Permalink
Find file
Fetching contributors…
Cannot retrieve contributors at this time
274 lines (220 sloc) 6.21 KB
/*
* bh1780gli.c
* ROHM Ambient Light Sensor Driver
*
* Copyright (C) 2010 Texas Instruments
* Author: Hemanth V <hemanthv@ti.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#define BH1780_REG_CONTROL 0x80
#define BH1780_REG_PARTID 0x8A
#define BH1780_REG_MANFID 0x8B
#define BH1780_REG_DLOW 0x8C
#define BH1780_REG_DHIGH 0x8D
#define BH1780_REVMASK (0xf)
#define BH1780_POWMASK (0x3)
#define BH1780_POFF (0x0)
#define BH1780_PON (0x3)
/* power on settling time in ms */
#define BH1780_PON_DELAY 2
struct bh1780_data {
struct i2c_client *client;
int power_state;
/* lock for sysfs operations */
struct mutex lock;
};
static int bh1780_write(struct bh1780_data *ddata, u8 reg, u8 val, char *msg)
{
int ret = i2c_smbus_write_byte_data(ddata->client, reg, val);
if (ret < 0)
dev_err(&ddata->client->dev,
"i2c_smbus_write_byte_data failed error %d Register (%s)\n",
ret, msg);
return ret;
}
static int bh1780_read(struct bh1780_data *ddata, u8 reg, char *msg)
{
int ret = i2c_smbus_read_byte_data(ddata->client, reg);
if (ret < 0)
dev_err(&ddata->client->dev,
"i2c_smbus_read_byte_data failed error %d Register (%s)\n",
ret, msg);
return ret;
}
static ssize_t bh1780_show_lux(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct platform_device *pdev = to_platform_device(dev);
struct bh1780_data *ddata = platform_get_drvdata(pdev);
int lsb, msb;
lsb = bh1780_read(ddata, BH1780_REG_DLOW, "DLOW");
if (lsb < 0)
return lsb;
msb = bh1780_read(ddata, BH1780_REG_DHIGH, "DHIGH");
if (msb < 0)
return msb;
return sprintf(buf, "%d\n", (msb << 8) | lsb);
}
static ssize_t bh1780_show_power_state(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct platform_device *pdev = to_platform_device(dev);
struct bh1780_data *ddata = platform_get_drvdata(pdev);
int state;
state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
if (state < 0)
return state;
return sprintf(buf, "%d\n", state & BH1780_POWMASK);
}
static ssize_t bh1780_store_power_state(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct platform_device *pdev = to_platform_device(dev);
struct bh1780_data *ddata = platform_get_drvdata(pdev);
unsigned long val;
int error;
error = strict_strtoul(buf, 0, &val);
if (error)
return error;
if (val < BH1780_POFF || val > BH1780_PON)
return -EINVAL;
mutex_lock(&ddata->lock);
error = bh1780_write(ddata, BH1780_REG_CONTROL, val, "CONTROL");
if (error < 0) {
mutex_unlock(&ddata->lock);
return error;
}
msleep(BH1780_PON_DELAY);
ddata->power_state = val;
mutex_unlock(&ddata->lock);
return count;
}
static DEVICE_ATTR(lux, S_IRUGO, bh1780_show_lux, NULL);
static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
bh1780_show_power_state, bh1780_store_power_state);
static struct attribute *bh1780_attributes[] = {
&dev_attr_power_state.attr,
&dev_attr_lux.attr,
NULL
};
static const struct attribute_group bh1780_attr_group = {
.attrs = bh1780_attributes,
};
static int __devinit bh1780_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
int ret;
struct bh1780_data *ddata = NULL;
struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) {
ret = -EIO;
goto err_op_failed;
}
ddata = kzalloc(sizeof(struct bh1780_data), GFP_KERNEL);
if (ddata == NULL) {
ret = -ENOMEM;
goto err_op_failed;
}
ddata->client = client;
i2c_set_clientdata(client, ddata);
ret = bh1780_read(ddata, BH1780_REG_PARTID, "PART ID");
if (ret < 0)
goto err_op_failed;
dev_info(&client->dev, "Ambient Light Sensor, Rev : %d\n",
(ret & BH1780_REVMASK));
mutex_init(&ddata->lock);
ret = sysfs_create_group(&client->dev.kobj, &bh1780_attr_group);
if (ret)
goto err_op_failed;
return 0;
err_op_failed:
kfree(ddata);
return ret;
}
static int __devexit bh1780_remove(struct i2c_client *client)
{
struct bh1780_data *ddata;
ddata = i2c_get_clientdata(client);
sysfs_remove_group(&client->dev.kobj, &bh1780_attr_group);
kfree(ddata);
return 0;
}
#ifdef CONFIG_PM
static int bh1780_suspend(struct device *dev)
{
struct bh1780_data *ddata;
int state, ret;
struct i2c_client *client = to_i2c_client(dev);
ddata = i2c_get_clientdata(client);
state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
if (state < 0)
return state;
ddata->power_state = state & BH1780_POWMASK;
ret = bh1780_write(ddata, BH1780_REG_CONTROL, BH1780_POFF,
"CONTROL");
if (ret < 0)
return ret;
return 0;
}
static int bh1780_resume(struct device *dev)
{
struct bh1780_data *ddata;
int state, ret;
struct i2c_client *client = to_i2c_client(dev);
ddata = i2c_get_clientdata(client);
state = ddata->power_state;
ret = bh1780_write(ddata, BH1780_REG_CONTROL, state,
"CONTROL");
if (ret < 0)
return ret;
return 0;
}
static SIMPLE_DEV_PM_OPS(bh1780_pm, bh1780_suspend, bh1780_resume);
#define BH1780_PMOPS (&bh1780_pm)
#else
#define BH1780_PMOPS NULL
#endif /* CONFIG_PM */
static const struct i2c_device_id bh1780_id[] = {
{ "bh1780", 0 },
{ },
};
static struct i2c_driver bh1780_driver = {
.probe = bh1780_probe,
.remove = bh1780_remove,
.id_table = bh1780_id,
.driver = {
.name = "bh1780",
.pm = BH1780_PMOPS,
},
};
static int __init bh1780_init(void)
{
return i2c_add_driver(&bh1780_driver);
}
static void __exit bh1780_exit(void)
{
i2c_del_driver(&bh1780_driver);
}
module_init(bh1780_init)
module_exit(bh1780_exit)
MODULE_DESCRIPTION("BH1780GLI Ambient Light Sensor Driver");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Hemanth V <hemanthv@ti.com>");