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
27 #define BH1780_REG_CONTROL 0x80
28 #define BH1780_REG_PARTID 0x8A
29 #define BH1780_REG_MANFID 0x8B
30 #define BH1780_REG_DLOW 0x8C
31 #define BH1780_REG_DHIGH 0x8D
32
33 #define BH1780_REVMASK (0xf)
34 #define BH1780_POWMASK (0x3)
35 #define BH1780_POFF (0x0)
36 #define BH1780_PON (0x3)
37
38 /* power on settling time in ms */
39 #define BH1780_PON_DELAY 2
40
41 struct bh1780_data {
42 struct i2c_client *client;
43 int power_state;
44 /* lock for sysfs operations */
45 struct mutex lock;
46 };
47
bh1780_write(struct bh1780_data * ddata,u8 reg,u8 val,char * msg)48 static int bh1780_write(struct bh1780_data *ddata, u8 reg, u8 val, char *msg)
49 {
50 int ret = i2c_smbus_write_byte_data(ddata->client, reg, val);
51 if (ret < 0)
52 dev_err(&ddata->client->dev,
53 "i2c_smbus_write_byte_data failed error %d Register (%s)\n",
54 ret, msg);
55 return ret;
56 }
57
bh1780_read(struct bh1780_data * ddata,u8 reg,char * msg)58 static int bh1780_read(struct bh1780_data *ddata, u8 reg, char *msg)
59 {
60 int ret = i2c_smbus_read_byte_data(ddata->client, reg);
61 if (ret < 0)
62 dev_err(&ddata->client->dev,
63 "i2c_smbus_read_byte_data failed error %d Register (%s)\n",
64 ret, msg);
65 return ret;
66 }
67
bh1780_show_lux(struct device * dev,struct device_attribute * attr,char * buf)68 static ssize_t bh1780_show_lux(struct device *dev,
69 struct device_attribute *attr, char *buf)
70 {
71 struct platform_device *pdev = to_platform_device(dev);
72 struct bh1780_data *ddata = platform_get_drvdata(pdev);
73 int lsb, msb;
74
75 lsb = bh1780_read(ddata, BH1780_REG_DLOW, "DLOW");
76 if (lsb < 0)
77 return lsb;
78
79 msb = bh1780_read(ddata, BH1780_REG_DHIGH, "DHIGH");
80 if (msb < 0)
81 return msb;
82
83 return sprintf(buf, "%d\n", (msb << 8) | lsb);
84 }
85
bh1780_show_power_state(struct device * dev,struct device_attribute * attr,char * buf)86 static ssize_t bh1780_show_power_state(struct device *dev,
87 struct device_attribute *attr,
88 char *buf)
89 {
90 struct platform_device *pdev = to_platform_device(dev);
91 struct bh1780_data *ddata = platform_get_drvdata(pdev);
92 int state;
93
94 state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
95 if (state < 0)
96 return state;
97
98 return sprintf(buf, "%d\n", state & BH1780_POWMASK);
99 }
100
bh1780_store_power_state(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)101 static ssize_t bh1780_store_power_state(struct device *dev,
102 struct device_attribute *attr,
103 const char *buf, size_t count)
104 {
105 struct platform_device *pdev = to_platform_device(dev);
106 struct bh1780_data *ddata = platform_get_drvdata(pdev);
107 unsigned long val;
108 int error;
109
110 error = strict_strtoul(buf, 0, &val);
111 if (error)
112 return error;
113
114 if (val < BH1780_POFF || val > BH1780_PON)
115 return -EINVAL;
116
117 mutex_lock(&ddata->lock);
118
119 error = bh1780_write(ddata, BH1780_REG_CONTROL, val, "CONTROL");
120 if (error < 0) {
121 mutex_unlock(&ddata->lock);
122 return error;
123 }
124
125 msleep(BH1780_PON_DELAY);
126 ddata->power_state = val;
127 mutex_unlock(&ddata->lock);
128
129 return count;
130 }
131
132 static DEVICE_ATTR(lux, S_IRUGO, bh1780_show_lux, NULL);
133
134 static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
135 bh1780_show_power_state, bh1780_store_power_state);
136
137 static struct attribute *bh1780_attributes[] = {
138 &dev_attr_power_state.attr,
139 &dev_attr_lux.attr,
140 NULL
141 };
142
143 static const struct attribute_group bh1780_attr_group = {
144 .attrs = bh1780_attributes,
145 };
146
bh1780_probe(struct i2c_client * client,const struct i2c_device_id * id)147 static int __devinit bh1780_probe(struct i2c_client *client,
148 const struct i2c_device_id *id)
149 {
150 int ret;
151 struct bh1780_data *ddata = NULL;
152 struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
153
154 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) {
155 ret = -EIO;
156 goto err_op_failed;
157 }
158
159 ddata = kzalloc(sizeof(struct bh1780_data), GFP_KERNEL);
160 if (ddata == NULL) {
161 ret = -ENOMEM;
162 goto err_op_failed;
163 }
164
165 ddata->client = client;
166 i2c_set_clientdata(client, ddata);
167
168 ret = bh1780_read(ddata, BH1780_REG_PARTID, "PART ID");
169 if (ret < 0)
170 goto err_op_failed;
171
172 dev_info(&client->dev, "Ambient Light Sensor, Rev : %d\n",
173 (ret & BH1780_REVMASK));
174
175 mutex_init(&ddata->lock);
176
177 ret = sysfs_create_group(&client->dev.kobj, &bh1780_attr_group);
178 if (ret)
179 goto err_op_failed;
180
181 return 0;
182
183 err_op_failed:
184 kfree(ddata);
185 return ret;
186 }
187
bh1780_remove(struct i2c_client * client)188 static int __devexit bh1780_remove(struct i2c_client *client)
189 {
190 struct bh1780_data *ddata;
191
192 ddata = i2c_get_clientdata(client);
193 sysfs_remove_group(&client->dev.kobj, &bh1780_attr_group);
194 kfree(ddata);
195
196 return 0;
197 }
198
199 #ifdef CONFIG_PM
bh1780_suspend(struct device * dev)200 static int bh1780_suspend(struct device *dev)
201 {
202 struct bh1780_data *ddata;
203 int state, ret;
204 struct i2c_client *client = to_i2c_client(dev);
205
206 ddata = i2c_get_clientdata(client);
207 state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
208 if (state < 0)
209 return state;
210
211 ddata->power_state = state & BH1780_POWMASK;
212
213 ret = bh1780_write(ddata, BH1780_REG_CONTROL, BH1780_POFF,
214 "CONTROL");
215
216 if (ret < 0)
217 return ret;
218
219 return 0;
220 }
221
bh1780_resume(struct device * dev)222 static int bh1780_resume(struct device *dev)
223 {
224 struct bh1780_data *ddata;
225 int state, ret;
226 struct i2c_client *client = to_i2c_client(dev);
227
228 ddata = i2c_get_clientdata(client);
229 state = ddata->power_state;
230 ret = bh1780_write(ddata, BH1780_REG_CONTROL, state,
231 "CONTROL");
232
233 if (ret < 0)
234 return ret;
235
236 return 0;
237 }
238 static SIMPLE_DEV_PM_OPS(bh1780_pm, bh1780_suspend, bh1780_resume);
239 #define BH1780_PMOPS (&bh1780_pm)
240 #else
241 #define BH1780_PMOPS NULL
242 #endif /* CONFIG_PM */
243
244 static const struct i2c_device_id bh1780_id[] = {
245 { "bh1780", 0 },
246 { },
247 };
248
249 static struct i2c_driver bh1780_driver = {
250 .probe = bh1780_probe,
251 .remove = bh1780_remove,
252 .id_table = bh1780_id,
253 .driver = {
254 .name = "bh1780",
255 .pm = BH1780_PMOPS,
256 },
257 };
258
bh1780_init(void)259 static int __init bh1780_init(void)
260 {
261 return i2c_add_driver(&bh1780_driver);
262 }
263
bh1780_exit(void)264 static void __exit bh1780_exit(void)
265 {
266 i2c_del_driver(&bh1780_driver);
267 }
268
269 module_init(bh1780_init)
270 module_exit(bh1780_exit)
271
272 MODULE_DESCRIPTION("BH1780GLI Ambient Light Sensor Driver");
273 MODULE_LICENSE("GPL");
274 MODULE_AUTHOR("Hemanth V <hemanthv@ti.com>");
275