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
tsl2550_set_operating_mode(struct i2c_client * client,int mode)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, TSL2550_MODE_RANGE[mode]);
57
58 data->operating_mode = mode;
59
60 return ret;
61 }
62
tsl2550_set_power_state(struct i2c_client * client,int state)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, data->operating_mode);
75 }
76
77 data->power_state = state;
78
79 return ret;
80 }
81
tsl2550_get_adc_value(struct i2c_client * client,u8 cmd)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, 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 */
tsl2550_calculate_lux(u8 ch0,u8 ch1)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
tsl2550_show_power_state(struct device * dev,struct device_attribute * attr,char * buf)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, "%u\n", data->power_state);
181 }
182
tsl2550_store_power_state(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)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, val);
196 mutex_unlock(&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
tsl2550_show_operating_mode(struct device * dev,struct device_attribute * attr,char * buf)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, "%u\n", data->operating_mode);
213 }
214
tsl2550_store_operating_mode(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)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, val);
231 mutex_unlock(&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
__tsl2550_show_lux(struct i2c_client * client,char * buf)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, "%d\n", ret);
266 }
267
tsl2550_show_lux1_input(struct device * dev,struct device_attribute * attr,char * buf)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(&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
tsl2550_init_client(struct i2c_client * client)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 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;
tsl2550_probe(struct i2c_client * client,const struct i2c_device_id * id)334 static int tsl2550_probe(struct i2c_client *client,
335 const struct i2c_device_id *id)
336 {
337 struct i2c_adapter *adapter = client->adapter;
338 struct tsl2550_data *data;
339 int *opmode, err = 0;
340
341 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE
342 | I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
343 err = -EIO;
344 goto exit;
345 }
346
347 data = kzalloc(sizeof(struct tsl2550_data), GFP_KERNEL);
348 if (!data) {
349 err = -ENOMEM;
350 goto exit;
351 }
352 data->client = client;
353 i2c_set_clientdata(client, data);
354
355 /* Check platform data */
356 opmode = client->dev.platform_data;
357 if (opmode) {
358 if (*opmode < 0 || *opmode > 1) {
359 dev_err(&client->dev, "invalid operating_mode (%d)\n",
360 *opmode);
361 err = -EINVAL;
362 goto exit_kfree;
363 }
364 data->operating_mode = *opmode;
365 } else
366 data->operating_mode = 0; /* default mode is standard */
367 dev_info(&client->dev, "%s operating mode\n",
368 data->operating_mode ? "extended" : "standard");
369
370 mutex_init(&data->update_lock);
371
372 /* Initialize the TSL2550 chip */
373 err = tsl2550_init_client(client);
374 if (err)
375 goto exit_kfree;
376
377 /* Register sysfs hooks */
378 err = sysfs_create_group(&client->dev.kobj, &tsl2550_attr_group);
379 if (err)
380 goto exit_kfree;
381
382 dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION);
383
384 return 0;
385
386 exit_kfree:
387 kfree(data);
388 exit:
389 return err;
390 }
391
tsl2550_remove(struct i2c_client * client)392 static int tsl2550_remove(struct i2c_client *client)
393 {
394 sysfs_remove_group(&client->dev.kobj, &tsl2550_attr_group);
395
396 /* Power down the device */
397 tsl2550_set_power_state(client, 0);
398
399 kfree(i2c_get_clientdata(client));
400
401 return 0;
402 }
403
404 #ifdef CONFIG_PM_SLEEP
405
tsl2550_suspend(struct device * dev)406 static int tsl2550_suspend(struct device *dev)
407 {
408 return tsl2550_set_power_state(to_i2c_client(dev), 0);
409 }
410
tsl2550_resume(struct device * dev)411 static int tsl2550_resume(struct device *dev)
412 {
413 return tsl2550_set_power_state(to_i2c_client(dev), 1);
414 }
415
416 static SIMPLE_DEV_PM_OPS(tsl2550_pm_ops, tsl2550_suspend, tsl2550_resume);
417 #define TSL2550_PM_OPS (&tsl2550_pm_ops)
418
419 #else
420
421 #define TSL2550_PM_OPS NULL
422
423 #endif /* CONFIG_PM_SLEEP */
424
425 static const struct i2c_device_id tsl2550_id[] = {
426 { "tsl2550", 0 },
427 { }
428 };
429 MODULE_DEVICE_TABLE(i2c, tsl2550_id);
430
431 static const struct of_device_id tsl2550_of_match[] = {
432 { .compatible = "taos,tsl2550" },
433 { }
434 };
435 MODULE_DEVICE_TABLE(of, tsl2550_of_match);
436
437 static struct i2c_driver tsl2550_driver = {
438 .driver = {
439 .name = TSL2550_DRV_NAME,
440 .of_match_table = tsl2550_of_match,
441 .pm = TSL2550_PM_OPS,
442 },
443 .probe = tsl2550_probe,
444 .remove = tsl2550_remove,
445 .id_table = tsl2550_id,
446 };
447
448 module_i2c_driver(tsl2550_driver);
449
450 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
451 MODULE_DESCRIPTION("TSL2550 ambient light sensor driver");
452 MODULE_LICENSE("GPL");
453 MODULE_VERSION(DRIVER_VERSION);
454