1/*
2 * bh1780gli.c
3 * ROHM Ambient Light Sensor Driver
4 *
5 * Copyright (C) 2010 Texas Instruments
6 * Author: Hemanth V <hemanthv@ti.com>
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as published by
10 * the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
15 * more details.
16 *
17 * You should have received a copy of the GNU General Public License along with
18 * this program.  If not, see <http://www.gnu.org/licenses/>.
19 */
20#include <linux/i2c.h>
21#include <linux/slab.h>
22#include <linux/mutex.h>
23#include <linux/platform_device.h>
24#include <linux/delay.h>
25#include <linux/module.h>
26#include <linux/of.h>
27
28#define BH1780_REG_CONTROL	0x80
29#define BH1780_REG_PARTID	0x8A
30#define BH1780_REG_MANFID	0x8B
31#define BH1780_REG_DLOW	0x8C
32#define BH1780_REG_DHIGH	0x8D
33
34#define BH1780_REVMASK		(0xf)
35#define BH1780_POWMASK		(0x3)
36#define BH1780_POFF		(0x0)
37#define BH1780_PON		(0x3)
38
39/* power on settling time in ms */
40#define BH1780_PON_DELAY	2
41
42struct bh1780_data {
43	struct i2c_client *client;
44	int power_state;
45	/* lock for sysfs operations */
46	struct mutex lock;
47};
48
49static int bh1780_write(struct bh1780_data *ddata, u8 reg, u8 val, char *msg)
50{
51	int ret = i2c_smbus_write_byte_data(ddata->client, reg, val);
52	if (ret < 0)
53		dev_err(&ddata->client->dev,
54			"i2c_smbus_write_byte_data failed error %d Register (%s)\n",
55			ret, msg);
56	return ret;
57}
58
59static int bh1780_read(struct bh1780_data *ddata, u8 reg, char *msg)
60{
61	int ret = i2c_smbus_read_byte_data(ddata->client, reg);
62	if (ret < 0)
63		dev_err(&ddata->client->dev,
64			"i2c_smbus_read_byte_data failed error %d Register (%s)\n",
65			ret, msg);
66	return ret;
67}
68
69static ssize_t bh1780_show_lux(struct device *dev,
70				struct device_attribute *attr, char *buf)
71{
72	struct platform_device *pdev = to_platform_device(dev);
73	struct bh1780_data *ddata = platform_get_drvdata(pdev);
74	int lsb, msb;
75
76	lsb = bh1780_read(ddata, BH1780_REG_DLOW, "DLOW");
77	if (lsb < 0)
78		return lsb;
79
80	msb = bh1780_read(ddata, BH1780_REG_DHIGH, "DHIGH");
81	if (msb < 0)
82		return msb;
83
84	return sprintf(buf, "%d\n", (msb << 8) | lsb);
85}
86
87static ssize_t bh1780_show_power_state(struct device *dev,
88					struct device_attribute *attr,
89					char *buf)
90{
91	struct platform_device *pdev = to_platform_device(dev);
92	struct bh1780_data *ddata = platform_get_drvdata(pdev);
93	int state;
94
95	state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
96	if (state < 0)
97		return state;
98
99	return sprintf(buf, "%d\n", state & BH1780_POWMASK);
100}
101
102static ssize_t bh1780_store_power_state(struct device *dev,
103					struct device_attribute *attr,
104					const char *buf, size_t count)
105{
106	struct platform_device *pdev = to_platform_device(dev);
107	struct bh1780_data *ddata = platform_get_drvdata(pdev);
108	unsigned long val;
109	int error;
110
111	error = kstrtoul(buf, 0, &val);
112	if (error)
113		return error;
114
115	if (val < BH1780_POFF || val > BH1780_PON)
116		return -EINVAL;
117
118	mutex_lock(&ddata->lock);
119
120	error = bh1780_write(ddata, BH1780_REG_CONTROL, val, "CONTROL");
121	if (error < 0) {
122		mutex_unlock(&ddata->lock);
123		return error;
124	}
125
126	msleep(BH1780_PON_DELAY);
127	ddata->power_state = val;
128	mutex_unlock(&ddata->lock);
129
130	return count;
131}
132
133static DEVICE_ATTR(lux, S_IRUGO, bh1780_show_lux, NULL);
134
135static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
136		bh1780_show_power_state, bh1780_store_power_state);
137
138static struct attribute *bh1780_attributes[] = {
139	&dev_attr_power_state.attr,
140	&dev_attr_lux.attr,
141	NULL
142};
143
144static const struct attribute_group bh1780_attr_group = {
145	.attrs = bh1780_attributes,
146};
147
148static int bh1780_probe(struct i2c_client *client,
149						const struct i2c_device_id *id)
150{
151	int ret;
152	struct bh1780_data *ddata;
153	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
154
155	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
156		return -EIO;
157
158	ddata = devm_kzalloc(&client->dev, sizeof(struct bh1780_data),
159			     GFP_KERNEL);
160	if (ddata == NULL)
161		return -ENOMEM;
162
163	ddata->client = client;
164	i2c_set_clientdata(client, ddata);
165
166	ret = bh1780_read(ddata, BH1780_REG_PARTID, "PART ID");
167	if (ret < 0)
168		return ret;
169
170	dev_info(&client->dev, "Ambient Light Sensor, Rev : %d\n",
171			(ret & BH1780_REVMASK));
172
173	mutex_init(&ddata->lock);
174
175	return sysfs_create_group(&client->dev.kobj, &bh1780_attr_group);
176}
177
178static int bh1780_remove(struct i2c_client *client)
179{
180	sysfs_remove_group(&client->dev.kobj, &bh1780_attr_group);
181
182	return 0;
183}
184
185#ifdef CONFIG_PM_SLEEP
186static int bh1780_suspend(struct device *dev)
187{
188	struct bh1780_data *ddata;
189	int state, ret;
190	struct i2c_client *client = to_i2c_client(dev);
191
192	ddata = i2c_get_clientdata(client);
193	state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
194	if (state < 0)
195		return state;
196
197	ddata->power_state = state & BH1780_POWMASK;
198
199	ret = bh1780_write(ddata, BH1780_REG_CONTROL, BH1780_POFF,
200				"CONTROL");
201
202	if (ret < 0)
203		return ret;
204
205	return 0;
206}
207
208static int bh1780_resume(struct device *dev)
209{
210	struct bh1780_data *ddata;
211	int state, ret;
212	struct i2c_client *client = to_i2c_client(dev);
213
214	ddata = i2c_get_clientdata(client);
215	state = ddata->power_state;
216	ret = bh1780_write(ddata, BH1780_REG_CONTROL, state,
217				"CONTROL");
218
219	if (ret < 0)
220		return ret;
221
222	return 0;
223}
224#endif /* CONFIG_PM_SLEEP */
225
226static SIMPLE_DEV_PM_OPS(bh1780_pm, bh1780_suspend, bh1780_resume);
227
228static const struct i2c_device_id bh1780_id[] = {
229	{ "bh1780", 0 },
230	{ },
231};
232
233MODULE_DEVICE_TABLE(i2c, bh1780_id);
234
235#ifdef CONFIG_OF
236static const struct of_device_id of_bh1780_match[] = {
237	{ .compatible = "rohm,bh1780gli", },
238	{},
239};
240
241MODULE_DEVICE_TABLE(of, of_bh1780_match);
242#endif
243
244static struct i2c_driver bh1780_driver = {
245	.probe		= bh1780_probe,
246	.remove		= bh1780_remove,
247	.id_table	= bh1780_id,
248	.driver = {
249		.name = "bh1780",
250		.pm	= &bh1780_pm,
251		.of_match_table = of_match_ptr(of_bh1780_match),
252	},
253};
254
255module_i2c_driver(bh1780_driver);
256
257MODULE_DESCRIPTION("BH1780GLI Ambient Light Sensor Driver");
258MODULE_LICENSE("GPL");
259MODULE_AUTHOR("Hemanth V <hemanthv@ti.com>");
260