1/*
2 *  isl29003.c - Linux kernel module for
3 * 	Intersil ISL29003 ambient light sensor
4 *
5 *  See file:Documentation/misc-devices/isl29003
6 *
7 *  Copyright (c) 2009 Daniel Mack <daniel@caiaq.de>
8 *
9 *  Based on code written by
10 *  	Rodolfo Giometti <giometti@linux.it>
11 *  	Eurotech S.p.A. <info@eurotech.it>
12 *
13 *  This program is free software; you can redistribute it and/or modify
14 *  it under the terms of the GNU General Public License as published by
15 *  the Free Software Foundation; either version 2 of the License, or
16 *  (at your option) any later version.
17 *
18 *  This program is distributed in the hope that it will be useful,
19 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
20 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
21 *  GNU General Public License for more details.
22 *
23 *  You should have received a copy of the GNU General Public License
24 *  along with this program; if not, write to the Free Software
25 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 */
27
28#include <linux/module.h>
29#include <linux/slab.h>
30#include <linux/i2c.h>
31#include <linux/mutex.h>
32#include <linux/delay.h>
33
34#define ISL29003_DRV_NAME	"isl29003"
35#define DRIVER_VERSION		"1.0"
36
37#define ISL29003_REG_COMMAND		0x00
38#define ISL29003_ADC_ENABLED		(1 << 7)
39#define ISL29003_ADC_PD			(1 << 6)
40#define ISL29003_TIMING_INT		(1 << 5)
41#define ISL29003_MODE_SHIFT		(2)
42#define ISL29003_MODE_MASK		(0x3 << ISL29003_MODE_SHIFT)
43#define ISL29003_RES_SHIFT		(0)
44#define ISL29003_RES_MASK		(0x3 << ISL29003_RES_SHIFT)
45
46#define ISL29003_REG_CONTROL		0x01
47#define ISL29003_INT_FLG		(1 << 5)
48#define ISL29003_RANGE_SHIFT		(2)
49#define ISL29003_RANGE_MASK		(0x3 << ISL29003_RANGE_SHIFT)
50#define ISL29003_INT_PERSISTS_SHIFT	(0)
51#define ISL29003_INT_PERSISTS_MASK	(0xf << ISL29003_INT_PERSISTS_SHIFT)
52
53#define ISL29003_REG_IRQ_THRESH_HI	0x02
54#define ISL29003_REG_IRQ_THRESH_LO	0x03
55#define ISL29003_REG_LSB_SENSOR		0x04
56#define ISL29003_REG_MSB_SENSOR		0x05
57#define ISL29003_REG_LSB_TIMER		0x06
58#define ISL29003_REG_MSB_TIMER		0x07
59
60#define ISL29003_NUM_CACHABLE_REGS	4
61
62struct isl29003_data {
63	struct i2c_client *client;
64	struct mutex lock;
65	u8 reg_cache[ISL29003_NUM_CACHABLE_REGS];
66	u8 power_state_before_suspend;
67};
68
69static int gain_range[] = {
70	1000, 4000, 16000, 64000
71};
72
73/*
74 * register access helpers
75 */
76
77static int __isl29003_read_reg(struct i2c_client *client,
78			       u32 reg, u8 mask, u8 shift)
79{
80	struct isl29003_data *data = i2c_get_clientdata(client);
81	return (data->reg_cache[reg] & mask) >> shift;
82}
83
84static int __isl29003_write_reg(struct i2c_client *client,
85				u32 reg, u8 mask, u8 shift, u8 val)
86{
87	struct isl29003_data *data = i2c_get_clientdata(client);
88	int ret = 0;
89	u8 tmp;
90
91	if (reg >= ISL29003_NUM_CACHABLE_REGS)
92		return -EINVAL;
93
94	mutex_lock(&data->lock);
95
96	tmp = data->reg_cache[reg];
97	tmp &= ~mask;
98	tmp |= val << shift;
99
100	ret = i2c_smbus_write_byte_data(client, reg, tmp);
101	if (!ret)
102		data->reg_cache[reg] = tmp;
103
104	mutex_unlock(&data->lock);
105	return ret;
106}
107
108/*
109 * internally used functions
110 */
111
112/* range */
113static int isl29003_get_range(struct i2c_client *client)
114{
115	return __isl29003_read_reg(client, ISL29003_REG_CONTROL,
116		ISL29003_RANGE_MASK, ISL29003_RANGE_SHIFT);
117}
118
119static int isl29003_set_range(struct i2c_client *client, int range)
120{
121	return __isl29003_write_reg(client, ISL29003_REG_CONTROL,
122		ISL29003_RANGE_MASK, ISL29003_RANGE_SHIFT, range);
123}
124
125/* resolution */
126static int isl29003_get_resolution(struct i2c_client *client)
127{
128	return __isl29003_read_reg(client, ISL29003_REG_COMMAND,
129		ISL29003_RES_MASK, ISL29003_RES_SHIFT);
130}
131
132static int isl29003_set_resolution(struct i2c_client *client, int res)
133{
134	return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
135		ISL29003_RES_MASK, ISL29003_RES_SHIFT, res);
136}
137
138/* mode */
139static int isl29003_get_mode(struct i2c_client *client)
140{
141	return __isl29003_read_reg(client, ISL29003_REG_COMMAND,
142		ISL29003_RES_MASK, ISL29003_RES_SHIFT);
143}
144
145static int isl29003_set_mode(struct i2c_client *client, int mode)
146{
147	return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
148		ISL29003_RES_MASK, ISL29003_RES_SHIFT, mode);
149}
150
151/* power_state */
152static int isl29003_set_power_state(struct i2c_client *client, int state)
153{
154	return __isl29003_write_reg(client, ISL29003_REG_COMMAND,
155				ISL29003_ADC_ENABLED | ISL29003_ADC_PD, 0,
156				state ? ISL29003_ADC_ENABLED : ISL29003_ADC_PD);
157}
158
159static int isl29003_get_power_state(struct i2c_client *client)
160{
161	struct isl29003_data *data = i2c_get_clientdata(client);
162	u8 cmdreg = data->reg_cache[ISL29003_REG_COMMAND];
163	return ~cmdreg & ISL29003_ADC_PD;
164}
165
166static int isl29003_get_adc_value(struct i2c_client *client)
167{
168	struct isl29003_data *data = i2c_get_clientdata(client);
169	int lsb, msb, range, bitdepth;
170
171	mutex_lock(&data->lock);
172	lsb = i2c_smbus_read_byte_data(client, ISL29003_REG_LSB_SENSOR);
173
174	if (lsb < 0) {
175		mutex_unlock(&data->lock);
176		return lsb;
177	}
178
179	msb = i2c_smbus_read_byte_data(client, ISL29003_REG_MSB_SENSOR);
180	mutex_unlock(&data->lock);
181
182	if (msb < 0)
183		return msb;
184
185	range = isl29003_get_range(client);
186	bitdepth = (4 - isl29003_get_resolution(client)) * 4;
187	return (((msb << 8) | lsb) * gain_range[range]) >> bitdepth;
188}
189
190/*
191 * sysfs layer
192 */
193
194/* range */
195static ssize_t isl29003_show_range(struct device *dev,
196				   struct device_attribute *attr, char *buf)
197{
198	struct i2c_client *client = to_i2c_client(dev);
199	return sprintf(buf, "%i\n", isl29003_get_range(client));
200}
201
202static ssize_t isl29003_store_range(struct device *dev,
203				    struct device_attribute *attr,
204				    const char *buf, size_t count)
205{
206	struct i2c_client *client = to_i2c_client(dev);
207	unsigned long val;
208	int ret;
209
210	ret = kstrtoul(buf, 10, &val);
211	if (ret)
212		return ret;
213
214	if (val > 3)
215		return -EINVAL;
216
217	ret = isl29003_set_range(client, val);
218	if (ret < 0)
219		return ret;
220
221	return count;
222}
223
224static DEVICE_ATTR(range, S_IWUSR | S_IRUGO,
225		   isl29003_show_range, isl29003_store_range);
226
227
228/* resolution */
229static ssize_t isl29003_show_resolution(struct device *dev,
230					struct device_attribute *attr,
231					char *buf)
232{
233	struct i2c_client *client = to_i2c_client(dev);
234	return sprintf(buf, "%d\n", isl29003_get_resolution(client));
235}
236
237static ssize_t isl29003_store_resolution(struct device *dev,
238					 struct device_attribute *attr,
239					 const char *buf, size_t count)
240{
241	struct i2c_client *client = to_i2c_client(dev);
242	unsigned long val;
243	int ret;
244
245	ret = kstrtoul(buf, 10, &val);
246	if (ret)
247		return ret;
248
249	if (val > 3)
250		return -EINVAL;
251
252	ret = isl29003_set_resolution(client, val);
253	if (ret < 0)
254		return ret;
255
256	return count;
257}
258
259static DEVICE_ATTR(resolution, S_IWUSR | S_IRUGO,
260		   isl29003_show_resolution, isl29003_store_resolution);
261
262/* mode */
263static ssize_t isl29003_show_mode(struct device *dev,
264				  struct device_attribute *attr, char *buf)
265{
266	struct i2c_client *client = to_i2c_client(dev);
267	return sprintf(buf, "%d\n", isl29003_get_mode(client));
268}
269
270static ssize_t isl29003_store_mode(struct device *dev,
271		struct device_attribute *attr, const char *buf, size_t count)
272{
273	struct i2c_client *client = to_i2c_client(dev);
274	unsigned long val;
275	int ret;
276
277	ret = kstrtoul(buf, 10, &val);
278	if (ret)
279		return ret;
280
281	if (val > 2)
282		return -EINVAL;
283
284	ret = isl29003_set_mode(client, val);
285	if (ret < 0)
286		return ret;
287
288	return count;
289}
290
291static DEVICE_ATTR(mode, S_IWUSR | S_IRUGO,
292		   isl29003_show_mode, isl29003_store_mode);
293
294
295/* power state */
296static ssize_t isl29003_show_power_state(struct device *dev,
297					 struct device_attribute *attr,
298					 char *buf)
299{
300	struct i2c_client *client = to_i2c_client(dev);
301	return sprintf(buf, "%d\n", isl29003_get_power_state(client));
302}
303
304static ssize_t isl29003_store_power_state(struct device *dev,
305					  struct device_attribute *attr,
306					  const char *buf, size_t count)
307{
308	struct i2c_client *client = to_i2c_client(dev);
309	unsigned long val;
310	int ret;
311
312	ret = kstrtoul(buf, 10, &val);
313	if (ret)
314		return ret;
315
316	if (val > 1)
317		return -EINVAL;
318
319	ret = isl29003_set_power_state(client, val);
320	return ret ? ret : count;
321}
322
323static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
324		   isl29003_show_power_state, isl29003_store_power_state);
325
326
327/* lux */
328static ssize_t isl29003_show_lux(struct device *dev,
329				 struct device_attribute *attr, char *buf)
330{
331	struct i2c_client *client = to_i2c_client(dev);
332
333	/* No LUX data if not operational */
334	if (!isl29003_get_power_state(client))
335		return -EBUSY;
336
337	return sprintf(buf, "%d\n", isl29003_get_adc_value(client));
338}
339
340static DEVICE_ATTR(lux, S_IRUGO, isl29003_show_lux, NULL);
341
342static struct attribute *isl29003_attributes[] = {
343	&dev_attr_range.attr,
344	&dev_attr_resolution.attr,
345	&dev_attr_mode.attr,
346	&dev_attr_power_state.attr,
347	&dev_attr_lux.attr,
348	NULL
349};
350
351static const struct attribute_group isl29003_attr_group = {
352	.attrs = isl29003_attributes,
353};
354
355static int isl29003_init_client(struct i2c_client *client)
356{
357	struct isl29003_data *data = i2c_get_clientdata(client);
358	int i;
359
360	/* read all the registers once to fill the cache.
361	 * if one of the reads fails, we consider the init failed */
362	for (i = 0; i < ARRAY_SIZE(data->reg_cache); i++) {
363		int v = i2c_smbus_read_byte_data(client, i);
364		if (v < 0)
365			return -ENODEV;
366
367		data->reg_cache[i] = v;
368	}
369
370	/* set defaults */
371	isl29003_set_range(client, 0);
372	isl29003_set_resolution(client, 0);
373	isl29003_set_mode(client, 0);
374	isl29003_set_power_state(client, 0);
375
376	return 0;
377}
378
379/*
380 * I2C layer
381 */
382
383static int isl29003_probe(struct i2c_client *client,
384				    const struct i2c_device_id *id)
385{
386	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
387	struct isl29003_data *data;
388	int err = 0;
389
390	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
391		return -EIO;
392
393	data = kzalloc(sizeof(struct isl29003_data), GFP_KERNEL);
394	if (!data)
395		return -ENOMEM;
396
397	data->client = client;
398	i2c_set_clientdata(client, data);
399	mutex_init(&data->lock);
400
401	/* initialize the ISL29003 chip */
402	err = isl29003_init_client(client);
403	if (err)
404		goto exit_kfree;
405
406	/* register sysfs hooks */
407	err = sysfs_create_group(&client->dev.kobj, &isl29003_attr_group);
408	if (err)
409		goto exit_kfree;
410
411	dev_info(&client->dev, "driver version %s enabled\n", DRIVER_VERSION);
412	return 0;
413
414exit_kfree:
415	kfree(data);
416	return err;
417}
418
419static int isl29003_remove(struct i2c_client *client)
420{
421	sysfs_remove_group(&client->dev.kobj, &isl29003_attr_group);
422	isl29003_set_power_state(client, 0);
423	kfree(i2c_get_clientdata(client));
424	return 0;
425}
426
427#ifdef CONFIG_PM_SLEEP
428static int isl29003_suspend(struct device *dev)
429{
430	struct i2c_client *client = to_i2c_client(dev);
431	struct isl29003_data *data = i2c_get_clientdata(client);
432
433	data->power_state_before_suspend = isl29003_get_power_state(client);
434	return isl29003_set_power_state(client, 0);
435}
436
437static int isl29003_resume(struct device *dev)
438{
439	int i;
440	struct i2c_client *client = to_i2c_client(dev);
441	struct isl29003_data *data = i2c_get_clientdata(client);
442
443	/* restore registers from cache */
444	for (i = 0; i < ARRAY_SIZE(data->reg_cache); i++)
445		if (i2c_smbus_write_byte_data(client, i, data->reg_cache[i]))
446			return -EIO;
447
448	return isl29003_set_power_state(client,
449		data->power_state_before_suspend);
450}
451
452static SIMPLE_DEV_PM_OPS(isl29003_pm_ops, isl29003_suspend, isl29003_resume);
453#define ISL29003_PM_OPS (&isl29003_pm_ops)
454
455#else
456#define ISL29003_PM_OPS NULL
457#endif /* CONFIG_PM_SLEEP */
458
459static const struct i2c_device_id isl29003_id[] = {
460	{ "isl29003", 0 },
461	{}
462};
463MODULE_DEVICE_TABLE(i2c, isl29003_id);
464
465static struct i2c_driver isl29003_driver = {
466	.driver = {
467		.name	= ISL29003_DRV_NAME,
468		.owner	= THIS_MODULE,
469		.pm	= ISL29003_PM_OPS,
470	},
471	.probe	= isl29003_probe,
472	.remove	= isl29003_remove,
473	.id_table = isl29003_id,
474};
475
476module_i2c_driver(isl29003_driver);
477
478MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
479MODULE_DESCRIPTION("ISL29003 ambient light sensor driver");
480MODULE_LICENSE("GPL v2");
481MODULE_VERSION(DRIVER_VERSION);
482