465 | MODULE_DESCRIPTION("TSL2550 ambient light sensor driver"); | |
466 | MODULE_LICENSE("GPL"); | |
e296fb7f | 467 | MODULE_VERSION(DRIVER_VERSION); |
a92c344d RG |
468 | |
469 | module_init(tsl2550_init); | |
470 | module_exit(tsl2550_exit); |