1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * tsl2550.c - Linux kernel modules for ambient light sensor |
4 | * |
5 | * Copyright (C) 2007 Rodolfo Giometti <giometti@linux.it> |
6 | * Copyright (C) 2007 Eurotech S.p.A. <info@eurotech.it> |
7 | */ |
8 | |
9 | #include <linux/module.h> |
10 | #include <linux/slab.h> |
11 | #include <linux/i2c.h> |
12 | #include <linux/mutex.h> |
13 | |
14 | #define TSL2550_DRV_NAME "tsl2550" |
15 | #define DRIVER_VERSION "1.2" |
16 | |
17 | /* |
18 | * Defines |
19 | */ |
20 | |
21 | #define TSL2550_POWER_DOWN 0x00 |
22 | #define TSL2550_POWER_UP 0x03 |
23 | #define TSL2550_STANDARD_RANGE 0x18 |
24 | #define TSL2550_EXTENDED_RANGE 0x1d |
25 | #define TSL2550_READ_ADC0 0x43 |
26 | #define TSL2550_READ_ADC1 0x83 |
27 | |
28 | /* |
29 | * Structs |
30 | */ |
31 | |
32 | struct tsl2550_data { |
33 | struct i2c_client *client; |
34 | struct mutex update_lock; |
35 | |
36 | unsigned int power_state:1; |
37 | unsigned int operating_mode:1; |
38 | }; |
39 | |
40 | /* |
41 | * Global data |
42 | */ |
43 | |
44 | static const u8 TSL2550_MODE_RANGE[2] = { |
45 | TSL2550_STANDARD_RANGE, TSL2550_EXTENDED_RANGE, |
46 | }; |
47 | |
48 | /* |
49 | * Management functions |
50 | */ |
51 | |
52 | static int tsl2550_set_operating_mode(struct i2c_client *client, int mode) |
53 | { |
54 | struct tsl2550_data *data = i2c_get_clientdata(client); |
55 | |
56 | int ret = i2c_smbus_write_byte(client, value: TSL2550_MODE_RANGE[mode]); |
57 | |
58 | data->operating_mode = mode; |
59 | |
60 | return ret; |
61 | } |
62 | |
63 | static int tsl2550_set_power_state(struct i2c_client *client, int state) |
64 | { |
65 | struct tsl2550_data *data = i2c_get_clientdata(client); |
66 | int ret; |
67 | |
68 | if (state == 0) |
69 | ret = i2c_smbus_write_byte(client, TSL2550_POWER_DOWN); |
70 | else { |
71 | ret = i2c_smbus_write_byte(client, TSL2550_POWER_UP); |
72 | |
73 | /* On power up we should reset operating mode also... */ |
74 | tsl2550_set_operating_mode(client, mode: data->operating_mode); |
75 | } |
76 | |
77 | data->power_state = state; |
78 | |
79 | return ret; |
80 | } |
81 | |
82 | static int tsl2550_get_adc_value(struct i2c_client *client, u8 cmd) |
83 | { |
84 | int ret; |
85 | |
86 | ret = i2c_smbus_read_byte_data(client, command: cmd); |
87 | if (ret < 0) |
88 | return ret; |
89 | if (!(ret & 0x80)) |
90 | return -EAGAIN; |
91 | return ret & 0x7f; /* remove the "valid" bit */ |
92 | } |
93 | |
94 | /* |
95 | * LUX calculation |
96 | */ |
97 | |
98 | #define TSL2550_MAX_LUX 1846 |
99 | |
100 | static const u8 ratio_lut[] = { |
101 | 100, 100, 100, 100, 100, 100, 100, 100, |
102 | 100, 100, 100, 100, 100, 100, 99, 99, |
103 | 99, 99, 99, 99, 99, 99, 99, 99, |
104 | 99, 99, 99, 98, 98, 98, 98, 98, |
105 | 98, 98, 97, 97, 97, 97, 97, 96, |
106 | 96, 96, 96, 95, 95, 95, 94, 94, |
107 | 93, 93, 93, 92, 92, 91, 91, 90, |
108 | 89, 89, 88, 87, 87, 86, 85, 84, |
109 | 83, 82, 81, 80, 79, 78, 77, 75, |
110 | 74, 73, 71, 69, 68, 66, 64, 62, |
111 | 60, 58, 56, 54, 52, 49, 47, 44, |
112 | 42, 41, 40, 40, 39, 39, 38, 38, |
113 | 37, 37, 37, 36, 36, 36, 35, 35, |
114 | 35, 35, 34, 34, 34, 34, 33, 33, |
115 | 33, 33, 32, 32, 32, 32, 32, 31, |
116 | 31, 31, 31, 31, 30, 30, 30, 30, |
117 | 30, |
118 | }; |
119 | |
120 | static const u16 count_lut[] = { |
121 | 0, 1, 2, 3, 4, 5, 6, 7, |
122 | 8, 9, 10, 11, 12, 13, 14, 15, |
123 | 16, 18, 20, 22, 24, 26, 28, 30, |
124 | 32, 34, 36, 38, 40, 42, 44, 46, |
125 | 49, 53, 57, 61, 65, 69, 73, 77, |
126 | 81, 85, 89, 93, 97, 101, 105, 109, |
127 | 115, 123, 131, 139, 147, 155, 163, 171, |
128 | 179, 187, 195, 203, 211, 219, 227, 235, |
129 | 247, 263, 279, 295, 311, 327, 343, 359, |
130 | 375, 391, 407, 423, 439, 455, 471, 487, |
131 | 511, 543, 575, 607, 639, 671, 703, 735, |
132 | 767, 799, 831, 863, 895, 927, 959, 991, |
133 | 1039, 1103, 1167, 1231, 1295, 1359, 1423, 1487, |
134 | 1551, 1615, 1679, 1743, 1807, 1871, 1935, 1999, |
135 | 2095, 2223, 2351, 2479, 2607, 2735, 2863, 2991, |
136 | 3119, 3247, 3375, 3503, 3631, 3759, 3887, 4015, |
137 | }; |
138 | |
139 | /* |
140 | * This function is described into Taos TSL2550 Designer's Notebook |
141 | * pages 2, 3. |
142 | */ |
143 | static int tsl2550_calculate_lux(u8 ch0, u8 ch1) |
144 | { |
145 | unsigned int lux; |
146 | |
147 | /* Look up count from channel values */ |
148 | u16 c0 = count_lut[ch0]; |
149 | u16 c1 = count_lut[ch1]; |
150 | |
151 | /* Avoid division by 0 and count 1 cannot be greater than count 0 */ |
152 | if (c1 <= c0) |
153 | if (c0) { |
154 | /* |
155 | * Calculate ratio. |
156 | * Note: the "128" is a scaling factor |
157 | */ |
158 | u8 r = c1 * 128 / c0; |
159 | |
160 | /* Calculate LUX */ |
161 | lux = ((c0 - c1) * ratio_lut[r]) / 256; |
162 | } else |
163 | lux = 0; |
164 | else |
165 | return 0; |
166 | |
167 | /* LUX range check */ |
168 | return lux > TSL2550_MAX_LUX ? TSL2550_MAX_LUX : lux; |
169 | } |
170 | |
171 | /* |
172 | * SysFS support |
173 | */ |
174 | |
175 | static ssize_t tsl2550_show_power_state(struct device *dev, |
176 | struct device_attribute *attr, char *buf) |
177 | { |
178 | struct tsl2550_data *data = i2c_get_clientdata(to_i2c_client(dev)); |
179 | |
180 | return sprintf(buf, fmt: "%u\n" , data->power_state); |
181 | } |
182 | |
183 | static ssize_t tsl2550_store_power_state(struct device *dev, |
184 | struct device_attribute *attr, const char *buf, size_t count) |
185 | { |
186 | struct i2c_client *client = to_i2c_client(dev); |
187 | struct tsl2550_data *data = i2c_get_clientdata(client); |
188 | unsigned long val = simple_strtoul(buf, NULL, 10); |
189 | int ret; |
190 | |
191 | if (val > 1) |
192 | return -EINVAL; |
193 | |
194 | mutex_lock(&data->update_lock); |
195 | ret = tsl2550_set_power_state(client, state: val); |
196 | mutex_unlock(lock: &data->update_lock); |
197 | |
198 | if (ret < 0) |
199 | return ret; |
200 | |
201 | return count; |
202 | } |
203 | |
204 | static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO, |
205 | tsl2550_show_power_state, tsl2550_store_power_state); |
206 | |
207 | static ssize_t tsl2550_show_operating_mode(struct device *dev, |
208 | struct device_attribute *attr, char *buf) |
209 | { |
210 | struct tsl2550_data *data = i2c_get_clientdata(to_i2c_client(dev)); |
211 | |
212 | return sprintf(buf, fmt: "%u\n" , data->operating_mode); |
213 | } |
214 | |
215 | static ssize_t tsl2550_store_operating_mode(struct device *dev, |
216 | struct device_attribute *attr, const char *buf, size_t count) |
217 | { |
218 | struct i2c_client *client = to_i2c_client(dev); |
219 | struct tsl2550_data *data = i2c_get_clientdata(client); |
220 | unsigned long val = simple_strtoul(buf, NULL, 10); |
221 | int ret; |
222 | |
223 | if (val > 1) |
224 | return -EINVAL; |
225 | |
226 | if (data->power_state == 0) |
227 | return -EBUSY; |
228 | |
229 | mutex_lock(&data->update_lock); |
230 | ret = tsl2550_set_operating_mode(client, mode: val); |
231 | mutex_unlock(lock: &data->update_lock); |
232 | |
233 | if (ret < 0) |
234 | return ret; |
235 | |
236 | return count; |
237 | } |
238 | |
239 | static DEVICE_ATTR(operating_mode, S_IWUSR | S_IRUGO, |
240 | tsl2550_show_operating_mode, tsl2550_store_operating_mode); |
241 | |
242 | static ssize_t __tsl2550_show_lux(struct i2c_client *client, char *buf) |
243 | { |
244 | struct tsl2550_data *data = i2c_get_clientdata(client); |
245 | u8 ch0, ch1; |
246 | int ret; |
247 | |
248 | ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC0); |
249 | if (ret < 0) |
250 | return ret; |
251 | ch0 = ret; |
252 | |
253 | ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC1); |
254 | if (ret < 0) |
255 | return ret; |
256 | ch1 = ret; |
257 | |
258 | /* Do the job */ |
259 | ret = tsl2550_calculate_lux(ch0, ch1); |
260 | if (ret < 0) |
261 | return ret; |
262 | if (data->operating_mode == 1) |
263 | ret *= 5; |
264 | |
265 | return sprintf(buf, fmt: "%d\n" , ret); |
266 | } |
267 | |
268 | static ssize_t tsl2550_show_lux1_input(struct device *dev, |
269 | struct device_attribute *attr, char *buf) |
270 | { |
271 | struct i2c_client *client = to_i2c_client(dev); |
272 | struct tsl2550_data *data = i2c_get_clientdata(client); |
273 | int ret; |
274 | |
275 | /* No LUX data if not operational */ |
276 | if (!data->power_state) |
277 | return -EBUSY; |
278 | |
279 | mutex_lock(&data->update_lock); |
280 | ret = __tsl2550_show_lux(client, buf); |
281 | mutex_unlock(lock: &data->update_lock); |
282 | |
283 | return ret; |
284 | } |
285 | |
286 | static DEVICE_ATTR(lux1_input, S_IRUGO, |
287 | tsl2550_show_lux1_input, NULL); |
288 | |
289 | static struct attribute *tsl2550_attributes[] = { |
290 | &dev_attr_power_state.attr, |
291 | &dev_attr_operating_mode.attr, |
292 | &dev_attr_lux1_input.attr, |
293 | NULL |
294 | }; |
295 | |
296 | static const struct attribute_group tsl2550_attr_group = { |
297 | .attrs = tsl2550_attributes, |
298 | }; |
299 | |
300 | /* |
301 | * Initialization function |
302 | */ |
303 | |
304 | static int tsl2550_init_client(struct i2c_client *client) |
305 | { |
306 | struct tsl2550_data *data = i2c_get_clientdata(client); |
307 | int err; |
308 | |
309 | /* |
310 | * Probe the chip. To do so we try to power up the device and then to |
311 | * read back the 0x03 code |
312 | */ |
313 | err = i2c_smbus_read_byte_data(client, TSL2550_POWER_UP); |
314 | if (err < 0) |
315 | return err; |
316 | if (err != TSL2550_POWER_UP) |
317 | return -ENODEV; |
318 | data->power_state = 1; |
319 | |
320 | /* Set the default operating mode */ |
321 | err = i2c_smbus_write_byte(client, |
322 | value: TSL2550_MODE_RANGE[data->operating_mode]); |
323 | if (err < 0) |
324 | return err; |
325 | |
326 | return 0; |
327 | } |
328 | |
329 | /* |
330 | * I2C init/probing/exit functions |
331 | */ |
332 | |
333 | static struct i2c_driver tsl2550_driver; |
334 | static int tsl2550_probe(struct i2c_client *client) |
335 | { |
336 | struct i2c_adapter *adapter = client->adapter; |
337 | struct tsl2550_data *data; |
338 | int *opmode, err = 0; |
339 | |
340 | if (!i2c_check_functionality(adap: adapter, I2C_FUNC_SMBUS_WRITE_BYTE |
341 | | I2C_FUNC_SMBUS_READ_BYTE_DATA)) { |
342 | err = -EIO; |
343 | goto exit; |
344 | } |
345 | |
346 | data = kzalloc(size: sizeof(struct tsl2550_data), GFP_KERNEL); |
347 | if (!data) { |
348 | err = -ENOMEM; |
349 | goto exit; |
350 | } |
351 | data->client = client; |
352 | i2c_set_clientdata(client, data); |
353 | |
354 | /* Check platform data */ |
355 | opmode = client->dev.platform_data; |
356 | if (opmode) { |
357 | if (*opmode < 0 || *opmode > 1) { |
358 | dev_err(&client->dev, "invalid operating_mode (%d)\n" , |
359 | *opmode); |
360 | err = -EINVAL; |
361 | goto exit_kfree; |
362 | } |
363 | data->operating_mode = *opmode; |
364 | } else |
365 | data->operating_mode = 0; /* default mode is standard */ |
366 | dev_info(&client->dev, "%s operating mode\n" , |
367 | data->operating_mode ? "extended" : "standard" ); |
368 | |
369 | mutex_init(&data->update_lock); |
370 | |
371 | /* Initialize the TSL2550 chip */ |
372 | err = tsl2550_init_client(client); |
373 | if (err) |
374 | goto exit_kfree; |
375 | |
376 | /* Register sysfs hooks */ |
377 | err = sysfs_create_group(kobj: &client->dev.kobj, grp: &tsl2550_attr_group); |
378 | if (err) |
379 | goto exit_kfree; |
380 | |
381 | dev_info(&client->dev, "support ver. %s enabled\n" , DRIVER_VERSION); |
382 | |
383 | return 0; |
384 | |
385 | exit_kfree: |
386 | kfree(objp: data); |
387 | exit: |
388 | return err; |
389 | } |
390 | |
391 | static void tsl2550_remove(struct i2c_client *client) |
392 | { |
393 | sysfs_remove_group(kobj: &client->dev.kobj, grp: &tsl2550_attr_group); |
394 | |
395 | /* Power down the device */ |
396 | tsl2550_set_power_state(client, state: 0); |
397 | |
398 | kfree(objp: i2c_get_clientdata(client)); |
399 | } |
400 | |
401 | #ifdef CONFIG_PM_SLEEP |
402 | |
403 | static int tsl2550_suspend(struct device *dev) |
404 | { |
405 | return tsl2550_set_power_state(to_i2c_client(dev), state: 0); |
406 | } |
407 | |
408 | static int tsl2550_resume(struct device *dev) |
409 | { |
410 | return tsl2550_set_power_state(to_i2c_client(dev), state: 1); |
411 | } |
412 | |
413 | static SIMPLE_DEV_PM_OPS(tsl2550_pm_ops, tsl2550_suspend, tsl2550_resume); |
414 | #define TSL2550_PM_OPS (&tsl2550_pm_ops) |
415 | |
416 | #else |
417 | |
418 | #define TSL2550_PM_OPS NULL |
419 | |
420 | #endif /* CONFIG_PM_SLEEP */ |
421 | |
422 | static const struct i2c_device_id tsl2550_id[] = { |
423 | { "tsl2550" , 0 }, |
424 | { } |
425 | }; |
426 | MODULE_DEVICE_TABLE(i2c, tsl2550_id); |
427 | |
428 | static const struct of_device_id tsl2550_of_match[] = { |
429 | { .compatible = "taos,tsl2550" }, |
430 | { } |
431 | }; |
432 | MODULE_DEVICE_TABLE(of, tsl2550_of_match); |
433 | |
434 | static struct i2c_driver tsl2550_driver = { |
435 | .driver = { |
436 | .name = TSL2550_DRV_NAME, |
437 | .of_match_table = tsl2550_of_match, |
438 | .pm = TSL2550_PM_OPS, |
439 | }, |
440 | .probe = tsl2550_probe, |
441 | .remove = tsl2550_remove, |
442 | .id_table = tsl2550_id, |
443 | }; |
444 | |
445 | module_i2c_driver(tsl2550_driver); |
446 | |
447 | MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>" ); |
448 | MODULE_DESCRIPTION("TSL2550 ambient light sensor driver" ); |
449 | MODULE_LICENSE("GPL" ); |
450 | MODULE_VERSION(DRIVER_VERSION); |
451 | |