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
 26#define BH1780_REG_CONTROL	0x80
 27#define BH1780_REG_PARTID	0x8A
 28#define BH1780_REG_MANFID	0x8B
 29#define BH1780_REG_DLOW	0x8C
 30#define BH1780_REG_DHIGH	0x8D
 31
 32#define BH1780_REVMASK		(0xf)
 33#define BH1780_POWMASK		(0x3)
 34#define BH1780_POFF		(0x0)
 35#define BH1780_PON		(0x3)
 36
 37/* power on settling time in ms */
 38#define BH1780_PON_DELAY	2
 39
 40struct bh1780_data {
 41	struct i2c_client *client;
 42	int power_state;
 43	/* lock for sysfs operations */
 44	struct mutex lock;
 45};
 46
 47static int bh1780_write(struct bh1780_data *ddata, u8 reg, u8 val, char *msg)
 48{
 49	int ret = i2c_smbus_write_byte_data(ddata->client, reg, val);
 50	if (ret < 0)
 51		dev_err(&ddata->client->dev,
 52			"i2c_smbus_write_byte_data failed error %d Register (%s)\n",
 53			ret, msg);
 54	return ret;
 55}
 56
 57static int bh1780_read(struct bh1780_data *ddata, u8 reg, char *msg)
 58{
 59	int ret = i2c_smbus_read_byte_data(ddata->client, reg);
 60	if (ret < 0)
 61		dev_err(&ddata->client->dev,
 62			"i2c_smbus_read_byte_data failed error %d Register (%s)\n",
 63			ret, msg);
 64	return ret;
 65}
 66
 67static ssize_t bh1780_show_lux(struct device *dev,
 68				struct device_attribute *attr, char *buf)
 69{
 70	struct platform_device *pdev = to_platform_device(dev);
 71	struct bh1780_data *ddata = platform_get_drvdata(pdev);
 72	int lsb, msb;
 73
 74	lsb = bh1780_read(ddata, BH1780_REG_DLOW, "DLOW");
 75	if (lsb < 0)
 76		return lsb;
 77
 78	msb = bh1780_read(ddata, BH1780_REG_DHIGH, "DHIGH");
 79	if (msb < 0)
 80		return msb;
 81
 82	return sprintf(buf, "%d\n", (msb << 8) | lsb);
 83}
 84
 85static ssize_t bh1780_show_power_state(struct device *dev,
 86					struct device_attribute *attr,
 87					char *buf)
 88{
 89	struct platform_device *pdev = to_platform_device(dev);
 90	struct bh1780_data *ddata = platform_get_drvdata(pdev);
 91	int state;
 92
 93	state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
 94	if (state < 0)
 95		return state;
 96
 97	return sprintf(buf, "%d\n", state & BH1780_POWMASK);
 98}
 99
100static ssize_t bh1780_store_power_state(struct device *dev,
101					struct device_attribute *attr,
102					const char *buf, size_t count)
103{
104	struct platform_device *pdev = to_platform_device(dev);
105	struct bh1780_data *ddata = platform_get_drvdata(pdev);
106	unsigned long val;
107	int error;
108
109	error = strict_strtoul(buf, 0, &val);
110	if (error)
111		return error;
112
113	if (val < BH1780_POFF || val > BH1780_PON)
114		return -EINVAL;
115
116	mutex_lock(&ddata->lock);
117
118	error = bh1780_write(ddata, BH1780_REG_CONTROL, val, "CONTROL");
119	if (error < 0) {
120		mutex_unlock(&ddata->lock);
121		return error;
122	}
123
124	msleep(BH1780_PON_DELAY);
125	ddata->power_state = val;
126	mutex_unlock(&ddata->lock);
127
128	return count;
129}
130
131static DEVICE_ATTR(lux, S_IRUGO, bh1780_show_lux, NULL);
132
133static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
134		bh1780_show_power_state, bh1780_store_power_state);
135
136static struct attribute *bh1780_attributes[] = {
137	&dev_attr_power_state.attr,
138	&dev_attr_lux.attr,
139	NULL
140};
141
142static const struct attribute_group bh1780_attr_group = {
143	.attrs = bh1780_attributes,
144};
145
146static int __devinit bh1780_probe(struct i2c_client *client,
147						const struct i2c_device_id *id)
148{
149	int ret;
150	struct bh1780_data *ddata = NULL;
151	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
152
153	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) {
154		ret = -EIO;
155		goto err_op_failed;
156	}
157
158	ddata = kzalloc(sizeof(struct bh1780_data), GFP_KERNEL);
159	if (ddata == NULL) {
160		ret = -ENOMEM;
161		goto err_op_failed;
162	}
163
164	ddata->client = client;
165	i2c_set_clientdata(client, ddata);
166
167	ret = bh1780_read(ddata, BH1780_REG_PARTID, "PART ID");
168	if (ret < 0)
169		goto err_op_failed;
170
171	dev_info(&client->dev, "Ambient Light Sensor, Rev : %d\n",
172			(ret & BH1780_REVMASK));
173
174	mutex_init(&ddata->lock);
175
176	ret = sysfs_create_group(&client->dev.kobj, &bh1780_attr_group);
177	if (ret)
178		goto err_op_failed;
179
180	return 0;
181
182err_op_failed:
183	kfree(ddata);
184	return ret;
185}
186
187static int __devexit bh1780_remove(struct i2c_client *client)
188{
189	struct bh1780_data *ddata;
190
191	ddata = i2c_get_clientdata(client);
192	sysfs_remove_group(&client->dev.kobj, &bh1780_attr_group);
193	kfree(ddata);
194
195	return 0;
196}
197
198#ifdef CONFIG_PM
199static int bh1780_suspend(struct device *dev)
200{
201	struct bh1780_data *ddata;
202	int state, ret;
203	struct i2c_client *client = to_i2c_client(dev);
204
205	ddata = i2c_get_clientdata(client);
206	state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
207	if (state < 0)
208		return state;
209
210	ddata->power_state = state & BH1780_POWMASK;
211
212	ret = bh1780_write(ddata, BH1780_REG_CONTROL, BH1780_POFF,
213				"CONTROL");
214
215	if (ret < 0)
216		return ret;
217
218	return 0;
219}
220
221static int bh1780_resume(struct device *dev)
222{
223	struct bh1780_data *ddata;
224	int state, ret;
225	struct i2c_client *client = to_i2c_client(dev);
226
227	ddata = i2c_get_clientdata(client);
228	state = ddata->power_state;
229	ret = bh1780_write(ddata, BH1780_REG_CONTROL, state,
230				"CONTROL");
231
232	if (ret < 0)
233		return ret;
234
235	return 0;
236}
237static SIMPLE_DEV_PM_OPS(bh1780_pm, bh1780_suspend, bh1780_resume);
238#define BH1780_PMOPS (&bh1780_pm)
239#else
240#define BH1780_PMOPS NULL
241#endif /* CONFIG_PM */
242
243static const struct i2c_device_id bh1780_id[] = {
244	{ "bh1780", 0 },
245	{ },
246};
247
248static struct i2c_driver bh1780_driver = {
249	.probe		= bh1780_probe,
250	.remove		= bh1780_remove,
251	.id_table	= bh1780_id,
252	.driver = {
253		.name = "bh1780",
254		.pm	= BH1780_PMOPS,
255},
256};
257
258static int __init bh1780_init(void)
259{
260	return i2c_add_driver(&bh1780_driver);
261}
262
263static void __exit bh1780_exit(void)
264{
265	i2c_del_driver(&bh1780_driver);
266}
267
268module_init(bh1780_init)
269module_exit(bh1780_exit)
270
271MODULE_DESCRIPTION("BH1780GLI Ambient Light Sensor Driver");
272MODULE_LICENSE("GPL");
273MODULE_AUTHOR("Hemanth V <hemanthv@ti.com>");