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>");