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#include <linux/of.h>
 27
 28#define BH1780_REG_CONTROL	0x80
 29#define BH1780_REG_PARTID	0x8A
 30#define BH1780_REG_MANFID	0x8B
 31#define BH1780_REG_DLOW	0x8C
 32#define BH1780_REG_DHIGH	0x8D
 33
 34#define BH1780_REVMASK		(0xf)
 35#define BH1780_POWMASK		(0x3)
 36#define BH1780_POFF		(0x0)
 37#define BH1780_PON		(0x3)
 38
 39/* power on settling time in ms */
 40#define BH1780_PON_DELAY	2
 41
 42struct bh1780_data {
 43	struct i2c_client *client;
 44	int power_state;
 45	/* lock for sysfs operations */
 46	struct mutex lock;
 47};
 48
 49static int bh1780_write(struct bh1780_data *ddata, u8 reg, u8 val, char *msg)
 50{
 51	int ret = i2c_smbus_write_byte_data(ddata->client, reg, val);
 52	if (ret < 0)
 53		dev_err(&ddata->client->dev,
 54			"i2c_smbus_write_byte_data failed error %d Register (%s)\n",
 55			ret, msg);
 56	return ret;
 57}
 58
 59static int bh1780_read(struct bh1780_data *ddata, u8 reg, char *msg)
 60{
 61	int ret = i2c_smbus_read_byte_data(ddata->client, reg);
 62	if (ret < 0)
 63		dev_err(&ddata->client->dev,
 64			"i2c_smbus_read_byte_data failed error %d Register (%s)\n",
 65			ret, msg);
 66	return ret;
 67}
 68
 69static ssize_t bh1780_show_lux(struct device *dev,
 70				struct device_attribute *attr, char *buf)
 71{
 72	struct platform_device *pdev = to_platform_device(dev);
 73	struct bh1780_data *ddata = platform_get_drvdata(pdev);
 74	int lsb, msb;
 75
 76	lsb = bh1780_read(ddata, BH1780_REG_DLOW, "DLOW");
 77	if (lsb < 0)
 78		return lsb;
 79
 80	msb = bh1780_read(ddata, BH1780_REG_DHIGH, "DHIGH");
 81	if (msb < 0)
 82		return msb;
 83
 84	return sprintf(buf, "%d\n", (msb << 8) | lsb);
 85}
 86
 87static ssize_t bh1780_show_power_state(struct device *dev,
 88					struct device_attribute *attr,
 89					char *buf)
 90{
 91	struct platform_device *pdev = to_platform_device(dev);
 92	struct bh1780_data *ddata = platform_get_drvdata(pdev);
 93	int state;
 94
 95	state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
 96	if (state < 0)
 97		return state;
 98
 99	return sprintf(buf, "%d\n", state & BH1780_POWMASK);
100}
101
102static ssize_t bh1780_store_power_state(struct device *dev,
103					struct device_attribute *attr,
104					const char *buf, size_t count)
105{
106	struct platform_device *pdev = to_platform_device(dev);
107	struct bh1780_data *ddata = platform_get_drvdata(pdev);
108	unsigned long val;
109	int error;
110
111	error = kstrtoul(buf, 0, &val);
112	if (error)
113		return error;
114
115	if (val < BH1780_POFF || val > BH1780_PON)
116		return -EINVAL;
117
118	mutex_lock(&ddata->lock);
119
120	error = bh1780_write(ddata, BH1780_REG_CONTROL, val, "CONTROL");
121	if (error < 0) {
122		mutex_unlock(&ddata->lock);
123		return error;
124	}
125
126	msleep(BH1780_PON_DELAY);
127	ddata->power_state = val;
128	mutex_unlock(&ddata->lock);
129
130	return count;
131}
132
133static DEVICE_ATTR(lux, S_IRUGO, bh1780_show_lux, NULL);
134
135static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
136		bh1780_show_power_state, bh1780_store_power_state);
137
138static struct attribute *bh1780_attributes[] = {
139	&dev_attr_power_state.attr,
140	&dev_attr_lux.attr,
141	NULL
142};
143
144static const struct attribute_group bh1780_attr_group = {
145	.attrs = bh1780_attributes,
146};
147
148static int bh1780_probe(struct i2c_client *client,
149						const struct i2c_device_id *id)
150{
151	int ret;
152	struct bh1780_data *ddata = NULL;
153	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
154
155	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE)) {
156		ret = -EIO;
157		goto err_op_failed;
158	}
159
160	ddata = kzalloc(sizeof(struct bh1780_data), GFP_KERNEL);
161	if (ddata == NULL) {
162		ret = -ENOMEM;
163		goto err_op_failed;
164	}
165
166	ddata->client = client;
167	i2c_set_clientdata(client, ddata);
168
169	ret = bh1780_read(ddata, BH1780_REG_PARTID, "PART ID");
170	if (ret < 0)
171		goto err_op_failed;
172
173	dev_info(&client->dev, "Ambient Light Sensor, Rev : %d\n",
174			(ret & BH1780_REVMASK));
175
176	mutex_init(&ddata->lock);
177
178	ret = sysfs_create_group(&client->dev.kobj, &bh1780_attr_group);
179	if (ret)
180		goto err_op_failed;
181
182	return 0;
183
184err_op_failed:
185	kfree(ddata);
186	return ret;
187}
188
189static int bh1780_remove(struct i2c_client *client)
190{
191	struct bh1780_data *ddata;
192
193	ddata = i2c_get_clientdata(client);
194	sysfs_remove_group(&client->dev.kobj, &bh1780_attr_group);
195	kfree(ddata);
196
197	return 0;
198}
199
200#ifdef CONFIG_PM_SLEEP
201static int bh1780_suspend(struct device *dev)
202{
203	struct bh1780_data *ddata;
204	int state, ret;
205	struct i2c_client *client = to_i2c_client(dev);
206
207	ddata = i2c_get_clientdata(client);
208	state = bh1780_read(ddata, BH1780_REG_CONTROL, "CONTROL");
209	if (state < 0)
210		return state;
211
212	ddata->power_state = state & BH1780_POWMASK;
213
214	ret = bh1780_write(ddata, BH1780_REG_CONTROL, BH1780_POFF,
215				"CONTROL");
216
217	if (ret < 0)
218		return ret;
219
220	return 0;
221}
222
223static int bh1780_resume(struct device *dev)
224{
225	struct bh1780_data *ddata;
226	int state, ret;
227	struct i2c_client *client = to_i2c_client(dev);
228
229	ddata = i2c_get_clientdata(client);
230	state = ddata->power_state;
231	ret = bh1780_write(ddata, BH1780_REG_CONTROL, state,
232				"CONTROL");
233
234	if (ret < 0)
235		return ret;
236
237	return 0;
238}
239#endif /* CONFIG_PM_SLEEP */
240
241static SIMPLE_DEV_PM_OPS(bh1780_pm, bh1780_suspend, bh1780_resume);
242
243static const struct i2c_device_id bh1780_id[] = {
244	{ "bh1780", 0 },
245	{ },
246};
247
248#ifdef CONFIG_OF
249static const struct of_device_id of_bh1780_match[] = {
250	{ .compatible = "rohm,bh1780gli", },
251	{},
252};
253
254MODULE_DEVICE_TABLE(of, of_bh1780_match);
255#endif
256
257static struct i2c_driver bh1780_driver = {
258	.probe		= bh1780_probe,
259	.remove		= bh1780_remove,
260	.id_table	= bh1780_id,
261	.driver = {
262		.name = "bh1780",
263		.pm	= &bh1780_pm,
264		.of_match_table = of_match_ptr(of_bh1780_match),
265	},
266};
267
268module_i2c_driver(bh1780_driver);
269
270MODULE_DESCRIPTION("BH1780GLI Ambient Light Sensor Driver");
271MODULE_LICENSE("GPL");
272MODULE_AUTHOR("Hemanth V <hemanthv@ti.com>");