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