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
42 struct bh1780_data {
43 struct i2c_client *client;
44 int power_state;
45 /* lock for sysfs operations */
46 struct mutex lock;
47 };
48
bh1780_write(struct bh1780_data * ddata,u8 reg,u8 val,char * msg)49 static 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
bh1780_read(struct bh1780_data * ddata,u8 reg,char * msg)59 static 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
bh1780_show_lux(struct device * dev,struct device_attribute * attr,char * buf)69 static 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
bh1780_show_power_state(struct device * dev,struct device_attribute * attr,char * buf)87 static 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
bh1780_store_power_state(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)102 static 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
133 static DEVICE_ATTR(lux, S_IRUGO, bh1780_show_lux, NULL);
134
135 static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
136 bh1780_show_power_state, bh1780_store_power_state);
137
138 static struct attribute *bh1780_attributes[] = {
139 &dev_attr_power_state.attr,
140 &dev_attr_lux.attr,
141 NULL
142 };
143
144 static const struct attribute_group bh1780_attr_group = {
145 .attrs = bh1780_attributes,
146 };
147
bh1780_probe(struct i2c_client * client,const struct i2c_device_id * id)148 static 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
bh1780_remove(struct i2c_client * client)178 static 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
bh1780_suspend(struct device * dev)186 static 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
bh1780_resume(struct device * dev)208 static 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
226 static SIMPLE_DEV_PM_OPS(bh1780_pm, bh1780_suspend, bh1780_resume);
227
228 static const struct i2c_device_id bh1780_id[] = {
229 { "bh1780", 0 },
230 { },
231 };
232
233 MODULE_DEVICE_TABLE(i2c, bh1780_id);
234
235 #ifdef CONFIG_OF
236 static const struct of_device_id of_bh1780_match[] = {
237 { .compatible = "rohm,bh1780gli", },
238 {},
239 };
240
241 MODULE_DEVICE_TABLE(of, of_bh1780_match);
242 #endif
243
244 static 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
255 module_i2c_driver(bh1780_driver);
256
257 MODULE_DESCRIPTION("BH1780GLI Ambient Light Sensor Driver");
258 MODULE_LICENSE("GPL");
259 MODULE_AUTHOR("Hemanth V <hemanthv@ti.com>");
260