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bh1780gli.c
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1 /*
2  * bh1780gli.c
3  * ROHM Ambient Light Sensor Driver
4  *
5  * Copyright (C) 2010 Texas Instruments
6  * Author: Hemanth V <[email protected]>
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;
44  /* lock for sysfs operations */
45  struct mutex lock;
46 };
47 
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 
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 
68 static ssize_t bh1780_show_lux(struct device *dev,
69  struct device_attribute *attr, char *buf)
70 {
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 
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 
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 
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 
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 
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 
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
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 
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 = __devexit_p(bh1780_remove),
252  .id_table = bh1780_id,
253  .driver = {
254  .name = "bh1780",
255  .pm = BH1780_PMOPS,
256  },
257 };
258 
259 module_i2c_driver(bh1780_driver);
260 
261 MODULE_DESCRIPTION("BH1780GLI Ambient Light Sensor Driver");
262 MODULE_LICENSE("GPL");
263 MODULE_AUTHOR("Hemanth V <[email protected]>");