Root/
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 | |
28 | #define TSL2550_DRV_NAME "tsl2550" |
29 | #define DRIVER_VERSION "1.2" |
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 | { |
98 | int ret; |
99 | |
100 | ret = i2c_smbus_read_byte_data(client, cmd); |
101 | if (ret < 0) |
102 | return ret; |
103 | if (!(ret & 0x80)) |
104 | return -EAGAIN; |
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 */ |
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; |
180 | else |
181 | return -EAGAIN; |
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 | struct tsl2550_data *data = i2c_get_clientdata(client); |
261 | u8 ch0, ch1; |
262 | int ret; |
263 | |
264 | ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC0); |
265 | if (ret < 0) |
266 | return ret; |
267 | ch0 = ret; |
268 | |
269 | ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC1); |
270 | if (ret < 0) |
271 | return ret; |
272 | ch1 = ret; |
273 | |
274 | /* Do the job */ |
275 | ret = tsl2550_calculate_lux(ch0, ch1); |
276 | if (ret < 0) |
277 | return ret; |
278 | if (data->operating_mode == 1) |
279 | ret *= 5; |
280 | |
281 | return sprintf(buf, "%d\n", ret); |
282 | } |
283 | |
284 | static ssize_t tsl2550_show_lux1_input(struct device *dev, |
285 | struct device_attribute *attr, char *buf) |
286 | { |
287 | struct i2c_client *client = to_i2c_client(dev); |
288 | struct tsl2550_data *data = i2c_get_clientdata(client); |
289 | int ret; |
290 | |
291 | /* No LUX data if not operational */ |
292 | if (!data->power_state) |
293 | return -EBUSY; |
294 | |
295 | mutex_lock(&data->update_lock); |
296 | ret = __tsl2550_show_lux(client, buf); |
297 | mutex_unlock(&data->update_lock); |
298 | |
299 | return ret; |
300 | } |
301 | |
302 | static DEVICE_ATTR(lux1_input, S_IRUGO, |
303 | tsl2550_show_lux1_input, NULL); |
304 | |
305 | static struct attribute *tsl2550_attributes[] = { |
306 | &dev_attr_power_state.attr, |
307 | &dev_attr_operating_mode.attr, |
308 | &dev_attr_lux1_input.attr, |
309 | NULL |
310 | }; |
311 | |
312 | static const struct attribute_group tsl2550_attr_group = { |
313 | .attrs = tsl2550_attributes, |
314 | }; |
315 | |
316 | /* |
317 | * Initialization function |
318 | */ |
319 | |
320 | static int tsl2550_init_client(struct i2c_client *client) |
321 | { |
322 | struct tsl2550_data *data = i2c_get_clientdata(client); |
323 | int err; |
324 | |
325 | /* |
326 | * Probe the chip. To do so we try to power up the device and then to |
327 | * read back the 0x03 code |
328 | */ |
329 | err = i2c_smbus_read_byte_data(client, TSL2550_POWER_UP); |
330 | if (err < 0) |
331 | return err; |
332 | if (err != TSL2550_POWER_UP) |
333 | return -ENODEV; |
334 | data->power_state = 1; |
335 | |
336 | /* Set the default operating mode */ |
337 | err = i2c_smbus_write_byte(client, |
338 | TSL2550_MODE_RANGE[data->operating_mode]); |
339 | if (err < 0) |
340 | return err; |
341 | |
342 | return 0; |
343 | } |
344 | |
345 | /* |
346 | * I2C init/probing/exit functions |
347 | */ |
348 | |
349 | static struct i2c_driver tsl2550_driver; |
350 | static int __devinit tsl2550_probe(struct i2c_client *client, |
351 | const struct i2c_device_id *id) |
352 | { |
353 | struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent); |
354 | struct tsl2550_data *data; |
355 | int *opmode, err = 0; |
356 | |
357 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE |
358 | | I2C_FUNC_SMBUS_READ_BYTE_DATA)) { |
359 | err = -EIO; |
360 | goto exit; |
361 | } |
362 | |
363 | data = kzalloc(sizeof(struct tsl2550_data), GFP_KERNEL); |
364 | if (!data) { |
365 | err = -ENOMEM; |
366 | goto exit; |
367 | } |
368 | data->client = client; |
369 | i2c_set_clientdata(client, data); |
370 | |
371 | /* Check platform data */ |
372 | opmode = client->dev.platform_data; |
373 | if (opmode) { |
374 | if (*opmode < 0 || *opmode > 1) { |
375 | dev_err(&client->dev, "invalid operating_mode (%d)\n", |
376 | *opmode); |
377 | err = -EINVAL; |
378 | goto exit_kfree; |
379 | } |
380 | data->operating_mode = *opmode; |
381 | } else |
382 | data->operating_mode = 0; /* default mode is standard */ |
383 | dev_info(&client->dev, "%s operating mode\n", |
384 | data->operating_mode ? "extended" : "standard"); |
385 | |
386 | mutex_init(&data->update_lock); |
387 | |
388 | /* Initialize the TSL2550 chip */ |
389 | err = tsl2550_init_client(client); |
390 | if (err) |
391 | goto exit_kfree; |
392 | |
393 | /* Register sysfs hooks */ |
394 | err = sysfs_create_group(&client->dev.kobj, &tsl2550_attr_group); |
395 | if (err) |
396 | goto exit_kfree; |
397 | |
398 | dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION); |
399 | |
400 | return 0; |
401 | |
402 | exit_kfree: |
403 | kfree(data); |
404 | exit: |
405 | return err; |
406 | } |
407 | |
408 | static int __devexit tsl2550_remove(struct i2c_client *client) |
409 | { |
410 | sysfs_remove_group(&client->dev.kobj, &tsl2550_attr_group); |
411 | |
412 | /* Power down the device */ |
413 | tsl2550_set_power_state(client, 0); |
414 | |
415 | kfree(i2c_get_clientdata(client)); |
416 | |
417 | return 0; |
418 | } |
419 | |
420 | #ifdef CONFIG_PM |
421 | |
422 | static int tsl2550_suspend(struct i2c_client *client, pm_message_t mesg) |
423 | { |
424 | return tsl2550_set_power_state(client, 0); |
425 | } |
426 | |
427 | static int tsl2550_resume(struct i2c_client *client) |
428 | { |
429 | return tsl2550_set_power_state(client, 1); |
430 | } |
431 | |
432 | #else |
433 | |
434 | #define tsl2550_suspend NULL |
435 | #define tsl2550_resume NULL |
436 | |
437 | #endif /* CONFIG_PM */ |
438 | |
439 | static const struct i2c_device_id tsl2550_id[] = { |
440 | { "tsl2550", 0 }, |
441 | { } |
442 | }; |
443 | MODULE_DEVICE_TABLE(i2c, tsl2550_id); |
444 | |
445 | static struct i2c_driver tsl2550_driver = { |
446 | .driver = { |
447 | .name = TSL2550_DRV_NAME, |
448 | .owner = THIS_MODULE, |
449 | }, |
450 | .suspend = tsl2550_suspend, |
451 | .resume = tsl2550_resume, |
452 | .probe = tsl2550_probe, |
453 | .remove = __devexit_p(tsl2550_remove), |
454 | .id_table = tsl2550_id, |
455 | }; |
456 | |
457 | static int __init tsl2550_init(void) |
458 | { |
459 | return i2c_add_driver(&tsl2550_driver); |
460 | } |
461 | |
462 | static void __exit tsl2550_exit(void) |
463 | { |
464 | i2c_del_driver(&tsl2550_driver); |
465 | } |
466 | |
467 | MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>"); |
468 | MODULE_DESCRIPTION("TSL2550 ambient light sensor driver"); |
469 | MODULE_LICENSE("GPL"); |
470 | MODULE_VERSION(DRIVER_VERSION); |
471 | |
472 | module_init(tsl2550_init); |
473 | module_exit(tsl2550_exit); |
474 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9