1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * ROHM 1780GLI Ambient Light Sensor Driver
4 *
5 * Copyright (C) 2016 Linaro Ltd.
6 * Author: Linus Walleij <linus.walleij@linaro.org>
7 * Loosely based on the previous BH1780 ALS misc driver
8 * Copyright (C) 2010 Texas Instruments
9 * Author: Hemanth V <hemanthv@ti.com>
10 */
11#include <linux/i2c.h>
12#include <linux/slab.h>
13#include <linux/platform_device.h>
14#include <linux/delay.h>
15#include <linux/module.h>
16#include <linux/mod_devicetable.h>
17#include <linux/pm_runtime.h>
18#include <linux/iio/iio.h>
19#include <linux/iio/sysfs.h>
20#include <linux/bitops.h>
21
22#define BH1780_CMD_BIT		BIT(7)
23#define BH1780_REG_CONTROL	0x00
24#define BH1780_REG_PARTID	0x0A
25#define BH1780_REG_MANFID	0x0B
26#define BH1780_REG_DLOW		0x0C
27#define BH1780_REG_DHIGH	0x0D
28
29#define BH1780_REVMASK		GENMASK(3,0)
30#define BH1780_POWMASK		GENMASK(1,0)
31#define BH1780_POFF		(0x0)
32#define BH1780_PON		(0x3)
33
34/* power on settling time in ms */
35#define BH1780_PON_DELAY	2
36/* max time before value available in ms */
37#define BH1780_INTERVAL		250
38
39struct bh1780_data {
40	struct i2c_client *client;
41};
42
43static int bh1780_write(struct bh1780_data *bh1780, u8 reg, u8 val)
44{
45	int ret = i2c_smbus_write_byte_data(bh1780->client,
46					    BH1780_CMD_BIT | reg,
47					    val);
48	if (ret < 0)
49		dev_err(&bh1780->client->dev,
50			"i2c_smbus_write_byte_data failed error "
51			"%d, register %01x\n",
52			ret, reg);
53	return ret;
54}
55
56static int bh1780_read(struct bh1780_data *bh1780, u8 reg)
57{
58	int ret = i2c_smbus_read_byte_data(bh1780->client,
59					   BH1780_CMD_BIT | reg);
60	if (ret < 0)
61		dev_err(&bh1780->client->dev,
62			"i2c_smbus_read_byte_data failed error "
63			"%d, register %01x\n",
64			ret, reg);
65	return ret;
66}
67
68static int bh1780_read_word(struct bh1780_data *bh1780, u8 reg)
69{
70	int ret = i2c_smbus_read_word_data(bh1780->client,
71					   BH1780_CMD_BIT | reg);
72	if (ret < 0)
73		dev_err(&bh1780->client->dev,
74			"i2c_smbus_read_word_data failed error "
75			"%d, register %01x\n",
76			ret, reg);
77	return ret;
78}
79
80static int bh1780_debugfs_reg_access(struct iio_dev *indio_dev,
81			      unsigned int reg, unsigned int writeval,
82			      unsigned int *readval)
83{
84	struct bh1780_data *bh1780 = iio_priv(indio_dev);
85	int ret;
86
87	if (!readval)
88		return bh1780_write(bh1780, (u8)reg, (u8)writeval);
89
90	ret = bh1780_read(bh1780, (u8)reg);
91	if (ret < 0)
92		return ret;
93
94	*readval = ret;
95
96	return 0;
97}
98
99static int bh1780_read_raw(struct iio_dev *indio_dev,
100			   struct iio_chan_spec const *chan,
101			   int *val, int *val2, long mask)
102{
103	struct bh1780_data *bh1780 = iio_priv(indio_dev);
104	int value;
105
106	switch (mask) {
107	case IIO_CHAN_INFO_RAW:
108		switch (chan->type) {
109		case IIO_LIGHT:
110			pm_runtime_get_sync(&bh1780->client->dev);
111			value = bh1780_read_word(bh1780, BH1780_REG_DLOW);
112			if (value < 0)
113				return value;
114			pm_runtime_mark_last_busy(&bh1780->client->dev);
115			pm_runtime_put_autosuspend(&bh1780->client->dev);
116			*val = value;
117
118			return IIO_VAL_INT;
119		default:
120			return -EINVAL;
121		}
122	case IIO_CHAN_INFO_INT_TIME:
123		*val = 0;
124		*val2 = BH1780_INTERVAL * 1000;
125		return IIO_VAL_INT_PLUS_MICRO;
126	default:
127		return -EINVAL;
128	}
129}
130
131static const struct iio_info bh1780_info = {
132	.read_raw = bh1780_read_raw,
133	.debugfs_reg_access = bh1780_debugfs_reg_access,
134};
135
136static const struct iio_chan_spec bh1780_channels[] = {
137	{
138		.type = IIO_LIGHT,
139		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
140				      BIT(IIO_CHAN_INFO_INT_TIME)
141	}
142};
143
144static int bh1780_probe(struct i2c_client *client)
145{
146	int ret;
147	struct bh1780_data *bh1780;
148	struct i2c_adapter *adapter = client->adapter;
149	struct iio_dev *indio_dev;
150
151	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
152		return -EIO;
153
154	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*bh1780));
155	if (!indio_dev)
156		return -ENOMEM;
157
158	bh1780 = iio_priv(indio_dev);
159	bh1780->client = client;
160	i2c_set_clientdata(client, indio_dev);
161
162	/* Power up the device */
163	ret = bh1780_write(bh1780, BH1780_REG_CONTROL, BH1780_PON);
164	if (ret < 0)
165		return ret;
166	msleep(BH1780_PON_DELAY);
167	pm_runtime_get_noresume(&client->dev);
168	pm_runtime_set_active(&client->dev);
169	pm_runtime_enable(&client->dev);
170
171	ret = bh1780_read(bh1780, BH1780_REG_PARTID);
172	if (ret < 0)
173		goto out_disable_pm;
174	dev_info(&client->dev,
175		 "Ambient Light Sensor, Rev : %lu\n",
176		 (ret & BH1780_REVMASK));
177
178	/*
179	 * As the device takes 250 ms to even come up with a fresh
180	 * measurement after power-on, do not shut it down unnecessarily.
181	 * Set autosuspend to a five seconds.
182	 */
183	pm_runtime_set_autosuspend_delay(&client->dev, 5000);
184	pm_runtime_use_autosuspend(&client->dev);
185	pm_runtime_put(&client->dev);
186
187	indio_dev->info = &bh1780_info;
188	indio_dev->name = "bh1780";
189	indio_dev->channels = bh1780_channels;
190	indio_dev->num_channels = ARRAY_SIZE(bh1780_channels);
191	indio_dev->modes = INDIO_DIRECT_MODE;
192
193	ret = iio_device_register(indio_dev);
194	if (ret)
195		goto out_disable_pm;
196	return 0;
197
198out_disable_pm:
199	pm_runtime_put_noidle(&client->dev);
200	pm_runtime_disable(&client->dev);
201	return ret;
202}
203
204static void bh1780_remove(struct i2c_client *client)
205{
206	struct iio_dev *indio_dev = i2c_get_clientdata(client);
207	struct bh1780_data *bh1780 = iio_priv(indio_dev);
208	int ret;
209
210	iio_device_unregister(indio_dev);
211	pm_runtime_get_sync(&client->dev);
212	pm_runtime_put_noidle(&client->dev);
213	pm_runtime_disable(&client->dev);
214	ret = bh1780_write(bh1780, BH1780_REG_CONTROL, BH1780_POFF);
215	if (ret < 0)
216		dev_err(&client->dev, "failed to power off (%pe)\n",
217			ERR_PTR(ret));
218}
219
220static int bh1780_runtime_suspend(struct device *dev)
221{
222	struct i2c_client *client = to_i2c_client(dev);
223	struct iio_dev *indio_dev = i2c_get_clientdata(client);
224	struct bh1780_data *bh1780 = iio_priv(indio_dev);
225	int ret;
226
227	ret = bh1780_write(bh1780, BH1780_REG_CONTROL, BH1780_POFF);
228	if (ret < 0) {
229		dev_err(dev, "failed to runtime suspend\n");
230		return ret;
231	}
232
233	return 0;
234}
235
236static int bh1780_runtime_resume(struct device *dev)
237{
238	struct i2c_client *client = to_i2c_client(dev);
239	struct iio_dev *indio_dev = i2c_get_clientdata(client);
240	struct bh1780_data *bh1780 = iio_priv(indio_dev);
241	int ret;
242
243	ret = bh1780_write(bh1780, BH1780_REG_CONTROL, BH1780_PON);
244	if (ret < 0) {
245		dev_err(dev, "failed to runtime resume\n");
246		return ret;
247	}
248
249	/* Wait for power on, then for a value to be available */
250	msleep(BH1780_PON_DELAY + BH1780_INTERVAL);
251
252	return 0;
253}
254
255static DEFINE_RUNTIME_DEV_PM_OPS(bh1780_dev_pm_ops, bh1780_runtime_suspend,
256				bh1780_runtime_resume, NULL);
257
258static const struct i2c_device_id bh1780_id[] = {
259	{ "bh1780", 0 },
260	{ },
261};
262
263MODULE_DEVICE_TABLE(i2c, bh1780_id);
264
265static const struct of_device_id of_bh1780_match[] = {
266	{ .compatible = "rohm,bh1780gli", },
267	{},
268};
269MODULE_DEVICE_TABLE(of, of_bh1780_match);
270
271static struct i2c_driver bh1780_driver = {
272	.probe		= bh1780_probe,
273	.remove		= bh1780_remove,
274	.id_table	= bh1780_id,
275	.driver = {
276		.name = "bh1780",
277		.pm = pm_ptr(&bh1780_dev_pm_ops),
278		.of_match_table = of_bh1780_match,
279	},
280};
281
282module_i2c_driver(bh1780_driver);
283
284MODULE_DESCRIPTION("ROHM BH1780GLI Ambient Light Sensor Driver");
285MODULE_LICENSE("GPL");
286MODULE_AUTHOR("Linus Walleij <linus.walleij@linaro.org>");
287