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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 <[email protected]>
6 * Copyright (C) 2007 Eurotech S.p.A. <[email protected]>
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
32struct 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
44static const u8 TSL2550_MODE_RANGE[2] = {
45 TSL2550_STANDARD_RANGE, TSL2550_EXTENDED_RANGE,
46};
47
48/*
49 * Management functions
50 */
51
52static 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
63static 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
82static 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
100static 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
120static 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 */
143static 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
175static 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
183static 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;
189 int ret;
190
191 if (kstrtoul(buf, 10, &val) || 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
204static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
205 tsl2550_show_power_state, tsl2550_store_power_state);
206
207static 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
215static 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;
221 int ret;
222
223 if (kstrtoul(buf, 10, &val) || 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
239static DEVICE_ATTR(operating_mode, S_IWUSR | S_IRUGO,
240 tsl2550_show_operating_mode, tsl2550_store_operating_mode);
241
242static 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
268static 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
286static DEVICE_ATTR(lux1_input, S_IRUGO,
287 tsl2550_show_lux1_input, NULL);
288
289static 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
296static const struct attribute_group tsl2550_attr_group = {
297 .attrs = tsl2550_attributes,
298};
299
300/*
301 * Initialization function
302 */
303
304static 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
333static struct i2c_driver tsl2550_driver;
334static 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(adapter, I2C_FUNC_SMBUS_WRITE_BYTE
341 | I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
342 err = -EIO;
343 goto exit;
344 }
345
346 data = kzalloc_obj(struct tsl2550_data);
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(&client->dev.kobj, &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
385exit_kfree:
386 kfree(data);
387exit:
388 return err;
389}
390
391static void tsl2550_remove(struct i2c_client *client)
392{
393 sysfs_remove_group(&client->dev.kobj, &tsl2550_attr_group);
394
395 /* Power down the device */
396 tsl2550_set_power_state(client, 0);
397
398 kfree(i2c_get_clientdata(client));
399}
400
401#ifdef CONFIG_PM_SLEEP
402
403static int tsl2550_suspend(struct device *dev)
404{
405 return tsl2550_set_power_state(to_i2c_client(dev), 0);
406}
407
408static int tsl2550_resume(struct device *dev)
409{
410 return tsl2550_set_power_state(to_i2c_client(dev), 1);
411}
412
413static 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
422static const struct i2c_device_id tsl2550_id[] = {
423 { .name = "tsl2550" },
424 { }
425};
426MODULE_DEVICE_TABLE(i2c, tsl2550_id);
427
428static const struct of_device_id tsl2550_of_match[] = {
429 { .compatible = "taos,tsl2550" },
430 { }
431};
432MODULE_DEVICE_TABLE(of, tsl2550_of_match);
433
434static 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
445module_i2c_driver(tsl2550_driver);
446
447MODULE_AUTHOR("Rodolfo Giometti <[email protected]>");
448MODULE_DESCRIPTION("TSL2550 ambient light sensor driver");
449MODULE_LICENSE("GPL");
450MODULE_VERSION(DRIVER_VERSION);