Root/drivers/misc/bh1780gli.c

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
41struct bh1780_data {
42    struct i2c_client *client;
43    int power_state;
44    /* lock for sysfs operations */
45    struct mutex lock;
46};
47
48static 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
58static 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
68static 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
86static 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
101static 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
132static DEVICE_ATTR(lux, S_IRUGO, bh1780_show_lux, NULL);
133
134static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
135        bh1780_show_power_state, bh1780_store_power_state);
136
137static struct attribute *bh1780_attributes[] = {
138    &dev_attr_power_state.attr,
139    &dev_attr_lux.attr,
140    NULL
141};
142
143static const struct attribute_group bh1780_attr_group = {
144    .attrs = bh1780_attributes,
145};
146
147static 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
183err_op_failed:
184    kfree(ddata);
185    return ret;
186}
187
188static 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
200static 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
222static 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}
238static 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
244static const struct i2c_device_id bh1780_id[] = {
245    { "bh1780", 0 },
246    { },
247};
248
249static 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
259module_i2c_driver(bh1780_driver);
260
261MODULE_DESCRIPTION("BH1780GLI Ambient Light Sensor Driver");
262MODULE_LICENSE("GPL");
263MODULE_AUTHOR("Hemanth V <hemanthv@ti.com>");
264

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