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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> | |
27 | #include <linux/delay.h> | |
28 | ||
29 | #define TSL2550_DRV_NAME "tsl2550" | |
e296fb7f | 30 | #define DRIVER_VERSION "1.1.1" |
a92c344d RG |
31 | |
32 | /* | |
33 | * Defines | |
34 | */ | |
35 | ||
36 | #define TSL2550_POWER_DOWN 0x00 | |
37 | #define TSL2550_POWER_UP 0x03 | |
38 | #define TSL2550_STANDARD_RANGE 0x18 | |
39 | #define TSL2550_EXTENDED_RANGE 0x1d | |
40 | #define TSL2550_READ_ADC0 0x43 | |
41 | #define TSL2550_READ_ADC1 0x83 | |
42 | ||
43 | /* | |
44 | * Structs | |
45 | */ | |
46 | ||
47 | struct tsl2550_data { | |
48 | struct i2c_client *client; | |
49 | struct mutex update_lock; | |
50 | ||
51 | unsigned int power_state : 1; | |
52 | unsigned int operating_mode : 1; | |
53 | }; | |
54 | ||
55 | /* | |
56 | * Global data | |
57 | */ | |
58 | ||
59 | static const u8 TSL2550_MODE_RANGE[2] = { | |
60 | TSL2550_STANDARD_RANGE, TSL2550_EXTENDED_RANGE, | |
61 | }; | |
62 | ||
63 | /* | |
64 | * Management functions | |
65 | */ | |
66 | ||
67 | static int tsl2550_set_operating_mode(struct i2c_client *client, int mode) | |
68 | { | |
69 | struct tsl2550_data *data = i2c_get_clientdata(client); | |
70 | ||
71 | int ret = i2c_smbus_write_byte(client, TSL2550_MODE_RANGE[mode]); | |
72 | ||
73 | data->operating_mode = mode; | |
74 | ||
75 | return ret; | |
76 | } | |
77 | ||
78 | static int tsl2550_set_power_state(struct i2c_client *client, int state) | |
79 | { | |
80 | struct tsl2550_data *data = i2c_get_clientdata(client); | |
81 | int ret; | |
82 | ||
83 | if (state == 0) | |
84 | ret = i2c_smbus_write_byte(client, TSL2550_POWER_DOWN); | |
85 | else { | |
86 | ret = i2c_smbus_write_byte(client, TSL2550_POWER_UP); | |
87 | ||
88 | /* On power up we should reset operating mode also... */ | |
89 | tsl2550_set_operating_mode(client, data->operating_mode); | |
90 | } | |
91 | ||
92 | data->power_state = state; | |
93 | ||
94 | return ret; | |
95 | } | |
96 | ||
97 | static int tsl2550_get_adc_value(struct i2c_client *client, u8 cmd) | |
98 | { | |
99 | unsigned long end; | |
100 | int loop = 0, ret = 0; | |
101 | ||
102 | /* | |
103 | * Read ADC channel waiting at most 400ms (see data sheet for further | |
104 | * info). | |
105 | * To avoid long busy wait we spin for few milliseconds then | |
106 | * start sleeping. | |
107 | */ | |
108 | end = jiffies + msecs_to_jiffies(400); | |
109 | while (time_before(jiffies, end)) { | |
110 | i2c_smbus_write_byte(client, cmd); | |
111 | ||
112 | if (loop++ < 5) | |
113 | mdelay(1); | |
114 | else | |
115 | msleep(1); | |
116 | ||
117 | ret = i2c_smbus_read_byte(client); | |
118 | if (ret < 0) | |
119 | return ret; | |
120 | else if (ret & 0x0080) | |
121 | break; | |
122 | } | |
123 | if (!(ret & 0x80)) | |
124 | return -EIO; | |
125 | return ret & 0x7f; /* remove the "valid" bit */ | |
126 | } | |
127 | ||
128 | /* | |
129 | * LUX calculation | |
130 | */ | |
131 | ||
132 | #define TSL2550_MAX_LUX 1846 | |
133 | ||
134 | static const u8 ratio_lut[] = { | |
135 | 100, 100, 100, 100, 100, 100, 100, 100, | |
136 | 100, 100, 100, 100, 100, 100, 99, 99, | |
137 | 99, 99, 99, 99, 99, 99, 99, 99, | |
138 | 99, 99, 99, 98, 98, 98, 98, 98, | |
139 | 98, 98, 97, 97, 97, 97, 97, 96, | |
140 | 96, 96, 96, 95, 95, 95, 94, 94, | |
141 | 93, 93, 93, 92, 92, 91, 91, 90, | |
142 | 89, 89, 88, 87, 87, 86, 85, 84, | |
143 | 83, 82, 81, 80, 79, 78, 77, 75, | |
144 | 74, 73, 71, 69, 68, 66, 64, 62, | |
145 | 60, 58, 56, 54, 52, 49, 47, 44, | |
146 | 42, 41, 40, 40, 39, 39, 38, 38, | |
147 | 37, 37, 37, 36, 36, 36, 35, 35, | |
148 | 35, 35, 34, 34, 34, 34, 33, 33, | |
149 | 33, 33, 32, 32, 32, 32, 32, 31, | |
150 | 31, 31, 31, 31, 30, 30, 30, 30, | |
151 | 30, | |
152 | }; | |
153 | ||
154 | static const u16 count_lut[] = { | |
155 | 0, 1, 2, 3, 4, 5, 6, 7, | |
156 | 8, 9, 10, 11, 12, 13, 14, 15, | |
157 | 16, 18, 20, 22, 24, 26, 28, 30, | |
158 | 32, 34, 36, 38, 40, 42, 44, 46, | |
159 | 49, 53, 57, 61, 65, 69, 73, 77, | |
160 | 81, 85, 89, 93, 97, 101, 105, 109, | |
161 | 115, 123, 131, 139, 147, 155, 163, 171, | |
162 | 179, 187, 195, 203, 211, 219, 227, 235, | |
163 | 247, 263, 279, 295, 311, 327, 343, 359, | |
164 | 375, 391, 407, 423, 439, 455, 471, 487, | |
165 | 511, 543, 575, 607, 639, 671, 703, 735, | |
166 | 767, 799, 831, 863, 895, 927, 959, 991, | |
167 | 1039, 1103, 1167, 1231, 1295, 1359, 1423, 1487, | |
168 | 1551, 1615, 1679, 1743, 1807, 1871, 1935, 1999, | |
169 | 2095, 2223, 2351, 2479, 2607, 2735, 2863, 2991, | |
170 | 3119, 3247, 3375, 3503, 3631, 3759, 3887, 4015, | |
171 | }; | |
172 | ||
173 | /* | |
174 | * This function is described into Taos TSL2550 Designer's Notebook | |
175 | * pages 2, 3. | |
176 | */ | |
177 | static int tsl2550_calculate_lux(u8 ch0, u8 ch1) | |
178 | { | |
179 | unsigned int lux; | |
180 | ||
181 | /* Look up count from channel values */ | |
182 | u16 c0 = count_lut[ch0]; | |
183 | u16 c1 = count_lut[ch1]; | |
184 | ||
185 | /* | |
186 | * Calculate ratio. | |
187 | * Note: the "128" is a scaling factor | |
188 | */ | |
189 | u8 r = 128; | |
190 | ||
191 | /* Avoid division by 0 and count 1 cannot be greater than count 0 */ | |
192 | if (c0 && (c1 <= c0)) | |
193 | r = c1 * 128 / c0; | |
194 | else | |
195 | return -1; | |
196 | ||
197 | /* Calculate LUX */ | |
198 | lux = ((c0 - c1) * ratio_lut[r]) / 256; | |
199 | ||
200 | /* LUX range check */ | |
201 | return lux > TSL2550_MAX_LUX ? TSL2550_MAX_LUX : lux; | |
202 | } | |
203 | ||
204 | /* | |
205 | * SysFS support | |
206 | */ | |
207 | ||
208 | static ssize_t tsl2550_show_power_state(struct device *dev, | |
209 | struct device_attribute *attr, char *buf) | |
210 | { | |
211 | struct tsl2550_data *data = i2c_get_clientdata(to_i2c_client(dev)); | |
212 | ||
213 | return sprintf(buf, "%u\n", data->power_state); | |
214 | } | |
215 | ||
216 | static ssize_t tsl2550_store_power_state(struct device *dev, | |
217 | struct device_attribute *attr, const char *buf, size_t count) | |
218 | { | |
219 | struct i2c_client *client = to_i2c_client(dev); | |
220 | struct tsl2550_data *data = i2c_get_clientdata(client); | |
221 | unsigned long val = simple_strtoul(buf, NULL, 10); | |
222 | int ret; | |
223 | ||
224 | if (val < 0 || val > 1) | |
225 | return -EINVAL; | |
226 | ||
227 | mutex_lock(&data->update_lock); | |
228 | ret = tsl2550_set_power_state(client, val); | |
229 | mutex_unlock(&data->update_lock); | |
230 | ||
231 | if (ret < 0) | |
232 | return ret; | |
233 | ||
234 | return count; | |
235 | } | |
236 | ||
237 | static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO, | |
238 | tsl2550_show_power_state, tsl2550_store_power_state); | |
239 | ||
240 | static ssize_t tsl2550_show_operating_mode(struct device *dev, | |
241 | struct device_attribute *attr, char *buf) | |
242 | { | |
243 | struct tsl2550_data *data = i2c_get_clientdata(to_i2c_client(dev)); | |
244 | ||
245 | return sprintf(buf, "%u\n", data->operating_mode); | |
246 | } | |
247 | ||
248 | static ssize_t tsl2550_store_operating_mode(struct device *dev, | |
249 | struct device_attribute *attr, const char *buf, size_t count) | |
250 | { | |
251 | struct i2c_client *client = to_i2c_client(dev); | |
252 | struct tsl2550_data *data = i2c_get_clientdata(client); | |
253 | unsigned long val = simple_strtoul(buf, NULL, 10); | |
254 | int ret; | |
255 | ||
256 | if (val < 0 || val > 1) | |
257 | return -EINVAL; | |
258 | ||
259 | if (data->power_state == 0) | |
260 | return -EBUSY; | |
261 | ||
262 | mutex_lock(&data->update_lock); | |
263 | ret = tsl2550_set_operating_mode(client, val); | |
264 | mutex_unlock(&data->update_lock); | |
265 | ||
266 | if (ret < 0) | |
267 | return ret; | |
268 | ||
269 | return count; | |
270 | } | |
271 | ||
272 | static DEVICE_ATTR(operating_mode, S_IWUSR | S_IRUGO, | |
273 | tsl2550_show_operating_mode, tsl2550_store_operating_mode); | |
274 | ||
275 | static ssize_t __tsl2550_show_lux(struct i2c_client *client, char *buf) | |
276 | { | |
277 | u8 ch0, ch1; | |
278 | int ret; | |
279 | ||
280 | ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC0); | |
281 | if (ret < 0) | |
282 | return ret; | |
283 | ch0 = ret; | |
284 | ||
285 | mdelay(1); | |
286 | ||
287 | ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC1); | |
288 | if (ret < 0) | |
289 | return ret; | |
290 | ch1 = ret; | |
291 | ||
292 | /* Do the job */ | |
293 | ret = tsl2550_calculate_lux(ch0, ch1); | |
294 | if (ret < 0) | |
295 | return ret; | |
296 | ||
297 | return sprintf(buf, "%d\n", ret); | |
298 | } | |
299 | ||
300 | static ssize_t tsl2550_show_lux1_input(struct device *dev, | |
301 | struct device_attribute *attr, char *buf) | |
302 | { | |
303 | struct i2c_client *client = to_i2c_client(dev); | |
304 | struct tsl2550_data *data = i2c_get_clientdata(client); | |
305 | int ret; | |
306 | ||
307 | /* No LUX data if not operational */ | |
308 | if (!data->power_state) | |
309 | return -EBUSY; | |
310 | ||
311 | mutex_lock(&data->update_lock); | |
312 | ret = __tsl2550_show_lux(client, buf); | |
313 | mutex_unlock(&data->update_lock); | |
314 | ||
315 | return ret; | |
316 | } | |
317 | ||
318 | static DEVICE_ATTR(lux1_input, S_IRUGO, | |
319 | tsl2550_show_lux1_input, NULL); | |
320 | ||
321 | static struct attribute *tsl2550_attributes[] = { | |
322 | &dev_attr_power_state.attr, | |
323 | &dev_attr_operating_mode.attr, | |
324 | &dev_attr_lux1_input.attr, | |
325 | NULL | |
326 | }; | |
327 | ||
328 | static const struct attribute_group tsl2550_attr_group = { | |
329 | .attrs = tsl2550_attributes, | |
330 | }; | |
331 | ||
332 | /* | |
333 | * Initialization function | |
334 | */ | |
335 | ||
e296fb7f | 336 | static int tsl2550_init_client(struct i2c_client *client) |
a92c344d RG |
337 | { |
338 | struct tsl2550_data *data = i2c_get_clientdata(client); | |
e296fb7f | 339 | int err; |
a92c344d | 340 | |
e296fb7f JD |
341 | /* |
342 | * Probe the chip. To do so we try to power up the device and then to | |
343 | * read back the 0x03 code | |
344 | */ | |
345 | err = i2c_smbus_write_byte(client, TSL2550_POWER_UP); | |
346 | if (err < 0) | |
347 | return err; | |
348 | mdelay(1); | |
349 | if (i2c_smbus_read_byte(client) != TSL2550_POWER_UP) | |
350 | return -ENODEV; | |
351 | data->power_state = 1; | |
352 | ||
353 | /* Set the default operating mode */ | |
354 | err = i2c_smbus_write_byte(client, | |
355 | TSL2550_MODE_RANGE[data->operating_mode]); | |
356 | if (err < 0) | |
357 | return err; | |
358 | ||
359 | return 0; | |
a92c344d RG |
360 | } |
361 | ||
362 | /* | |
363 | * I2C init/probing/exit functions | |
364 | */ | |
365 | ||
366 | static struct i2c_driver tsl2550_driver; | |
d2653e92 JD |
367 | static int __devinit tsl2550_probe(struct i2c_client *client, |
368 | const struct i2c_device_id *id) | |
a92c344d RG |
369 | { |
370 | struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); | |
371 | struct tsl2550_data *data; | |
372 | int *opmode, err = 0; | |
373 | ||
374 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) { | |
375 | err = -EIO; | |
376 | goto exit; | |
377 | } | |
378 | ||
379 | data = kzalloc(sizeof(struct tsl2550_data), GFP_KERNEL); | |
380 | if (!data) { | |
381 | err = -ENOMEM; | |
382 | goto exit; | |
383 | } | |
384 | data->client = client; | |
385 | i2c_set_clientdata(client, data); | |
386 | ||
387 | /* Check platform data */ | |
388 | opmode = client->dev.platform_data; | |
389 | if (opmode) { | |
390 | if (*opmode < 0 || *opmode > 1) { | |
391 | dev_err(&client->dev, "invalid operating_mode (%d)\n", | |
392 | *opmode); | |
393 | err = -EINVAL; | |
394 | goto exit_kfree; | |
395 | } | |
396 | data->operating_mode = *opmode; | |
397 | } else | |
398 | data->operating_mode = 0; /* default mode is standard */ | |
399 | dev_info(&client->dev, "%s operating mode\n", | |
400 | data->operating_mode ? "extended" : "standard"); | |
401 | ||
a92c344d RG |
402 | mutex_init(&data->update_lock); |
403 | ||
404 | /* Initialize the TSL2550 chip */ | |
e296fb7f JD |
405 | err = tsl2550_init_client(client); |
406 | if (err) | |
407 | goto exit_kfree; | |
a92c344d RG |
408 | |
409 | /* Register sysfs hooks */ | |
410 | err = sysfs_create_group(&client->dev.kobj, &tsl2550_attr_group); | |
411 | if (err) | |
412 | goto exit_kfree; | |
413 | ||
414 | dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION); | |
415 | ||
416 | return 0; | |
417 | ||
418 | exit_kfree: | |
419 | kfree(data); | |
420 | exit: | |
421 | return err; | |
422 | } | |
423 | ||
424 | static int __devexit tsl2550_remove(struct i2c_client *client) | |
425 | { | |
426 | sysfs_remove_group(&client->dev.kobj, &tsl2550_attr_group); | |
427 | ||
428 | /* Power down the device */ | |
429 | tsl2550_set_power_state(client, 0); | |
430 | ||
431 | kfree(i2c_get_clientdata(client)); | |
432 | ||
433 | return 0; | |
434 | } | |
435 | ||
1b3e5baa RG |
436 | #ifdef CONFIG_PM |
437 | ||
438 | static int tsl2550_suspend(struct i2c_client *client, pm_message_t mesg) | |
439 | { | |
440 | return tsl2550_set_power_state(client, 0); | |
441 | } | |
442 | ||
443 | static int tsl2550_resume(struct i2c_client *client) | |
444 | { | |
445 | return tsl2550_set_power_state(client, 1); | |
446 | } | |
447 | ||
448 | #else | |
449 | ||
450 | #define tsl2550_suspend NULL | |
451 | #define tsl2550_resume NULL | |
452 | ||
453 | #endif /* CONFIG_PM */ | |
454 | ||
a92c344d RG |
455 | static struct i2c_driver tsl2550_driver = { |
456 | .driver = { | |
457 | .name = TSL2550_DRV_NAME, | |
458 | .owner = THIS_MODULE, | |
459 | }, | |
1b3e5baa RG |
460 | .suspend = tsl2550_suspend, |
461 | .resume = tsl2550_resume, | |
a92c344d RG |
462 | .probe = tsl2550_probe, |
463 | .remove = __devexit_p(tsl2550_remove), | |
464 | }; | |
465 | ||
466 | static int __init tsl2550_init(void) | |
467 | { | |
468 | return i2c_add_driver(&tsl2550_driver); | |
469 | } | |
470 | ||
471 | static void __exit tsl2550_exit(void) | |
472 | { | |
473 | i2c_del_driver(&tsl2550_driver); | |
474 | } | |
475 | ||
476 | MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>"); | |
477 | MODULE_DESCRIPTION("TSL2550 ambient light sensor driver"); | |
478 | MODULE_LICENSE("GPL"); | |
e296fb7f | 479 | MODULE_VERSION(DRIVER_VERSION); |
a92c344d RG |
480 | |
481 | module_init(tsl2550_init); | |
482 | module_exit(tsl2550_exit); |